liu.seSearch for publications in DiVA
Change search
Refine search result
123 1 - 50 of 128
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Bakoglidis, Konstantinos D.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schmidt, Susann
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Garbrecht, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Greczynski, Grzegorz
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Low-temperature growth of low friction wear-resistant amorphous carbon nitride thin films by mid-frequency, high power impulse, and direct current magnetron sputtering2015In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 33, no 5, article id 05E112Article in journal (Refereed)
    Abstract [en]

    Amorphous carbon nitride (a-CNx) thin films were deposited on steel AISI52100 and Si(001) substrates using mid-frequency magnetron sputtering (MFMS) with an MF bias voltage, high power impulse magnetron sputtering (HiPIMS) with a synchronized HiPIMS bias voltage, and direct current magnetron sputtering (DCMS) with a DC bias voltage. The films were deposited at a low substrate temperature of 150 °C and a N2/Ar flow ratio of 0.16 at the total pressure of 400 mPa. The negative bias voltage (Vs) was varied from 20 V to 120 V in each of the three deposition modes. The microstructure of the films was characterized by high-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED), while the film morphology was investigated by scanning electron microscopy (SEM). All films possessed amorphous microstructure with clearly developed columns extending throughout the entire film thickness. Layers grown with the lowest substrate bias of 20 V exhibited pronounced intercolumnar porosity, independent of the technique used. Voids closed and dense films formed at Vs ≥ 60 V, Vs ≥ 100 V and Vs = 120 V for MFMS, DCMS and HiPIMS, respectively. X-ray photoelectron spectroscopy (XPS) revealed that the nitrogen-to-carbon ratio, N/C, of the films ranged between 0.2 and 0.24. Elastic recoil detection analysis (ERDA) showed that Ar content varied between 0 and 0.8 at% and increases as a function of Vs for all deposition techniques. All films exhibited compressive residual stress, σ, which depends on the growth method; HiPIMS produces the least stressed films with stress between – 0.4 and – 1.2 GPa for all Vs values, while for CNx films deposited by MFMS σ = – 4.2 GPa. Nanoindentation showed a significant increase in film hardness and reduced elastic modulus with increasing Vs for all techniques. The harder films were produced by MFMS with hardness as high as 25 GPa. Low friction coefficients, between 0.05 and 0.06, were recorded for all films. Furthermore, CNx films produced by MFMS and DCMS at Vs = 100 V and 120 V presented a high wear resistance with wear coefficients of k ≤ 2.3 x 10-5 mm3/Nm.

  • 2.
    Booker, Ian D.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Farkas, Ildiko
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ul Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Chloride-based SiC growth on a-axis 4H-€“SiC substrates2016In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 480, p. 23-25Article in journal (Refereed)
    Abstract [en]

    Abstract SiC has, during the last few years, become increasingly important as a power-device material for high voltage applications. The thick, low-doped voltage-supporting epitaxial layer is normally grown by CVD on 4° off-cut 4H–SiC substrates at a growth rate of 5 – 10 ÎŒ m / h using silane (SiH4) and propane (C3H8) or ethylene (C2H4) as precursors. The concentrations of epitaxial defects and dislocations depend to a large extent on the underlying substrate but can also be influenced by the actual epitaxial growth process. Here we will present a study on the properties of the epitaxial layers grown by a Cl-based technique on an a-axis (90° off-cut from c-direction) 4H–SiC substrate.

  • 3.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Toropov, A. A.
    Terentev, Ya. V.
    Sorokin, S. V.
    Lebedev, A. V.
    Ivanov, S. V.
    Kopev, P. S.
    Tunable laser spectroscopy of spin injection in ZnMnSe/ZnCdSe quantum structures2002In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 81, no 12, p. 2196-Article in journal (Refereed)
    Abstract [en]

     Magneto-optical spectroscopy in combination with tunable laser excitation is employed to study exciton spin alignment and injection in ZnMnSe/ZnCdSe quantum structures. This approach enables us to selectively create preferred spin orientation and to separately monitor subsequent spin injection from individual spin states, thus shedding light on a possible source of spin loss. It is shown that the limited spin polarization in a nonmagnetic quantum well due to spin injection from a ZnMnSe-based diluted magnetic semiconductor (DMS) is not caused by a limited degree of spin alignment in the DMS, which is in fact complete, but rather occurs during subsequent processes.

  • 4.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Izadifard, Morteza
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Chen, Wei Min
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Felici, M.
    Polimeni, A.
    Capizzi, M.
    Hong, Y.G.
    Xin, H.P.
    Tu, C.W.
    Unusual effects of hydrogen in GaNP alloys: A general property of dilute nitrides2005In: 2005 MRS Spring Meeting,2005, 2005, p. 135-Conference paper (Other academic)
  • 5.
    Buyanova, Irina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Izadifard, Morteza
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Chen, Weimin
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Felici, M.
    Dipartimento di Fisica, Università di Roma “La Sapienza,” Roma, Italy .
    Polimeni, A.
    Dipartimento di Fisica, Università di Roma “La Sapienza,” Roma, Italy .
    Capizzi, M.
    Dipartimento di Fisica, Università di Roma “La Sapienza,” Roma, Italy .
    Hong, Y. G.
    Department of Electrical and Computer Engineering, University of California, La Jolla, California, USA .
    Xin, H. P.
    Department of Electrical and Computer Engineering, University of California, La Jolla, California, USA .
    Tu, C. W.
    Department of Electrical and Computer Engineering, University of California, La Jolla, California, USA .
    Direct experimental evidence for unusual effects of hydrogen on the electronic and vibrational properties of GaNxP1−x alloys: a proof for a general property of dilute nitrides2004In: Physical Review B Condensed Matter, ISSN 0163-1829, E-ISSN 1095-3795, Vol. 70, no 24, p. 245215-245219Article in journal (Refereed)
    Abstract [en]

    Direct experimental evidence for dramatic effects of hydrogen incorporation on the electronic structure and lattice properties of GaNxP1−x alloys is presented. By employing photoluminescence excitation spectroscopy, postgrowth hydrogenation is shown to reopen the band gap of the GaNP alloys and to efficiently reduce the N-induced coupling between the conduction band states. By Raman spectroscopy, these effects are shown to be accompanied by hydrogen-induced breaking of the Ga-P bond in the alloy, evident from disappearance of the corresponding vibrational mode. According to the performed Raman and x-ray diffraction measurements, the hydrogenation is also found to cause a strong expansion of the GaNP lattice, which changes the sign of strain from tensile in the as-grown GaNP epilayers to compressive in the posthydrogenated structures, due to the formation of complexes between N and H.

  • 6.
    Buyanova, Irina
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Izadifard, Morteza
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Birch, Jens
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Polimeni, A.
    Capizzi, M.
    Hong, Y. G.
    Tu, C. W.
    Effects of hydrogen on electronic and crystalline structure of GaNP2004In: EMRS-2004 Spring Meeting,2004, 2004Conference paper (Other academic)
  • 7.
    Choubina, Tatiana
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Glazov, M.M.
    Toropov, A.A.
    Gippius, N.A.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Usui, A.
    Vasson, A.
    Leymarie, J.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Kopev, P.S.
    Slow light in GaN2008In: 16th Int. Symp. ¿Nanostructures: Physics and Technology,2008, 2008, p. 257-Conference paper (Refereed)
  • 8.
    Choubina, Tatiana
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Glazov, M.M.
    Toropov, A.A.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Gippius, N.A.
    Vasson, A.
    Leymaire, J.
    Kavokin, A.
    Usui, A.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Pozina, Galia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Realization of slow light in GaN crystals2008In: IWN 2008,2008, 2008Conference paper (Refereed)
  • 9.
    Donchev, V.
    et al.
    Faculty of Physics, Sofia Univ., 5 Blvd. James B., Sofia, Bulgaria.
    Germanova, K.
    Faculty of Physics, Sofia Univ., 5 Blvd. James B., Sofia, Bulgaria.
    Shtinkov, N.
    Faculty of Physics, Sofia Univ., 5 Blvd. James B., Sofia, Bulgaria.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Vlaev, S.
    Inst. of Gen. and Inorg. Chemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria.
    Photoluminescence study of AlAs/GaAs superlattices containing enlarged wells2000In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 364, no 1, p. 224-227Article in journal (Refereed)
    Abstract [en]

    Photoluminescence (PL) spectra of MBE grown short-period AlAs/GaAs superlattices with one or two enlarged wells (5 and 12 nm) have been measured at 2 K. Sharp PL peaks corresponding to excitonic transitions between the lowest electron and heavy-hole states in the enlarged wells are observed. The excitonic transition energies are calculated by means of an envelope function based model, taking into account the exciton binding energies. The model incorporates a smooth potential at the interfaces, which is represented by a diffusion potential, the diffusion length being a parameter. The calculated and experimentally observed excitonic transition energies agree well if diffusion lengths of 3.5 and 4.5 monolayers are considered in the samples with and without a buffer layer, respectively. These values are consistent with the complicated nature of the growth kinetics and mechanisms of quantum heterostructures. The PL spectra reveal also complicated structures connected with the superlattice. Their qualitative discussion confirms the smooth potential model. Thus, an attempt is made to extend the analysis of complicated AlAs/GaAs heterostructures towards real interfaces, which is essential for advanced device fabrication.

  • 10.
    Donchev, V.
    et al.
    Faculty of Physics, Dept. Condensed Matter Phys., S., Sofia, Bulgaria.
    Ivanov, Tzv.
    Faculty of Physics, Dept. Condensed Matter Phys., S., Sofia, Bulgaria.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Angelov, M.
    Faculty of Physics, Dept. Condensed Matter Phys., S., Sofia, Bulgaria.
    Germanova, K.
    Faculty of Physics, Dept. Condensed Matter Phys., S., Sofia, Bulgaria.
    High-temperature excitons in GaAs quantum wells embedded in AlAs/GaAs superlattices2000In: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 58, no 2, p. 478-484Article in journal (Refereed)
    Abstract [en]

    Photoluminescence (PL) spectra of GaAs quantum wells embedded in short-period AlAs/GaAs superlattices have been measured at 2 K and at room temperature. Two approaches have been applied in order to investigate the mechanisms of radiative recombination in these structures. In the first one, we studied the excitation density dependence of the PL intensity. In the second approach a line-shape analysis of the PL spectra is performed by means of a statistical model, which includes both free exciton, and free carrier recombinations. The fit based on this model reproduces with high accuracy the experimental spectra and allows to assess the relative contributions of excitons and free carriers to the radiative recombination process. The results of both approaches indicate the predominance of free excitons in the radiative recombination at room temperature.

  • 11.
    Donchev, V.
    et al.
    Department of Condensed Matter Physics, Faculty of Physics, Sofia University, 5 Blvd. J. Bourchier, Sofia 1164, Bulgaria.
    Shtinkov, N.
    Department of Condensed Matter Physics, Faculty of Physics, Sofia University, 5 Blvd. J. Bourchier, Sofia 1164, Bulgaria.
    Germanova, K.
    Department of Condensed Matter Physics, Faculty of Physics, Sofia University, 5 Blvd. J. Bourchier, Sofia 1164, Bulgaria.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Brachkov, H.
    Department of Condensed Matter Physics, Faculty of Physics, Sofia University, 5 Blvd. J. Bourchier, Sofia 1164, Bulgaria.
    Ivanov, Tzv.
    Department of Condensed Matter Physics, Faculty of Physics, Sofia University, 5 Blvd. J. Bourchier, Sofia 1164, Bulgaria.
    Photoluminescene line-shape analysis in quantum wells embedded in superlattices2001In: Materials science & engineering. C, biomimetic materials, sensors and systems, ISSN 0928-4931, E-ISSN 1873-0191, Vol. 15, no 1-2, p. 75-77Article in journal (Refereed)
    Abstract [en]

    The temperature evolution of the main photoluminescence (PL) mechanisms, in GaAs quantum wells embedded in short-period AlAs/GaAs superlattices, is investigated. PL spectra are measured from 2 to 300 K. A detailed line-shape analysis of the PL peaks is performed by means of a statistical model, including both free exciton and free carrier recombination. The fits based on this model reproduce satisfactorily the experimental PL line shapes and allow to assess quantitatively the relative contributions of free excitons and free carriers to the radiative recombination at different temperatures. The results indicate the predominant role of free excitons in the radiative recombination up to room temperature, and are consistent with the mass action law. © 2001 Elsevier Science B.V. All rights reserved.

  • 12.
    Egilsson, T.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Henry, Anne
    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.
    Ellison, A.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Excitation properties of hydrogen-related photoluminescence in 6H-SiC2000In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 62, no 11, p. 7162-7168Article in journal (Refereed)
    Abstract [en]

    We have studied the excitation properties of a well-known hydrogen-related bound exciton (H-BE) photoluminescence (PL) in 6H-SiC. In the case of the so-called primary H-BE's, photoluminescence excitation (PLE) spectroscopy reveals several excited states that have not been reported previously. In order to explain these states we propose a pseudodonor model. The primary H-BE's are thus regarded as donors where strongly localized holes serve as the positive cores. From a comparison between the PLE spectra of the three different primary H-BE's corresponding to the three inequivalent substitutional lattice sites in 6H-SiC, we attempt to distinguish between the hexagonal and cubic lattice sites. We have also investigated the dependence of the optically induced quenching of the H-BE PL on the energy of the exciting light. We observe that the quenching of the H-BE PL is only efficient when the exciting light has energy above the threshold for phonon-assisted free-exciton (FE) formation or when its energy coincides with the energy needed for resonant absorption into the H-BE states. When creating FE's, we observe different types of behavior depending on the initial conditions. We argue that our results are best explained by the existence of two configurations of the same charge state of the H defect, namely a stable one: A (giving rise to the H-BE PL), and a metastable one: B (not revealed in the PL spectrum). The recombination of excitons bound at these two configurations can give rise to the transformations A?B and B?A. The existence of the B configuration is revealed through the effect of the B?A process on the temporal changes of the H-BE PL.

  • 13. Egilsson, T.
    et al.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Excitation spectra of nitrogen bound excitons in 4H- and 6H-SiC2002In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 91, no 3, p. 2028-2032Article in journal (Refereed)
    Abstract [en]

    We report photoluminescence excitation spectra of the nitrogen (N) donor bound excitons (BE) in 4H- and 6H-SiC. The spectra reveal several excited states of the N-BEs. An attempt is made in the article to classify the N-BE states according to a simple shell model. © 2002 American Institute of Physics.

  • 14.
    Egilsson, T
    et al.
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Pseudo-donors in SiC2000In: Materials Science Forum, Vols. 338-342, 2000, Vol. 338-342, p. 647-650Conference paper (Refereed)
    Abstract [en]

    We report on the properties of two well known bound excitons (BE) in silicon carbide, the D-1-BE and a hydrogen related BE, here called the II-BE. We find that in both cases the BE may be regarded as a pseudo-donor, a strongly localised hole serving as the positive core. In order to study the donor-like states of the BE, we use photoluminescence excitation (PLE) spectroscopy. Where possible, we have compared our results with the predictions of effective-mass-theory.

  • 15.
    Egilsson, T
    et al.
    Linkoping Univ, IFM, Dept Phys & Measurement Technol, S-58183 Linkoping, Sweden ABB Corp Res, S-72178 Vasteras, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Zeeman spectroscopy of the D-1 bound exciton in 3C-, and 4H-SiC1999In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 274, p. 677-680Article in journal (Refereed)
    Abstract [en]

    We have studied the D1 bound exciton (BE) in 3C-SiC (cubic) and 4H-SiC (hexagonal) by means of Zeeman spectroscopy. We show that the D-1-BE can be described by an electron-hole pair consisting of an (L-e = 0, S-e = 1/2) electron and a (L-h = 1, S-h = 1/2) hole, influenced by a number of interactions. In order to model the behaviour of the D-1-BE in magnetic field, an appropriate Hamiltonian equation is solved by using perturbation theory. The spin-orbit parameter and orbital g-value are small, indicating that the hole is tightly bound. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 16.
    Egilsson, T
    et al.
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Son, Nguyen Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Bergman, Peder
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Exciton and defect photoluminescence from SiC2003In: Silicon carbide and related materials 2002: ECSCRM 2002 proceedings of the 4th European Conference on Silicon Carbide and Related Materials, September 2-5, 2002, Linköping, Sweden / [ed] Zhe Chuan Feng, Jian H. Zhao, 2003, p. 81-120Chapter in book (Other academic)
    Abstract [en]

    Wide-bandgap semiconductors such as SiC, III-V nitrides and related compounds are attracting rapidly increasing attention due to their other, very interesting, physical properties which are often superior in many ways to those of conventional semiconductors. Steady improvements in crystal quality, and improved knowledge concerning their physical properties, are leading to rapid developments in high-power, high-temperature, high-frequency electronics and blue-light emitters. This book comprises the proceedings of the fourth European Conference on Silicon Carbide and Related Materials, held on the 1 to 5 September 2002 in Link3œping, Sweden. This conference series continued its tradition of being the main forum for presenting results, and discussing progress, among university and industry researchers who are active in the fields of SiC and related materials. These proceedings therefore document the latest experimental and theoretical understanding of the growth of bulk and epitaxial layers, the properties of the resultant material, the development of suitable processes and of electronic devices that can exploit and benefit best from the outstanding physical properties offered by wide-bandgap materials

  • 17.
    Eriksson, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering.
    Puglisi, Donatella
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering.
    Strandqvist, Carl
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering. Graphensic AB Linköping, Sweden.
    Gunnarsson, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Ekeroth, Sebastian
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. 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.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Graphensic AB Linköping, Sweden.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, Faculty of Science & Engineering.
    Modified Epitaxial Graphene on SiC for Extremely Sensitive andSelective Gas Sensors2016In: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 858, p. 1145-1148Article in journal (Refereed)
    Abstract [en]

    Two-dimensional materials offer a unique platform for sensing where extremely high sensitivity is a priority, since even minimal chemical interaction causes noticeable changes inelectrical conductivity, which can be used for the sensor readout. However, the sensitivity has to becomplemented with selectivity, and, for many applications, improved response- and recovery times are needed. This has been addressed, for example, by combining graphene (for sensitivity) with metal/oxides (for selectivity) nanoparticles (NP). On the other hand, functionalization or modification of the graphene often results in poor reproducibility. In this study, we investigate thegas sensing performance of epitaxial graphene on SiC (EG/SiC) decorated with nanostructured metallic layers as well as metal-oxide nanoparticles deposited using scalable thin-film depositiontechniques, like hollow-cathode pulsed plasma sputtering. Under the right modification conditions the electronic properties of the surface remain those of graphene, while the surface chemistry can betuned to improve sensitivity, selectivity and speed of response to several gases relevant for airquality monitoring and control, such as nitrogen dioxide, benzene, and formaldehyde.

  • 18. Falth, JF
    et al.
    Gurusinghe, MN
    Liu, XY
    Andersson, TG
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Yao, HH
    Wang, SC
    Influence of dislocation density on photoluminescence intensity of GaN2005In: Journal of Crystal Growth, ISSN 0022-0248, E-ISSN 1873-5002, Vol. 278, no 01-Apr, p. 406-410Article in journal (Refereed)
    Abstract [en]

    The influence of dislocation density on photoluminescence intensity is investigated experimentally and compared to a model. GaN samples were grown by molecular beam epitaxy and metal-organic chemical vapour deposition. Different growth parameters and thicknesses of the layers resulted in different dislocation densities. The threading dislocation density, measured by atomic force microscopy, scanning electron microscopy and X-ray diffraction, covered a range from 5 x 10(8) to 3 x 10(10) cm(-2). Carrier concentration was measured by capacitance-voltage-, and Hall effect measurements and photoluminescence at 2 K was recorded. A model which accounts for the photoluminescence intensity as a function of dislocation density and carrier concentration in GaN is developed. The model shows good agreement with experimental results for typical GaN dislocation densities, 5 x 10(8)-1 x 10(10) cm(-2), and carrier concentrations 4 x 10(16)-1 x 10(18) cm(-3). ©, 2005 Elsevier B.V. All rights reserved.

  • 19.
    Forsberg, Urban
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Kakanakova-Georgieva, Anelia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Hot-wall MOCVD growth and characterization of III-nitrides for HEMT application2006In: WOCSDICE 2006,2006, 2006Conference paper (Other academic)
  • 20.
    Gali, Adam
    et al.
    Department of Atomic Physics, Budapest Univ. of Technol./Economics, Budafoki út 8, H-1111 Budapest, Hungary.
    Deak, P.
    Deák, P., Department of Atomic Physics, Budapest Univ. of Technol./Economics, Budafoki út 8, H-1111 Budapest, Hungary.
    Rauls, E.
    Theoretische Physik, Universität Paderborn, D-33098 Paderborn, Germany.
    Nguyen, Tien Son
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Carlsson, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Choyke, W.J.
    Department of Physics, University of Pittsburgh, Pittsburgh, PA 15260, United States.
    Anti-site pair in SiC: A model of the DI center2003In: Physica B, 2003, Vol. 340-342, p. 175-179Conference paper (Refereed)
    Abstract [en]

    The DI low-temperature photoluminescence center is a well-known defect stable up to 1700°C annealing in SiC, still its structure is not known after decades of study. Combining experimental and theoretical studies in this paper we will show that the properties of an anti-site pair can reproduce the measured one-electron level position and local vibration modes of the D I center and the model is consistent with other experimental findings as well. We give theoretical values of the hyperfine constants of the anti-site pair in its paramagnetic state as a means to confirm our model. © 2003 Elsevier B.V. All rights reserved.

  • 21.
    Gali, Adam
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Deak, P
    Rauls, E
    Nguyen, Tien Son
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Carlsson, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Choyke, WJ
    Correlation between the antisite pair and the D-I center in SiC2003In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 67, no 15Article in journal (Refereed)
    Abstract [en]

    The D-I low temperature photoluminescence center is a well-known defect stable up to 1700 degreesC annealing in SiC, still its structure is not yet known. Combining experimental and theoretical studies, in this paper we will show that the properties of an antisite pair can reproduce the measured one-electron level position and local vibration modes of the D-I center, and are consistent with other experimental findings as well. We give theoretical values of the hyperfine constants of the antisite pair in its paramagnetic state as a means to confirm a model.

  • 22. Gali, Adam
    et al.
    Deák, P.
    Rauls, E.
    Nguyen, Son Tien
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Carlsson, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Choyke, W.J.
    Antisites as possible origin of irradiation induced photoluminescence centers in SiC: A theoretical study on clusters of antisites and carbon interstitials in 4H-SiC2004In: Mater. Sci. Forum, Vol. 457-460, Trans Tech Publications Inc. , 2004, p. 443-Conference paper (Refereed)
  • 23. Gogova, Daniela
    et al.
    Kanev, S.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Talik, E.
    Growth and characterization of free-standing HVPE GaN on two-step epitaxial lateral overgrown GaN template2005Conference paper (Refereed)
  • 24.
    Gogova, Daniela
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Kasic, A.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Larsson, Henrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Pécz, B.
    Research Institute for Technical Physics and Materials Science of the Hungarian Academy of Sci., Budapest, Hungary .
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Characterization of high-quality free-standing GaN grown by HVPE2004In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. T114, p. 18-21Article in journal (Refereed)
    Abstract [en]

    Single-crystalline 330µm thick GaN has been grown on 2'' Al2O3 (0 0 0 1) by hydride vapour phase epitaxy (HVPE). Upon laser-induced lift-off the GaN was delaminated from the sapphire substrate, and bulk-like free-standing GaN was achieved. Various characterization methods were utilized to assess the structural and optical quality of the freestanding material. The X-ray rocking curves of the (1 0–1 4) and (0 0 0 2) diffraction peaks revealed full width at half maximum (FWHM) values of 96 and 129arcsec, respectively. These data compare well with the smallest corresponding values published so far for bulk-like HVPE-GaN. The dislocation density determined by plan-view transmission electron microscopy studies is 1–2 × 107cm–2. The low-temperature near-band-gap photoluminescence spectrum shows the main donor bound exciton (DBE) peak at 3.4718eV with a FWHM of 1.4meV, verifying the high crystalline quality of the bulk-like GaN. The DBE peak position suggests complete stress relief. The phonon spectra measured by infrared spectroscopic ellipsometry confirm as well, that the free-standing material is of high crystalline quality and virtually stress-free.

  • 25.
    Gogova, Daniela
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Larsson, Henrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Kasic, A.
    Yazdi, Gholam Reza
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Aujol, E.
    Frayssinet, E.
    Faurie, J-P.
    Beaumont, B.
    Gibart, P.
    High-Quality 2'' Bulk-Like Free-Standing GaN Grown by HydrideVapour Phase Epitaxy on a Si-doped Metal Organic Vapour Phase Epitaxial GaN Template with an Ultra Low Dislocation Density2005In: Japanese Journal of Applied Physics, ISSN 0021-4922, E-ISSN 1347-4065, Vol. 44, p. 1181-1185Article in journal (Refereed)
  • 26.
    Gogova, Daniela
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Larsson, Henrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Zolnai, Z.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Fast growth of high quality GaN2003In: Physica status solidi. A, Applied research, ISSN 0031-8965, E-ISSN 1521-396X, Vol. 200, no 1, p. 13-17Article in journal (Refereed)
    Abstract [en]

    We have grown bulk-like GaN with a thickness up to 335 μm on 2″ sapphire substrates in a vertical HVPE reactor with a bottom-fed design. A very high growth rate of 250 μm/h is reached with high crystalline quality of the grown material. The low temperature PL spectra show the free A-exciton line at 3.483 eV and rather narrow I2 lines with FWHM of 1–2 meV indicating high crystalline quality and low doping concentration. This HVPE-GaN has the potential to provide lattice-matched and thermally-matched substrates for further epitaxial growth of high quality GaN with a low dislocation density for advanced heterostructure devices.

  • 27.
    Gogova, Daniela
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Talik, E.
    Institute of Physics, University of Silesia, Universytecka 4, 40007 Katowice, Poland.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Large-area free-standing GaN substrate grown by hydride vapor phase epitaxy on epitaxial lateral overgrown GaN template2006In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 371, no 1, p. 133-139Article in journal (Refereed)
    Abstract [en]

    In this paper, the potential of the high growth rate hydride vapor phase epitaxy technique and laser lift-off for the fabrication of large-area (2?) free-standing GaN substrates is revealed. Structural and optical properties of 250-µm-thick GaN layer grown on a MOVPE epitaxial lateral overgrown GaN template have been investigated employing different analytical experimental techniques. A low value of dislocation density of ~1×107 cm-2 on the Ga-terminated face of the free-standing material was determined from AFM images. X-ray diffraction (XRD), Raman scattering measurements, and low-temperature photoluminescence (PL) were exploited to assess the structural and optical quality of the GaN. The full-width at half-maximum value of XRD ?-scans of the free-standing GaN material was determined to be 264 arcsec for the (101¯4) reflection. The XRD and low-temperature PL mapping measurements consistently proved the good crystalline quality and lateral homogeneity and small residual stress inside the material. Hence, the free-standing GaN achieved is highly advantageous for a lattice-constant and thermal-expansion-coefficient matched substrate for additional strain-free homoepitaxy of III-nitrides-based device heterostructures. © 2005 Elsevier B.V. All rights reserved.

  • 28.
    Gueorguiev Ivanov, Ivan
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gällström, Andreas
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Leone, Stefano
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kordina, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Tien Son, Nguyen
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ivády, Viktor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, The Institute of Technology.
    Gali, Adam
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Optical properties of the niobium centre in 4H, 6H, and 15R SiC2013In: SILICON CARBIDE AND RELATED MATERIALS 2012, Trans Tech Publications , 2013, Vol. 740-742, p. 405-408Conference paper (Refereed)
    Abstract [en]

    A set of lines in the photoluminescence spectra of 4H-, 6H-, and 15R-SiC in the near-infrared are attributed to Nb-related defects on the ground of doping experiments conducted with 4H-SiC. A model based on a an exciton bound at the Nb-centre in an asymmetric split vacancy configuration at a hexagonal site is proposed, which explains the structure of the luminescence spectrum and the observed Zeeman splitting of the lines.

  • 29.
    Gällström, Andreas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Magnusson, Björn
    Norstel AB, Norrköping, Sweden.
    Beyer, Franziska
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gali, Adam
    Budapest University of Technology and Economics and Hungarian Academy of Science, Budapest, Hungary .
    Son, Nguyen Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Leone, Stefano
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ivanov, Ivan G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hemmingsson, Carl
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Electronic Configuration of Tungsten in 4H-, 6H-, and 15R-SiC2012In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 211-216Conference paper (Refereed)
    Abstract [en]

    A commonly observed unidentified photoluminescence center in SiC is UD-1. In this report, the UD-1 center is identified to be tungsten related. The identification is based on (i) a W-doping study, the confirmation of W in the samples was made using deep level transient spectroscopy (DLTS), (ii) the optical activation energy of the absorption of UD-1 in weakly n-type samples corresponds to the activation energy of the deep tungsten center observed using DLTS. The tungsten-related optical centers are reported in 4H-, 6H-, and 15R-SiC. Further, a crystal field model for a tungsten atom occupying a Si-site is suggested. This crystal field model is in agreement with the experimental data available: polarization, temperature dependence and magnetic field splitting.

  • 30.
    Gällström, Andreas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Magnusson, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Beyer, Franziska
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gali, Adam
    Budapest University of Technology and Economics, Hungary.
    Son Tien, Nguyen
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Leone, Stefano
    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.
    Hemmingsson, Carl
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Optical identification and electronic configuration of tungsten in 4H-and 6H-SiC2012In: Physica. B, Condensed matter, ISSN 0921-4526, E-ISSN 1873-2135, Vol. 407, no 10, p. 1462-1466Article in journal (Refereed)
    Abstract [en]

    Several optically observed deep level defects in SiC are still unidentified and little is published on their behavior. One of the commonly observed deep level defects in semi-insulating SiC is UD-1. less thanbrgreater than less thanbrgreater thanThis report suggests that UD-1 is Tungsten related, based on a doping study and previously reported deep level transient spectroscopy data, as well as photo-induced absorption measurements. The electronic levels involved in the optical transitions of UD-1 are also deduced. The transitions observed in the photoluminescence of UD-1 are from a Gamma(C3v)(4), to two different final states, which transform according to Gamma(C3v)(5)circle plus Gamma(C3v)(6) and Gamma(C3v)(4), respectively.

  • 31.
    Gällström, Andreas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Magnusson, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ellison, A.
    Gali, Adam
    Wigner Research Center for Physics, Hungarian Academy of Sciences / Department of Atomic Physics, Budapest University of Technology and Economics, Hungary.
    Ivanov, Ivan G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    A defect center for quantum computing: Mo in SiCManuscript (preprint) (Other academic)
    Abstract [en]

    The electronic structure and vibrational properties of molybdenum (Mo) in SiC are analyzed and investigated in detail. Mo is considered as occupying the silicon-carbon divacancy in the so-called asymmetric split vacancy (ASV) configuration. Group-theoretical considerations within this model are used to explain the experimental results (optical properties and behavior in magnetic field). The vibrational properties of the defect are studied using simple the “defect molecule” model with parameters determined phenomenologically from the experimental data. The position of Mo in the ASV configuration deduced from this model is shown to be in good agreement with the earlier reported data from ab initio supercell calculations. The usefulness of molybdenum in SiC in quantum computing is investigated, and it shown that Mo is a highly promising candidate for quantum computing.

  • 32.
    Gällström, Andreas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Magnusson, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Leone, Stefano
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Kordina, Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Son, Nguyen Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivády, Viktor
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Wigner Research Center for Physics, Hungarian Academy of Sciences, Hungary.
    Gali, Adam
    Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest Hungary; Department of Atomic Physics, Budapest University of Technology and Economics, Budapest, Hungary.
    Abrikosov, Igor A.
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Materials Modeling and Development Laboratory, NUST “MISIS,” Moscow, Russia; LACOMAS Laboratory, Tomsk State University, Tomsk, Russia.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Optical properties and Zeeman spectroscopy of niobium in silicon carbide2015In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 92, no 7, p. 1-14, article id 075207Article in journal (Refereed)
    Abstract [en]

    The optical signature of niobium in the low-temperature photoluminescence spectra of three common polytypes of SiC (4H, 6H, and 15R) is observed and confirms the previously suggested concept that Nb occupies preferably the Si-C divacancy with both Si and C at hexagonal sites. Using this concept we propose a model considering a Nb-bound exciton, the recombination of which is responsible for the observed luminescence. The exciton energy is estimated using first-principles calculation and the result is in very good agreement with the experimentally observed photon energy in 4H SiC at low temperature. The appearance of six Nb-related lines in the spectra of the hexagonal 4H and 6H polytypes at higher temperatures is tentatively explained on the grounds of the proposed model and the concept that the Nb center can exist in both C1h and C3v symmetries. The Zeeman splitting of the photoluminescence lines is also recorded in two different experimental geometries and the results are compared with theory based on phenomenological Hamiltonians. Our results show that Nb occupying the divacancy at the hexagonal site in the studied SiC polytypes behaves like a deep acceptor.

  • 33.
    Gällström, Andreas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Magnusson, Björn
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Tien Son, Nguyen
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ivanov, Ivan G.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Optical identification of intrinsic nearest-neighbor defects in SiC2015Manuscript (preprint) (Other academic)
    Abstract [en]

    The optical signature of two types of intrinsic nearest-neighbor defects in SiC is observed in 4H- and 6H-SiC. The first optical signature belong to a defect previously known as UD-2 and identified as the divacancy pair, and the second – to a defect referred to here as UD-0, an unidentified defect. In both these defects, the number of optical centers is equal to the number of possible configurations for nearest-neighbor pairs in the unit cells of these polytypes. The polarization of all optical transitions is investigated. The formation of the two defects by means of electron irradiation and subsequent annealing in samples with different Fermi levels is studied, too. The observed transitions are investigated using group-theoretical analysis and UD-0 is tentatively assigned to the carbon-vacancy carbonantisite pair, based on energy positions of the lines and spin configuration.

  • 34.
    Hallin, Christer
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Wahab, Qamar Ul
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Homoepitaxial On-Axis Growth of 4H- and 6H-SiC by CVD2004In: Materials Science Forum, Vols. 457-460, Trans Tech Publications Inc. , 2004, p. 193-Conference paper (Refereed)
  • 35.
    Henry, Anne
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Egilsson, T
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden ABB Corp Res, SE-72178 Vasteras, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Metastability of a hydrogen-related defect in 6H-SiC2000In: Materials Science Forum, Vols. 338-342, Stafa-Zurich, Switzerland: Trans Tech Publications Inc., 2000, Vol. 338-3, p. 651-654Conference paper (Refereed)
    Abstract [en]

    We report on the metastability behavior of a hydrogen related defect in 6H-SiC. This defect gives rise to a low temperature photoluminescence spectrum and several excited states have been observed using photoluminescence excitation. A quenching of the luminescence intensity is observed when using prolonged optical excitation either with energy higher than the threshold for phonon assisted free-exciton formation or when the excitation energy is resonant with an excited state of the hydrogen related bound exciton. Depending on the initial conditions different types of behavior can be observed.

  • 36.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gueorguiev Ivanov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Hatayama, Tomoaki
    Nara Institute of Science and Technology, Japan.
    Yano, Hiroshi
    Nara Institute of Science and Technology, Japan.
    Fuyuki, Takashi
    Nara Institute of Science and Technology, Japan.
    Photoluminescence of 8H-SiC2013In: 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. 347-350Conference paper (Refereed)
    Abstract [en]

    8H-SiC epilayers grown on small 8H-SiC Lely platelets are investigated optically using photoluminescence spectroscopy. At low temperature the near band gap emission detected in the 2.78 to 2.67 eV range contains sharp lines associated to nitrogen-bound-exciton recombination. Three different no-phonon lines are detected accompanied by their phonon replicas. Free-exciton replicas are also observed which allows the determination of the excitonic band gap. The binding energy of the bound excitons can thus be determined and the ionization energies of the three nitrogen levels in 8H-SiC are estimated and found to be rather shallow compared to the values for other hexagonal polytypes. Additional bound-exciton lines are observed when the experimental photoluminescence temperature is increased.

  • 37.
    Henry, Anne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lundskog, Anders
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. 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.
    Ivanov, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kakanakova-Georgieva, Anelia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Forsberg, Urban
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Persson, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    AlGaN Multiple Quantum Wells and AlN Grown in a Hot-wall MOCVD for Deep UV Applications2009In: ECS Transactions, Vol. 25, Iss. 8, ECS , 2009, p. 837-844Conference paper (Refereed)
    Abstract [en]

    AlxGa1-xN multiple quantum wells (MQW) were grown on AlN epilayer grown on 4H-SiC substrate. The growth was performed without interruption in a horizontal hot-wall MOCVD reactor using a mixture of hydrogen and nitrogen as carrier gases. The precursors were ammonia, trimethylaluminum and trimethylgallium. Results obtained from X-ray diffraction and infra-red reflectance were used to obtain the composition of the films when growing simple AlxGa1 xN layer. Visible reflectance was used to evaluate the thickness of the films. Finally the MQW parameters as thicknesses and composition variation were obtained by scanning transmission electron microscopy and demonstrated an agreement with the growth parameters used

  • 38.
    Hänninen, Tuomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schmidt, Susann
    IHI Ionbond AG, Industriestraße 211, Olten CH-4600, Switzerland.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Silicon carbonitride thin films deposited by reactive high power impulse magnetron sputtering2018In: Surface & Coatings Technology, ISSN 0257-8972, E-ISSN 1879-3347, Vol. 335, p. 248-256Article in journal (Refereed)
    Abstract [en]

    Amorphous silicon carbonitride thin films for biomedical applications were deposited in an industrial coating unit from a silicon target in different argon/nitrogen/acetylene mixtures by reactive high power impulse magnetron sputtering (rHiPIMS). The effects of acetylene (C2H2) flow rate, substrate temperature, substrate bias voltage, and HiPIMS pulse frequency on the film properties were investigated. Low C2H2 flow rates (<10 sccm) resulted in silicon nitride-like film properties, seen from a dense morphology when viewed in cross-sectional scanning electron microscopy, a hardness up to ∼22 GPa as measured by nanoindentation, and Si-N bonds dominating over Si-C bonds in X-ray photoelectron spectroscopy core-level spectra. Higher C2H2 flows resulted in increasingly amorphous carbon-like film properties, with a granular appearance of the film morphology, mass densities below 2 g/cm3 as measured by X-ray reflectivity, and a hardness down to 4.5 GPa. Increasing substrate temperatures and bias voltages resulted in slightly higher film hardnesses and higher compressive residual stresses. The film H/E ratio showed a maximum at film carbon contents ranging between 15 and 30 at.% and at elevated substrate temperatures from 340 °C to 520 °C.

  • 39.
    Imam, Mewlude
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. European Spallat Source ESS AB, Sweden.
    Höglund, Carina
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. European Spallation Source ERIC, Lund, Sweden.
    Jensen, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schmidt, Susann
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. European Spallation Source ERIC, Lund, Sweden.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Hall-Wilton, Richard
    European Spallation Source ERIC, Lund, Sweden.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Trimethylboron as single-source precursor for boron-carbonthin film synthesis by plasma chemical vapor deposition2015Manuscript (preprint) (Other academic)
    Abstract [en]

    Boron-carbon (BxC) thin films are potential neutron converting layers for 10B-based neutron detectors. However, as common material choices for such detectors do not tolerate temperature above 500°C, a low temperature deposition route is required for this application. Here we study trimethylboron B(CH3)3 (TMB) as a single-source precursor for the deposition of BxC thin films by plasma CVD using Ar plasma. The effect of plasma power, TMB/Ar ratio and total pressure on the film composition, morphology and structure are investigated. The highest B/C ratio of 1.9 was achieved at high TMB flow in a low total pressure and high plasma power which rendered an approximate substrate temperature of ~ 300 °C. X-ray photoelectron spectroscopy shows that B-C bonds prevail in the films, although C-C and B-O bonds are also present. Raman spectroscopy confirms the presence of amorphous carbon phases in the films. The H content in the films is found to be 15±5 at. % by the time of flight elastic recoil detection analysis (Tof-ERDA). The film density as determined from X-ray reflectivity (XRR) measurements is 2. 16 ± 0.01  g/cm3 and the internal compressive stresses are measured to be less than 400 MPa.

  • 40.
    Ivanov, I. G.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gällström, A
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Coble, R.
    University of Pittsburgh, USA.
    Devaty, R. P.
    University of Pittsburgh, USA.
    Choyke, W. J.
    University of Pittsburgh, USA.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Investigation of intrinsic carbon-related defects in 4H-SiC by selective-excitation photoluminescence spectroscopy2012In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, p. 259-262Conference paper (Refereed)
    Abstract [en]

    Emission of carbon-related defects is investigated by means of selectively-excited photoluminescence in high purity 4H-SiC electron-irradiated with very low dose. Two new centers with clearly associated phonon replicas are observed, one of which is tentatively assigned to the carbon split interstitial at the hexagonal site. The temperature dependence of the spectrum is also studied and indicates that at least some of the observed luminescence lines arise from recombination of excitons bound to isoelectronic centers.

  • 41.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Egilsson, T
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Resonant sharp hot free-exciton luminescence in 6H-and 4H-SiC due to inhibited exciton-phonon interaction2001In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 64, no 8Article in journal (Refereed)
    Abstract [en]

    Experimentally observed sharp luminescence lines from hot free-exciton recombination in high-purity 6H- and 4H-SiC are presented. The phenomenon is explained in terms of inhibition of the exciton-phonon scattering, prohibited for excitons created resonantly near the bottom of the lowest exciton band at low temperatures. This gives rise to the hot, sharp luminescence. The model is in agreement with the observed quenching of the hot luminescence at higher temperatures (>5 K) and in more highly doped samples, as well as with the dispersion of the exciton band obtained from the measured electron and hole effective masses.

  • 42.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Egilsson, T
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Zhang, J
    Ellison, A
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Intrinsic photoconductivity of 6H-SiC and the free-exciton binding energy2001In: Materials Science Forum, Vols. 353-356, 2001, Vol. 353-3, p. 405-408Conference paper (Refereed)
    Abstract [en]

    The paper presents a study of the low-temperature photoconductivity of 6H-SiC. The photocurrent at the absorption edge is assigned to Auger recombination of excitons captured to impurities. This is shown to saturate and decrease with increasing the photon energy, so the further increase in the photocurrent, observed in the purest sample, can be attributed to free excitons created in non-bound states in the exciton continuum. Thus, the exciton binding energy can be estimated, E-bx approximate to 60 +/- 5 meV in 6H-SiC.

  • 43.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Ellison, A
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Donor-acceptor pair luminescence in 4H-SiC doped with nitrogen and aluminum2003In: Materials Science Forum, Vols. 433-436, 2003, Vol. 433-4, p. 321-324Conference paper (Refereed)
    Abstract [en]

    The paper presents a fit of the experimental spectrum resulting from donor-acceptor pair recombination in 4H-SiC with a theoretically modeled one. The features of this polytype of SiC arising from its uniaxial property and presence of non-equivalent lattice sites are considered. The nitrogen donor and aluminum acceptor binding energies are discussed.

  • 44.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Donor-acceptor Pair Luminescence of Phosphorus-Aluminum and Nitrogen-Aluminum Pairs in 4H SiC2006In: Materials Science forum, Vols. 527-529, 2006, p. 601-Conference paper (Refereed)
  • 45.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Henry, Anne
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Ionization energies of phosphorus and nitrogen donors and aluminum acceptors in 4H silicon carbide from the donor-acceptor pair emission2005In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 71, no 24, p. 241201-241201-4Article in journal (Refereed)
    Abstract [en]

    This paper deals with fitting the donor-acceptor pair luminescence due to P-Al pairs in 4H-SiC. It was possible to identify P at the Si cubic site as the shallower donor with ionization energy of 60.7meV, as well as to distinguish the contribution in the spectrum from pairs involving this donor and Al acceptors from both the cubic and hexagonal lattice sites, leading to justification of their ionization energies. The case of N-Al pair luminescence was revisited and the ionization energy of the deeper Nc donor at the cubic site was determined, 125.5meV. © 2005 The American Physical Society.

  • 46.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Henry, Anne
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Yan, Fei
    University of Pittsburgh.
    Choyke, W J
    University of Pittsburgh.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ionization energy of the phosphorus donor in 3C-SiC from the donor-acceptor pair emission2010In: JOURNAL OF APPLIED PHYSICS, ISSN 0021-8979, Vol. 108, no 6, p. 063532-Article in journal (Refereed)
    Abstract [en]

    Donor-acceptor pair luminescence of P-Al and N-Al pairs in 3C-SiC is analyzed. The structures in the spectra corresponding to recombination of pairs at intermediate distances are fitted with theoretical spectra of type I (P-Al pairs) and type II (N-Al pairs). It is shown that in the regions chosen for fitting the line positions obey the equation (h) over bar omega(R)=E-G-E-D-E-A+e(2)/epsilon R, where (h) over bar omega(R) is the energy of the photon emitted by recombination of a pair at a distance R, e is the electron charge, epsilon is the static dielectric constant, and E-G, E-D, and E-A are the electronic band gap and the donor and acceptor ionization energies, respectively. The fits yield the values E-G-E-D-E-A for the N-Al (2094 meV) and P-Al (2100.1 meV) cases. Using the known value of the nitrogen ionization energy, 54.2 meV, phosphorus ionization energy of 48.1 meV is obtained. Identification of the sharp lines corresponding to recombination of close pairs in the P-Al spectrum is suggested.

  • 47.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Photoluminescence Excitation Spectroscopy on the Donor-Acceptor Pair Luminescence in 4H and 6H SiC2004In: Mater. Sci. Forum, Vol. 457-460, Trans Tech Publications Inc. , 2004, p. 585-Conference paper (Refereed)
  • 48.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Resonant ionization of shallow donors in electric field2014In: Physica Scripta, ISSN 0031-8949, E-ISSN 1402-4896, Vol. 89, no 8, p. 085802-Article in journal (Refereed)
    Abstract [en]

    In this paper, we report on our experimental observations of the resonant ionization of a phosphorus donor in silicon in a homogeneous electric field, which is expressed in the sudden rise of the conductivity of the sample at a low temperature when the electric field approaches the critical value of ∼3.2 MV m-1. The effect is discussed in terms of the field-induced interaction of the states using a simplified model based on the effective-mass theory. The results from our model are qualitatively similar to the previously published advanced model base, which is based on the first principles; this predicts the ionization thresholds at approximate fields of 2.45 and 3.25 MV m-1, the latter being in very good agreement with our experiment. The possibility of observing more than one resonance is also discussed.

  • 49.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Theory of the Stark Effect on the Donor Levels in 4H Silicon Carbide2007In: Materials Science Forum, vol. 556-557, Trans Tech Publications , 2007, p. 435-Conference paper (Refereed)
  • 50.
    Ivanov, Ivan Gueorguiev
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Magnusson, Björn
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Analysis of the sharp donor-acceptor pair luminescence in 4H-SiC doped with nitrogen and aluminum2003In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 67, no 16Article in journal (Refereed)
    Abstract [en]

    We analyze the sharp lines in the donor-acceptor (nitrogen-aluminum) emission spectrum in 4H-SiC by means of a fit with theoretically calculated spectra. The theory accounts for the anisotropy and the presence of inequivalent sites in this polytype of SiC, and it is shown that the predominant emission in the linear part of the spectrum is due to pairs involving nitrogen donor and aluminum acceptor at hexagonal sites. The fit allows determination of the ionization energy of the aluminum at hexagonal site, 199+/-2 meV, which is in excellent agreement with the results obtained using free-to-bound spectra.

123 1 - 50 of 128
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf