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  • 101.
    de las Casas, Charles F.
    et al.
    University of Chicago, IL 60637 USA.
    Christle, David J.
    University of Chicago, IL 60637 USA.
    Ul-Hassan, Jawad
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Ohshima, Takeshi
    National Institute Quantum and Radiol Science and Technology, Japan.
    Nguyen, Son Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Awschalom, David D.
    University of Chicago, IL 60637 USA.
    Stark tuning and electrical charge state control of single divacancies in silicon carbide2017In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 111, no 26, article id 262403Article in journal (Refereed)
    Abstract [en]

    Neutrally charged divacancies in silicon carbide (SiC) are paramagnetic color centers whose long coherence times and near-telecom operating wavelengths make them promising for scalable quantum communication technologies compatible with existing fiber optic networks. However, local strain inhomogeneity can randomly perturb their optical transition frequencies, which degrades the indistinguishability of photons emitted from separate defects and hinders their coupling to optical cavities. Here, we show that electric fields can be used to tune the optical transition frequencies of single neutral divacancy defects in 4H-SiC over a range of several GHz via the DC Stark effect. The same technique can also control the charge state of the defect on microsecond timescales, which we use to stabilize unstable or non-neutral divacancies into their neutral charge state. Using fluorescence-based charge state detection, we show that both 975 nm and 1130 nm excitation can prepare their neutral charge state with near unity efficiency. (C) 2017 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons. org/licenses/by/4.0/).

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  • 102.
    Ding, B.F.
    et al.
    Surface Physics Laboratory, Fudan University, Shanghai 200433, China.
    Zhan, Yiqiang
    Fudan University.
    Sun, Z.Y.
    Surface Physics Laboratory, Fudan University, Shanghai 200433, China.
    Ding, X.M.
    Surface Physics Laboratory, Fudan University, Shanghai 200433, China.
    Hou, X.Y.
    Surface Physics Laboratory, Fudan University, Shanghai 200433, China.
    Wu, Y.Z.
    Surface Physics Laboratory, Fudan University, Shanghai 200433, China.
    Bergenti, I.
    ISMN-CNR, Via Gobetti 101, 40129 Bologna, Italy.
    Dediu, V.
    ISMN-CNR, Via Gobetti 101, 40129 Bologna, Italy.
    Electroluminescence and magnetoresistance of the organic light-emitting diode with a La0.7 Sr0.3 Mn O3 anode2008In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 93, no 18Article in journal (Refereed)
    Abstract [en]

    Electroluminescence (EL) with brightness up to 300 cd m2 is observed from organic light-emitting diodes fabricated on oxygen-treated La0.7 Sr0.3 Mn O 3 anodes. An external magnetic field of 150 mT applied parallel to the device surface can enhance the EL intensity by 10%, accompanied by a raised current efficiency. In-plane magnetization of the ferromagnetic anode is found to be the main origin of increase in the current contributable to EL, though magnetoresistance of the organic functional materials also plays a role in the EL enhancement observed in the magnetic field. © 2008 American Institute of Physics.

  • 103.
    Dobrovolsky, A.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Sukrittanon, S.
    Grad Program Mat Science and Engn, CA 92093 USA.
    Kuang, Y. J.
    University of Calif San Diego, CA 92093 USA.
    Tu, C. W.
    University of Calif San Diego, CA 92093 USA.
    Chen, Weimin
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Buyanova, Irina
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Raman spectroscopy of GaP/GaNP core/shell nanowires2014In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 105, no 19, p. 193102-Article in journal (Refereed)
    Abstract [en]

    Raman spectroscopy is employed to characterize structural and phonon properties of GaP/GaNP core/shell nanowires (NWs) grown by molecular beam epitaxy on Si substrates. According to polarization-dependent measurements performed on single NWs, the dominant Raman modes associated with zone-center optical phonons obey selection rules in a zinc-blende lattice, confirming high crystalline quality of the NWs. Two additional modes at 360 and 397 cm(-1) that are specific to the NW architecture are also detected in resonant Raman spectra and are attributed to defect-activated scattering involving zone-edge transverse optical phonons and surface optical phonons, respectively. It is concluded that the formation of the involved defect states are mainly promoted during the NW growth with a high V/III ratio.

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  • 104.
    Dobrovolsky, Alexandr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Stehr, Jan Eric
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Chen, Shula
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Kuang, Y. J.
    Department of Physics, University of California, La Jolla, California, USA.
    Sukrittanon, S.
    Graduate Program of Materials Science and Engineering, La Jolla, California, USA .
    Tu, C. W.
    Department of Electrical and Computer Engineering, University of California, San Diego, La Jolla, California, USA .
    Chen, Weimin
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Buyanova, Irina
    Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials. Linköping University, The Institute of Technology.
    Mechanism for radiative recombination and defect properties of GaP/GaNP core/shell nanowires2012In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, no 16, p. 163106-1-163106-4Article in journal (Refereed)
    Abstract [en]

    Recombination processes in GaP/GaNP core/shell nanowires (NWs) grown on a Si substrate by molecular beam epitaxy are examined using a variety of optical characterization techniques, including cw- and time-resolved photoluminescence and optically detected magnetic resonance (ODMR). Superior optical quality of the structures is demonstrated based on the observation of intense emission from a single NW at room temperature. This emission is shown to originate from radiative transitions within N-related localized states. From ODMR, growth of GaP/GaNP NWs is also found to facilitate formation of complex defects containing a P atom at its core that act as centers of competing non-radiative recombination.

  • 105.
    Dong, S.
    et al.
    Nanjing University, MA 02460 USA.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Wang, Z. Q.
    Nanjing University, MA 02460 USA.
    Liu, J. -M.
    Nanjing University, MA 02460 USA.
    Ren, Z. F.
    Nanjing University, MA 02460 USA.
    Surface phase separation in nanosized charge-ordered manganites2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 90, no 8, p. 082508-Article in journal (Refereed)
    Abstract [en]

    Recent experiments showed that the robust charge ordering in manganites can be weakened by reducing the grain size down to nanoscale. Weak ferromagnetism was evidenced in both nanoparticles and nanowires of charge-ordered manganites. To explain these observations, a phenomenological model based on surface phase separation is proposed. The relaxation of superexchange interaction on the surface layer allows formation of a ferromagnetic shell, whose thickness increases with decreasing grain size. Possible exchange bias and softening of the ferromagnetic transition in nanosized charge-ordered manganites are predicted. (c) 2007 American Institute of Physics.

  • 106.
    Du, Chun-Xia
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Duteil, F.
    Hansson, Göran
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics .
    Ni, Wei-Xin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics .
    Si/SiGe/Si: Er2001In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 78, no 12, p. 1697-1699Article in journal (Refereed)
    Abstract [en]

    Si/SiGe/Si:Er:O heterojunction bipolar transistor (HBT) type light-emitting devices with Er3+ ions incorporated in the collector region have been fabricated using a layered structure grown by differential molecular-beam epitaxy. Electroluminescence measurements on processed light-emitting HBTs can be performed in either constant driving current mode or constant applied bias mode, which is an important advantage over conventional Si:Er light-emitting diodes. Intense room-temperature light emission at the Er3+ characteristic wavelength of 1.54 µm has been observed at low driving current density, e.g., 0.1 A cm-2, and low applied bias, e.g., 3 V, across the collector and emitter. © 2001 American Institute of Physics.

  • 107.
    Du, Chun-Xia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Duteil, Fabrice
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hansson, Göran
    Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics . Linköping University, The Institute of Technology.
    Ni, Wei-Xin
    Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics . Linköping University, The Institute of Technology.
    Si/SiGe/Si : Er : O light-emitting transistors prepared by differential molecular-beam epitaxy2001In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 78, no 12, p. 1697-1699Article in journal (Refereed)
    Abstract [en]

    Si/SiGe/Si:Er:O heterojunction bipolar transistor (HBT) type light-emitting devices with Er3+ ions incorporated in the collector region have been fabricated using a layered structure grown by differential molecular-beam epitaxy. Electroluminescence measurements on processed light-emitting HBTs can be performed in either constant driving current mode or constant applied bias mode, which is an important advantage over conventional Si:Er light-emitting diodes. Intense room-temperature light emission at the Er3+ characteristic wavelength of 1.54 mum has been observed at low driving current density, e.g., 0.1 A cm(-2), and low applied bias, e.g., 3 V, across the collector and emitter. (C) 2001 American Institute of Physics.

  • 108.
    Duc, Tran Thien
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Pozina, Galia
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. 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.
    Janzén, Erik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Ohshima, Takeshi
    Japan Atomic Energy Agency (JAEA), Takasaki, Japan.
    Hemmingsson, Carl
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Radiation-induced defects in GaN bulk grown by halide vapor phase epitaxy2014In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 105, no 10, p. 102103-Article in journal (Refereed)
    Abstract [en]

    Defects induced by electron irradiation in thick free-standing GaN layers grown by halide vapor phase epitaxy were studied by deep level transient spectroscopy. In as-grown materials, six electron traps, labeled D2 (E-C-0.24 eV), D3 (E-C-0.60 eV), D4 (E-C-0.69 eV), D5 (E-C-0.96 eV), D7 (E-C-1.19 eV), and D8, were observed. After 2MeV electron irradiation at a fluence of 1 x 10(14) cm(-2), three deep electron traps, labeled D1 (E-C-0.12 eV), D5I (E-C-0.89 eV), and D6 (E-C-1.14 eV), were detected. The trap D1 has previously been reported and considered as being related to the nitrogen vacancy. From the annealing behavior and a high introduction rate, the D5I and D6 centers are suggested to be related to primary intrinsic defects.

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  • 109.
    Dufåker, Daniel
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Mereni, L. O.
    Tyndall National Institute, University College Cork, Ireland.
    Karlsson, Fredrik K.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Dimastrodonato, V.
    Tyndall National Institute, University College Cork, Ireland.
    Juska, G.
    Tyndall National Institute, University College Cork, Ireland.
    Holtz, Per-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Pelucchi, E.
    Tyndall National Institute, University College Cork, Ireland.
    Exciton-phonon coupling in single quantum dots with different barriers2011In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 98, no 25, p. 251911-Article in journal (Refereed)
    Abstract [en]

    The coupling between longitudinal-optical (LO) phonons and neutral excitons in two different kinds of InGaAs pyramidal quantum dots embedded in either AlGaAs or GaAs barriers is experimentally examined. We find a slightly weaker exciton-LO-phonon coupling and increased linewidth of the phonon replicas for the quantum dots with GaAs barriers compared to the ones with AlGaAs barriers. These results, combined with the fact that the LO-phonon energy of the exciton is the same for both kinds of dots, are taken as evidence that the excitons mainly couple to LO-phonons within the QDs.

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  • 110.
    Eless, V
    et al.
    National Phys Lab, England.
    Yager, T
    Chalmers, Sweden.
    Spasov, S
    University of London, England.
    Lara-Avila, S
    Chalmers, Sweden.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Kubatkin, S
    Chalmers, Sweden.
    Janssen, T J B M.
    National Phys Lab, England.
    Tzalenchuk, A
    National Phys Lab, England.
    Antonov, V
    University of London, England.
    Phase coherence and energy relaxation in epitaxial graphene under microwave radiation2013In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 103, no 9Article in journal (Refereed)
    Abstract [en]

    We have performed low-temperature magnetotransport measurements on monolayer epitaxial graphene under microwave radiation and extracted the radiation-induced effective temperatures, energy relaxation, and the dephasing times. We established that the response of the graphene sample is entirely bolometric at least up to 170 GHz. Dynamic dephasing, i.e., the time-reversal symmetry breaking effect of the ac electromagnetic field rather than mediated by heating, may become significant in the terahertz frequency range and in samples with longer phase coherence time.

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  • 111.
    Elfving, Anders
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics . Linköping University, The Institute of Technology.
    Karim, Amir
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hansson, Göran V.
    Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics . Linköping University, The Institute of Technology.
    Ni, Wei-Xin
    Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics . Linköping University, The Institute of Technology.
    Three-terminal Ge dot/SiGe quantum-well photodetectors for near-infrared light detection2006In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 89, p. 083510-083513Article in journal (Refereed)
    Abstract [en]

    A three-terminal metal-oxide-semiconductor field-effect transistor type of photodetector has been fabricated with a multiple stack of Ge dot/SiGe quantum-well heterostructures as the active region for light detection at 1.3–1.55  µm. Gate-dependent edge incidence photoconductivity measurements at room temperature revealed a strong dependence of the photoresponse on the gate voltage. At positive gate bias, the hole transport from the dots into the wells was improved, resulting in a faster response. The high photoresponsivity at negative VG, measured to be 350  mA  W–1 at 1.31  µm and 30  mA  W–1 at 1.55  µm, was ascribed to the photoconductive gain.

  • 112.
    Elofsson, Viktor
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanoscale engineering. Linköping University, The Institute of Technology.
    Saraiva, M.
    Sandvik Coromant AB, Sweden.
    Boyd, Robert
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, The Institute of Technology.
    Sarakinos, Kostas
    Linköping University, Department of Physics, Chemistry and Biology, Nanoscale engineering. Linköping University, The Institute of Technology.
    Double in-plane alignment in biaxially textured thin films2014In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 105, no 23, p. 233113-Article in journal (Refereed)
    Abstract [en]

    The scientific interest and technological relevance of biaxially textured polycrystalline thin films stem from their microstructure that resembles that of single crystals. To explain the origin and predict the type of biaxial texture in off-normally deposited films, Mahieu et al. have developed an analytical model [S. Mahieu et al., Thin Solid Films 515, 1229 (2006)]. For certain materials, this model predicts the occurrence of a double in-plane alignment, however, experimentally only a single in-plane alignment has been observed and the reason for this discrepancy is still unknown. The model calculates the resulting in-plane alignment by considering the growth of faceted grains with an out-of-plane orientation that corresponds to the predominant film out-of-plane texture. This approach overlooks the fact that in vapor condensation experiments where growth kinetics is limited and only surface diffusion is active, out-of-plane orientation selection is random during grain nucleation and happens only upon grain impingement. Here, we compile and implement an experiment that is consistent with the key assumptions set forth by the in-plane orientation selection model by Mahieu et al.; a Cr film is grown off-normally on a fiber textured Ti epilayer to pre-determine the out-of-plane orientation and only allow for competitive growth with respect to the in-plane alignment. Our results show unambiguously a biaxially textured Cr (110) film that possesses a double in-plane alignment, in agreement with predictions of the in-plane selection model. Thus, a long standing discrepancy in the literature is resolved, paving the way towards more accurate theoretical descriptions and hence knowledge-based control of microstructure evolution in biaxially textured thin films.

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  • 113.
    Eriksson, Jens
    et al.
    CNR IMM.
    Hung Weng, Ming
    CNR IMM.
    Roccaforte, Fabrizio
    CNR IMM.
    Giannazzo, Filippo
    CNR IMM.
    Leone, Stefano
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Raineri, Vito
    CNR IMM.
    Toward an ideal Schottky barrier on 3C-SiC2009In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 95, no 8Article in journal (Refereed)
    Abstract [en]

    The electrical characteristics of Au/3C-SiC Schottky diodes were studied as a function of contact area. While the larger diodes were characterized by conventional current-voltage measurements, conductive atomic force microscopy was used to perform current-voltage measurements on diodes of contact radius down to 5 mu m. The results show that the Schottky barrier height increases upon reducing the contact area, and for the smallest diodes the value approaches the ideal barrier height of the system. The results were correlated with defects in the 3C-SiC and an analytical expression was derived to describe the dependence of the barrier height on the defect density.

  • 114.
    Eriksson, Jens
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Pearce, Ruth
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Iakimov, Tihomir
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Virojanadara, Chariya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Gogova, Daniela
    Leibniz Institute of Crystal Growth, Berlin, Germany .
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Syväjärvi, Mikael
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Yakimova, Rositza
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    The influence of substrate morphology on thickness uniformity and unintentional doping of epitaxial graphene on SiC2012In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 100, no 24, p. 241607-Article in journal (Refereed)
    Abstract [en]

    A pivotal issue for the fabrication of electronic devices on epitaxial graphene on SiC is controlling the number of layers and reducing localized thickness inhomogeneities. Of equal importance is to understand what governs the unintentional doping of the graphene from the substrate. The influence of substrate surface topography on these two issues was studied by work function measurements and local surface potential mapping. The carrier concentration and the uniformity of epitaxial graphene samples grown under identical conditions and on substrates of nominally identical orientation were both found to depend strongly on the terrace width of the SiC substrate after growth.

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  • 115.
    Eriksson, Jens
    et al.
    CNR-IMM, Catania, Italy; Università di Catania, Italy .
    Roccaforte, Fabrizio
    CNR-IMM, Catania, Italy.
    Giannazzo, Filippo
    CNR-IMM, Catania, Italy.
    Lo Nigro, Raffaella
    CNR-IMM, Catania, Italy.
    Raineri, Vito
    CNR-IMM, Catania, Italy.
    Lorenzzi, Jean
    LMI, UMR-CNRS 5615, UCB-Lyon1, Villeurbanne, France .
    Ferro, Gabriel
    LMI, UMR-CNRS 5615, UCB-Lyon1, Villeurbanne, France .
    Improved Ni/3C-SiC contacts by effective contact area and conductivity increases at the nanoscale2009In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 94, p. 112104-1-112104-3Article in journal (Refereed)
    Abstract [en]

    We report on the evolution of the electrical and structural properties of Ni/3C-SiC contacts during annealing in the temperature range of 600–950 °C . A structural analysis showed the formation of different nickel silicide phases upon annealing. A combination of transmission line model and conductive atomic force microscopy measurements demonstrated a correlation between the macroscale specific contact resistance and the nanoscale resistance, measured locally across the sample. These results further revealed that the structural evolution is accompanied by an increased uniformity of the local current distribution, indicating that an increase of the effective contact area contributes to the improvement of the contact properties.

  • 116.
    Feneberg, Martin
    et al.
    University of Magdeburg, Germany.
    Nguyen, Son Tien
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Kakanakova-Gueorguie, Anelia
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Exciton luminescence in AIN triggered by hydrogen and thermal annealing2015In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 106, no 24, p. 242101-Article in journal (Refereed)
    Abstract [en]

    Exciton recombination bands in homoepitaxial AIN layers are strongly dependent on the presence of hydrogen. By thermal treatment under hydrogen-free and hydrogen-rich ambient, respectively, several sharp bound exciton lines are modulated in intensity reversibly. In contrast, the exciton bound at the neutral donor silicon remains unaffected. The mechanism causing these effects is most probably hydrogen in-and out-diffusion into the AIN sample. The main factor determining hydrogenation of AIN layers is found to be molecular H-2 in contrast to NH3. We find hints that carbon incorporation into AIN may be closely related with that of hydrogen. Besides photoluminescence spectra of exciton bands, our model is supported by theoretical reports and comparison to the case of hydrogen in GaN.

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  • 117.
    Filippini, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Adaptive illumination in computer screen assisted spectral fingerprinting2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, no 8, p. 084101-Article in journal (Refereed)
    Abstract [en]

    The computer screen photoassisted technique (CSPT) uses displays as controlled light sources for measuring spectral fingerprints of color substances, such as those present in bioassays. Here, the possibility of tuning the illuminating sequences for matching CSPT fingerprints with target spectral transmittances is demonstrated. This approach enables robust classification, orders of magnitude form mismatches, and establish a systematic method for adapting optimum illuminating sequences to any unknown measuring platform. © 2005 American Institute of Physics.

  • 118.
    Filippini, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Chemical images generated by large area homogeneous illumination of metal-insulator-semiconductor structures2003In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 82, no 21, p. 3791-3793Article in journal (Refereed)
    Abstract [en]

    The induction of distinctive chemical images in the field-effect devices upon gas exposure by the use of a controlled large area illumination provided by a computer screen was reported. To generate two-dimensional photocurrent images, the concurrent optical and chemical modulation of the semiconductor surface potential of a single metal-oxide-semiconductor capacitor was used. It was concluded that the use of a computer screen as a programmable light source simplifies a normally complex setup.

  • 119.
    Filippini, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Chemical imaging by a computer screen aided scanning light pulse technique2002In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 81, no 20, p. 3891-3893Article in journal (Refereed)
    Abstract [en]

    The demonstration of a scanning light pulse technique (SLPT) for the generation of selective chemical images was done. The programmable light source provided by a standard cathode-rays tube computer screen was used for this purpose. The testing of the concept was done with a metal-oxide-semiconductor capacitor with catalytic gates of platinum and palladium spatially distributed in transversal directions.

  • 120.
    Filippini, Daniel
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Uchida, H.
    Faculty of Engineering, Saitama University, 255 Shimo-Okubo, Urawa 338, Japan.
    Gap-gate field effect gas sensing device for chemical image generation2004In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 84, no 15, p. 2946-2948Article in journal (Refereed)
    Abstract [en]

    A field effect chemically sensing device, suited for the generation of scanning light pulse technique (SLPT) chemical images, was proposed. The device was a MOS capacitor made on p-Si (10 ?), thermally oxidized to 120 nm and metallized on its underside with 200 nm of Al. The biasing electrodes were two parallel Al tracks 100 nm thick spaced 1 mm from each other. The results demonstrate the complete separation between biasing and sensing functions in devices designed for SLPT chemical image generation.

  • 121.
    Fischer, A.M.
    et al.
    Department of Physics, Arizona State University, Tempe, AZ 85287-1504, United States.
    Srinivasan, S.
    Department of Physics, Arizona State University, Tempe, AZ 85287-1504, United States.
    Ponce, F.A.
    Department of Physics, Arizona State University, Tempe, AZ 85287-1504, United States.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Bertram, F.
    Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, PSF 4120, 39106 Magdeburg, Germany.
    Christen, J.
    Institute of Experimental Physics, Otto-von-Guericke-University Magdeburg, PSF 4120, 39106 Magdeburg, Germany.
    Time-resolved cathodoluminescence of Mg-doped GaN2008In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 93, no 15Article in journal (Refereed)
    Abstract [en]

    The optical properties of GaN films doped with magnesium concentrations of the order of 1018 and 1019 cm-3 have been analyzed by picosecond time-resolved cathodoluminescence spectroscopy. Two luminescence bands in the vicinity of ~3.45 and ~3.27 eV are observed to increase in intensity with Mg concentration. They have been identified as related to acceptor-bound exciton and donor-acceptor pair (DAP) transitions, respectively. Time-resolved cathodoluminescence spectra, taken at low temperatures (~4 K), show that the lifetime of the DAP peak (3.27 eV) and of what appears to be its first longitudinal-optical phonon replica at ~3.19 eV decrease with increasing Mg concentration. These peaks differ in their recombination kinetics, strongly suggesting the existence of an underlying broad emission band which may be related to Mg. © 2008 American Institute of Physics.

  • 122.
    Flatten, Tim
    et al.
    Forschungszentrum Julich, Germany; JARA, Germany.
    Matthes, Frank
    Forschungszentrum Julich, Germany; JARA, Germany.
    Petruhins, Andrejs
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Salikhov, Ruslan
    Univ Duisburg Essen, Germany; Univ Duisburg Essen, Germany.
    Wiedwald, Ulf
    Univ Duisburg Essen, Germany.
    Farle, Michael
    Univ Duisburg Essen, Germany.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Buergler, Daniel E.
    Forschungszentrum Julich, Germany; JARA, Germany.
    Schneider, Claus M.
    Forschungszentrum Julich, Germany; JARA, Germany; Univ Duisburg Essen, Germany; Univ Duisburg Essen, Germany.
    Direct measurement of anisotropic conductivity in a nanolaminated (Mn0.5Cr0.5)(2)GaC thin film2019In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 115, no 9, article id 094101Article in journal (Refereed)
    Abstract [en]

    The direct and parameter-free measurement of anisotropic electrical resistivity of a magnetic M(n+1)AX(n) (MAX) phase film is presented. A multitip scanning tunneling microscope is used to carry out 4-probe transport measurements with variable probe spacing s. The observation of the crossover from the 3D regime for small s to the 2D regime for large s enables the determination of both in-plane and perpendicular-to-plane resistivities rho(ab) and rho(c). A (Cr0.5Mn0.5)(2)GaC MAX phase film shows a large anisotropy ratio rho(c)/rho(ab) = 525 +/- 49. This is a consequence of the complex bonding scheme of MAX phases with covalent M-X and metallic M-M bonds in the MX planes and predominately covalent, but weaker bonds between the MX and A planes. Published under license by AIP Publishing.

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  • 123.
    Gadisa, Abay
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Perzon, Erik
    Department of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden.
    Andersson, M. R.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Red and near infrared polarized light emission from polyfluorene copolymer based light emitting diodes2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 90, no 11, p. 113510-Article in journal (Refereed)
    Abstract [en]

    The authors report polarized red, electroluminescence peak at 705  nm and near infrared, electroluminescence peak at 950  nm, light emission from light emitting diodes based on two polyfluorene copolymers. The copolymers are synthesized from a fluorene monomer combined with donor-acceptor-donor comonomers and designed to have a low band gap and form birefringent liquid crystalline phases. Emission occurs from aligned thin films of polymer layers. The emissive layers are aligned by spin coating on a layer of rubbed conducting polymer poly(3,4-ethylene dioxythiophene)-poly(styrene sulphonate) and thermally converted into glassy nematic liquid crystalline state.

  • 124. Gali, A
    et al.
    Hornos, T
    Deák, P
    Nguyen, Son Tien
    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 .
    Choyke, W
    Activation of shallow boron acceptor in CB coimplanted silicon carbide: A theoretical study2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 86, no 10, p. 102108-Article in journal (Refereed)
    Abstract [en]

    Ab initio supercell calculations have been carried out to investigate the complexes of boron acceptors with carbon self-interstitials in cubic silicon carbide. Based on the calculated binding energies, the complex formation of carbon interstitials with shallow boron acceptor and boron interstitial is energetically favored in silicon carbide. These bistable boron defects possess deep, negative- U occupation levels in the band gap. The theoretical results can explain the observed activation rates in carbon-boron coimplantation experiments. © 2005 American Institute of Physics.

  • 125.
    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.
    Nguyen, Tien Son
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Janzén, Erik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Hydrogen passivation of nitrogen in SiC2003In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 83, no 7, p. 1385-1387Article in journal (Refereed)
    Abstract [en]

    A study is performed on hydrogen passivation of nitrogen in SiC. The first-principles calculations show that hydrogen may form stable complexes with substitutional nitrogen, passivating the shallow nitrogen donor. It is found that the complex is stable with respect to negatively charged hydrogen interstitials and isolated positive donors.

  • 126.
    Gallo, P.
    et al.
    Ecole Polytechnique Fédérale de Lausanne .
    Felici, M.
    Ecole Polytechnique Fédérale de Lausanne .
    Dwir, B.
    Ecole Polytechnique Fédérale de Lausanne .
    Atlasov, K.A.
    Ecole Polytechnique Fédérale de Lausanne .
    Karlsson, Fredrik
    Ecole Polytechnique Fédérale de Lausanne .
    Rudra, A.
    Ecole Polytechnique Fédérale de Lausanne .
    Mohan, A.
    Ecole Polytechnique Fédérale de Lausanne .
    Biasiol, G.
    TASC INFM-CNR.
    Sorba, L.
    NEST INFM-CNR and Scuola Normale Superiore.
    Kapon, E.
    Ecole Polytechnique Fédérale de Lausanne .
    Integration of site-controlled pyramidal quantum dots and photonic crystal membrane cavities2008In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 92, p. 263101-Article in journal (Refereed)
    Abstract [en]

    The authors demonstrate the deterministic coupling between a single, site-controlled InGaAs/GaAs pyramidal quantum dot (QD) and a photonic crystal membrane cavity defect. The growth of self-ordered pyramidal QDs in small (300 nm base side) tetrahedral recesses etched on (111)B GaAs substrates was developed in order to allow their integration within the thin GaAs membranes. Accurate (better than 50 nm) positioning of the QD with respect to the optical cavity mode is achieved reproducibly owing to the site control. Coupling of the dot emission with the cavity mode is evidenced in photoluminescence measurements. The deterministic positioning of the pyramidal QDs and the control of their emission spectrum opens the way for devices based on QDs integrated with coupled nanocavities.

  • 127.
    Gao, Feng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Li, P. L.
    Nanjing University, China.
    Weng, Y. Y.
    Nanjing University, China.
    Dong, S.
    Nanjing University, China.
    Wang, L. F.
    Nanjing University, China.
    Lv, L. Y.
    Nanjing University, China.
    Wang, K. F.
    Nanjing University, China.
    Liu, J.-M.
    Nanjing University, China.
    Ren, Z. F.
    Nanjing University, MA 02467 USA.
    Charge order suppression and weak ferromagnetism in La1/3Sr2/3FeO3 nanoparticles2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 7, p. 072504-Article in journal (Refereed)
    Abstract [en]

    Perovskite-type polycrystalline La1/3Sr2/3FeO3 particles with different sizes (80-2000 nm) were prepared using a simple sol-gel technique. In samples of nanoparticles with a diameter of less than 300 nm, weak ferromagnetism was observed at room temperature, which was attributed to the lattice distortion. The magnetic and specific heat measurements suggest that the charge ordering state was largely suppressed due to the lowering of the particle size, but the charge ordering temperature remained unaffected. (C) 2007 American Institute of Physics.

  • 128.
    Gao, Feng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, The Institute of Technology.
    Yuan, Y.
    Nanjing University, 210093 China.
    Wang, K. F.
    Nanjing University, 210093 China.
    Chen, X. Y.
    Nanjing University, 210093 China.
    Chen, F.
    Nanjing University, 210093 China.
    Liu, J. -M.
    Nanjing University, 210093 China.
    Preparation and photoabsorption characterization of BiFeO3 nanowires2006In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 89, no 10, p. 102506-Article in journal (Refereed)
    Abstract [en]

    Perovskite-type polycrystalline BiFeO3 (BFO) nanowires (similar to 50 nm in diameter and similar to 5 mu m in length) were synthesized using the anodized alumina template technique. An energy band gap of similar to 2.5 eV was determined from the UV-visible diffuse reflectance spectrum, and its photocatalytic ability to produce O-2 was revealed under UV irradiation. Weak ferromagnetism at room temperature and superparamagnetism at low temperature were observed for the BFO nanowires, different from the antiferromagnetic order in bulk BFO, reflecting the significant size effects on the magnetic ordering of BFO. (c) 2006 American Institute of Physics.

  • 129.
    Ghafoor, Naureen
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Eriksson, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Gullikson, Eric M
    Lawrence Berkeley Laboratory.
    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.
    Incorporation of nitrogen in Cr/Sc multilayers giving improved soft x-ray reectivity2008In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 92, no 9, p. 091913-Article in journal (Refereed)
    Abstract [en]

    Soft x-ray reflectivity (SXR) of Cr/Sc multilayer with bilayer thickness of =1.56  nm was increased by 100% by an intentional introduction of nitrogen during magnetron sputtering. Multilayers deposited at background pressures of 2×10−6 Torr exhibited amorphous layers with flat interfaces. At 2×10−5 Torr, understoichiometric CrNx/ScNy multilayer with a nitrogen content of ~34  at.  % was formed. CrNx/ScNy multilayer comprising of only 100 periods exhibited a SXR of 11.5%. X-ray and electron microscopy analyses showed that the improvement in performance is a result of reduced interfacial diffusion yielding interface widths of 0.29  nm. The CrNx/ScNy multilayer exhibited thermal stability up to >380  °C.

  • 130.
    Gigli, G.
    et al.
    Dept. of Phys. and Msrmt. Technology, Linkoping University, S-58183 Linkoping, Sweden.
    Inganas, O.
    Inganäs, O., Dept. of Phys. and Msrmt. Technology, Linkoping University, S-58183 Linkoping, Sweden.
    Anni, M.
    INFM, Dipto. Ingegneria Elettron. D., Università di Lecce, Via Arnesano, 73100 Lecce, Italy.
    De, Vittorio M.
    De Vittorio, M., INFM, Dipto. Ingegneria Elettron. D., Università di Lecce, Via Arnesano, 73100 Lecce, Italy.
    Cingolani, R.
    INFM, Dipto. Ingegneria Elettron. D., Università di Lecce, Via Arnesano, 73100 Lecce, Italy.
    Barbarella, G.
    Consiglio Nazionale Ricerche, ICoCEA, Via Gobetti 101, I-40129 Bologna, Italy.
    Favaretto, L.
    Consiglio Nazionale Ricerche, ICoCEA, Via Gobetti 101, I-40129 Bologna, Italy.
    Multicolor oligothiophene-based light-emitting diodes2001In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 78, no 11, p. 1493-1495Article in journal (Refereed)
    Abstract [en]

    We demonstrate wide tunability, from green to near infrared, of the electroluminescence emission of substituted oligothiophene compounds. The compounds are characterized by high chemical stability, electron affinities up to 3.1 eV and photoluminescence efficiencies up to 70%. These characteristics make these materials excellent candidates for application in light-emitting diodes. We obtain low turn-on voltage devices with electroluminescence efficiency up to 0.2%, more than one order of magnitude larger than the values reported for unsubstituted oligothiophene compounds. © 2001 American Institute of Physics.

  • 131.
    Gomes, P.F.
    et al.
    Intituto de Física Gleb Wataghin, Unicamp, CP 6165, Campinas, São Paulo 13083-970, Brazil.
    Iikawa, F.
    Intituto de Física Gleb Wataghin, Unicamp, CP 6165, Campinas, São Paulo 13083-970, Brazil.
    Cerdeira, F.
    Intituto de Física Gleb Wataghin, Unicamp, CP 6165, Campinas, São Paulo 13083-970, Brazil.
    Larsson, Mats
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Elfving, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics .
    Hansson, Göran
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics .
    Ni, Wei-Xin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics .
    Holtz, Per-Olof
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Type-I optical emissions in GeSi quantum dots2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 5Article in journal (Refereed)
    Abstract [en]

    The authors studied the optical emission of GeSi quantum dots under externally applied biaxial stress using samples grown with different temperatures varying from 430 to 700 °C. The optical emission energy of samples grown at low temperatures is rather insensitive to the applied external stress, consistent with the type-II band alignment. However, for samples grown at high temperatures we observed a large blueshift, which suggests type-I alignment. The result implies that recombination strength can be controlled by the growth temperature, which can be useful for optical device applications. © 2007 American Institute of Physics.

  • 132.
    Gommans, HHP
    et al.
    Eindhoven University of Technology, Netherlands.
    Kemerink, Martijn
    Eindhoven University of Technology, Netherlands.
    Kramer, JM
    Eindhoven University of Technology, Netherlands.
    Janssen, RAJ
    Eindhoven University of Technology, Netherlands.
    Field and temperature dependence of the photocurrent in polymer/fullerene bulk heterojunction solar cells2005In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 87, no 12, article id 122104Article in journal (Refereed)
    Abstract [en]

    The photocurrent in polymer/fullerene blends is characterized as a function of bias at temperatures ranging from 125 to 300 K. Assuming a constant generation rate and bimolecular recombination, the results are numerically modeled within the drift-diffusion approximation. Bimolecular recombination is found to be a dominant factor in the field dependence of the photocurrent in the entire measured voltage range. Inclusion of field dependent geminate pair dissociation and recombination via the Onsager expressions gives a much stronger field dependence than experimentally observed. From the temperature dependence of the extracted mobilities, we can simultaneously estimate the broadening of the transporting highest occupied and lowest unoccupied molecular orbital levels. (c) 2005 American Institute of Physics.

  • 133. Greczynski, G.
    et al.
    Salaneck, William R
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry .
    Photoelectron spectroscopy of hybrid interfaces for light emitting diodes: Influence of the substrate work function2001In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 79, no 19, p. 3185-3187Article in journal (Refereed)
    Abstract [en]

    Photoelectron spectroscopy results of studies of a conjugated polymer poly(9, 9-dioctylfluorene) thin films embedded between two contacts with different work functions are reported in this work. It is demonstrated that, depending on the work function of contact material involved, the binding energy of the C(1s) core level of the polymer, changes according to the resulting built-in potential in the polymer layer. The deposition of the same metal onto a polymer surface can lead to binding energy shifts of the core-level spectra in either direction, determined by the work function of the underlying substrate. © 2001 American Institute of Physics.

  • 134.
    Greczynski, Grzegorz
    et al.
    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.
    In-situ observation of self-cleansing phenomena during ultra-high vacuum anneal of transition metal nitride thin films: Prospects for non-destructive photoelectron spectroscopy2016In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 109, no 21, article id 211602Article in journal (Refereed)
    Abstract [en]

    Self-cleansing of transition metal nitrides is discovered to take place during ultra-high vacuum annealing of TiN, NbN, and VN thin films. Native oxide layers from air exposure disappear after isothermal anneal at 1000 degrees C. Also, for TiN, the Ti 2p and N 1s X-ray photoelectron spectra (XPS) recorded after the anneal are identical to those obtained from in-situ grown and analyzed epitaxial TiN(001). These unexpected effects are explained by oxide decomposition in combination with N-replenishing of the nitride during recrystallization. The finding opens up new possibilities for true bonding assignments through non-destructive XPS analyses, thus avoiding artefacts from Ar etching. (C) 2016 Author(s).

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  • 135.
    Greczynski, Grzegorz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Rhein Westfal TH Aachen, Germany.
    Mraz, S.
    Rhein Westfal TH Aachen, Germany.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Schneider, J. M.
    Rhein Westfal TH Aachen, Germany.
    Venting temperature determines surface chemistry of magnetron sputtered TiN films2016In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 108, no 4, p. 041603-1-041603-5Article in journal (Refereed)
    Abstract [en]

    Surface properties of refractory ceramic transition metal nitride thin films grown by magnetron sputtering are essential for resistance towards oxidation necessary in all modern applications. Here, typically neglected factors, including exposure to residual process gases following the growth and the venting temperature T-v, each affecting the surface chemistry, are addressed. It is demonstrated for the TiN model materials system that T-v has a substantial effect on the composition and thickness-evolution of the reacted surface layer and should therefore be reported. The phenomena are also shown to have impact on the reliable surface characterization by x-ray photoelectron spectroscopy. (C) 2016 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

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  • 136.
    Greczynski, Grzegorz
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering. Rhein Westfal TH Aachen, Germany.
    Mraz, S.
    Rhein Westfal TH Aachen, Germany.
    Schneider, J. M.
    Rhein Westfal TH Aachen, Germany.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Native target chemistry during reactive dc magnetron sputtering studied by ex-situ x-ray photoelectron spectroscopy2017In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 111, no 2, article id 021604Article in journal (Refereed)
    Abstract [en]

    We report x-ray photoelectron spectroscopy (XPS) analysis of native Ti target surface chemistry during magnetron sputtering in an Ar/N-2 atmosphere. To avoid air exposure, the target is capped immediately after sputtering with a few-nm-thick Al overlayers; hence, information about the chemical state of target elements as a function of N-2 partial pressure p(N2) is preserved. Contrary to previous reports, which assume stoichiometric TiN formation, we present direct evidence, based on core-level XPS spectra and TRIDYN simulations, that the target surface is covered by TiNx with x varying in a wide range, from 0.27 to 1.18, depending on p(N2). This has far-reaching consequences both for modelling of the reactive sputtering process and for everyday thin film growth where detailed knowledge of the target state is crucial. Published by AIP Publishing.

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  • 137. Hai, P. N.
    et al.
    Chen, Weimin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Buyanova, Irina
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Functional Electronic Materials.
    Xin, H. P.
    Tu, C. W.
    Direct determination of electron effective mass in GaNAs/GaAs quantum wells2000In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 77, no 12, p. 1843-1845Article in journal (Refereed)
    Abstract [en]

    Electron effective mass (m*e) in GaNxAs1-x/GaAs quantum wells (QWs) is investigated by the optically detected cyclotron resonance technique. The m*e values of 0.12m0 and 0.19m0 are directly determined for the 70-A-thick QWs with N composition of 1.2% and 2.0%, respectively. This sizable increase in the electron effective mass is consistent with the earlier theoretical predictions based on the strong interaction of the lowest conduction band states with the upper lying band states or impurity band induced by the incorporation of N. ⌐ 2000 American Institute of Physics.

  • 138.
    Hansson, Göran
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics .
    Ni, Wei-Xin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics .
    Du, Chun-Xia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Elfving, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Surface and Semiconductor Physics .
    Duteil, F.
    Origin of abnormal temperature dependence of electroluminescence from Er/O-doped Si diodes2001In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 78, no 15, p. 2104-2106Article in journal (Refereed)
    Abstract [en]

    The temperature dependencies of the current-voltage characteristics and the electroluminescence (EL) intensity of molecular beam epitaxy grown Er/O-doped Si light emitting diodes at reverse bias have been studied. To minimize the scattering of electrons injected from the p-doped Si1-xGex electron emitters, an intrinsic Si layer was used in the depletion region. For many diodes, there is a temperature range where the EL intensity increases with temperature. Data are reported for a structure that shows increasing intensity up to 100°C. This is attributed to an increasing fraction of the pumping current being due to phonon-assisted tunneling, which gives a higher saturation intensity, compared to ionization-dominated breakdown at lower temperatures. © 2001 American Institute of Physics.

  • 139.
    Hao, L
    et al.
    National Phys Lab, England .
    Gallop, J
    National Phys Lab, England .
    Goniszewski, S
    National Phys Lab, England .
    Shaforost, O
    University of London Imperial Coll Science Technology and Med, England .
    Klein, N
    University of London Imperial Coll Science Technology and Med, England .
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Non-contact method for measurement of the microwave conductivity of graphene2013In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 103, no 12Article in journal (Refereed)
    Abstract [en]

    We report a non-contact method for conductivity and sheet resistance measurements of monolayer and few layers graphene samples using a high Q microwave dielectric resonator perturbation technique, with the aim of fast and accurate measurement. The dynamic range of the microwave conductivity measurements makes this technique sensitive to a range of imperfections and impurities and can provide rapid non-contacting characterisation. As a demonstration of the power of the technique, we present results for graphene samples grown by three different methods with widely differing sheet resistance values.

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  • 140.
    Harada, K.
    et al.
    Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany.
    Li, Fenghong
    Technische Universität Dresden.
    Maennig, B.
    Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany, Heliatek GmbH, Liebigstraße 26, 01187 Dresden, Germany.
    Pfeiffer, M.
    Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany, Heliatek GmbH, Liebigstraße 26, 01187 Dresden, Germany.
    Leo, K.
    Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany.
    Ionized impurity scattering in n -doped C60 thin films2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 91, no 9Article in journal (Refereed)
    Abstract [en]

    Carrier transport in organic films is usually dominated by hopping process, leading to different temperature dependence from that of inorganic crystals. The aurhors demonstrate that n -doped C60 films show temperature dependence analogous to inorganic semiconductors. At low temperatures, the conductivity increases with temperature, around room temperature, a maximum is reached and then the conductivity decreases. These observations are confirmed by the dependence of mobility on doping level. In contrast to previous reports for organic thin films, the C60 films show a decrease of mobility with increasing doping levels, i.e., they follow the well-known Matthiessen rule which is generally observed in inorganic semiconductors. © 2007 American Institute of Physics.

  • 141.
    Harati Zadeh, Hamid
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Monemar, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Paskov, Plamen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Bergman, Peder
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Sernelius, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics .
    Holtz, Per-Olof
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Iwaya, M
    Kamiyama, S
    Amano, H
    Akasaki, I
    Photoluminescence study of Si-doped GaN/Al0.07Ga0.93N multiple quantum wells with different dopant position2004In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 84, no 25, p. 5071-5073Article in journal (Refereed)
    Abstract [en]

    The Si-doped GaN/Al0.07Ga0.93N multiple quantum wells (MQW) were investigated, using photoluminescence (PL) and time-resolved (PL) measurements. The influence of Si doping on the emission energy and recombination dynamics of the MWQs were also investigated, with different dopant position in the wells. It was observed that the redshifted emission of the MQWs was 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. It was also observed that the PL decay time of the sample was ∼760 ps, at low temperature.

  • 142.
    Harati Zadeh, Hamid
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Paskov, Plamen
    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 .
    Holtz, Per-Olof
    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 .
    Kamiyama, S.
    Iwaya, M.
    Amano, H.
    Akasaki, I.
    Effect of n-type modulation doping on the photoluminescence of GaN/Al0.07Ga0.93N multiple quantum wells2002In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 80, no 8, p. 1373-Article in journal (Refereed)
    Abstract [en]

    [No abstract available]

  • 143.
    Haverkort, JEM
    et al.
    Eindhoven University of Technology, Netherlands.
    Dorren, BHP
    Eindhoven University of Technology, Netherlands.
    Kemerink, Martijn
    Eindhoven University of Technology, Netherlands.
    Silov, AY
    Eindhoven University of Technology, Netherlands.
    Wolter, JH
    Eindhoven University of Technology, Netherlands.
    Design of composite InAsP/InGaAs quantum wells for a 1.55 mu m polarization independent semiconductor optical amplifier1999In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 75, no 18, p. 2782-2784Article in journal (Refereed)
    Abstract [en]

    We investigate a composite InAsP/InGaAs quantum well in which an 8 nm tensile strained InGaAs well is surrounded by two compressively strained InAsP layers which feature a 70:30 conduction band offset ratio. The composite quantum well is found to provide a high TM differential gain. The InAsP layers provide strain compensation while simultaneously shifting the band gap to the relevant 1.55 mu m wavelength region and increasing the electron confinement. Composite InAsP/InGaAs quantum wells are a promising candidate for realizing a polarization independent semiconductor optical amplifier at 1.55 mu m. (C) 1999 American Institute of Physics. [S0003-6951(99)01944-0].

  • 144. Hellgren, N.
    et al.
    Guo, J.
    Department of Physics, Uppsala University, Box 530, SE-75121 Uppsala, Sweden.
    Sathe, C.
    Såthe, C., Department of Physics, Uppsala University, Box 530, SE-75121 Uppsala, Sweden.
    Agui, A.
    Department of Physics, Uppsala University, Box 530, SE-75121 Uppsala, Sweden.
    Nordgren, J.
    Department of Physics, Uppsala University, Box 530, SE-75121 Uppsala, Sweden.
    Luo, Y.
    Theoretical Chemistry, Royal Institute of Technology, Teknikringen 30, SE-10044 Stockholm, Sweden.
    Agren, H.
    Ågren, H., Theoretical Chemistry, Royal Institute of Technology, Teknikringen 30, SE-10044 Stockholm, Sweden.
    Sundgren, J.-E.
    Nitrogen bonding structure in carbon nitride thin films studied by soft x-ray spectroscopy2001In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 79, no 26, p. 4348-4350Article in journal (Refereed)
    Abstract [en]

    Soft x-ray absorption (SXAS) and emission (SXES) spectroscopies were applied to study the nitrogen bonding structure in magnetron sputtered CNx thin films. By comparing with calculated spectra of N in different model systems, N in three main bonding environments can be identified: (i) CN bonds, with a sharp SXAS peak at 399.5 eV, (ii) pyridine-like N (i.e., N bonded to two C atoms), with an x-ray absorption resonance at ~398.5 eV, and (iii) N substituted in graphite, possibly with one sp3 carbon as a neighbor (SXAS energy ~401 eV). These bondings are present in all CNx films analyzed, however, as shown earlier, the relative intensities between the peaks may vary with the growth conditions. Differences in the coordination of the nearest or second nearest C neighbors only cause slight changes in the peak positions and spectrum shape. © 2001 American Institute of Physics.

  • 145. Hellgren, N.
    et al.
    Johansson, M.P.
    Broitman, E.
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Sundgren, J.-E.
    Anisotropies in magnetron sputtered carbon nitride thin films2001In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 78, no 18, p. 2703-2705Article in journal (Refereed)
    Abstract [en]

    Carbon nitride CNx (O=x=0.35) thin films, deposited by reactive dc magnetron sputtering in Ar/N2 discharges have been studied with respect to microstructure using electron microscopy, and elastic modulus using nanoindentation and surface acoustic wave analyses. For growth temperature of 100°C, the films were amorphous, and with an isotropic Young's modulus of ~170-200 GPa essentially unaffected by the nitrogen fraction. The films grown at elevated temperatures (350-550°C) show anisotropic mechanical properties due to a textured microstructure with standing basal planes, as observed from measuring the Young's modulus in different directions. The modulus measured in the plane of the film was ~60-80 GPa, while in the vertical direction the modulus increased considerably from ~25 to ~200 GPa as the nitrogen content was increased above ~15 at. %. © 2001 American Institute of Physics.

  • 146.
    Hennerdal, Lars-Olov
    et al.
    Acreo AB.
    Berggren, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Picture-to-picture switching in full-color thermochromic paper displays2011In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 99, no 18, p. 183303-Article in journal (Refereed)
    Abstract [en]

    Presently, we contemplate the merger of paper and electronics in different forms. There is a great desire to further explore this twinning of the information displaying features of printed papers and electronic inks. Here, we report a full-color paperboard display technology comprised of thermochromic and static inks combined with a patterned heater foil. Black and full-color thermochromic ink dots were screen-printed adjacent to, and on top of, static ink dots using a zero-angle mesh and template pattern orientation. As the heater is turned on and off, the display alter its content in between two predefined four-color pictures.

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  • 147.
    Higashiwaki, Masataka
    et al.
    National Institute Informat and Commun Technology, Japan.
    Konishi, Keita
    National Institute Informat and Commun Technology, Japan.
    Sasaki, Kohei
    National Institute Informat and Commun Technology, Japan; Tamura Corp, Japan.
    Goto, Ken
    Tamura Corp, Japan; Tokyo University of Agriculture and Technology, Japan.
    Nomura, Kazushiro
    National Institute Informat and Commun Technology, Japan; Tokyo University of Agriculture and Technology, Japan.
    Quang Tu Thieu; Togashi, Rie
    Tokyo University of Agriculture and Technology, Japan.
    Murakami, Hisashi
    Tokyo University of Agriculture and Technology, Japan.
    Kumagai, Yoshinao
    Tokyo University of Agriculture and Technology, Japan.
    Monemar, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Tokyo University of Agriculture and Technology, Japan.
    Koukitu, Akinori
    Tokyo University of Agriculture and Technology, Japan.
    Kuramata, Akito
    Tamura Corp, Japan.
    Yamakoshi, Shigenobu
    Tamura Corp, Japan.
    Temperature-dependent capacitance-voltage and current-voltage characteristics of Pt/Ga2O3 (001) Schottky barrier diodes fabricated on n(-)-Ga2O3 drift layers grown by halide vapor phase epitaxy2016In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 108, no 13, p. 133503-Article in journal (Refereed)
    Abstract [en]

    We investigated the temperature-dependent electrical properties of Pt/Ga2O3 Schottky barrier diodes (SBDs) fabricated on n(-)-Ga2O3 drift layers grown on single-crystal n(+)-Ga2O3 (001) substrates by halide vapor phase epitaxy. In an operating temperature range from 21 degrees C to 200 degrees C, the Pt/Ga2O3 (001) Schottky contact exhibited a zero-bias barrier height of 1.09-1.15 eV with a constant near-unity ideality factor. The current-voltage characteristics of the SBDs were well-modeled by thermionic emission in the forward regime and thermionic field emission in the reverse regime over the entire temperature range. (C) 2016 AIP Publishing LLC.

  • 148.
    Hilfiker, Matthew
    et al.
    Univ Nebraska Lincoln, NE 68588 USA.
    Kilic, Ufuk
    Univ Nebraska Lincoln, NE 68588 USA.
    Mock, Alyssa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Knight, Sean
    Univ Nebraska Lincoln, NE 68588 USA.
    Korlacki, Rafal
    Univ Nebraska Lincoln, NE 68588 USA.
    Mauze, Akhil
    Univ Calif Santa Barbara, CA 93106 USA.
    Zhang, Yuewei
    Univ Calif Santa Barbara, CA 93106 USA.
    Speck, James
    Univ Calif Santa Barbara, CA 93106 USA.
    Schubert, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Univ Nebraska Lincoln, NE 68588 USA; Leibniz Inst Polymerforsch eV, Germany.
    Dielectric function tensor (1.5 eV to 9.0 eV), anisotropy, and band to band transitions of monoclinic -(AlxGa1-x)(2)O-3 (x 0.21) films2019In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 114, no 23, article id 231901Article in journal (Refereed)
    Abstract [en]

    A set of monoclinic -(AlxGa1-x)(2)O-3 films coherently grown by plasma-assisted molecular beam epitaxy onto (010)-oriented -Ga2O3 substrates for compositions x0.21 is investigated by generalized spectroscopic ellipsometry at room temperature in the spectral range of 1.5eV-9.0eV. We present the composition dependence of the excitonic and band to band transition energy parameters using a previously described eigendielectric summation approach for -Ga2O3 from the study by Mock et al. All energies shift to a shorter wavelength with the increasing Al content in accordance with the much larger fundamental band to band transition energies of Al2O3 regardless of crystal symmetry. The observed increase in the lowest band to band transition energy is in excellent agreement with recent theoretical predictions. The most important observation is that charge confinement in heterostructures will strongly depend on the growth condition due to the strongly anisotropic properties of the band to band transitions.

  • 149.
    Hofmann, T.
    et al.
    University of Nebraska, USA .
    Kuehne, P.
    University of Nebraska, USA .
    Schöche, S.
    University of Nebraska, USA .
    Chen, Jr-Tai
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Forsberg, Urban
    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.
    Ben Sedrine, N.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Health Sciences.
    Herzinger, C. M
    JA Woollam Co Inc, USA .
    Woollam, J. A
    JA Woollam Co Inc, USA .
    Schubert, M.
    University of Nebraska, USA .
    Darakchieva, Vanya
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Temperature dependent effective mass in AlGaN/GaN high electron mobility transistor structures2012In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 101, no 19Article in journal (Refereed)
    Abstract [en]

    The temperature-dependence of free-charge carrier mobility, sheet density, and effective mass of a two-dimensional electron gas in a AlGaN/GaN heterostructure deposited on SiC substrate is determined using the THz optical Hall effect in the spectral range from 0.22 to 0.32 THz for temperatures from 1.5 to 300 K. The THz optical Hall-effect measurements are combined with room temperature mid-infrared spectroscopic ellipsometry measurements to determine the layer thickness, phonon mode, and free-charge carrier parameters of the heterostructure constituents. An increase of the electron effective mass from (0.22 +/- 0.01)m(0) at 1.5 K to (0.36 +/- 0.03)m(0) at 300 K is observed, which is indicative for a reduction in spatial confinement of the two-dimensional electron gas at room temperature. The temperature-dependence of the mobility and the sheet density is in good agreement with electrical measurements reported in the literature.

  • 150. Hsiao, C.L.
    et al.
    Liu, T.W.
    Wu, C.T.
    Hsu, H.C.
    Hsu, G.M.
    Chen, L.C.
    Shiao, W.Y.
    Yang, C.C.
    Gällström, Andreas
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Holtz, Per-Olof
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Chen, C.C.
    Chen, K.H.
    High-phase-purity zinc-blende InN on r -plane sapphire substrate with controlled nitridation pretreatment2008In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 92, no 11Article in journal (Refereed)
    Abstract [en]

    High-phase-purity zinc-blende (zb) InN thin film has been grown by plasma-assisted molecular-beam epitaxy on r -plane sapphire substrate pretreated with nitridation. X-ray diffraction analysis shows that the phase of the InN films changes from wurtzite (w) InN to a mixture of w-InN and zb-InN, to zb-InN with increasing nitridation time. High-resolution transmission electron microscopy reveals an ultrathin crystallized interlayer produced by substrate nitridation, which plays an important role in controlling the InN phase. Photoluminescence emission of zb-InN measured at 20 K shows a peak at a very low energy, 0.636 eV, and an absorption edge at ∼0.62 eV is observed at 2 K, which is the lowest bandgap reported to date among the III-nitride semiconductors. © 2008 American Institute of Physics.

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