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  • 1.
    Alnoor, Hatim
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Seed layer synthesis effect on the concentration of interface defects and emission spectra of ZnO nanorods/p-GaN light-emitting diode2017In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 214, no 1, article id 1600333Article in journal (Refereed)
    Abstract [en]

    As the low-temperature aqueous chemical synthesis (LT-ACS), holds great promises for the synthesis of one-dimensional (1D) ZnO nanostructure-based light-emitting diodes (LEDs) and hence require parameter tuning for optimal performance. N-ZnO nanorods (NRs)/p-GaN heterojunction LEDs have been synthesized by the LT-ACS using ZnO nanoparticle (NPs) seed layers prepared with different precursor solutions. The effect of these seed layers on the interface defect properties and emission intensity of the as-synthesized n-Zn/p-GaN heterojunction LEDs has been demonstrated by spatially resolved cathodoluminescence (CL) and electroluminescence (EL) measurements, respectively. A significant reduction of the interface defects in the n-ZnO NRs/p-GaN heterostructure synthesized from a seed layer prepared from zinc acetate (ZnAc) with a mixture of potassium hydroxide (KOH) and hexamethylenetetramine (HMTA) (donated as ZKH seed) compared with those prepared from ZnAc and KOH (donated as ZK seed) is observed as revealed by spatially resolved CL. Consequently, the LEDs based on n-ZnO NRs/p-GaN prepared from ZKH seed show an improvement in the yellow emission (approximate to 578nm) compared to that based on the ZK seed as deduced from the electroluminescence measurements. The improvement in the yellow EL emission on the ZKH LED probably attributed to the low presence of the non-radiative defect as deduced by light-output current (L-I) characteristics analysis.

  • 2.
    Arwin, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Karlsson, Linda
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Kozarcanin, A.
    Thompson, D.W.
    Center for Microelectronic and Optical Materials Research and Department of Electrical Engineering University of Nebraska, USA.
    Tiwald, T.
    J.A. Woollam Co., Inc. Lincoln, USA.
    Woollam, J.A.
    Center for Microelectronic and Optical Materials Research and Department of Electrical Engineering University of Nebraska, USA.
    Carbonic anhydrase adsorption in porous silicon studied with infrared ellipsometry2005In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 202, p. 1688-1692Article in journal (Refereed)
  • 3.
    Arwin, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Poksinski, Michal
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Johansen, Knut
    Scientific Engineering QED, Linköping, Sweden.
    Enhancement in ellipsometric thin film sensitivity near surface plasmon resonance conditions2008In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 205, no 4, p. 817-820Article in journal (Refereed)
    Abstract [en]

    Ellipsometry used in internal reflection mode exhibits enhanced thin film sensitivity if operated close to surface plasmon resonance conditions. Compared to conventional ellipsometry, the changes in the ellipsometric parameter Δ are several orders of magnitude larger. Here, the origin of this large sensitivity is discussed by analysing thin film approximations of the complex reflectance ratio. It is found that the thickness sensitivity in Δ is proportional to the inverse of the difference between the intrinsic and the radiation-induced damping of the surface plasmons.

  • 4.
    Beshkova, Milena
    et al.
    Bulgarian Acad Sci, Bulgaria.
    Deminskyi, Petro
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Hsu, Chih-Wei
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Shtepliuk, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Avramova, Ivalina
    Bulgarian Acad Sci, Bulgaria.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Atomic Layer Deposition of AlN on Graphene2021In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 218, no 17, article id 2000684Article in journal (Refereed)
    Abstract [en]

    Graphene is a material with great promise for several applications within electronics. However, using graphene in any such application requires its integration in a stack of thin layers of materials. The ideal structure of graphene has a fully saturated surface without any binding sites for chemisorption of growth species, making film growth on graphene highly challenging. Herein, an attempt to deposit very thin layers of AlN using an atomic layer deposition approach is reported. It is demonstrated using X-ray photoelectron spectroscopy that Al-N are formed in the films deposited on graphene and shown by scanning electron microscopy and atomic force microscopy that the films have an island morphology. These results may be considered promising toward the development of a growth protocol for AlN on graphene and possibly also for 2D AlN fabrication.

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  • 5.
    Buyanova, Irina A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Tu, C. W.
    Univ Calif, Dept Elect & Comp Engn, La Jolla, CA USA.
    Optical and electronic properties of GaInNP alloys - a new material system for lattice matching to GaAs2008In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 205, no 1, p. 101-106Article in journal (Refereed)
    Abstract [en]

    In this paper we will review our recent results from optical characterization studies of GaInNP. We will show that N incorporation in these alloys affects their structural and defect properties, as well as the electronic structure. The main structural changes include (i) increasing carrier localization due to strong compositional fluctuations, which is typical for all dilute nitrides, and (ii) N-induced long range ordering effects, specific for GaInNP. The observed degradation of radiative efficiency of the alloys upon increasing N content is attributed to formation of several defects acting as centres of efficient non-radiative recombination. One of the defects is identified as a complex involving a Ga interstitial atom. N incorporation is also found to change the band line up from the type I in the GaInP/GaAs structures to the type 11 in the GaInNP/GaAs heterojunctions with [N] > 0.5%. For the range of N compositions studied ([N] <= 2%), a conduction band offset at the GaInNP/GaAs interface is found to nearly linearly depend on [N] at -0.10 eV/%, whereas the valence band offset remains unaffected. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 6.
    Chey, Chan Oeurn
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Alnoor, Hatim
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Abbasi, Mazhar Ali
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Fast synthesis, morphology transformation, structural and optical properties of ZnO nanorods grown by seed-free hydrothermal method2014In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, no 11, p. 2611-2615Article in journal (Refereed)
    Abstract [en]

    A fast and low cost seed-free hydrothermal synthesis method to synthesize zinc oxide (ZnO) nanorods with controllable morphology, size and structure has been developed. Ammonia is used to react with water to tailor the ammonium hydroxide concentration, which provides a continuous source of OH− for hydrolysis and precipitation of the final products. Hence, allowing ZnO nanorods to growth on large areas of metal (Au and Ag coated glass), p-type Si and organic flexible (PEDOT: PSS) substrates. Increasing the growth time, the morphology transforms from pencil-like to hexagonal shape rod-like morphology. Within one hour the length of the ZnO nanorods has reached almost 1 µm. The optical characteristics has shown that the grown ZnO nanorods are dominated by two emission peaks, one is in the UV range centered at 381 nm and other one with relatively high intensity appears in the visible range and centered at 630 nm. While the growth duration was increased from 2 h to 6 h, the optical band gap was observed to increase from 2.8 eV to 3.24 eV, respectively. This fast and low cost method is suitable for LEDs, UV-photodetector, sensing, photocatalytic, multifunctional devices and other optoelectronic devices, which can be fabricated on any substrates, including flexible and foldable substrates.

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  • 7.
    Demeyu, Lemi
    et al.
    Department of Physics Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
    Stafström, Sven
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Computational Physics.
    Monte Carlo simulation of controlled charge carriers diffusion in highly ordered iodine doped pentacene film2007In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 204, no 10, p. 3545-3555Article in journal (Refereed)
  • 8.
    Diplas, Spyros
    et al.
    SINTEF Ind, Norway.
    Kyratsi, Theodora
    Univ Cyprus, Cyprus.
    Sun, Jianwu
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Pirriera, Monica Della
    LEITAT Technol Ctr, Spain.
    Ulyashin, Alexander G.
    SINTEF Ind, Norway.
    Materials for Energy Harvesting2018In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 215, no 17, article id 1800645Article in journal (Other academic)
    Abstract [en]

    n/a

  • 9.
    Gallas, B.
    et al.
    Inst de NanoSciences de Paris - CNRS, Université Pierre et Marie Curie, France.
    Rivory, J.
    Inst de NanoSciences de Paris - CNRS, Université Pierre et Marie Curie, France.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Vidal, F.
    Inst de NanoSciences de Paris - CNRS, Université Pierre et Marie Curie, France.
    Etgens, V.H.
    Inst de NanoSciences de Paris - CNRS, Université Pierre et Marie Curie, France.
    Changes in optical properties of MnAs thin films on GaAs(001) induced by a- to B-phase transition2008In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 205, no 4, p. 859-862Article in journal (Refereed)
    Abstract [en]

    MnAs layers with 45 nm thickness were grown epitaxially on GaAs(001) substrates. Ellipsometry measurements were made in the spectral range 0.045 eV to 6 eV as a function of temperature (between –10 °C and 50 °C) at 70° of incidence. In this way the transition from the hexagonal α-phase to the orthorhombic β-phase could be monitored. Non-zero off-diagonal elements of the Jones matrix for an azimuth of 38° off the [10] axis of the substrate indicate that the optical functions of MnAs are anisotropic in both phases. The optical conductivity exhibits low-energy interband transitions around 0.3 eV, more clearly seen in the α-phase than in the β-phase. Extrapolation of the optical conductivity to zero frequency confirms that the α-phase is about two times more conducting than the β-phase. A broad structure is observed in the visible range around 3 eV. The α-phase is characterised by an anisotropy induced energy difference of this structure with a maximum at 2.8 eV for the extraordinary index and at 3.15 eV for the ordinary index. This difference vanishes in the β-phase in which anisotropy mainly induces changes in amplitude of the 3 eV structure. The assignment of the structures will be discussed.

  • 10.
    Gallas, B.
    et al.
    Inst des NanoSciences de Paris - CNRS, Université Pierre et Marie Curie, France.
    Rivory, J.
    Inst des NanoSciences de Paris - CNRS, Université Pierre et Marie Curie, France.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Vidal, F.
    Inst des NanoSciences de Paris - CNRS, Université Pierre et Marie Curie, France.
    Stchakovsky, M.
    Thin Film Division, Jobin-Yvon S.A.S. Horiba Group, France.
    Monitoring the a to B-phase transition in MnAs/GaAs(001) thin films as funcion of temperature2008In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 205, no 4, p. 863-866Article in journal (Refereed)
    Abstract [en]

    MnAs layers with a 5 nm thick amorphous GaAs capping layer were grown epitaxially on GaAs(001). Generalized ellipsometric measurements were made on a 45 nm thick layer in the spectral range 1.5–4 eV at temperatures between –10 °C and 50 °C in steps of 5 °C. By using both the diagonal and off-diagonal elements of the Jones matrix, the in-plane unixial anisotropy of MnAs was determined in terms of the ordinary and extraordinary complex dielectric functions. The measurements at each temperature could be well reproduced by modeling using the optical properties of the two limiting phases α-MnAs and β-MnAs determined at –10 °C and 50 °C, respectively. The best sensitivity to the volume fractions of the two phases was obtained near 2.2 eV by monitoring the generalized ellipsometric parameter Δp for which the variations reached 30°.

  • 11.
    Giannazzo, F.
    et al.
    CNR, Italy.
    Fisichella, G.
    CNR, Italy.
    Greco, G.
    CNR, Italy.
    La Magna, A.
    CNR, Italy.
    Roccaforte, F.
    CNR, Italy.
    Pecz, B.
    HAS, Hungary.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Dagher, R.
    CNRS, France; University of Nice Sophia Antipolis, France.
    Michon, A.
    CNRS, France.
    Cordier, Y.
    CNRS, France.
    Graphene integration with nitride semiconductors for high power and high frequency electronics2017In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 214, no 4, article id 10600460Article in journal (Refereed)
    Abstract [en]

    Group III nitride semiconductors (III-N), including GaN, AlN, InN, and their alloys, are currently the materials of choice for many applications in optoelectronics (light-emitting diodes, laser diodes), and high-power and high-frequency transistors. Due to its attractive electrical, optical, mechanical, and thermal properties, graphene (Gr) integration with III-N technology has been considered in the last few years, in order to address some of the major issues which still limit the performances of GaN-based devices. To date, most of the studies have been focused on the use of Gr as transparent conductive electrode (TCE) to improve current spreading from top electrodes and light extraction in GaN-LEDs. This paper will review recent works evaluating the benefits of Gr integration with III-N for high power and high frequency electronics. From the materials side, recent progresses in the growth of high quality GaN layers on Gr templates and in the deposition of Gr on III-N substrates and templates will be presented. From the applications side, strategies to use Gr for thermal management in high-power AlGaN/GaN transistors will be discussed. Finally, recent proposals of implementing new ultra-high-frequency (THz) transistors, such as the Gr base hot electron transistor (GBHET), by Gr integration with III-N will be highlighted. (C) 2016 WILEY-VCH Verlag GmbH amp; Co. KGaA, Weinheim

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  • 12.
    Goto, Ken
    et al.
    Tokyo Univ Agr & Technol, Japan.
    Takekawa, Nao
    Tokyo Univ Agr & Technol, Japan.
    Nagashima, Toru
    Tokuyama Corp, Japan.
    Yamamoto, Reo
    Tokuyama Corp, Japan.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Dalmau, Rafael
    HexaTech Inc, NC 27560 USA.
    Schlesser, Raoul
    HexaTech Inc, NC 27560 USA.
    Collazo, Ramon
    North Carolina State Univ, NC 27695 USA.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Sitar, Zlatko
    North Carolina State Univ, NC 27695 USA.
    Bockowski, Michal
    Polish Acad Sci, Poland; Tokyo Univ Agr & Technol, Japan.
    Kumagai, Yoshinao
    Tokyo Univ Agr & Technol, Japan; Tokyo Univ Agr & Technol, Japan.
    Study of Dislocations in Homoepitaxially and Heteroepitaxially Grown AlN Layers2020In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 217, no 24, article id 2000465Article in journal (Refereed)
    Abstract [en]

    Dislocation densities in AlN layers grown on c-plane sapphire and physical vapor transport-grown AlN (PVT-AlN) (0001) substrates, by metalorganic vapor phase epitaxy (MOVPE) and hydride vapor phase epitaxy (HVPE), respectively, are evaluated from the density of etch pits formed in sodium hydroxide (NaOH)/potassium hydroxide (KOH) eutectic heated to 450 degrees C. In the heteroepitaxial layers grown by MOVPE on the sapphire substrates, etch pits with different sizes are formed. Cross-sectional transmission electron microscopy (TEM) observations reveal that the large, medium, and small pits, with densities of 1.4 x 10(6), 2.6 x 10(7), and 6.9 x 10(9) cm(-2), respectively, correspond to screw, mixed, and edge dislocations, respectively. In contrast, in the homoepitaxial layers grown by HVPE on the PVT-AlN substrates, only one kind of etch pit with uniform size corresponding to the edge dislocations is formed with a density of 10(3)-10(4) cm(-2). Cross-sectional TEM observation confirms that the edge dislocations in the homoepitaxial layer propagate from the substrate through the interface, which indicates that the dislocation density does not increase during homoepitaxial growth by HVPE. The HVPE-AlN homoepitaxial layers grown on the PVT-AlN substrates are found to have very low dislocation density.

  • 13. Haratizadeh, H
    et al.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Amano, H
    Effects of Si doping position on the emission energy and recombination dynamics of GaN/AlGaN multiple quantum wells2006In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 203, no 1, p. 149-153Article in journal (Refereed)
    Abstract [en]

    We report results from detailed optical spectroscopy from MOCVD grown GaN/Al0.07Ga0.93N multiple quantum wells (MQWs). Effects of Si doping position on the emission energy and recombination dynamics were studied by means of photoluminescence (PL) and time-resolved PL measurements. The samples were Si doped with the same level but different position of the dopant layer. Only the sample doped in the well shows the MQW emission redshifted compare to the GaN bandgap. The redshift is attributed to the self-energy shift of the electron states due to the correlated motion of the electrons exposed to the fluctuating potential of the donor ions. At low temperature the PL decay time of the sample doped in the well by a factor of two is longer than for the barrier doped case. The difference is explained by the effect of interplay of free carriers and ions on the screening of the polarization field in these doped structures.

  • 14.
    Hussain, Mushtaque
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Ali Abbasi, Mazhar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain Ibupoto, Zafar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    The improved piezoelectric properties of ZnO nanorods with oxygen plasma treatment on the single layer graphene coated polymer substrate2014In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, no 2, p. 455-459Article in journal (Refereed)
    Abstract [en]

    The step towards the fabrication of nanodevices with improved performance is of high demand; therefore, in this study, oxygen plasma treated ZnO nanorods based piezoelectric nanogenerator is developed on the single layer graphene coated PET flexible polymer substrate. ZnO nanorods on the single layer graphene are grown by hydrothermal growth method and the structural study is carried out by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The piezoelectric properties of ZnO nanorods with and without plasma treatment were investigated by atomic force microscopy (AFM). The oxygen plasma treated sample of ZnO nanorods showed significant increase in the piezoelectric potential which could be due to the decrease in the defects levels in the ZnO and also increase in the mechanical properties of ZnO nanorods. Furthermore X-ray photoelectron spectroscopy (XPS) confirms that the filling of vacancies by oxygen in the matrix of ZnO using oxygen plasma treatment has gave an enhanced piezoelectric potential compared to the sample of ZnO nanorods not treated with oxygen plasma. In addition to XPS experiment, cathodoluminescence (CL) technique was used for the determination of defect level in the ZnO nanorods after the treatment of oxygen plasma and the obtained information supported the XPS data of oxygen plasma treatment sample by showing the decreased level of defect levels in the prepared sample. From the XPS and CL studies, it is observed that the defect level has significant influence on the piezoelectric potential of the ZnO nanostructures.

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  • 15.
    Khan, Azam
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain, Mushtaque
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Analysis of direct and converse piezoelectric responses from zinc oxide nanowires grown on a conductive fabric2015In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 212, no 3, p. 579-584Article in journal (Refereed)
    Abstract [en]

    Single crystalline hexagonal wurtzite zinc oxide nanowires were grown on conductive commercial textile fabric as piezoelectric material. Aqueous chemical growth (ACG) method was used for the synthesis of ZnO nanowires. Field emission surface scanning electron microscopy and X-ray diffraction techniques were used for surface and structural analysis of grown nanowires. The mechanical and piezoelectric properties of the nanowires were investigated by nanoindantation. Piezoelectric potentials up to 0.013 V were measured in response to direct applied loads in the range 0 - 11 mN. Also, a DC voltage was applied for measurement of converse piezoelectric response under a low constant applied force (~5 μN) and the piezoelectric coefficient was found to be 33.2 pm/V. This study performed on commercial conductive textile demonstrates the feasibility to fabricate wearable nanogenerator clothing.

  • 16.
    Khranovskyy, Volodymyr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Tsiaoussis, Ioannis
    Aristotle University of Thessaloniki, Greece.
    Eriksson, Martin
    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.
    Effect of Ag doping on the microstructure and photoluminescence of ZnO nanostructures2014In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, no 9, p. 2109-2114Article in journal (Refereed)
    Abstract [en]

    ZnO nanostructures were obtained by metal-organic chemical vapor deposition via Ag catalyst-assisted growth in a temperature range of 200-500 degrees C. Growth at temperatures above 500 degrees C resulted in vertically aligned ZnO nanorods (NLs). Ag incorporation into ZnO up to 0.4 at.% promoted creation of basal plane stacking fault (BSF) defects and corrugation of the side facets of the NLs. The presence of BSFs give rise to an additional photoluminescence peak with a wavelength of similar to 386 nm, which is slightly red-shifted compared to the commonly observed NBE emission at similar to 375 nm. The observed emission was found to be specifically observed from the side facets of the NLs. It is suggested that this emission is due to a high concentration of BSFs in the ZnO as a result of an incorporation of Ag as acceptor dopant. [GRAPHICS] SEM image of an Ag-doped ZnO nanorod with corrugated side facets. The observed corrugation is accompanied by a high concentration of basal plane stacking faults.

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  • 17.
    Khranovskyy, Volodymyr
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Yazdi, Gholamreza
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Lashkarev, G.
    Inst Problems Mat Sci, UA-03680 Kiev, Ukraine.
    Ulyashin, A.
    Inst Energy Technol, N-2027 Kjeller, Norway.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Investigation of ZnO as a perspective material for photonics2008In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 205, no 1, p. 144-149Article in journal (Refereed)
    Abstract [en]

    Emissive properties of ZnO are of great interests in terms of the UV LED device design. The persistent "green" luminescence due to deep defect is an obstacle for obtaining an intense UV emission, expected from ZnO. We report the positive role of thermally diffused H toward quenching the defect emission in ZnO. It is suggested that hydrogen passivates defects responsible for DLE, resulting in efficient near band edge luminescence. As-grown ZnO/SiNx :H/Si films, deposited at 350 degrees C demonstrate intense narrow peaks of UV emission at 380 nm and a ratio of emission intensities, NBE/DLE approximate to 42. [GRAPHICS]

  • 18.
    Khun, Kimleang
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hussain Ibupoto, Zafar
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Development of fast and sensitive ultraviolet photodetector using p-type NiO/n-type TiO2 heterostructures2013In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 210, no 12, p. 2720-2724Article in journal (Refereed)
    Abstract [en]

    The fast and sensitive ultraviolet (UV) photodetector are of high demand due to their potential applications in several fields. Therefore, the present study describes the synthesis of well aligned TiO2 nanorods, NiO nanostructures and their composite hetero-structures on the fluorine doped tin oxide (FTO) glass substrate by hydrothermal method. The material characterization was performed by scanning electron microscopy and X-ray diffraction. The synthesized nanostructures are well aligned, dense, and uniform on the substrate. TiO2 nanostructures are tetragonal in shape with rutile phase. The current-voltage (I-V) characteristics were measured at room temperature. The photodiode exhibits nonlinear and rectifying behavior with high sensitivity and fast UV detection response. The enhanced photocurrent and less dark current are the attractive features of the fabricated photodiode. The observed UV response for the photodetector describes its worth and potential application in the respective fields.

  • 19.
    Klangtakai, Pawinee
    et al.
    Khon Kaen University, Thailand Nanotec KKU Centre Excellence Adv Nanomat Energy Pro, Thailand Khon Kaen University, Thailand .
    Sanorpim, Sakuntam
    Chulalongkorn University, Thailand .
    Karlsson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Pimanpang, Samuk
    Khon Kaen University, Thailand Nanotec KKU Centre Excellence Adv Nanomat Energy Pro, Thailand Khon Kaen University, Thailand .
    Onabe, Kentaro
    University of Tokyo, Japan .
    Anomalous excitation-power-dependent photoluminescence of InGaAsN/GaAs T-shaped quantum wire2014In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, no 8, p. 1740-1744Article in journal (Refereed)
    Abstract [en]

    The selected InGaAsN/GaAs T-shaped quantum wire (T-QWR) fabricated by metal organic vapor phase epitaxy has been investigated by microphotoluminescence (m-PL) and excitation-power-dependent mu-PL. The optical characteristics of one-dimensional structure were taken at low-temperature (4 K) and room temperature (RT) to clarify the intersection of two familiar quantum wells (QWs) in the [001] and [110] directions, named QW1 and QW2, respectively. For the excitation-power-dependent measurement, the intensity of the excitation source was used in the range of 0.001I(0) to I-0. The result shows that all of emissions related to QW1 and QWR peaks have a nonsymmetric line shape as evidenced by the tailing on the lower-energy side. All peaks shift to higher-energy side (blueshift) with the increase of the excitation power intensity. The blueshift and the low-energy tailing of PL peaks are attributed to the alloying effect. However, the emission peak related to QWR region shows a larger blueshift rate than that of QW1 on increasing of the excitation power intensity. This is an anomalous characteristic for the low-dimensional structure, affected by the large fluctuation state in the QWR region. This fluctuation state is combined of both edges of QWs (QW1 and QW2).

  • 20.
    Kneissl, Michael
    et al.
    TU Berlin, Germany.
    Christen, Juergen
    Univ Magdeburg, Germany.
    Hoffmann, Axel
    TU Berlin, Germany.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Wernicke, Tim
    TU Berlin, Germany.
    Schwarz, Ulrich
    TU Chemnitz, Germany.
    Haglund, Asa
    Chalmers Univ Technol, Sweden.
    Meneghini, Matteo
    Univ Padua, Italy.
    Nitride Semiconductors2023In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 220, no 16, article id 2300484Article in journal (Other academic)
  • 21.
    Lenz, Thomas
    et al.
    Max Planck Institute Polymer Research, Germany; Grad School Mat Science Mainz, Germany.
    Zhao, Dong
    Max Planck Institute Polymer Research, Germany.
    Richardson, George
    University of London Imperial Coll Science Technology and Med, England; University of London Imperial Coll Science Technology and Med, England.
    Katsouras, Ilias
    Max Planck Institute Polymer Research, Germany; Holst Centre, Netherlands.
    Asadi, Kamal
    Max Planck Institute Polymer Research, Germany; Max Planck Grad Centre, Germany.
    Glasser, Gunnar
    Max Planck Institute Polymer Research, Germany.
    Zimmermann, Samuel T.
    University of London Imperial Coll Science Technology and Med, England; University of London Imperial Coll Science Technology and Med, England.
    Stingelin, Natalie
    University of London Imperial Coll Science Technology and Med, England; University of London Imperial Coll Science Technology and Med, England.
    Christian Roelofs, W. S.
    Eindhoven University of Technology, Netherlands.
    Kemerink, Martijn
    Linköping University, Department of Physics, Chemistry and Biology, Complex Materials and Devices. Linköping University, Faculty of Science & Engineering. Eindhoven University of Technology, Netherlands.
    Blom, Paul W. M.
    Max Planck Institute Polymer Research, Germany; Grad School Mat Science Mainz, Germany.
    de Leeuw, Dago M.
    Max Planck Institute Polymer Research, Germany; King Abdulaziz University, Saudi Arabia.
    Microstructured organic ferroelectric thin film capacitors by solution micromolding2015In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 212, no 10, p. 2124-2132Article in journal (Refereed)
    Abstract [en]

    Ferroelectric nanostructures offer a promising route for novel integrated electronic devices such as non-volatile memories. Here we present a facile fabrication route for ferroelectric capacitors comprising a linear array of the ferroelectric random copolymer of vinylidenefluoride and trifluoroethylene (P(VDF-TrFE)) interdigitated with the electrically insulating polymer polyvinyl alcohol (PVA). Micrometer size line gratings of both polymers were fabricated over large area by solution micromolding, a soft lithography method. The binary linear arrays were realized by backfilling with the second polymer. We investigated in detail the device physics of the patterned capacitors. The electrical equivalent circuit is a linear capacitor of PVA in parallel with a ferroelectric capacitor of P(VDF-TrFE). The binary arrays are electrically characterized by both conventional Sawyer-Tower and shunt measurements. The dependence of the remanent polarization on the array topography is explained by numerical simulation of the electric field distribution.

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  • 22.
    Misheva, M.
    et al.
    Department of Physics, Sofia University, Sofia, Bulgaria.
    Larsson, Henrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Gogova, Daniela
    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.
    Positron annihilation study of HVPE grown thick GaN layers2005In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 202, no 5, p. 713-717Article in journal (Refereed)
    Abstract [en]

    Single-crystalline GaN layers with a thickness up to 330 µm were grown by hydride vapor phase epitaxy on basal plane sapphire at gallium stable conditions in a bottom-fed vertical reactor at atmospheric pressure. Positron annihilation spectroscopy experiments were implemented in order to identify native point defects in the as-grown non-intentionally doped n-type GaN. Comparatively low concentrations of Ga vacancy related defects in the order of 1016 to 1017 cm–3 were extracted from the positron annihilation spectroscopy data. The Ga vacancy defect concentration was related to the intensity of the yellow photoluminescence band centered at 2.2 eV. The influence of the growth rate on the Ga vacancy related defect concentration was investigated. A trend of decreasing of the defect concentration with increasing of layer thickness is observed, which correlates with improving crystalline quality with the thickness.

  • 23.
    Monemar, Bo
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Paskov, Plamen
    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.
    Keller, S.
    DenBaars, S. P.
    Mishra, U. K.
    Effect of an (Al,In)N insertion layer on the radiative emission properties of (In,Ga)N/GaN multiple quantum well structures2007In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 204, no 1, p. 304-308Article in journal (Refereed)
    Abstract [en]

    As an effort to investigate new techniques to reduce the effect of the strong internal polarization fields in (In,Ga)N/GaN quantum well (QW) structures we have studied the influence of inserting a thin wide band-gap AI(0 95)In(0.05)N interlayer inside the QWs, in order to modify the potential and increase the electron-hole overlap. A strong reduction of the decay times of the photoluminescence (PL) was observed in this case at all temperatures up to 300 K, without a strong reduction in PL intensity. The tunneling electron-hole transition across the interlayer is observed to be dominant at room temperature for high excitation conditions. (c) 2007 WILEYNCH Verlag GmbH & Co. KGaA, Weinheim.

  • 24.
    Nour, Eiman
    et al.
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Chey, Chan
    Department of Physics, Faculty of Science, Royal University of Phnom Penh, Phnom Penh, Cambodia.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    Low frequency accelerator sensor based on piezoelectric ZnO nanorods grown by low temperature scalable process2016In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 213, no 9, p. 2503-2508Article in journal (Refereed)
    Abstract [en]

    Piezoelectric vertically aligned zinc oxide (ZnO) nanorods (NRs) were grown by low temperature aqueous chemical approach and successfully used as a low frequency self-powered accelerator detector system. The nanogenerator (NG) device was tested under the influence of low frequency vibrations, different load masses, and finger prints pressure. The experimental results show relatively high sensitivity to frequencies as low as 5 Hz. This energy conversion device has produced a maximum output voltage of about 0.3 and 1.4 V under a frequency of 41 Hz and a mass of 1000 g, respectively. The fabricated NG can be used as an accelerator sensor with a good performance in the range from about 0.67 to 5.5 m s−2 with a sensitivity of 0.045 V s2 m−1. Furthermore, it has been demonstrated that the NG is able to harvest energy under finger-print scanning. The result from the finger-print pressure was consistent with the masses testing results. This energy-harvesting technology also provides a simple and cost-effective platform to capture low-frequency mechanical energy, i.e., body movements, and other applications like developing a sensitive finger print camera, etc.

  • 25. Ochalski, TJ
    et al.
    Grzegorczyk, A
    Rudzinski, M
    Larsen, PK
    Holtz, Per-Olof
    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.
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Optical study of AlGaN/GaN based HEMT structures grown on sapphire and SiC2005In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 202, no 7, p. 1300-1307Article in journal (Refereed)
    Abstract [en]

    A detailed photoluminescence (PL), time-resolved photoluminescence (TRPL), and photoreflectance (PR) analysis of AlGaN/GaN heterostructures grown on different substrates: sapphire and silicon carbide (SiC) is presented in this paper. The properties of high electron mobility transistors (HEMTs) based on AlGaN/GaN structures are strongly dependent on the quality of the AlxGa1-xN top layer. We have examined a number of samples, grown on sapphire, in which the thicknesses of the Al0.3Ga0.7N layers vary from 18 to 75 nm. Room temperature PL under pulsed 266 nm excitation allowed for determination of the AI content in the examined thin AlGaN layers. Time-resolved PL measured at 1.6 K showed huge difference in the emission dynamics for different Al0.3Ga0.7N layer thicknesses. We observed an enormous increase of the emission decay time above the critical thickness of the AlGaN layer. PR spectra (associated with the GaN main layer) measured on AlGaN/GaN systems are discussed in terms of the thickness of the capping layer. The PR modulated by a high power 266 nm pulsed laser measured on a transistor structure exhibited an additional feature placed between signals related to the GaN and AlGaN layers, respectively. Such a transition is possible to monitor only for the structures of the best quality and is accordingly observable only on samples grown on SiC. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 26.
    Porro, Samuele
    et al.
    Department of Physics, Polytechnic of Torino, Torino, Italy.
    Ciechonski, Rafal
    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.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Electrical Analysis and Interface States Evaluation of of Ni Schottky diodes on 4H-SiC thick epilayers2005In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 202, no 13, p. 2508-2514Article in journal (Refereed)
    Abstract [en]

    This work has been focused on characterization of thick 4H-SiC layers produced by sublimation epitaxy. Nickel Schottky contacts have been fabricated in order to characterize the grown material and evaluate the interfacial layer between metal and semiconductor. The characterization study includes current-voltage and capacitance-voltage high temperature measurements, from which Schottky barrier, net donor concentration and on-state resistance values have been extracted. The diodes show a typical behavior of J-V and C-V curves with temperature, with Schottky barrier heights of 1.3 eV ÷ 1.4 eV and net donor concentration of 4 × 1015 cm-3 ÷ 1 × 1016 cm-3. From the Bardeen's model on reverse J-V, the density of states of the interfacial layer has been estimated to 7 × 1011 eV-1 cm-2 ÷ 8 × 1011 eV-1 cm-2, a value that is similar to the density of states of oxide layers in deliberated MOS structures realized on the same epilayers.

  • 27.
    Pozina, Galia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hemmingsson, Carl
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Belonovskii, Alexei V.
    St Petersburg Acad Univ, Russia.
    Levitskii, Iaroslav V.
    ITMO Univ, Russia; Ioffe Inst, Russia.
    Mitrofanov, Maxim I.
    ITMO Univ, Russia; Ioffe Inst, Russia.
    Girshova, Elizaveta I.
    St Petersburg Acad Univ, Russia; ITMO Univ, Russia; Ioffe Inst, Russia.
    Ivanov, Konstantin A.
    ITMO Univ, Russia.
    Rodin, Sergey N.
    Ioffe Inst, Russia.
    Morozov, Konstantin M.
    St Petersburg Acad Univ, Russia; ITMO Univ, Russia.
    Evtikhiev, Vadim P.
    Ioffe Inst, Russia.
    Kaliteevski, Mikhail A.
    St Petersburg Acad Univ, Russia; ITMO Univ, Russia; Ioffe Inst, Russia.
    Emission Properties of GaN Planar Hexagonal Microcavities2020In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 217, no 14, article id 1900894Article in journal (Refereed)
    Abstract [en]

    Fabrication of microcavities based on III-nitrides is challenging due to difficulties with the coherent growth of heterostructures having a large number of periods, at the same time keeping a good precision in terms of thickness and composition of the alloy. A planar design for GaN microresonators supporting whispering gallery modes is suggested. GaN hexagonal microstructures are fabricated by selective-area metalorganic vapor phase epitaxy using focused ion beam for mask patterning. Low-temperature cathodoluminescence spectra measured with a high spatial resolution demonstrate two dominant emission lines in the near bandgap region. These lines merge at room temperature into a broad emission band peaking at approximate to 3.3 eV, which is shifted toward lower energies compared with the reference excitonic spectrum measured for the GaN layer. A numerical analysis of exciton-polariton modes shows that some strongly localized cavity modes can have high Purcell coefficients and can strongly interact with the GaN exciton.

  • 28.
    Pozina, Galia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hsu, Chih-Wei
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hemmingsson, Carl
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Doping of beta-Ga2O3 Layers by Zn Using Halide Vapor-Phase Epitaxy Process2021In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 218, no 21, article id 2100486Article in journal (Refereed)
    Abstract [en]

    Development of ultrawide bandgap semiconductor beta-Ga2O3 is important considering its great potential for high-power high-voltage electronic applications. Halide vapor-phase epitaxy is used to produce Zn-doped beta-Ga2O3 layers on sapphire (0001). Zn doping concentrations is estimated to be in the range between 6 x 10(18) and 2.5 x 10(20) cm(-3). As a precursor for Zn acceptor dopant, ZnCl2 formed by flowing of diluted Cl-2 gas over a melt of metallic Zn is used. Modeling of the growth chamber and calculations of precursor concentrations inside the growth zone is carried out to optimize process parameters. The Zn doping is not affecting the optical emission properties; however, growth under oxygen-rich conditions and formation of crystalline particles on the layer surface are factors responsible for modification of beta-Ga2O3 luminescence spectrum. It is observed that the UV band at 3.35 eV vanishes, whereas relative intensities of the blue and green bands at 2.4-2.8 eV increase.

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  • 29. Radnóczi, G. Z.
    et al.
    Seppänen, Timo
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Pécz, B.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Growth of highly curved Al1-xinxN nanocrystals2005In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 202, no 7Article in journal (Refereed)
    Abstract [en]

    A materials structure is reported that is characterized by high lattice curvature assigned to a compositional gradient. The phenomenon occurs for physical vapour deposition of Al1-xInxN epitaxial thin films with directional fluxes of Al and In at kinetically limited growth conditions. According to our growth model unit cells are incorporated on the growth surfaces of emerging whiskers (nanowires) with a continuously varying lattice parameter depending on their position with respect to Al- and In-rich sides of the whisker. Such curved crystals are effectively quenched solid solutions. We present a description of this generic, self-assembled curved crystal structure and its implications. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  • 30.
    Schnitter, Claudia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Materials design. 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.
    Epitaxial Growth of Magnetron-Sputtered ZrB2 Films on Si(100) Substrates2022In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 219, no 21, article id 2200330Article in journal (Refereed)
    Abstract [en]

    Epitaxial growth of ZrB2 films on Si(100) substrates at 900 degrees C is demonstrated using direct-current magnetron sputter deposition from sintered ZrB2 targets. This case of epitaxial growth is structurally more challenging than on Si(111), 4 H-SiC(001), and Al2O3(001). From pole figure measurements, two epitaxial relationships are determined: A) in-plane: ZrB 2 [ 001 ] parallel to Si [ 110 ] and ZrB 2 [ 110 ] parallel to Si [ 110 ] , out-of-plane: ZrB 2 ( 100 ) parallel to Si ( 100 ) , and B) in-plane: ZrB 2 [ 1 2 over bar 1 ] parallel to Si [ 110 ] and the same multiply rotated 90 degrees around the 102 axis, out of plane: ZrB 2 ( 102 ) parallel to Si ( 100 ) . From full width at half maximum (FWHM) values from rocking curve measurements (omega-scans) of the 100 and 102 peaks, a measure of epitaxial quality for these two preferred orientations is obtained. Both omega-scans and theta/2 theta diffractograms show higher quality for the A-type with a FWHM value of 2.00 degrees compared with 4.97 degrees for the B-type. The film composition is found to be ZrB2.3 from time-of-flight elastic recoil detection analysis. The B-type crystallographic relationship ZrB 2 ( 102 ) parallel to Si ( 100 ) and ZrB 2 [ 1 2 over bar 0 ] parallel to Si [ 110 ] has not been previously reported.

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  • 31.
    Shtepliuk, Ivan
    et al.
    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.
    Pliatsikas, Nikolaos
    Linköping University, Department of Physics, Chemistry and Biology, Nanoscale engineering. Linköping University, Faculty of Science & Engineering.
    Iakimov, Tihomir
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Beshkova, Milena
    Bulgarian Acad Sci, Bulgaria.
    Sarakinos, Kostas
    Linköping University, Department of Physics, Chemistry and Biology, Nanoscale engineering. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Exploring the Interface Landscape of Noble Metals on Epitaxial Graphene2021In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 218, no 17, article id 2000673Article in journal (Refereed)
    Abstract [en]

    Understanding the interaction between noble metals (NMs) and epitaxial graphene is essential for the design and fabrication of novel devices. Within this framework, a combined experimental and theoretical investigation of the effect of vapor-deposited NM (silver [Ag] and gold [Au]) nanostructures on the vibrational and electronic properties of monolayer epitaxial graphene (MLG) on 4H-SiC is presented. Large sets of Raman scattering data are analyzed using supervised classification and statistical methods. This analysis enables identification of the specific Raman fingerprints of Au- and Ag-decorated MLG originating from different dispersion interactions and charge transfer at the metal nanostructure/MLG interface. It is found that Raman scattering spectra of Au-decorated MLG feature a set of allowed phonon modes similar to those in pristine MLG, whereas the stronger Ag physisorption triggers an activation of defect-related phonon modes and electron doping of MLG. A principal component analysis (PCA) and linear discriminant analysis (LDA) are leveraged to highlight the features in phonon dispersion of MLG that emanate from the NM deposition process and to robustly classify large-scale Raman spectra of metal-decorated graphene. The present results can be advantageous for designing highly selective sensor arrays on MLG patches decorated with different metals.

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  • 32.
    Shubina, Tatiana
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Ivanov, SV
    Jmerik, VN
    Glazov, MM
    Kalvarskii, AP
    Tkachman, MG
    Vasson, A
    Leymarie, J
    Kavokin, A
    Amano, H
    Akasaki, I
    Butcher, KSA
    Guo, Q
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Kop'ev, PS
    Optical properties of InN with stoichoimetry violation and indium clustering2005In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 202, no 3, p. 377-382Article in journal (Refereed)
    Abstract [en]

    We demonstrate that nonstoichiometry is one of the main reason of strong deviation of the InN optical gap in the 0.7-2 eV range, with N/In < 1 and N/In > 1 corresponding to the lower and higher energies, respectively. The phenomenon is discussed in terms of atomic orbital energies, which are strongly different for indium and nitrogen, therefore both excess atom incorporation and elimination could change the optical gap. We estimate such trends using the approximation of the empirical nearest-neighbor tight binding theory. It is also demonstrated that resonant absorption in In-enriched regions is an additional factor lowering an effective absorption edge.

  • 33.
    Shubina, Tatiana
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Leymarie, J.
    Jmerik, V.N.
    Amano, H.
    Schaff, W.J.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Ivanov, S.V.
    Optical properties of InN related to surface plasmons2005In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 202, no 14, p. 2633-2641Article in journal (Refereed)
    Abstract [en]

    We report on the complex nature of infrared luminescence and absorption in InN films, which cannot be entirely explained by the concept of a conventional narrow-gap semiconductor. In particular, it concerns the detection of peaks near absorption edges by both thermally detected optical absorption and photoluminescence excitation spectroscopy and the observation of extraordinarily strong resonant enhancement of emission. To describe the experimental data a model is proposed, which takes into account surface plasmons in metal-like inclusions, modifying the optical properties of InN. © 2005 WILEY-VCH Verlag GmbH & Co. KGaA,.

  • 34.
    Tamm, Aile
    et al.
    University of Tartu, Estonia .
    Kozlova, Jekaterina
    University of Tartu, Estonia .
    Aarik, Lauri
    University of Tartu, Estonia .
    Aidla, Aleks
    University of Tartu, Estonia .
    Lu, Jun
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Kiisler, Alma-Asta
    University of Tartu, Estonia .
    Kasikov, Aarne
    University of Tartu, Estonia .
    Ritslaid, Peeter
    University of Tartu, Estonia .
    Maendar, Hugo
    University of Tartu, Estonia .
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sammelselg, Vaeino
    University of Tartu, Estonia University of Tartu, Estonia .
    Kukli, Kaupo
    University of Tartu, Estonia University of Helsinki, Finland .
    Aarik, Jaan
    University of Tartu, Estonia .
    Atomic layer deposition of ZrO2 for graphene-based multilayer structures: In situ and ex situ characterization of growth process2014In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 211, no 2, p. 397-402Article in journal (Refereed)
    Abstract [en]

    Real time monitoring of atomic layer deposition by quartz crystal microbalance (QCM) was used to follow the growth of ZrO2 thin films on graphene. The films were grown from ZrCl4 and H2O on graphene prepared by chemical vapor deposition method on 100-nm thick nickel film or on Cu-foil and transferred onto QCM sensor. The deposition was performed at a substrate temperature of 190 degrees C. The growth of the dielectric film on graphene was significantly retarded compared to the process carried out on QCM without graphene. After the deposition of dielectric films, the basic structure of graphene was retained.

  • 35. Toropov, AA
    et al.
    Nekrutkina, OV
    Shubina, Tatiana
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Gruber, T
    Kirchner, C
    Waag, A
    Karlsson, K.Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Temperature-dependent polarized luminescence of exciton polaritons in a ZnO film2005In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 202, no 3, p. 392-395Article in journal (Refereed)
    Abstract [en]

    We report on the studies of linearly polarized photoluminescence (PL) in a (0001) oriented ZnO epitaxial film, grown by metal organic chemical vapor deposition on a GaN template. The emission of mixed longitudinal-transverse exciton polariton modes was observed up to 130 K that evidences polaritonic nature of the excitonic spectrum up to this elevated temperature.

  • 36.
    Wang, Jianpu
    et al.
    University of Cambridge, England.
    Sun, Baoquan
    University of Cambridge, England.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Greenham, Neil C.
    University of Cambridge, England.
    Memristive devices based on solution-processed ZnO nanocrystals2010In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 207, no 2, p. 484-487Article in journal (Refereed)
    Abstract [en]

    We present a memristive device fabricated using low-cost solution-processed colloidal ZnO nanocrystals. Taking advantage of the large surface area of ZnO nanocrystals, we find that an oxygen depletion region can be naturally formed by chemical interaction between an Al electrode and the ZnO nanocrystals. Strong electrical hysteresis, history-dependent conductance, and sweep-rate-dependent current-voltage (J-V) curves are observed in our devices. The resistance can be modified between similar to 1 and similar to 10(4) Omega cm(2), which is promising for application in non-volatile memory devices and in low-cost organic circuits, where typical feature sizes are about 10-100 mu m and the circuit current is low. (C) 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim

  • 37.
    Wiklund, Henrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Järrendahl, Kenneth
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    A FEM-based application for numerical calculations of ellipsometric data2008In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 205, no 4, p. 945-948Article in journal (Refereed)
    Abstract [en]

    For modeling of advanced optical structures there is a need for stronger and more flexible modeling tools. Our aim is to develop and verify an application tool for calculations based on the Finite Element Method (FEM) of optical structures. To be able to understand which effects in the results that arises from limitations in the model, we begin by verifying the application tool for the most basic surface structures and gradually increase the complexity of the structures.

  • 38.
    Willander, Magnus
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Lozovik, Yu E
    Institute Spect, Moscow Region Russia .
    Wadeasa, Amal
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Semenov, A G
    Institute Spect, Moscow Region Russia .
    Voronova, N S
    Institute Spect, Moscow Region Russia .
    Erratum: Light emission from different ZnO junctions and nanostructures (vol 206, pg 853, 2009)2011In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 208, no 5, p. 1207-1207Article in journal (Refereed)
    Abstract [en]

    n/a

  • 39.
    Wronkowska, A.A.
    et al.
    Inst of Mathematics and Physics University of Technology and Life Sciences, Poland.
    Skowronski, L.
    Inst of Mathematics and Physics University of Technology and Life Sciences, Poland.
    Wronkowski, A.
    Inst of Mathematics and Physics University of Technology and Life Sciences, Poland.
    Firszt, F.
    Inst of Physics, Nicholas Copernicus University, Poland.
    Meczynska, H.
    Inst of Physics, Nicholas Copernicus University, Poland.
    Legowski, S.
    Inst of Physics, Nicholas Copernicus University, Poland.
    Strzalkowski, K.
    Inst of Physics, Nicholas Copernicus University, Poland.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Spectroscopic ellipsometry and photoluminescence investigation of Zn1-x-yBexMgySe and Cd1-x-yBexZnySe Crystals2008In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 205, no 4, p. 854-858Article in journal (Refereed)
    Abstract [en]

    Optical and luminescence properties of the Bridgman-grown Cd1–xyBex Zny Se and Zn1–xyBex Mgy Se crystals are reported. Spectroscopic ellipsometry was employed for determination of spectral dependence of the complex dielectric function (E) in the photon energy range 0.75–6.5 eV. Below the absorption edge the refractive indices n (E) of the alloys were modelled using a Sellmeier-type relation. The excitonic band-gap energies were estimated from the ellipsometric and photoluminescence measurements. Compositional effects in the ellipsometric and photoluminescence spectra are discussed.

  • 40.
    Wronkowska, A.A.
    et al.
    Institute of Mathematics and Physics, University of Technology and Life Sciences, Bydgoszcz, Poland.
    Skowronski, L.
    Institute of Mathematics and Physics, University of Technology and Life Sciences, Bydgoszcz, Poland.
    Wronkowski, A.
    Institute of Mathematics and Physics, University of Technology and Life Sciences, Bydgoszcz, Poland.
    Zielinski, L.
    Institute of Mathematics and Physics, University of Technology and Life Sciences, Bydgoszcz, Poland.
    Firszt, F.
    Institute of Physics, Nicholas Copernicus University, Toruń, Poland.
    Marasek, A.
    Institute of Physics, Nicholas Copernicus University, Toruń, Poland.
    Paszkowicz, W.
    Institute of Physics, Polish Academy of Sciences, Warszawa, Poland.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Lattice absorption of Be-containing semiconductor alloys determined by spectroscopic ellipsometry2008In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 205, no 4, p. 849-853Article in journal (Refereed)
    Abstract [en]

    Lattice absorption of Zn1–xyBex Mgy Se and Cd1–xyBex Zny Se mixed crystals grown by a high pressure Bridgman method has been investigated by infrared spectroscopic ellipsometry in the wave number range from 230 cm–1 to 5000 cm–1. Ellipsometric spectra of Cd1–xyBex Zny Se crystals display features in the spectral range 350–550 cm–1 associated with BeSe-type phonon modes. In the optical spectra of Zn1–xyBex Mgy Se crystals both BeSe-type and MgSe-type lattice absorption bands are detected. The MgSe-like modes are located at approximately 300 cm–1. The frequencies and oscillator strengths of optical phonon modes depend strongly on the alloy composition

  • 41.
    Yousuf Soomro, Muhammad
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Hussain, Sajad
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Bano, Nargis
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Hussain, Ijaz
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Nur, Omer
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Hybrid organic zinc oxide white-light-emitting diodes on disposable paper substrate2013In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 210, no 8, p. 1600-1605Article in journal (Refereed)
    Abstract [en]

    ZnO-organic hybrid white-light-emitting diodes (WLEDs) were demonstrated on a paper substrate. The configuration used for ZnO-organic hybrid WLEDs consists a layer of poly (9,9)-(dioctylfluorene) (PFO) on poly (3,4-ethylenedioxythiophene) poly (styrenesulfonate) (PEDOT: PSS) on n-type ZnO nanorods grown by a low-temperature chemical aqueous method on paper substrate. Room temperature photoluminescence, electroluminescence, and cathodoluminescence (CL) spectra reveal a broad visible region covering the range from 420 to 800nm. By using room temperature-CL, we got luminescence information, especially to verify the origin of specific emissions, the internal absorption of the ultraviolet and the spatial distribution of radiative defects. It was observed that the visible wavelength range depends on the penetration depth of the excitation. This suggests that the concentration of deep levels responsible for the visible luminescence is at the sample surface to a depth of 1-2 mu m when using an accelerating voltage up to 20-30kV. The results indicate that demonstration of WLEDs on paper substrate with reasonable electrical performance greatly influences the reduction of substrate cost, furthermore, this may open way to fabricate optoelectronics devices on disposable substrates for large-area applications.

  • 42.
    Zukauskaite, Agne
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Sandström, Per
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Birch, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Nanoprobe Mechanical and Piezoelectric Characterization of ScxAl1-xN(0001) Thin Films2015In: Physica Status Solidi (a) applications and materials science, ISSN 1862-6300, E-ISSN 1862-6319, Vol. 212, no 3, p. 666-673Article in journal (Refereed)
    Abstract [en]

    Nanoindentation with in-situ electrical characterization was used to characterize piezoelectric scandium aluminum nitride (ScxAl1-xN) thin films with Sc contents up to x=0.3. The films were prepared by reactive magnetron sputtering using Al2O3 substrates with TiN seed layer/bottom electrodes at a substrate temperature of 400 °C. X-ray diffraction shows c-axis oriented wurtzite ScxAl1-xN, where the crystal quality decreases with increasing x. Piezoresponse force microscopy in mapping mode shows a single piezoelectric polarization phase in all samples. The hardness and decreases from 17 GPa in AlN to 11 GPa in Sc0.3Al0.7N, while reduced elastic modulus decreases from 265 GPa to 224 GPa, respectively. Both direct and converse piezoelectric measurements are demonstrated by first applying the load and generating the voltage and later by applying the voltage and measuring film displacement using a conductive boron doped nanoindenter tip. The Sc0.2Al0.8N films exhibit an increase in generated voltage by 15% in comparison to AlN and a correspondingly larger displacement upon applied voltage, comparable to results obtained by double beam interferometry and piezoresponse force microscopy.

     

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