physica status solidi (RRL) - Rapid Research Letters

Cover image for Vol. 4 Issue 11

November 2010

Volume 4, Issue 11

Pages A99–A111, 299–339

  1. Cover Picture

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    4. NEW IN pss
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    1. Cover Picture: Phys. Status Solidi RRL 11/2010

      Version of Record online: 11 NOV 2010 | DOI: 10.1002/pssr.201090015

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      Micromorph silicon solar cells have the potential to combine low costs with high efficiencies in a thin film photovoltaic technology. To this achievement, light scattering is a crucial point. In their Letter on page 326, the authors configure the cell front electrode to enable separate studies of its light scattering and carrier absorption properties as factors influencing the device efficiency. They can thus link directly the fraction of light that is transmitted diffusively by the front electrode with the current output, and give the minimal value required to exploit the full potential of a micromorph cell.

  2. Contents

    1. Top of page
    2. Cover Picture
    3. Contents
    4. NEW IN pss
    5. Rapid Research Letters
    6. Conference calendar
    7. Information for authors
  3. NEW IN pss

    1. Top of page
    2. Cover Picture
    3. Contents
    4. NEW IN pss
    5. Rapid Research Letters
    6. Conference calendar
    7. Information for authors
  4. Rapid Research Letters

    1. Top of page
    2. Cover Picture
    3. Contents
    4. NEW IN pss
    5. Rapid Research Letters
    6. Conference calendar
    7. Information for authors
    1. Fabrication of open-ended TiO2 nanotube arrays by a simple two-step anodization (pages 299–301)

      Zhi-Kun Zhang, Deng-Zhu Guo, Ying-Jie Xing and Geng-Min Zhang

      Version of Record online: 8 SEP 2010 | DOI: 10.1002/pssr.201004327

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      The removal of barrier layer at the bottom of anodized TiO2 nanotube arrays is considered to have positive effects on their photocatalytic activity and potential applications. The Letter demonstrates a two-step anodizing approach for the fabrication of large-scale open-ended TiO2 nanotube arrays from a Ti/Au bilayer film. The approach is simple and acid-free, and the generated opening diameter at the bottom almost equals to the pore diameter at the top.

    2. High-temperature stability of suspended single-layer graphene (pages 302–304)

      Kwanpyo Kim, William Regan, Baisong Geng, Benjamín Alemán, B. M. Kessler, Feng Wang, M. F. Crommie and A. Zettl

      Version of Record online: 18 AUG 2010 | DOI: 10.1002/pssr.201000244

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      This letter investigates high-temperature stability of suspended single-layer graphene via in situ Joule heating in a transmission electron microscope. Thermally-driven degradation of pre-deposited Au nanoparticles on the graphene is monitored and used for local temperature estimation. The suspended monolayer graphene has exceptional thermal stability up to at least 2600 K.

    3. Chloride-based CVD of 3C-SiC epitaxial layers on 6H(0001) SiC (pages 305–307)

      Stefano Leone, Franziska C. Beyer, Anne Henry, Olof Kordina and Erik Janzén

      Version of Record online: 11 NOV 2010 | DOI: 10.1002/pssr.201004271

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      The authors achieved single-domain 3C-SiC epitaxial growth by chloride-base CVD. By optimizing a low temperature process and a carbon-rich surface preparation, the growth of very pure and high crystalline quality 3C-SiC layer was performed on 6H-SiC on-axis substrates, at a rate of 10 μm/h. The use chlorinated chemistry allowed a wider window of operating parameters, while the intentional doping of nitrogen favored the growth of single domain 3C-SiC.

    4. Characterization of InGaGdN layers prepared by molecular beam epitaxy (pages 308–310)

      Siti Nooraya Mohd Tawil, Rina Kakimi, Daivasigamani Krishnamurthy, Shuichi Emura, Hiroyuki Tambo, Shigehiko Hasegawa and Hajime Asahi

      Version of Record online: 31 AUG 2010 | DOI: 10.1002/pssr.201004273

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      In this Letter, the authors explore the realization of InGaGdN epilayers through in-situ doping of Gd into InGaN by molecular-beam epitaxy. The magnetization versus magnetic field curves of InGaGdN indicate a possible ferromagnetic behavior at 10 K and 300 K. Co-doping with Si into InGaGdN has further enhanced its magnetic and electronic properties.

    5. Mg-doped Al0.85Ga0.15N layers grown by hot-wall MOCVD with low resistivity at room temperature (pages 311–313)

      A. Kakanakova-Georgieva, D. Nilsson, M. Stattin, U. Forsberg, Å. Haglund, A. Larsson and E. Janzén

      Version of Record online: 2 SEP 2010 | DOI: 10.1002/pssr.201004290

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      This work is tackling the low resistivity of p-type AlGaN layers, an obstacle for the advancement of deep ultraviolet LED technology. A room temperature resistivity of 7 kΩcm for Mg-doped AlxGa1–xN layers with an Al content as high as x ∼ 0.85 grown on SiC is reported. The enhanced p-type conductivity is believed to be due to reduced compensation by native defects achieved by growth conditions enabled by the distinct hot-wall MOCVD system.

    6. Magnetic characterization of Bi2FeMnO6 film grown on (100) SrTiO3 substrate (pages 314–316)

      Hongyang Zhao, Hideo Kimura, Zhenxiang Cheng, Xiaolin Wang, Kiyoshi Ozawa and Takashi Nishida

      Version of Record online: 1 SEP 2010 | DOI: 10.1002/pssr.201004337

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      Because of the complexity of the double perovskite system, there are still open questions about the violation of Goodenough–Kanamori rules in some cases. The authors chose the Bi2FeMnO6 (BFM) system in order to discuss three aspects in their Letter: The origin of the ferromagnetism or antiferromagnetism, the origin of in-plane/out-of-plane anisotropy, and the spin-glass-like behavior in BFM films.

    7. Improved thermoelectric figure of merit of self-doped Ag8–xGeTe6 compounds with glass-like thermal conductivity (pages 317–319)

      T. J. Zhu, S. N. Zhang, S. H. Yang and X. B. Zhao

      Version of Record online: 11 NOV 2010 | DOI: 10.1002/pssr.201004278

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      This Letter reports thermal conductivity of Ag8–x GeTe6 thermoelectric materials with complex crystal structure close to the theoretical minimum thermal conductivity κmin, indicating that the compounds approach the ideal “phonon-glass” materials. Ag deficiency leads to the improved electrical properties and a maximum thermoelectric figure of merit ZT of 0.85 was obtained for Ag7.99GeTe6, about 30% increase compared to that of Ag8GeTe6.

    8. Effect of localized states on internal quantum efficiency of III-nitride LEDs (pages 320–322)

      Sergey Yu. Karpov

      Version of Record online: 7 SEP 2010 | DOI: 10.1002/pssr.201004325

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      In this Letter a simple model is suggested accounting for the effect of localized states induced by composition fluctuations in InGaN quantum wells and Auger recombination on internal quantum efficiency (IQE) of III-nitride LEDs. Within the unified approach, the model provides an explanation of the IQE behavior recently measured in a wide range of temperature and current density variation.

    9. High critical oxygen concentration in microcrystalline silicon solar cells (pages 323–325)

      Tsvetelina Merdzhanova, Jan Woerdenweber, Wolfhard Beyer, Uwe Zastrow, Helmut Stiebig and Aad Gordijn

      Version of Record online: 18 AUG 2010 | DOI: 10.1002/pssr.201004312

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      This letter presents the effect of discharge power on the critical oxygen concentration (COcrit) for the intrinsic layer of μc-Si:H p–i–n solar cells prepared by plasma-enhanced chemical vapour deposition. The COcrit defines the lowest concentration that causes a deterioration of the cell performance. A regime with a lower power (0.2 W/cm2) was used to deposit state-of-the-art cells with a COcrit of 1 × 1020 cm–3. The authors propose that a low power cannot decompose the Si–O–Si molecules (reaction of oxygen and silane) and the incorporation of oxygen occurs in an electrically inactive configuration.

    10. Unlinking absorption and haze in thin film silicon solar cells front electrodes (pages 326–328)

      Mathieu Boccard, Peter Cuony, Corsin Battaglia, Matthieu Despeisse and Christophe Ballif

      Version of Record online: 26 AUG 2010 | DOI: 10.1002/pssr.201004303

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      This Letter reports on a cell where the front electrode is configured to enable separate studies of its light scattering and carrier absorption properties as factors influencing the device efficiency. The authors directly link the fraction of light that is transmitted diffusively by the front electrode with the current output, and give the minimal value required to exploit the full potential of a micromorph cell.

    11. Organic solar cells with very high fill factor and voltage using tetrapropyl-tetraphenyl-diindenoperylene as green donor (pages 329–331)

      Jan Meiss, Markus Hummert, Hannah Ziehlke, Karl Leo and Moritz Riede

      Version of Record online: 7 SEP 2010 | DOI: 10.1002/pssr.201004310

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      A tetrapropyl-tetraphenyl-diindenoperylene derivative (P4-Ph4-DIP) is presented as green donor for small-molecule organic solar cells. Using the fullerene C60 as acceptor, flat heterojunction devices with extremely high fill factors >76% and high voltages (0.99 V) are obtained. The performance of such devices is limited by the photocurrent, which may be linked to the exciton diffusion length.

    12. Impacts of fluorine on GaN high electron mobility transistors: Theoretical study (pages 332–334)

      Ki-Ha Hong, Injun Hwang, Hyuk Soon Choi, Jaejoon Oh, Jaikwang Shin, U-In Chung and Jongseob Kim

      Version of Record online: 10 SEP 2010 | DOI: 10.1002/pssr.201004313

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      In this Letter the role of fluorine incorporated in GaN-based HEMTs is investigated by performing first principle calculations and device TCAD simulations. Formation energy calculations of F in GaN and AlN reveal that interstitial F (Fi) and substitutional F at N sites (FN) could play an important role in the performance of HEMTs. Fi is responsible for positive threshold voltage (Vth) shift and the degradation of device performance at high temperature is ascribed to FN.

    13. Investigation of electron delay in the base on noise performance in InGaP heterojunction bipolar transistors (pages 335–337)

      A. Shimukovitch, P. Sakalas, P. Zampardi, M. Schroter and A. Matulionis

      Version of Record online: 10 SEP 2010 | DOI: 10.1002/pssr.201004340

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      This Letter investigates the noise performance of devices with a different base width, revealing that the minority carrier delay in the base is not the main mechanism shaping the NFmin(JC) behaviour. Inter-valley transfer from Γ to L or X valleys is partly responsible, introducing space charge and additional signal delay and Coulomb shot noise blockade. The Fano factor in the expression for the spectral density of collector current noise power plays a significant role reducing collector current shot noise.

    14. Fe valence state at the surface of the Fe0.5Cu0.5Cr2S4 spinel (pages 338–339)

      Christian Taubitz, Zhiwei Hu, Nils Hollmann, Yi-Ying Chin, Karsten Kuepper, Vladimir Tsurkan, H.-J. Lin, C. T. Chen, L. H. Tjeng and Manfred Neumann

      Version of Record online: 10 SEP 2010 | DOI: 10.1002/pssr.201004302

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      The authors of this Letter investigate single crystalline Fe0.5Cu0.5Cr2S4 in order to solve a long standing issue. This material has attracted considerable attention due to a variety of interesting electronic and magnetic properties. In spite of many efforts, the Fe valence state of Fe0.5Cu0.5Cr2S4 is still under discussion. Here X-ray absorption spectra are presented that, surprisingly, show Fe to be in an inhomogeneous valence state.

  5. Conference calendar

    1. Top of page
    2. Cover Picture
    3. Contents
    4. NEW IN pss
    5. Rapid Research Letters
    6. Conference calendar
    7. Information for authors
  6. Information for authors

    1. Top of page
    2. Cover Picture
    3. Contents
    4. NEW IN pss
    5. Rapid Research Letters
    6. Conference calendar
    7. Information for authors

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