The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform

Wan Ping Chen - One of the best experts on this subject based on the ideXlab platform.

  • Hydrogen-Induced Degradation in SrTiO3-based grain boundary barrier layer ceramic capacitors
    Ceramics International, 2009
    Co-Authors: Zj J. Shen, Wan Ping Chen, Yu Wang, K. Zhu, Y. Zhuang, Helen L. W. Chan
    Abstract:

    Abstract Hydrogen-Induced Degradation in SrTiO3-based grain boundary barrier layer ceramic capacitors was studied through electrochemical hydrogen charging, in which the capacitors were placed in 0.01 M NaOH solution with hydrogen deposited on their electrodes from the electrolysis of water. The properties of the capacitors were greatly degraded after 0.5 h of treatment: The capacitance was dramatically decreased and the dielectric loss was dramatically increased over the frequency range of 102–105 Hz, the leakage current was increased by orders of magnitude. It was proposed that atomic hydrogen diffused relatively easily along the grain boundaries and Induced a reduction reaction to the grain boundary layer, which resulted in the Degradation observed. Hydrogen-Induced Degradation is more serious in SrTiO3-based grain boundary barrier layer ceramic capacitors than in other ceramic capacitors and great efforts should be made to prevent hydrogen-Induced Degradation in them.

  • Water-Induced Degradation in BaTiO3-based barrier layer capacitors
    Journal of Electroceramics, 2007
    Co-Authors: Wen Chao You, Wan Ping Chen, Wang Xiang, Hong Ming Zhou
    Abstract:

    Water-Induced Degradation in BaTiO3-based surface barrier layer capacitors (BLCs) were studied through two comparison treatments: in one treatment some BLCs were simply immersed in a 0.01-M NaOH for some time, while in the other treatment, some BLCs were placed in a 0.01-M NaOH solution with their silver electrodes acting as the cathode to electrolyze water. No Degradation occurred in the samples that were immersed in the NaOH solution, but for the samples treated by the electrolysis of water, their leakage current was increased by orders of magnitude, their capacitance dramatically decreased, and the dielectric loss dramatically increased at low frequencies. It is proposed that atomic hydrogen generated in the electrolysis of water entered into the barrier layer of the BLCs, increased the concentration of charge carriers by reducing some Ti4+ to Ti3+ in the barrier layer. Much attention should be paid to prevent water-Induced Degradation in BLCs.

  • Hydrogen-Induced Degradation in CaCu3Ti4O12 ceramics
    Journal of Alloys and Compounds, 2006
    Co-Authors: Wan Ping Chen, Wang Xiang, Ming Sen Guo, Wen Chao You, Xing Zhong Zhao, Helen L. W. Chan
    Abstract:

    Abstract Hydrogen-Induced Degradation in CaCu 3 Ti 4 O 12 (CCTO) ceramics was studied using an electrochemical hydrogen charging method, in which the silver electrodes of CCTO ceramic pellets were made a cathode in 0.01 M NaOH solution to deposit hydrogen through the electrolysis of water. The dielectric loss was greatly increased and the insulation resistance was greatly decreased after the treatment. X-ray diffraction analysis showed that no new phases were formed. It is proposed that atomic hydrogen is diffused into CCTO lattice and free electrons are formed through the ionization of hydrogen atoms, which lead to the observed Degradation. Hydrogen-Induced Degradation occurs very quickly in CCTO ceramics and it is important to prevent hydrogen-Induced Degradation in CCTO ceramics.

  • Hydrogen-Induced Degradation in strontium titanate single crystals
    Applied Physics A, 2005
    Co-Authors: Wan Ping Chen, Jiyan Dai, Yu Wang, Helen L. W. Chan
    Abstract:

    Hydrogen-Induced Degradation in strontium titanate single crystals was studied through an electrochemical hydrogen charging process, in which the silver electrodes of the crystals were made a cathode in 0.01 M NaOH solution to evolve hydrogen by electrolysis of water. After the process, the resistance of the crystals was decreased by more than one order of magnitude, the dielectric loss was obviously increased, and the capacitance became more dependent on frequency. It is proposed that atomic hydrogen generated by electrolysis of water diffuses into the crystals and exists as a charged interstitial impurity donating electrons to the conduction band of the crystals. Attention should be paid to this hydrogen-Induced Degradation when the reliability of perovskite-type ferroelectric devices and components is studied.

  • Hydrogen-Induced Degradation in NiCuZn ferrite-based multilayer chip inductors
    Materials Letters, 2005
    Co-Authors: Wan Ping Chen, Yu Wang, X-h. Wang, Zw W., Helen L. W. Chan
    Abstract:

    Abstract Hydrogen-Induced Degradation in Ni 0.38 Cu 0.12 Zn 0.50 Fe 2 O 4 -based multilayer ceramic chip inductors was studied through an electrochemical hydrogen charging method, in which the silver electrodes of the inductors were made a cathode in 0.01 M NaOH solution to evolve hydrogen by the electrolysis of water. After the treatment, the inductance and the quality factor of the inductors at high frequencies were dramatically decreased. The Degradation showed a little spontaneous recovery at room temperature and could be mostly recovered through a heat-treatment of 4 h at 250 °C in N 2 . It is proposed that hydrogen generated by the electrolysis of water is incorporated into the ferrite lattice and exists as an interstitial proton after reducing Fe 3+ to Fe 2+ . The stability of hydrogen in ferrites decreased with increasing temperature and its outdiffusion resulted in the recovery. Hydrogen-Induced Degradation is important to ferrite-based chip inductors in fabrication and in operation.

Yusuke Mori - One of the best experts on this subject based on the ideXlab platform.

Martin C. Schubert - One of the best experts on this subject based on the ideXlab platform.

  • Light-Induced Degradation and Regeneration in n-type Silicon
    Energy Procedia, 2015
    Co-Authors: Tim Niewelt, Juliane Broisch, Jonas Schön, Jonas Haunschild, Stefan Rein, Wilhelm Warta, Martin C. Schubert
    Abstract:

    Abstract Whereas n-type silicon wafers are used for many high-efficiency cells concepts, the unfavourable segregation coefficient of phosphorus leads to significant resistivity variation along the ingot. Crystals grown by counter doping with boron or from umg silicon feedstock might offer a solution, but these materials suffer from light-Induced Degradation due to the boron oxygen defect. In this manuscript, we demonstrate the application of a curing process to B-P compensated n-type Cz silicon. Significant charge carrier lifetime improvements are achieved and a high degree of stability is proven with extensive light soaking experiments. The observation of slight lifetime changes during light soaking is attributed to incompleteness of the curing due to not optimized process parameters. We demonstrate stable lifetimes exceeding 1 ms in wafers with high boron and interstitial oxygen concentrations. Similar top-type silicon the illumination intensity and process temperature are found to be crucial for the regeneration process in n-type silicon as well. Furthermore the influence of different diffusion conditions is studied and we attribute the results to an influence of diffusion peak temperature rather than thermal budget. Thus, we can report an illumination-stable high-lifetime state of the BO-defect in compensated n-type silicon and provide further insight to the phenomenon of light-Induced Degradation.

  • Light‐Induced Degradation in copper‐contaminated gallium‐doped silicon
    physica status solidi (RRL) - Rapid Research Letters, 2013
    Co-Authors: Jeanette Lindroos, Marko Yli-koski, Antti Haarahiltunen, Martin C. Schubert, Hele Savin
    Abstract:

    To date, gallium-doped Czochralski (Cz) silicon has constituted a solar cell bulk material free of light-Induced Degradation. However, we measure light-Induced Degradation in gallium-doped Cz silicon in the presence of copper impurities. The measured Degradation depends on the copper concentration and the material resistivity. Gallium-doped Cz silicon is found to be less sensitive to copper impurities than boron-doped Cz silicon, emphasizing the role of boron in the formation of copper-related light-Induced Degradation. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Hele Savin - One of the best experts on this subject based on the ideXlab platform.

  • Preventing light-Induced Degradation in multicrystalline silicon
    Journal of Applied Physics, 2014
    Co-Authors: Jeanette Lindroos, Marko Yli-koski, Yacine Boulfrad, Hele Savin
    Abstract:

    Multicrystalline silicon (mc-Si) is currently dominating the silicon solar cell market due to low ingot costs, but its efficiency is limited by transition metals, extended defects, and light-Induced Degradation (LID). LID is traditionally associated with a boron-oxygen complex, but the origin of the Degradation in the top of the commercial mc-Si brick is revealed to be interstitial copper. We demonstrate that both a large negative corona charge and an aluminum oxide thin film with a built-in negative charge decrease the interstitial copper concentration in the bulk, preventing LID in mc-Si.

  • Light‐Induced Degradation in copper‐contaminated gallium‐doped silicon
    physica status solidi (RRL) - Rapid Research Letters, 2013
    Co-Authors: Jeanette Lindroos, Marko Yli-koski, Antti Haarahiltunen, Martin C. Schubert, Hele Savin
    Abstract:

    To date, gallium-doped Czochralski (Cz) silicon has constituted a solar cell bulk material free of light-Induced Degradation. However, we measure light-Induced Degradation in gallium-doped Cz silicon in the presence of copper impurities. The measured Degradation depends on the copper concentration and the material resistivity. Gallium-doped Cz silicon is found to be less sensitive to copper impurities than boron-doped Cz silicon, emphasizing the role of boron in the formation of copper-related light-Induced Degradation. (© 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

  • Room-temperature method for minimizing light-Induced Degradation in crystalline silicon
    Applied Physics Letters, 2012
    Co-Authors: Jeanette Lindroos, Marko Yli-koski, Antti Haarahiltunen, Hele Savin
    Abstract:

    Although light-Induced Degradation (LID) in crystalline silicon is attributed to the formation of boron-oxygen recombination centers, copper contamination of silicon has recently been observed to result in similar Degradation. As positively charged interstitial copper stays mobile at room temperature in silicon, we show that the bulk copper concentration can be reduced by depositing a large negative charge onto the wafer surface. Consequently, light-Induced Degradation is reduced significantly in both low- and high-resistivity boron-doped Czochralski-grown silicon.

Malcolm Abbott - One of the best experts on this subject based on the ideXlab platform.

  • Hydrogen Induced Degradation: A possible mechanism for light- and elevated temperature- Induced Degradation in n-type silicon
    Solar Energy Materials and Solar Cells, 2018
    Co-Authors: Daniel Chen, Shaoyang Liu, Ran Chen, Catherine Chan, Moonyong Kim, Phillip Hamer, Tsun Hang Fung, Gabrielle Bourret-sicotte, Alison Ciesla, Malcolm Abbott
    Abstract:

    Abstract In this work, we demonstrate a form of minority carrier Degradation on n-type Cz silicon that affects both the bulk and surface related lifetimes. We identify three key behaviors of the Degradation mechanism; 1) a firing dependence for the extent of Degradation, 2) the appearance of bulk Degradation when wafers are fired in the presence of a diffused emitter and 3) a firing related apparent surface Degradation when wafers are fired in the absence of an emitter. We further report a defect capture cross-section ratio of σn/σp = 0.028 ± 0.003 for the defect in n-type. Utilizing our understanding of light and elevated temperature Induced Degradation (LeTID) in p-type silicon, we demonstrate that the Degradation behaviors in both n-type and p-type silicon are closely correlated. In light of numerous reports on the involvement of hydrogen, the potential role of a hydrogen-Induced Degradation mechanism is discussed in both p- and n-type silicon, particularly in relation to the diffusion of hydrogen and influence of hydrogen-dopant interactions.

  • Eliminating Light-Induced Degradation in Commercial p-Type Czochralski Silicon Solar Cells
    MDPI AG, 2017
    Co-Authors: Brett Hallam, Stuart Wenham, Phillip Hamer, Malcolm Abbott, Axel Herguth, Nitin Nampalli, Svenja Wilking, Giso Hahn
    Abstract:

    This paper discusses developments in the mitigation of light-Induced Degradation caused by boron-oxygen defects in boron-doped Czochralski grown silicon. Particular attention is paid to the fabrication of industrial silicon solar cells with treatments for sensitive materials using illuminated annealing. It highlights the importance and desirability of using hydrogen-containing dielectric layers and a subsequent firing process to inject hydrogen throughout the bulk of the silicon solar cell and subsequent illuminated annealing processes for the formation of the boron-oxygen defects and simultaneously manipulate the charge states of hydrogen to enable defect passivation. For the photovoltaic industry with a current capacity of approximately 100 GW peak, the mitigation of boron-oxygen related light-Induced Degradation is a necessity to use cost-effective B-doped silicon while benefitting from the high-efficiency potential of new solar cell concepts