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  • 1.
    Ariyawong, Kanaparin
    et al.
    Laboratoire des Matériaux et du Génie Physique, Grenoble INP – CNRS, France.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Step Instability in Sublimation Epitaxy on Low Off-Axis 6H-SiC2013Conference paper (Refereed)
  • 2.
    Asghar, M.
    et al.
    Islamia University of Bahawalpur, Pakistan .
    Iqbal, F.
    Islamia University of Bahawalpur, Pakistan .
    Faraz, Sadia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wahab, Qamar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Characterization of deep level defects in sublimation grown p-type 6H-SiC epilayers by deep level transient spectroscopy2012Conference paper (Refereed)
    Abstract [en]

    In this study deep level transient spectroscopy has been performed on boron-nitrogen co-doped 6H-SiC epilayers exhibiting p-type conductivity with free carrier concentration (N-A-N-D)similar to 3 x 10(17) cm(-3). We observed a hole H-1 majority carrier and an electron E-1 minority carrier traps in the device having activation energies E-nu + 0.24 eV, E-c -0.41 eV, respectively. The capture cross-section and trap concentration of H-1 and E-1 levels were found to be (5 x 10(-19) cm(2), 2 x 10(15) cm(-3)) and (1.6 x 10(-16) cm(2), 3 x 10(15) cm(-3)), respectively. Owing to the background involvement of aluminum in growth reactor and comparison of the obtained data with the literature, the H-1 defect was identified as aluminum acceptor. A reasonable justification has been given to correlate the E-1 defect to a nitrogen donor.

  • 3.
    Asghar, M.
    et al.
    Islamia University of Bahawalpur, Pakistan .
    Iqbal, F.
    Islamia University of Bahawalpur, Pakistan .
    Faraz, Sadia Municha
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Wahab, Qamar
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Study of deep level defects in doped and semi-insulating n-6H-SiC epilayers grown by sublimation method2012Conference paper (Refereed)
    Abstract [en]

    Deep level transient spectroscopy (DLTS) is employed to study deep level defects in n-6H-SiC (silicon carbide) epilayers grown by the sublimation method. To study the deep level defects in n-6H-SiC, we used as-grown, nitrogen doped and nitrogen-boron co-doped samples represented as ELS-1, ELS-11 and ELS-131 having net (N-D-N-A) similar to 2.0 x 10(12) cm(-3), 2 x 10(16) cm(-3) and 9 x 10(15) cm(3), respectively. The DLTS measurements performed on ELS-1 and ELS-11 samples revealed three electron trap defects (A, B and C) having activation energies E-c - 0.39 eV, E-c - 0.67 eV and E-c - 0.91 eV, respectively. While DLTS spectra due to sample ELS-131 displayed only A level. This observation indicates that levels B and C in ELS-131 are compensated by boron and/or nitrogen-boron complex. A comparison with the published data revealed A, B and C to be E-1/E-2, Z(1)/Z(2) and R levels, respectively.

  • 4.
    Gavryushin, V.
    et al.
    Institute of Applied Research, Vilnius University, Lithuania .
    Gulbinas, K
    Institute of Applied Research, Vilnius University, Lithuania .
    Grivickas, V.
    Institute of Applied Research, Vilnius University, Lithuania .
    Karaliunas, M.
    Institute of Applied Research, Vilnius University, Lithuania .
    Stasiūpnas, M.
    Institute of Applied Research, Vilnius University, Lithuania .
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Examination of Photoluminescence Temperature Dependencies in N-B Co-doped 6H-SiC2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012003-Article in journal (Refereed)
    Abstract [en]

    Two overlapping photoluminescent (PL) bands with a peaks (half-width) at 1.95 eV (0.45 eV) and 2.15 eV (0.25 eV), correspondingly at 300 K, are observed in heavily B-N co-doped 6H-SiC epilayers under high-level excitation condition. The low energy band dominates at low temperatures and decreases towards 300 K which is assigned to DAP emission from the nitrogen trap to the deep boron (dB) with phonon-assistance. The 2.15 eV band slightly increases with temperature and becomes comparable with the former one at 300 K. We present a modelling comprising electron de-trapping from the N-trap, i.e. calculating trapping and de-trapping probabilities. The T-dependence of the 2.15 eV band can be explained by free electron emission from the conduction band into the dB center provided by similar phonon-assistance

  • 5.
    Grivickas, V.
    et al.
    Institute of Applied Research, Vilnius University, Lithuania .
    Gulbinas, K
    Institute of Applied Research, Vilnius University, Lithuania .
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Karaliunas, M.
    Institute of Applied Research, Vilnius University, Lithuania.
    Kamiyama, Satoshi
    Meijo University, Nagoya, Japan .
    Linnarsson, Margareta
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Carrier Lifetimes and Influence of In-Grown Defects in N-B Co-Doped 6H-SiC2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012004-Article in journal (Refereed)
    Abstract [en]

    The thick N-B co-doped epilayers were grown by the fast sublimation growth method and the depth-resolved carrier lifetimes have been investigated by means of the free-carrier absorption (FCA) decay under perpendicular probe-pump measurement geometry. In some samples, we optically reveal in-grown carbon inclusions and polycrystalline defects of substantial concentration and show that these defects slow down excess carrier lifetime and prevent donor-acceptor pair photo luminescence (DAP PL). A pronounced electron lifetime reduction when injection level approaches the doping level was observed. It is caused by diffusion driven non-radiative recombination. However, the influence of surface recombination is small and insignificant at 300 K.

  • 6.
    Gulbinas, Karolis
    et al.
    Vilnius University, Lithuania .
    Ščajev, P,
    Vilnius University, Lithuania .
    Bikbajavas, V.
    Vilnius University, Lithuania .
    Grivickas, V.
    Vilnius University, Lithuania .
    Korolik, O.V.
    Belarusian State University, Minsk, Belarus .
    Mazanik, A.V
    Belarusian State University, Minsk, Belarus .
    Fedotov, A.K.
    Belarusian State University, Minsk, Belarus .
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Linnarsson, Margareta
    Royal Institute of Technology, Kista, Sweden .
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kamiyama, Satoshi
    Meijo University, Nagoya, Japan .
    Raman Scattering and Carrier Diffusion Study in Heavily Co-doped 6H-SiC Layers2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012005-Article in journal (Refereed)
    Abstract [en]

    Thick 6H-SiC epilayers were grown using the fast sublimation method on low-off-axis substrates. They were co-doped with N and B impurities of ≈1019 cm−3 and (41016–51018) cm−3 concentration, respectively. The epilayers exhibited donor-acceptor pair (DAP) photoluminescence. The micro-Raman spectroscopic study exposed a compensated n-6H-SiC epilayer of common quality with some 3C-SiC inclusions. The compensation ratio of B through 200 μm thick epilayer varied in 20-30% range. The free carrier diffusivity was studied by transient grating technique at high injection level. The determined ambipolar diffusion coefficient at RT was found to decrease from 1.15 cm2/s to virtually 0 cm2/s with boron concentration increasing by two orders.

  • 7.
    Hens, Philip
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wagner, G
    Leibniz Institute for Crystal Growth, Max-Born-Strasse 2, D-12489 Berlin, Germany.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wellmann, P
    Materials for Electronics and Energy Technology, University Erlangen-Nuremberg, Martensstrasse 7, D-91058 Erlangen, Germany.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sublimation growth of thick freestanding 3C-SiC using CVD-templates on silicon as seeds2012In: Materials letters (General ed.), ISSN 0167-577X, E-ISSN 1873-4979, Vol. 67, no 1, p. 300-302Article in journal (Refereed)
    Abstract [en]

    Cubic silicon carbide is a promising material for medium power electronics operating at high frequencies and for the subsequent growth of gallium nitride for more efficient light emitting diodes. We present a new approach to produce freestanding cubic silicon carbide (3C-SiC) with the ability to obtain good crystalline quality regarding increased domain size and reduced defect density. This would pave the way to achieve substrates of 3C-SiC so that the applications of cubic silicon carbide material having selectively (111) or (001) oriented surfaces can be explored. Our method is based on the combination of the chemical vapor deposition method and the fast sublimation growth process. Thin layers of cubic silicon carbide grown heteroepitaxially on silicon substrates are for the first time used for a subsequent sublimation growth step to increase layer thicknesses. We have been able to realize growth of freestanding (001) oriented 3C-SiC substrates using growth rates around 120 μm/h and diameters of more than 10 mm. The structural quality from XRD rocking curve measurements of (001) oriented layers shows good FWHM values down to 78 arcsec measured over an area of 1 × 2 mm2, which is a quality improvement of 2–3 times compared with other methods like CVD.

  • 8.
    Hupfer, Thomas
    et al.
    University of Erlangen-Nuremberg, Germany.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Modeling of the Mass Transport during Homo-Epitaxial Growth of Silicon Carbide by Fast Sublimation Epitaxy2013Conference paper (Refereed)
    Abstract [en]

    Ballistic and diffusive growth regimes in the Fast Sublimation Growth Process of silicon carbide can be determined using suggested theoretical model for the mean free path calculations. The influences of temperature and inert gas pressure on the mass transport for the growth of epitaxial layers were analyzed theoretically and experimentally.

  • 9.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hens, P.
    University of Erlangen-Nuremberg.
    Liljedahl, Richard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, M.
    University of Erlangen-Nuremberg.
    Wellmann, P.
    University of Erlangen-Nuremberg.
    Sano, S.
    ADMAP INC. 16-2, Tamahara 3-chome, Tamano, Okayama.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kamiyama, S.
    Meijo University, Nagoya .
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Effects of source material on epitaxial growth of fluorescent SiC2012In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 522, p. 7-10Article in journal (Refereed)
    Abstract [en]

    The growth of fluorescent SiC using Fast Sublimation Growth Process was demonstrated using different types of SiC source materials. These were prepared by (i) high-temperature hot pressing, (ii) chemical vapor deposition and (iii) physical vapor transport. The optimized growth rates of 50 μm/h, 170 μm/h and 200 μm/h were achieved using the three types of sources, respectively. The best results in respect to growth rates are obtained using higher density sources. Fluorescent SiC layers with mirror-like morphology, very good crystal quality and yellowish or warm white light photoluminescence at room temperature were grown using all three types of the source materials.

  • 10.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Huang, Ho Hsuan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Schimmel, Saskia
    University of Erlangen-Nuremberg, Germany.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Towards Bulk-Like 3C-SiC Growth Using Low Off-Axis Substrates2013Conference paper (Other academic)
  • 11.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Huang, Ho-Hsuan
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Schimmel, Saskia
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Towards bulk-like 3C-SiC growth using low off-axis substrates2013In: SILICON CARBIDE AND RELATED MATERIALS 2012, Trans Tech Publications , 2013, Vol. 740-742, p. 275-278Conference paper (Refereed)
    Abstract [en]

    Bulk-like 3C-SiC was grown on 1.2 degrees low off-axis 6H-SiC substrates using a sublimation epitaxy technique. The effects of temperature ramp-up and increase in layer thickness on the 3C-SiC domain formation were explored. The temperature ramp-up had no significant effect on the domain size. The domain size was considerably increased and the crystal quality was significantly improved by increasing the thickness of the layer towards bulk-like material. Average full width at half maximum values of 149 arcsec and 65 arcsec were measured in samples with thicknesses of 305 mu m and 1080 mu m, respectively, at a footprint of 1x3 mm(2). This result implies that heteropeitaxial growth of 3C-SiC on low off-axis 6H-SiC substrates by a sublimation method can be used to prepare 3C-SiC seeds or can be further developed for growth of bulk 3C-SiC material.

  • 12.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Morphological and Optical Stability in Growth of Fluorescent SiC on Low Off-Axis Substrates2013In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 740-742, p. 19-22Article in journal (Refereed)
    Abstract [en]

    Fluorescent silicon carbide was grown using the fast sublimation growth process on low off-axis 6H-SiC substrates. In this case, the morphology of the epilayer and the incorporation of dopants are influenced by the Si/C ratio. Differently converted tantalum foils were introduced into the growth cell in order to change vapor phase stochiometry during the growth. Fluorescent SiC grown using fresh and fully converted tantalum foils contained morphological instabilities leading to lower room temperature photoluminescence intensity while an improved morphology and optical stability was achieved with partly converted tantalum foil. This work reflects the importance of considering the use of Ta foil in sublimation epitaxy regarding the morphological and optical stability in fluorescent silicon carbide.

  • 13.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Richard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Yiyu
    Technical University of Denmark, Lyngby.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Kamiyama, Satoshi
    Meijo University, Nagoya.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Geometrical Control of 3C and 6H-SiC Nucleation on Low Off-Axis Substrates2011In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 679-680, p. 103-106Article in journal (Refereed)
    Abstract [en]

    Growth of 3C or 6H-SiC epilayers on low off-axis 6H-SiC substrates can be mastered by changing the size of the on axis plane formed by long terraces in the epilayer using geometrical control. The desired polytype can be selected in thick (~200 µm) layers of both 6H-SiC and 3C-SiC polytypes on substrates with off-orientation as low as 1.4 and 2 degrees. The resultant crystal quality of the 3C and the 6H-SiC epilayers, grown under the same process parameters, deteriorates when lowering the off-orientation of the substrate.

  • 14.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Stability in growth of 6H-SiC and 3C-SiC for LEDs and solar cells2012In: 2012 CONFERENCE ON LASERS AND ELECTRO-OPTICS (CLEO), IEEE , 2012Conference paper (Refereed)
    Abstract [en]

    6H- and 3C-SiC layers were grown using a sublimation based process. The polytype balance is mainly given by the substrate orientation and growth temperature. This paves the way to use 6H- and 3C-SiC in optoelectronic applications.

  • 15.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lundqvist, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kamiyama, Satoshi
    Meijo University, Nagoya, Japan.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    On stabilization of 3C-SiC using low off-axis 6H-SiC substrates2012Conference paper (Refereed)
    Abstract [en]

    Heteroepitaxial growth of 3C-SiC on 0.8 and 1.2 degree off-oriented 6H-SiC substrates was studied using a sublimation growth process. The 3C-SiC layers were grown at high growth rates with layer thickness up to 300 µm. The formation and the quality of 3C-SiC are influenced by the off-orientation of the substrate, the growth temperature (studied temperature range from 1750 oC to 1850oC), and the growth ambient (vacuum at 5*10-5 mbar and nitrogen at 5*10-1 mbar). The largest domains of 3C-SiC and the lowest number of double positioning boundaries were grown using nitrogen ambient and the highest growth temperature. The combined use of low off-axis substrate and high growth rate is a potential method to obtain material with bulk properties.

  • 16.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Palisaitis, Justinas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Vasiliauskas, Remigijus
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Macrodefects in cubic silicon carbide crystals2010In: Materials Science Forum, Vols. 645-648, Transtec Publications; 1999 , 2010, Vol. 645-648, p. 375-378Conference paper (Refereed)
    Abstract [en]

    Different sublimation growth conditions of 3C-SiC approaching a bulk process have been investigated with the focus on appearance of macrodefects. The growth rate of 3C-SiC crystals grown on 6H-SiC varied from 380 to 460 mu m/h with the thickness of the crystals from 190 to 230 mu m, respectively. The formation of macrodefects with void character was revealed at the early stage of 3C-SiC crystal growth. The highest concentration of macrodefects appears in the vicinity of the domain in samples grown under high temperature gradient: and fastest temperature ramp up. The formation of macrodefects was related to carbon deficiency which appear due to high Si/C ratio which is used to enable formation of the 3C-SiC polytype.

  • 17.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xinyu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yazdi, Gholamreza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Growth optimization and applicability of thick on-axis SiC layers using sublimation epitaxy in vacuum2016In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 448, p. 51-57Article in journal (Refereed)
    Abstract [en]

    We demonstrate growth of thick SiC layers (100–200 µm) on nominally on-axis hexagonal substrates using sublimation epitaxy in vacuum (10−5 mbar) at temperatures varying from 1700 to 1975 °C with growth rates up to 270 µm/h and 70 µm/h for 6H- and 4H–SiC, respectively. The stability of hexagonal polytypes are related to process growth parameters and temperature profile which can be engineered using different thermal insulation materials and adjustment of the induction coil position with respect to the graphite crucible. We show that there exists a range of growth rates for which single-hexagonal polytype free of foreign polytype inclusions can be maintained. Further on, foreign polytypes like 3C–SiC can be stabilized by moving out of the process window. The applicability of on-axis growth is demonstrated by growing a 200 µm thick homoepitaxial 6H–SiC layer co-doped with nitrogen and boron in a range of 1018 cm−3 at a growth rate of about 270 µm/h. Such layers are of interest as a near UV to visible light converters in a monolithic white light emitting diode concept, where subsequent nitride-stack growth benefits from the on-axis orientation of the SiC layer.

  • 18.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Silicon Carbide Surface Cleaning and Etching2018In: Advancing Silicon Carbide Electronics Technology I / [ed] Konstantinos Zekentes and Konstantin Vasilevskiy, Materials Research Forum LLC , 2018, p. 1-26Chapter in book (Refereed)
    Abstract [en]

    Silicon carbide (SiC) surface cleaning and etching (wet, electrochemical, thermal) are important technological processes in preparation of SiC wafers for crystal growth, defect analysis or device processing. While removal of organic, particulate and metallic contaminants by chemical cleaning is a routine process in research and industrial production, the etching which, in addition to structural defects analysis, can also be used to modify wafer surface structure, is very interesting for development of innovative device concepts. In this book chapter we review SiC chemical cleaning and etching procedures and present perspectives of SiC etching for new device development.

  • 19.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yazdi, G. Reza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lateral Enlargement Growth Mechanism of 3C-SiC on Off-Oriented 4H-SiC Substrates2014In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, no 12, p. 6514-6520Article in journal (Refereed)
    Abstract [en]

    We introduce a 3C-SiC growth concept on off-oriented 4H-SiC substrates using a sublimation epitaxial method. A growth model of 3C-SiC layer development via a controlled cubic polytype nucleation on in situ formed on-axis area followed by a lateral enlargement of 3C-SiC domains along the step-flow direction is outlined. Growth process stability and reproducibility of high crystalline quality material are demonstrated in a series of 3C-SiC samples with a thickness of about 1 mm. The average values of full width at half-maximum of ω rocking curves on these samples vary from 34 to 48 arcsec indicating high crystalline quality compared to values found in the literature. The low temperature photoluminescence measurements also confirm a high crystalline quality of 3C-SiC and indicate that the residual nitrogen concentration is about 1–2 × 1016 cm–3. Such a 3C-SiC growth concept may be applied to produce substrates for homoepitaxial 3C-SiC growth or seeds which could be explored in bulk growth of 3C-SiC.

  • 20.
    Jokubavicius, Valdas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yazdi, Gholam Reza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xinyu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Philipp, Schuh
    University of Erlangen, Erlangen, Germany.
    Wilhelm, Martin
    University of Erlangen, Erlangen, Germany.
    Wellmann, Peter
    University of Erlangen, Erlangen, Germany.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Single Domain 3C-SiC Growth on Off-Oriented 4H-SiC Substrates2015In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 15, no 6, p. 2940-2947Article in journal (Refereed)
    Abstract [en]

    We investigated the formation of structural defects in thick (∼1 mm) cubic silicon carbide (3C-SiC) layers grown on off-oriented 4H-SiC substrates via a lateral enlargement mechanism using different growth conditions. A two-step growth process based on this technique was developed, which provides a trade-off between the growth rate and the number of defects in the 3C-SiC layers. Moreover, we demonstrated that the two-step growth process combined with a geometrically controlled lateral enlargement mechanism allows the formation of a single 3C-SiC domain which enlarges and completely covers the substrate surface. High crystalline quality of the grown 3C-SiC layers is confirmed using high resolution X-ray diffraction and low temperature photoluminescence measurements.

  • 21.
    Jokubavičius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sublimation Growth of 3C-SiC: From Thick Layers to Bulk Material2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Silicon carbide (SiC) is a semiconductor material which holds high promises for various device applications. It can be obtained in different crystal structures called polytypes. The most common ones are hexagonal (6H- and 4H-SiC) and cubic (3C-SiC) silicon carbide. The 6H- and 4H-SiC single crystal substrates are commercially available, while technologies for the growth of 3C-SiC are still under development. The unique 3C-SiC properties like isotropy, narrower bandgap (2.4 eV)  compared to hexagonal polytypes (about 3 eV) and high electron mobility make it better over hexagonal counterparts for some semiconductor applications, for example, metal oxide semiconductor field effect transistors (MOSFETs). However, due to lack of high quality material, the full potential of 3C-SiC in device applications has not been revealed. In addition, it has properties suitable to explore new concepts in efficient photovoltaics or solar driven hydrogen generation by water splitting.

    There is a need for 3C-SiC seeds to grow large 3C-SiC crystals by the widely used Physical Vapor Transport (PVT) technique. In case of hexagonal SiC polytypes such seeds were produced by the Lely method during which hexagonal SiC crystals spontaneously nucleate on the inner walls of a crucible. However, the formation of 3C-SiC using the Lely method is rarely observed. Therefore, the 3C-SiC has to be heteroepitaxially grown on silicon or hexagonal SiC substrates. Silicon is an inexpensive material with very high crystalline quality. However, due to almost 20% mismatch in lattice parameters and 8% difference in thermal expansion coefficient there is a high density of structural defects formed at the 3C-SiC/Si interface. In contrast, the 3C-SiC/hexagonal SiC material system does not encounter such problems, but there are other challenges like polytype stability or formation of structural defects called double positioning boundaries (DPBs).

    This thesis work mainly focuses on the growth of 3C-SiC on hexagonal SiC substrates using sublimation epitaxy. The research covers the development of growth process for thick (~1 mm) 3C-SiC layers, advancement of the growth process to eliminate DPBs and growth of bulk material using thick 3C-SiC layers as seeds. The 3C-SiC was grown on off-oriented hexagonal SiC substrates. The surfaces of such substrates contain high density of steps. Therefore, they have mostly been used for the growth of homoepitaxial hexagonal layers or bulk crystals via step flow mechanism. However, as demonstrated in this thesis, under special conditions the 3C-SiC with high crystalline quality can also be grown on off-oriented hexagonal substrates. The stability window for the growth of hexagonal and cubic polytypes on nominally on-axis hexagonal SiC substrates is also explored. Moreover, it is demonstrated how the temperature profile inside the graphite crucible is influenced by the change in thermal insulation properties and how such change results in enhanced polytype stability during the growth of thick SiC layers. In addition, different sources for sublimation epitaxial growth of doped SiC layers were analyzed to gain further understanding of new parameter windows.

    As a part of this thesis, a sublimation etching of 6H-, 4H- and 3C-SiC polytypes is presented using two different etching arrangements in vacuum (10-5 mbar) and Ar ambient. It is demonstrated that this technique can be used to remove residual scratches on the surface as well as to obtain various surface step structures which could be used for the growth of graphene nanostructures.

    List of papers
    1. Lateral Enlargement Growth Mechanism of 3C-SiC on Off-Oriented 4H-SiC Substrates
    Open this publication in new window or tab >>Lateral Enlargement Growth Mechanism of 3C-SiC on Off-Oriented 4H-SiC Substrates
    Show others...
    2014 (English)In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, no 12, p. 6514-6520Article in journal (Refereed) Published
    Abstract [en]

    We introduce a 3C-SiC growth concept on off-oriented 4H-SiC substrates using a sublimation epitaxial method. A growth model of 3C-SiC layer development via a controlled cubic polytype nucleation on in situ formed on-axis area followed by a lateral enlargement of 3C-SiC domains along the step-flow direction is outlined. Growth process stability and reproducibility of high crystalline quality material are demonstrated in a series of 3C-SiC samples with a thickness of about 1 mm. The average values of full width at half-maximum of ω rocking curves on these samples vary from 34 to 48 arcsec indicating high crystalline quality compared to values found in the literature. The low temperature photoluminescence measurements also confirm a high crystalline quality of 3C-SiC and indicate that the residual nitrogen concentration is about 1–2 × 1016 cm–3. Such a 3C-SiC growth concept may be applied to produce substrates for homoepitaxial 3C-SiC growth or seeds which could be explored in bulk growth of 3C-SiC.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2014
    National Category
    Physical Sciences Chemical Sciences
    Identifiers
    urn:nbn:se:liu:diva-112510 (URN)10.1021/cg501424e (DOI)000345884000043 ()
    Available from: 2014-11-29 Created: 2014-11-29 Last updated: 2017-12-05Bibliographically approved
    2. Single Domain 3C-SiC Growth on Off-Oriented 4H-SiC Substrates
    Open this publication in new window or tab >>Single Domain 3C-SiC Growth on Off-Oriented 4H-SiC Substrates
    Show others...
    2015 (English)In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 15, no 6, p. 2940-2947Article in journal (Refereed) Published
    Abstract [en]

    We investigated the formation of structural defects in thick (∼1 mm) cubic silicon carbide (3C-SiC) layers grown on off-oriented 4H-SiC substrates via a lateral enlargement mechanism using different growth conditions. A two-step growth process based on this technique was developed, which provides a trade-off between the growth rate and the number of defects in the 3C-SiC layers. Moreover, we demonstrated that the two-step growth process combined with a geometrically controlled lateral enlargement mechanism allows the formation of a single 3C-SiC domain which enlarges and completely covers the substrate surface. High crystalline quality of the grown 3C-SiC layers is confirmed using high resolution X-ray diffraction and low temperature photoluminescence measurements.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2015
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-118525 (URN)10.1021/acs.cgd.5b00368 (DOI)000355890400051 ()
    Note

    Swedish Energy Agency; Swedish Research Council; Swedish Governmental Agency for Innovation Systems (Vinnova)

    Available from: 2015-05-29 Created: 2015-05-29 Last updated: 2017-12-04
    3. Growth optimization and applicability of thick on-axis SiC layers using sublimation epitaxy in vacuum
    Open this publication in new window or tab >>Growth optimization and applicability of thick on-axis SiC layers using sublimation epitaxy in vacuum
    Show others...
    2016 (English)In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 448, p. 51-57Article in journal (Refereed) Published
    Abstract [en]

    We demonstrate growth of thick SiC layers (100–200 µm) on nominally on-axis hexagonal substrates using sublimation epitaxy in vacuum (10−5 mbar) at temperatures varying from 1700 to 1975 °C with growth rates up to 270 µm/h and 70 µm/h for 6H- and 4H–SiC, respectively. The stability of hexagonal polytypes are related to process growth parameters and temperature profile which can be engineered using different thermal insulation materials and adjustment of the induction coil position with respect to the graphite crucible. We show that there exists a range of growth rates for which single-hexagonal polytype free of foreign polytype inclusions can be maintained. Further on, foreign polytypes like 3C–SiC can be stabilized by moving out of the process window. The applicability of on-axis growth is demonstrated by growing a 200 µm thick homoepitaxial 6H–SiC layer co-doped with nitrogen and boron in a range of 1018 cm−3 at a growth rate of about 270 µm/h. Such layers are of interest as a near UV to visible light converters in a monolithic white light emitting diode concept, where subsequent nitride-stack growth benefits from the on-axis orientation of the SiC layer.

    Keywords
    Mass transfer;Substrates;Single crystal growth;Semiconducting materials
    National Category
    Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-128610 (URN)10.1016/j.jcrysgro.2016.05.017 (DOI)
    Available from: 2016-05-25 Created: 2016-05-25 Last updated: 2017-11-30
    4. Surface engineering of SiC via sublimation etching
    Open this publication in new window or tab >>Surface engineering of SiC via sublimation etching
    Show others...
    2016 (English)In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 390, p. 816-822Article in journal (Refereed) Published
    Abstract [en]

    We present a technique for etching of SiC which is based on sublimation and can be used to modify the morphology and reconstruction of silicon carbide surface for subsequent epitaxial growth of various materials, for example graphene. The sublimation etching of 6H-, 4H- and 3C-SiC was explored in vacuum (10−5 mbar) and Ar (700 mbar) ambient using two different etching arrangements which can be considered as Si-C and Si-C-Ta chemical systems exhibiting different vapor phase stoichiometry at a given temperature. The surfaces of different polytypes etched under similar conditions are compared and the etching mechanism is discussed with an emphasis on the role of tantalum as a carbon getter. To demonstrate applicability of such etching process graphene nanoribbons were grown on a 4H-SiC surface that was pre-patterned using the thermal etching technique presented in this study.

    Place, publisher, year, edition, pages
    Amsterdam: Elsevier, 2016
    National Category
    Natural Sciences Materials Chemistry
    Identifiers
    urn:nbn:se:liu:diva-131817 (URN)10.1016/j.apsusc.2016.08.149 (DOI)000385900700098 ()
    Note

    Funding agencies: Swedish Research Council [621-2014-5825]; Graphene Flagship [CNECT-ICT-604391]; AForsk foundation [16-576]; Swedish Foundation for Strategic Research (SSF); Knut and Allice Wallenberg Foundation

    Available from: 2016-10-08 Created: 2016-10-08 Last updated: 2017-11-30Bibliographically approved
    5. Effects of source material on epitaxial growth of fluorescent SiC
    Open this publication in new window or tab >>Effects of source material on epitaxial growth of fluorescent SiC
    Show others...
    2012 (English)In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 522, p. 7-10Article in journal (Refereed) Published
    Abstract [en]

    The growth of fluorescent SiC using Fast Sublimation Growth Process was demonstrated using different types of SiC source materials. These were prepared by (i) high-temperature hot pressing, (ii) chemical vapor deposition and (iii) physical vapor transport. The optimized growth rates of 50 μm/h, 170 μm/h and 200 μm/h were achieved using the three types of sources, respectively. The best results in respect to growth rates are obtained using higher density sources. Fluorescent SiC layers with mirror-like morphology, very good crystal quality and yellowish or warm white light photoluminescence at room temperature were grown using all three types of the source materials.

    Place, publisher, year, edition, pages
    Elsevier, 2012
    Keywords
    Sublimation growth; Fluorescence; Photoluminescence; Silicon carbide
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-73709 (URN)10.1016/j.tsf.2011.10.176 (DOI)000310782000003 ()
    Available from: 2012-01-11 Created: 2012-01-11 Last updated: 2017-12-08
  • 22.
    Kaiser, Michl
    et al.
    University of Erlangen-Nuremberg, Germany.
    Hupfer, Thomas
    University of Erlangen-Nuremberg, Germany.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Schimmel, Saskia
    University of Erlangen-Nuremberg, Germany.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Yiyu
    Technical University of Denmark, Lyngby.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Linnarsson, Margareta
    KTH Royal Institute of Technology, Kista, Sweden.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Polycrystalline SiC as Source Material for the Growth of Fluorescent SiC Layers2013Conference paper (Refereed)
    Abstract [en]

    Polycrystalline doped SiC act as source for fluorescent SiC. We have studied the growth of individual grains with different polytypes in the source material. We show an evolution and orientation of grains of different polytypes in polycrystalline SiC ingots grown by the Physical Vapor Transport method. The grain influence on the growth rate of fluorescent SiC layers grown by a sublimation epitaxial process is discussed in respect of surface kinetics.

  • 23.
    Kaiser, Michl
    et al.
    University of Erlangen, Germany.
    Schimmel, Saskia
    University of Erlangen, Germany.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Linnarsson, Margareta
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wellmann, Peter
    University of Erlangen, Germany.
    Nucleation and growth of polycrystalline SiC2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012001-Article in journal (Refereed)
    Abstract [en]

    The nucleation and bulk growth of polycrystalline SiC in a 2 inch PVT setup using isostatic and pyrolytic graphite as substrates was studied. Textured nucleation occurs under near-thermal equilibrium conditions at the initial growth stage with hexagonal platelet shaped crystallites of 4H, 6H and 15R polytypes. It is found that pyrolytic graphite results in enhanced texturing of the nucleating gas species. Reducing the pressure leads to growth of the crystallites until a closed polycrystalline SiC layer containing voids with a rough surface is developed. Bulk growth was conducted at 35 mbar Ar pressure at 2250°C in diffusion limited mass transport regime generating a convex shaped growth form of the solid-gas interface leading to lateral expansion of virtually [001] oriented crystallites. Growth at 2350°C led to the stabilization of 6H polytypic grains. The micropipe density in the bulk strongly depends on the substrate used.

  • 24.
    Kwasnicki, Pawel
    et al.
    CNRS, L2C UMR 5221, F-34095, Montpellier, France.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Peyre, H.
    Université Montpellier 2, L2C UMR 5221, F-34095, Montpellier, France .
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Camasse, J.
    CNRS, L2C UMR 5221, F-34095, Montpellier, France .
    Juillaguet, S.
    Université Montpellier 2, L2C UMR 5221, F-34095, Montpellier, France.
    Optical investigation of 3C-SiC hetero-epitaxial layers grown by sublimation epitaxy under gas atmosphere2014In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 778-780, p. 243-246Article in journal (Refereed)
    Abstract [en]

    We investigated three 3C-SiC samples grown on 6H SiC substrate by sublimation epitaxy under gas atmosphere. We focus on the low temperature photoluminescence and Raman measurements to show that compare to a growth process under vacuum atmosphere, the gas atmosphere favor the incorporation of impurities at already existing and/or newly created defect sites.

  • 25.
    Li, Fan
    et al.
    University of Warwick, Coventry, United Kingdom.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jennings, Michael
    University of Warwick, Coventry, United Kingdom.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Tomas, Amador Perez
    ICN2, CSIC and the Barcelona Institute of Science and Technology, Bellaterra, Barcelona, Spain.
    Russell, Stephen
    University of Warwick, Coventry, United Kingdom.
    Sharma, Yogesh
    University of Warwick, Coventry, United Kingdom.
    Roccaforte, Fabrizio
    CNR-IMM, sezione di Catania, Catania, Italy.
    Mawby, Philip
    University of Warwick, Coventry, United Kingdom.
    La Via, Francesco
    CNR-IMM, sezione di Catania, Catania, Italy.
    Electrical Characterisation of Thick 3C-SiC Layers Grown on Off-Axis 4H-SiC Substrates2019In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 963, p. 353-356Article in journal (Refereed)
    Abstract [en]

    300 μm thick 3C-SiC epilayer was grown on off-axis 4H-SiC(0001) substrate with a high growth rate of 1 mm/hour. Dry oxidation, wet oxidation and N2O anneal were applied to fabricate lateral MOS capacitors on these 3C-SiC layers. MOS interface obtained by N2O anneal has the lowest interface trap density of 3~4x1011 eV-1cm-2. Although all MOS capacitors still have positive net charges at the MOS interface, the wet oxidised sample has the lowest effective charge density of ~9.17x1011 cm-2.

  • 26.
    Linnarsson, Margareta
    et al.
    KTH Royal Institute of Technology, Kista, Sweden.
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Yiyu
    Technical University of Denmark, Lyngby.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lateral Boron Distribution in Polycrystalline SiC Source Materials2013Conference paper (Refereed)
    Abstract [en]

    Polycrystalline SiC containing boron and nitrogen are used in growth of fluorescent SiC for white LEDs. Two types of doped polycrystalline SiC have been studied in detail with secondary ion mass spectrometry: sintered SiC and poly-SiC prepared by sublimation in a physical vapor transport setup. The materials are co-doped materials with nitrogen and boron to a concentration of 1x1018 cm-3 and 1x1019 cm-3, respectively. Depth profiles as well as ion images have been recorded. According to ocular inspection, the analyzed poly-SiC consists mainly of 4H-SiC and 6H-SiC grains. In these grains, the boron concentration is higher and the nitrogen concentration is lower in the 6H-SiC compared to the 4H-SiC polytype. No inter-diffusion between grains is observed.

  • 27.
    Lu, Wei Fang
    et al.
    Technical University of Denmark.
    Ou, Yiyu
    Technical University of Denmark.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Fadi, lAhmed
    Technical University of Denmark.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Buschmann, Volker
    PicoQuant GmbH, Rudower Chaussee 29, 12489 Berlin, Germany.
    Rüttinger, Steffen
    PicoQuant GmbH, Rudower Chaussee 29, 12489 Berlin, Germany.
    Petersen, Paul Michael
    Technical University of Denmark.
    Ou, Haiyan
    Technical University of Denmark.
    Photoluminescence enhancement in nano-textured fluorescent SiC passivated by atomic layer deposited Al2O3 films2016In: Silicon Carbide and Related Materials 2015, 2016, Vol. 858, p. 493-496Conference paper (Refereed)
    Abstract [en]

    The influence of thickness of atomic layer deposited Al2O3 films on nanotextured fluorescent 6H-SiC passivation is investigated. The passivation effect on the light emission has been characterized by photoluminescence and time-resolved photoluminescence at room temperature. The results show that 20nm thickness of Al2O3 layer is favorable to observe a large photoluminescence enhancement (25.9%) and long carrier lifetime (0.86ms). This is a strong indication for an interface hydrogenation that takes place during post-thermal annealing. These result show that an Al2O3 layer could serve as passivation in fluorescent SiC based white LEDs applications.

  • 28.
    Lu, Weifang
    et al.
    Technical University of Denmark, Denmark.
    Ou, Yiyu
    Technical University of Denmark, Denmark.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Fadil, Ahmed
    Technical University of Denmark, Denmark.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Michael Petersen, Paul
    Technical University of Denmark, Denmark.
    Ou, Haiyan
    Technical University of Denmark, Denmark.
    Surface passivation of nano-textured fluorescent SiC by atomic layer deposited TiO22016In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 91, no 7, p. 074001-Article in journal (Refereed)
    Abstract [en]

    Nano-textured surfaces have played a key role in optoelectronic materials to enhance the light extraction efficiency. In this work, morphology and optical properties of nano-textured SiC covered with atomic layer deposited (ALD) TiO2 were investigated. In order to obtain a high quality surface for TiO2 deposition, a three-step cleaning procedure was introduced after RIE etching. The morphology of anatase TiO2 indicates that the nano-textured substrate has a much higher surface nucleated grain density than a flat substrate at the beginning of the deposition process. The corresponding reflectance increases with TiO2 thickness due to increased surface diffuse reflection. The passivation effect of ALD TiO2 thin film on the nano-textured fluorescent 6H-SiC sample was also investigated and a PL intensity improvement of 8.05% was obtained due to the surface passivation.

  • 29.
    Ma, Quanbao
    et al.
    University of Oslo.
    Carvalho, Patricia
    SINTEF.
    Galeckas, Augustinas
    University of Oslo.
    Alexander, Azarov
    University of Oslo.
    Hovden, Sigurd
    SINTEF.
    Thøgersen, Annett
    SINTEF.
    Wright, Daniel N.
    SINTEF ICT.
    Diplas, Spyros
    SINTEF.
    Løvvik, Ole M.
    SINTEF.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Svensson, Bengt G.
    University of Oslo.
    Characterization of B-Implanted 3C-SiC for Intermediate Band Solar Cells2017In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 897, p. 299-302Article in journal (Refereed)
    Abstract [en]

    Sublimation-grown 3C-SiC crystals were implanted with B ions at elevated temperature (400 °C) using multiple energies (100 to 575 keV) with a total dose of 1.3×1017 atoms/cm2 in order to form intermediate band (IB) in 3C-SiC. The samples were then annealed at 1400 °C for 60 min. An anomalous area in the center was observed in the PL emission pattern. The SIMS analysis indicated that the B concentration was the same both within and outside the anomalous area. The buried boron box-like concentration profile can reach ~3×1021 cm-3 in the plateau region. In the anomalous area a broad emission band (possible IB) emerges at around ~1.7-1.8 eV, which may be associated with B-precipitates having a sufficiently high density.

  • 30.
    Ma, Quanbao
    et al.
    University of Oslo, Norway.
    Galeckas, Augustinas
    University of Oslo, Norway.
    Alexander, Azarov
    University of Oslo, Norway.
    Thøgersen, Annett
    SINTEF Materials and Chemistry, Norway.
    Carvalho, Patricia
    SINTEF Materials and Chemistry, Norway.
    Wright, Daniel N.
    SINTEF ICT, Norway.
    Diplas, Spyros
    SINTEF Materials and Chemistry, Norway.
    Løvvik, Ole M.
    SINTEF Materials and Chemistry, Norway.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xinyu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Svensson, Bengt G.
    University of Oslo, Norway.
    Boron-implanted 3C-SiC for intermediate band solar cells2016In: Silicon Carbide and Related Materials 2015, 2016, Vol. 858, p. 291-294Conference paper (Refereed)
    Abstract [en]

    Sublimation-grown 3C-SiC crystals were implanted with 2 atomic percent of boron ions at elevated temperature (400 °C) using multiple energies (100 to 575 keV) with a total dose of 8.5×1016 atoms/cm2. The samples were then annealed at 1400, 1500 and 1600 °C for 1h at each temperature. The buried boron box-like concentration profile can reach ~2×1021 cm-3 in the plateau region. The optical activity of the incorporated boron atoms was deduced from the evolution in absorption and emission spectra, indicating possible pathway for achieving an intermediate band behavior in boron doped 3C-SiC at sufficiently high dopant concentrations.                    

  • 31.
    Manolis, G
    et al.
    Institute of Applied Research, Vilnius University, Lithuania .
    Gulbinas, K
    Institute of Applied Research, Vilnius University, Lithuania.
    Grivickas, V.
    Institute of Applied Research, Vilnius University, Lithuania.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Linnarsson, Margareta
    Royal Institute of Technology, Kista, Sweden .
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Temperature Dependencies of Free-Carrier-Absorption Lifetime in Fluorescent 6H-SiC Layers2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012006-Article in journal (Refereed)
    Abstract [en]

    The nonradiative decay of majority electrons has been studied over a wide temperature range from 80 K to 600 K using the time-resolved free-carrier-absorption (FCA) technique. At high injection level of the highly-luminescent N-B codoped 6H-SiC epilayer, we revealed three main relaxation components of injected free electrons over ps-to-ms time ranges. By means of temperature dependency, two components can be ascribed to thermal activation of holes from a shallow (200 meV) and a deep (500 meV) acceptor. The third one, which has a hundred us-time scale, we attribute to minority hole recombination from the valance band into the electron trap (53 meV). This recombination channel seems to compete with the deep-acceptor (Boron) to-donor (Nitrogen) pair visible emission at and below 300 K.

  • 32.
    Murugesan, Murali
    et al.
    Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Gothenburg, Sweden.
    Zanden, Carl
    Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Gothenburg, Sweden.
    Luo, Xin
    Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Gothenburg, Sweden; School of Mechatronics and Mechanical Engineering, Key Laboratory of New Displays and System Integration, Shanghai University, China .
    Ye, Lilei
    SHT Smart High-Tech AB, Gothenburg, Sweden.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liu, Johan
    Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, Gothenburg, Sweden; School of Mechatronics and Mechanical Engineering, Key Laboratory of New Displays and System Integration, Shanghai University, China .
    A carbon fiber solder matrix composite for thermalmanagement of microelectronic devices2014In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 2, no 35, p. 7184-7187Article in journal (Refereed)
    Abstract [en]

    A carbon fiber based tin-silver-copper alloy matrix composite (CF-TIM) was developed via electrospinning of a mesophase pitch with polyimide and carbonization at 1000 °C, followed by sputter coating with titanium and gold, and alloy infiltration. The carbonized fibers, in film form, showed a thermal conductivity of ∼4 W m-1 K-1 and the CF-TIM showed an anisotropic thermal conductivity of 41 ± 2 W m-1 K-1 in-plane and 20 ± 3 W m-1 K-1 through-plane. The thermal contact resistance of the CF-TIM was estimated to be below 1 K mm2 W-1. The CF-TIM showed no reduction in effective through-plane thermal conductivity after 1000 temperature cycles, which indicates the potential use of CF-TIM in thermal management applications.

  • 33.
    Ou, Haiyan
    et al.
    Technical University of Denmark, Lyngby, Denmark .
    Ou, Yiyu
    Technical University of Denmark, Lyngby, Denmark .
    Argyraki, Aikaterini
    Technical University of Denmark, Lyngby, Denmark .
    Schimmel, Saskia
    University of Erlangen-Nuremberg, Erlangen, Germany .
    Kaiser, Michl
    University of Erlangen-Nuremberg, Erlangen, Germany .
    Wellmann, Peter
    University of Erlangen-Nuremberg, Erlangen, Germany .
    Linnarsson, Margareta
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Advances in wide bandgap SiC for optoelectronics2014In: European Physical Journal B: Condensed Matter Physics, ISSN 1434-6028, E-ISSN 1434-6036, Vol. 87, p. 58-Article in journal (Refereed)
    Abstract [en]

    Silicon carbide (SiC) has played a key role in power electronics thanks to its unique physical properties like wide bandgap, high breakdown field, etc. During the past decade, SiC is also becoming more and more active in optoelectronics thanks to the progress in materials growth and nanofabrication. This paper will review the advances in fluorescent SiC for white light-emitting diodes, covering the poly-crystalline doped SiC source material growth, single crystalline epitaxy growth of fluorescent SiC, and nanofabrication of SiC to enhance the extraction efficiency for fluorescent SiC based white LEDs.

  • 34.
    Ou, Yiyu
    et al.
    Technical University of Denmark, Lyngby, Denmark.
    Aijaz, Imran
    Technical University of Denmark, Lyngby, Denmark.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Haiyan
    Technical University of Denmark, Lyngby, Denmark.
    Broadband antireflection silicon carbide surface by self-assembled nanopatterned reactive-ion etching2013In: OPTICAL MATERIALS EXPRESS, ISSN 2159-3930, Vol. 3, no 1, p. 86-94Article in journal (Refereed)
    Abstract [en]

    An approach of fabricating pseudoperiodic antireflective subwavelength structures on silicon carbide by using self-assembled Au nanopatterns as etching mask is demonstrated. The nanopatterning process is more time-efficiency than the e-beam lithography or nanoimprint lithography process. The influences of the reactive-ion etching conditions and deposited Au film thickness to the subwavelength structure profile and its corresponding surface reflectance have been systematically investigated. Under the optimal experimental conditions, the average reflectance of the silicon carbide in the range of 390-784 nm is dramatically suppressed from 21.0 % to 1.9 % after introducing the pseudoperiodic nanostructures. A luminescence enhancement of 226 % was achieved at an emission angle of 20 degrees on the fluorescent silicon carbide. Meanwhile, the angle-resolved photoluminescence study presents a considerable omnidirectional luminescence enhancement.

  • 35.
    Ou, Yiyu
    et al.
    Technical University of Denmark, Lyngby.
    Jokubavicius, Valdas
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, Michl
    University of Erlangen-Nurnberg, Erlangen, Germany .
    Wellmann, Peter
    University of Erlangen-Nurnberg, Erlangen, Germany.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Broadband and omnidirectional light harvesting enhancement of fluorescent SiC2012In: Optics Express, ISSN 1094-4087, E-ISSN 1094-4087, Vol. 20, no 7, p. 7575-7579Article in journal (Refereed)
    Abstract [en]

    In the present work, antireflective sub-wavelength structures have been fabricated on fluorescent 6H-SiC to enhance the white light extraction efficiency by using the reactive-ion etching method. Broadband and omnidirectional antireflection characteristics show that 6H-SiC with antireflective sub-wavelength structures suppress the average surface reflection significantly from 20.5 % to 1.01 % over a wide spectral range of 390-784 nm. The luminescence intensity of the fluorescent 6H-SiC could be enhanced in the whole emission angle range. It maintains an enhancement larger than 91 % up to the incident angle of 70 degrees, while the largest enhancement of 115.4 % could be obtained at 16 degrees. The antireflective sub-wavelength structures on fluorescent 6H-SiC could also preserve the luminescence spectral profile at a large emission angle by eliminating the Fabry-Perot microcavity interference effect.

  • 36.
    Ou, Yiyu
    et al.
    Technical University of Denmark, Lyngby.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kaiser, Michl
    University of Erlangen-Nuremberg, Germany.
    Wellmann, Peter
    University of Erlangen-Nuremberg, Germany.
    Linnarsson, Margareta
    KTH Royal Institute of Technology, Kista, Sweden.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Fabrication of Broadband Antireflective Sub-Wavelength Structures on Fluorescent SiC2013Conference paper (Refereed)
    Abstract [en]

    Surface nanocones on 6H-SiC have been developed and demonstrated as an effective method of enhancing the light extraction efficiency from fluorescent SiC layers. The surface reflectance, measured from the opposite direction of light emission, over a broad bandwidth range is significantly suppressed from 20.5% to 1.0 % after introducing the sub-wavelength structures. An omnidirectional light harvesting enhancement (>91%), is also achieved which promotes fluorescent SiC as a good candidate of wavelength converter for white light-emitting diodes.

  • 37.
    Ou, Yiyu
    et al.
    Technical University of Denmark, Lyngby.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kamiyama, Satoshi
    Meijo University, Nagoya.
    Liu, Chuan
    Technical University of Denmark, Lyngby.
    Berg, Rolf W.
    Technical University of Denmark, Lyngby.
    Linnarsson, Margareta
    School of Information and Communication Technology, Royal Institute of Technology, Kista.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Haiyan
    Meijo University, Nagoya .
    Donor-acceptor-pair emission characterization in N-B doped fluorescent in SiC2011In: Optical Materials Express, ISSN 2159-3930, Vol. 1, no 8, p. 1439-1446Article in journal (Refereed)
    Abstract [en]

    In the present work, we investigated donor-acceptor-pair emission in N-B doped fluorescent 6H-SiC, by means of photoluminescence, Raman spectroscopy, and angle-resolved photoluminescence. The photoluminescence results were interpreted by using a band diagram with Fermi-Dirac statistics. It is shown that with N and B concentrations in a range of 1018cm−3 the samples exhibit the most intense luminescence when the concentration difference (n-type) is about 4.6x1018cm−3. Raman spectroscopy studies further verified the doping type and concentrations for the samples. Furthermore, strong luminescence intensity in a large emission angle range was achieved from angle-resolved photoluminescence. The results indicate N-B doped fluorescent SiC as a good wavelength converter in white LEDs applications.

  • 38.
    Ou, Yiyu
    et al.
    Technical University of Denmark, Lyngby.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Linnarsson, Margareta
    Royal Institute of Technology, Kista, Sweden .
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Characterization of donor–acceptor-pair emission in fluorescent 6H-SiC2012In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T148, p. 014003-Article in journal (Refereed)
    Abstract [en]

    We investigated donor–acceptor-pair emission in N–B-doped 6H-SiC samples by using photoluminescence (PL) and angle-resolved PL. It is shown that n-type doping with concentrations larger than 1018 cm−3 is favorable for observing luminescence, and increasing nitrogen results in stronger luminescence. A dopant concentration difference greater than 4×1018 cm−3 is proposed to help achieve intense PL. Angular-dependent PL was observed that was attributed to the Fabry–Pérot microcavity interference effect, and a strong luminescence intensity in a large emission angle range was also achieved. The results indicate that N–B-doped fluorescent SiC is a good wavelength converter in white LED applications.

  • 39.
    Ou, Yiyu
    et al.
    Technical University of Denmark, Lyngby.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liu, Chuan
    Technical University of Denmark, Lyngby.
    Berg, Rolf W.
    Technical University of Denmark, Lyngby.
    Linnarsson, Margareta
    Kamiyama, Satoshi
    Meijo University, Nagoya, Japan.
    Lu, Zhaoyue
    Technical University of Denmark, Lyngby.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Photoluminescence and Raman spectroscopy characterization of boron and nitrogen-doped 6H silicon carbide2012Conference paper (Refereed)
    Abstract [en]

    Nitrogen-boron doped 6H-SiC epilayers grown on low off-axis 6H-SiC substrates have been characterized by photoluminescence and Raman spectroscopy. The photoluminescence results show that a doping larger than 1018 cm-3 is favorable to observe the luminescence and addition of nitrogen is resulting in an increased luminescence. A dopant concentration difference larger than 4x1018 cm-3 is proposed to achieve intense photoluminescence. Raman spectroscopy further confirmed the doping type and concentrations for the samples. The results indicate that N-B doped SiC is being a good wavelength converter in white LEDs applications.

  • 40.
    Ou, Yiyu
    et al.
    Department of Photonics Engineering, Technical University of Denmark, Lyngby.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Haiyan
    Department of Photonics Engineering, Technical University of Denmark, Lyngby.
    Omnidirectional luminescence enhancement of fluorescent SiC via pseudoperiodic antireflective subwavelength structures2012In: Optics Letters, ISSN 0146-9592, E-ISSN 1539-4794, Vol. 37, no 18, p. 3816-3818Article in journal (Refereed)
    Abstract [en]

    In the present work, an approach of fabricating pseudoperiodic antireflective subwavelength structures (ARS) on fluorescent SiC by using self-assembled etch mask is demonstrated. By applying the pseudoperiodic (ARS), the average surface reflectance at 6° incidence over the spectral range of 390–785 nm is dramatically suppressed from 20.5% to 1.62%, and the hydrophobic surface with a large contact angle of 98° is also achieved. The angle-resolved photoluminescence study presents a considerable omnidirectional luminescence enhancement with an integral intensity enhancement of 66.3% and a fairly preserved spatial emission pattern.

  • 41.
    Ou, Yiyu
    et al.
    Technical University of Denmark.
    Zhu, Xiaolong
    Technical University of Denmark.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Mortensen, N. Asger
    Technical University of Denmark.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Xiao, Sanshui
    Technical University of Denmark.
    Ou, Haiyan
    Technical University of Denmark.
    Broadband Antireflection and Light Extraction Enhancement in Fluorescent SiC with Nanodome Structures2014In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 4, p. 4662-Article in journal (Refereed)
    Abstract [en]

    We demonstrate a time-efficient and low-cost approach to fabricate Si3N4 coated nanodome structures in fluorescent SiC. Nanosphere lithography is used as the nanopatterning method and SiC nanodome structures with Si3N4 coating are formed via dry etching and thin film deposition process. By using this method, a significant broadband surface antireflection and a considerable omnidirectional luminescence enhancement are obtained. The experimental observations are then supported by numerical simulations. It is believed that our fabrication method will be well suitable for large-scale production in the future.

  • 42.
    Patricia, Carvalho
    et al.
    SINTEF Materials Physics, Oslo, Norway; University of Lisbon, Instituto Superior Tecnico, Lisbon, Portugal.
    Annett, Thørgesen
    SINTEF Materials Physics, Oslo, Norway.
    Quanbao, Ma
    University of Oslo, Department of Physics, Oslo, Norway.
    Daniel Nielsen, Wright
    SINTEF Instrumentation, Oslo, Norway.
    Spyros, Diplas
    SINTEF Materials Physics, Oslo, Norway; University of Oslo, Department of Chemistry, Oslo, Norway.
    Augustinas, Galeckas
    University of Oslo, Department of Physics, Oslo, Norway.
    Alexander, Azarov
    University of Oslo, Department of Physics, Oslo, Norway.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu W.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Bengt Gunnar, Svensson
    University of Oslo, Department of Physics, Oslo, Norway.
    Ole Martin, Løvvik
    SINTEF Materials Physics, Oslo, Norway; University of Oslo, Department of Physics, Oslo, Norway.
    Boron-doping of cubic SiC for intermediate band solar cells: a scanning transmission electron microscopy study2018In: SciPost Physics, ISSN 2542-4653, Vol. 5, no 3, p. 1-17Article in journal (Refereed)
    Abstract [en]

    Boron (B) has the potential for generating an intermediate band in cubic silicon carbide (3C-SiC), turning this material into a highly efficient absorber for single-junction solar cells. The formation of a delocalized band demands high concentration of the foreign element, but the precipitation behavior of B in the 3C polymorph of SiC is not well known. Here, probe-corrected scanning transmission electron microscopy and secondary-ion mass spectrometry are used to investigate precipitation mechanisms in B-implanted 3C-SiC as a function of temperature. Point-defect clustering was detected after annealing at 1273 K, while stacking faults, B-rich precipitates and dislocation networks developed in the 1573 - 1773 K range. The precipitates adopted the rhombohedral B13C2 structure and trapped B up to 1773 K. Above this temperature, higher solubility reduced precipitation and free B diffused out of the implantation layer. Dopant concentrations E19 at.cm-3 were achieved at 1873 K.

  • 43.
    Rankl, Dominik
    et al.
    Crystal Growth Lab, University of Erlangen.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Wellmann, Peter
    Crystal Growth Lab, University of Erlangen.
    Quantitative Study on the Role of Supersaturation during Sublimation Growth on the Yield of 50 mm diameter 3C-SiC2015In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 821, p. 77-80Article in journal (Refereed)
    Abstract [en]

    We have investigated the growth of 3C-SiC using sublimation growth in the temperature range from 1800°C to 1950°C. The supersaturation was determined using numerical modeling of the temperature field and gas phase composition by applying quasi-equilibrium thermodynamic conditions. Analysis of the 3C-SiC yield was carried out by optical microscopy, optical absorption, Raman spectroscopy and x-ray analysis. Quantitative data on supersaturation are compared with most stable 3C-SiC nucleation and growth condition. Finally the application to large area growth in a physical vapor transport growth reactor is briefly addressed.

  • 44.
    Schimmel, Saskia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology. University of Erlangen, Germany.
    Kaiser, Michl
    University of Erlangen, Germany.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Yi Yu
    Technical University of Denmark, Lyngby.
    Ou, Hai Yan
    Technical University of Denmark, Lyngby.
    Linnarsson, Margareta K.
    KTH Royal Institute of Technology, Sweden.
    Wellmann, Peter
    University of Erlangen, Germany.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Step-flow growth of fluorescent 4H-SiC layers on 4 degree off-axis substrates2013In: Silicon Carbide and Related Materials 2012 / [ed] Alexander A. Lebedev, Sergey Yu. Davydov, Pavel A. Ivanov and Mikhail E. Levinshtein, Trans Tech Publications , 2013, Vol. 740-742, p. 185-188Conference paper (Refereed)
    Abstract [en]

    Homoepitaxial layers of fluorescent 4H-SiC were grown on 4 degree off-axis substrates by sublimation epitaxy. Luminescence in the green spectral range was obtained by co-doping with nitrogen and boron utilizing donor-acceptor pair luminescence. This concept opens possibilities to explore green light emitting diodes using a new materials platform.

  • 45.
    Schimmel, Saskia
    et al.
    University of Erlangen, Germany .
    Kaiser, Michl
    University of Erlangen, Germany .
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Yiyu
    Technical University of Denmark, Lyngby.
    Hens, Philip
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Linnarsson, Margareta K.
    School of Information and Communication Technology, KTH Royal Institute of Technology, Kista, Sweden.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ou, Haiyan
    Technical University of Denmark, Lyngby.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Wellmann, Peter
    University of Erlangen, Germany .
    The role of defects in fluorescent silicon carbide layers grown by sublimation epitaxy2014In: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 56, no 1, p. 012002-Article in journal (Refereed)
    Abstract [en]

    Donor-acceptor co-doped SiC is a promising light converter for novel monolithic all-semiconductor white LEDs due to its broad-band donor-acceptor pair luminescence and potentially high internal quantum efficiency. Besides sufficiently high doping concentrations in an appropriate ratio yielding short radiative lifetimes, long nonradiative lifetimes are crucial for efficient light conversion. The impact of different types of defects is studied by characterizing fluorescent silicon carbide layers with regard to photoluminescence intensity, homogeneity and efficiency taking into account dislocation density and distribution. Different doping concentrations and variations in gas phase composition and pressure are investigated.

  • 46.
    Shi, Yuchen
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Höjer, Pontus
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yazdi, Gholamreza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu W.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    A comparative study of high-quality C-face and Si-face 3C-SiC(1 1 1) grown on off-oriented 4H-SiC substrates2019In: Journal of Physics D: Applied Physics, ISSN 0022-3727, E-ISSN 1361-6463, Vol. 52, no 34Article in journal (Refereed)
    Abstract [en]

    We present a comparative study of the C-face and Si-face of 3C-SiC(111) grown on off-oriented 4H-SiC substrates by the sublimation epitaxy. By the lateral enlargement method, we demonstrate that the high-quality bulk-like C-face 3C-SiC with thickness of ~1 mm can be grown over a large single domain without double positioning boundaries (DPBs), which are known to have a strongly negative impact on the electronic properties of the material. Moreover, the C-face sample exhibits a smoother surface with one unit cell height steps while the surface of the Si-face sample exhibits steps twice as high as on the C-face due to step-bunching. High-resolution XRD and low temperature photoluminescence measurements show that C-face 3C-SiC can reach the same high crystalline quality as the Si-face 3C-SiC. Furthermore, cross-section studies of the C- and Si-face 3C-SiC demonstrate that in both cases an initial homoepitaxial 4H-SiC layer followed by a polytype transition layer are formed prior to the formation and lateral expansion of 3C-SiC layer. However, the transition layer in the C-face sample is extending along the step-flow direction less than that on the Si-face sample, giving rise to a more fairly consistent crystalline quality 3C-SiC epilayer over the whole sample compared to the Si-face 3C-SiC where more defects appeared on the surface at the edge. This facilitates the lateral enlargement of 3C-SiC growth on hexagonal SiC substrates.

  • 47.
    Shi, Yuchen
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Zakharov, Alexei A.
    MAXIV Laboratory, Lund, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yazdi, Gholamreza Reza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Elimination of step bunching in the growth of large-area monolayer and multilayer graphene on off-axis 3CSiC (111)2018In: Carbon, ISSN 0008-6223, E-ISSN 1873-3891, Vol. 140, p. 533-542Article in journal (Refereed)
    Abstract [en]

    Multilayer graphene has exhibited distinct electronic properties such as the tunable bandgap for optoelectronic applications. Among all graphene growth techniques, thermal decomposition of SiC is regarded as a promising method for production of device-quality graphene. However, it is still very challenging to grow uniform graphene over a large-area, especially multilayer graphene. One of the main obstacles is the occurrence of step bunching on the SiC surface, which significantly influences the formation process and the uniformity of the multilayer graphene. In this work, we have systematically studied the growth of monolayer and multilayer graphene on off-axis 3CSiC(111). Taking advantage of the synergistic effect of periodic SiC step edges as graphene nucleation sites and the unique thermal decomposition energy of 3CSiC steps, we demonstrate that the step bunching can be fully eliminated during graphene growth and large-area monolayer, bilayer, and four-layer graphene can be controllably obtained on high-quality off-axis 3CSiC(111) surface. The low energy electron microscopy results demonstrate that a uniform four-layer graphene has been grown over areas of tens of square micrometers, which opens the possibility to tune the bandgap for optoelectronic devices. Furthermore, a model for graphene growth along with the step bunching elimination is proposed.

    The full text will be freely available from 2020-08-24 11:11
  • 48.
    Shtepliuk, I
    et al.
    Kiev, Ukraine.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lashkarev, G
    Kiev, Ukraine.
    Khomyak, V.
    Chernivtsi, Ukraine.
    Lazorenko, V
    Kiev, Ukraine.
    Ievtushenko, A
    Kiev, Ukraine.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Electrical properties of n-Zn0.94Cd0.06O/p-SiC heterostructures2013In: Solid-State Electronics, ISSN 0038-1101, E-ISSN 1879-2405, Vol. 81, p. 72-77Article in journal (Refereed)
    Abstract [en]

    We report the low-temperature (250 °C) fabrication of n-ZnCdO/p-SiC heterostructures by direct current magnetron sputtering (DC MS) technique. As-grown heterostructures exhibit diode characteristics: current–voltage measurements showed a typical rectifying characteristic of a p–n junction and the presence of series resistance. It is found that the turn-on voltage of heterostructures depends on the acceptor concentration in p-SiC. Via Cd doping of ZnO the energy barrier for holes can be lowered, which promotes the hole injection from the p-type layer to the n-type layer as well as favors the radiative recombination in the n-ZnCdO layer.

  • 49.
    Sun, Jianwu
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Gao, L.
    Department of Chemical Engineering and Chemistry, Eindhoven University of of Technology, P.O. Box 513, Eindhoven, Netherlands.
    Booker, Ian Don
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jansson, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, Faculty of Science & Engineering.
    Liu, Xinyu
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Hofmann, J.P.
    Department of Chemical Engineering and Chemistry, Eindhoven University of of Technology, P.O. Box 513, Eindhoven, Netherlands.
    Hensen, E.J.M.
    Department of Chemical Engineering and Chemistry, Eindhoven University of of Technology, P.O. Box 513, Eindhoven, Netherlands.
    Linnarsson, M.
    School of Information and Communication Technology, KTH Royal Institute of Technology, Kista, Sweden.
    Wellmann, P.
    Department of Materials Science 6, University of of Erlangen-Nuremberg, Martensstr. 7, Erlangen, Germany.
    Ramiro, I.
    Instituto de Energía Solar, Universidad Politécnica de Madrid, E.T.S.I. Telecomunicación, Av. De la Complutense 30, Madrid, Spain.
    Marti, A.
    Instituto de Energía Solar, Universidad Politécnica de Madrid, E.T.S.I. Telecomunicación, Av. De la Complutense 30, Madrid, Spain.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Solar driven energy conversion applications based on 3C-SiC2016In: Materials Science Forum, Trans Tech Publications Ltd , 2016, Vol. 858, p. 1028-1031Conference paper (Refereed)
    Abstract [en]

    There is a strong and growing worldwide research on exploring renewable energy resources. Solar energy is the most abundant, inexhaustible and clean energy source, but there are profound material challenges to capture, convert and store solar energy. In this work, we explore 3C-SiC as an attractive material towards solar-driven energy conversion applications: (i) Boron doped 3C-SiC as candidate for an intermediate band photovoltaic material, and (ii) 3C-SiC as a photoelectrode for solar-driven water splitting. Absorption spectrum of boron doped 3C-SiC shows a deep energy level at ~0.7 eV above the valence band edge. This indicates that boron doped 3C-SiC may be a good candidate as an intermediate band photovoltaic material, and that bulk like 3C-SiC can have sufficient quality to be a promising electrode for photoelectrochemical water splitting. © 2016 Trans Tech Publications, Switzerland.

  • 50.
    Sun, Jianwu
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Jokubavicius, Valdas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Liljedahl, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Juillaguet, S.
    Université Montpellier 2, France.
    Camassel, J.
    CNRS, Montpellier, France.
    Kamiyama, S.
    Meijo University, Nagoya, Japan.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Room temperature luminescence properties of fluorescent SiC as white light emitting diode medium2012In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 522, p. 33-35Article in journal (Refereed)
    Abstract [en]

    The high quantum efficiency of donor–acceptor-pair emission in N and B co-doped 6H–SiC opens the way for SiC to constitute as an efficient light-emitting medium for white light-emitting diodes. In this work, we evidence room temperature luminescence in N and B co-doped 6H–SiC fluorescent material grown by the Fast Sublimation Growth Process. Three series of samples, with eight different N and B doping levels, were investigated. In most samples, from photoluminescence measurements a strong N–B donor–acceptor-pair emission band was observed at room temperature, with intensity dependent on the nitrogen pressure in the growth chamber and boron doping level in the source. Low temperature photoluminescence spectra showed that N bound exciton peaks exhibited a continuous broadening with increasing N2 pressure during the growth, unambiguously indicating an opportunity to control the N doping in the epilayer by conveniently changing the N2 pressure. Finally, the crystal quality of the N and B doped 6H–SiC was evaluated by X-ray diffraction measurements. The ω rocking curves of (0006) Bragg diffractions from the samples grown with lower and higher N2 pressure show almost the same value of the full width at half maximum as that collected from the substrate. This suggests that the N and B doping, which is expected to give rise to an efficient donor–acceptor-pair emission at room temperature, does not degrade the crystal quality.

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