The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

Laurens W. Molenkamp - One of the best experts on this subject based on the ideXlab platform.

  • large Depletion Region at the epitaxial n znse gaas heterointerface
    Semiconductor Science and Technology, 2009
    Co-Authors: A Frey, F. Lehmann, P. Grabs, C. Gould, Georg Schmidt, K Brunner, Laurens W. Molenkamp
    Abstract:

    The extent of the Depletion Region at an n-ZnSe/GaAs heterointerface in MBE grown epilayers has been investigated by thickness-dependent Hall measurements. Exceptionally large Depletion widths of up to 110 nm have been found on the ZnSe side. The Depletion cannot be caused by charge transfer or interface states alone, but is attributed to compensation due to large scale atomic interdiffusion across the heterointerface. A II?VI buffer layer structure is demonstrated to shield the effects of the Depletion from sensitive device layers grown on top, and to prevent parallel conduction by lateral and vertical transport through the substrate and the lower-lying buffer layers.

  • Large Depletion Region at the epitaxial n-ZnSe/GaAs heterointerface
    Semiconductor Science and Technology, 2009
    Co-Authors: A Frey, F. Lehmann, P. Grabs, C. Gould, Georg Schmidt, K Brunner, Laurens W. Molenkamp
    Abstract:

    The extent of the Depletion Region at an n-ZnSe/GaAs heterointerface in MBE grown epilayers has been investigated by thickness-dependent Hall measurements. Exceptionally large Depletion widths of up to 110 nm have been found on the ZnSe side. The Depletion cannot be caused by charge transfer or interface states alone, but is attributed to compensation due to large scale atomic interdiffusion across the heterointerface. A II?VI buffer layer structure is demonstrated to shield the effects of the Depletion from sensitive device layers grown on top, and to prevent parallel conduction by lateral and vertical transport through the substrate and the lower-lying buffer layers.

Zhigang Zou - One of the best experts on this subject based on the ideXlab platform.

  • oriented growth ta3n5 srtao2n array heterojunction with extended Depletion Region for improved water oxidation
    Applied Catalysis B-environmental, 2020
    Co-Authors: Yanghui Hou, Shicheng Yan, Zhigang Zou
    Abstract:

    Abstract Depletion Region at solid-solid or solid-liquid interface is mainly responsible for separating charge. Extending Depletion Region is an effective strategy to promote charge separation, and thus improving photoelectrochemical (PEC) performance. Herein, we designed an array heterojunction photoanode consisting of a-axis oriented-growth Ta3N5 nanorod arrays coated by SrTaO2N shell. This array heterojunction with a contiguous Ta3N5/SrTaO2N solid-solid and SrTaO2N/electrolyte solid-liquid junctions maximizes the charge separation and light absorption in Depletion layer, shortens the hole diffusion distance to electrolyte, and effectively transfers electrons along the a-axis (light electron effective mass) of Ta3N5 to conductive substrate. As a result, compared with Ta3N5, Ta3N5/SrTaO2N array heterojunction exhibits more excellent PEC performance. Our results demonstrated a potential crystal oriented growth strategy of nanostructured heterojunctions with extended Depletion Region for promoting charge separation and overcoming the short carrier diffusion distance.

  • Oriented-growth Ta3N5/SrTaO2N array heterojunction with extended Depletion Region for improved water oxidation
    Applied Catalysis B: Environmental, 2020
    Co-Authors: Yanghui Hou, Shicheng Yan, Zhigang Zou
    Abstract:

    Abstract Depletion Region at solid-solid or solid-liquid interface is mainly responsible for separating charge. Extending Depletion Region is an effective strategy to promote charge separation, and thus improving photoelectrochemical (PEC) performance. Herein, we designed an array heterojunction photoanode consisting of a-axis oriented-growth Ta3N5 nanorod arrays coated by SrTaO2N shell. This array heterojunction with a contiguous Ta3N5/SrTaO2N solid-solid and SrTaO2N/electrolyte solid-liquid junctions maximizes the charge separation and light absorption in Depletion layer, shortens the hole diffusion distance to electrolyte, and effectively transfers electrons along the a-axis (light electron effective mass) of Ta3N5 to conductive substrate. As a result, compared with Ta3N5, Ta3N5/SrTaO2N array heterojunction exhibits more excellent PEC performance. Our results demonstrated a potential crystal oriented growth strategy of nanostructured heterojunctions with extended Depletion Region for promoting charge separation and overcoming the short carrier diffusion distance.

Bashar Bakour - One of the best experts on this subject based on the ideXlab platform.

  • influence of Depletion Region width on performance of solar cell under sunlight concentration
    Energy Procedia, 2011
    Co-Authors: Khalaf Al Abdullah, Bashar Bakour
    Abstract:

    Abstract A new interpretation of high injection effect of minority carriers,np, which is happened in solar cell under sunlight concentration and imposed a limitation on its expected efficiency- has been introduced. This interpretation declare that: increasing of minority carrier, np, recombination current Irecom in deplation Region when sunlight concentration C increase,s due to the Depletion layer widen because the increasing of drift electric field at the junction boundary correspond to population inversion phenomena which happens at the interfaces between the base Region and the Depletion Region. Experiments was performed with operating solar cells under high injection conditions (sunlight concentration simulator) to get I-V characteristics, then we characterize the relation between the Depletion Region width w and Irecom, by suggesting a new model which enable us to optimize a solar sell under sunlight concentration. In consequence we cocnlude that: Irecom is responsible of depleting a significant part of minority carrier, consequently, Irecom causes the solar cell efficiency degradation.

  • influence of Depletion Region width on performance of solar cell under sunlight concentration
    Energy Procedia, 2011
    Co-Authors: Khalaf Al Abdullah, Bashar Bakour
    Abstract:

    Abstract A new interpretation of high injection effect of minority carriers,np, which is happened in solar cell under sunlight concentration and imposed a limitation on its expected efficiency- has been introduced. This interpretation declare that: increasing of minority carrier, np, recombination current Irecom in deplation Region when sunlight concentration C increase,s due to the Depletion layer widen because the increasing of drift electric field at the junction boundary correspond to population inversion phenomena which happens at the interfaces between the base Region and the Depletion Region. Experiments was performed with operating solar cells under high injection conditions (sunlight concentration simulator) to get I-V characteristics, then we characterize the relation between the Depletion Region width w and Irecom, by suggesting a new model which enable us to optimize a solar sell under sunlight concentration. In consequence we cocnlude that: Irecom is responsible of depleting a significant part of minority carrier, consequently, Irecom causes the solar cell efficiency degradation.

Mark S. Hybertsen - One of the best experts on this subject based on the ideXlab platform.

  • semiconductor based photoelectrochemical water splitting at the limit of very wide Depletion Region
    Advanced Functional Materials, 2016
    Co-Authors: Mingzhao Liu, John L. Lyons, Danhua Yan, Mark S. Hybertsen
    Abstract:

    In semiconductor-based photoelectrochemical (PEC) water splitting, carrier separation and delivery largely relies on the Depletion Region formed at the semiconductor/water interface. As a Schottky junction device, the trade-off between photon collection and minority carrier delivery remains a persistent obstacle for maximizing the performance of a water splitting photoelectrode. Here, it is demonstrated that the PEC water splitting efficiency for an n-SrTiO3 (n-STO) photoanode is improved very significantly despite its weak indirect band gap optical absorption (α 3 photoanodes are fabricated with their bulk heavily doped with oxygen vacancies but their surface lightly doped over a tunable depth of a few hundred nanometers, through a simple low temperature re-oxidation technique. The graded doping profile widens the Depletion Region to over 500 nm, thus leading to very efficient charge carrier separation and high quantum efficiency (>70%) for the weak indirect transition. As a result, this simultaneous optimization of the light absorption, minority carrier (hole) delivery, and majority carrier (electron) transport by means of a graded doping architecture may be useful for other indirect band gap photocatalysts that suffer from a similar problem of weak optical absorption.

  • Semiconductor‐Based Photoelectrochemical Water Splitting at the Limit of Very Wide Depletion Region
    Advanced Functional Materials, 2015
    Co-Authors: Mingzhao Liu, John L. Lyons, Danhua Yan, Mark S. Hybertsen
    Abstract:

    In semiconductor-based photoelectrochemical (PEC) water splitting, carrier separation and delivery largely relies on the Depletion Region formed at the semiconductor/water interface. As a Schottky junction device, the trade-off between photon collection and minority carrier delivery remains a persistent obstacle for maximizing the performance of a water splitting photoelectrode. Here, it is demonstrated that the PEC water splitting efficiency for an n-SrTiO3 (n-STO) photoanode is improved very significantly despite its weak indirect band gap optical absorption (α 3 photoanodes are fabricated with their bulk heavily doped with oxygen vacancies but their surface lightly doped over a tunable depth of a few hundred nanometers, through a simple low temperature re-oxidation technique. The graded doping profile widens the Depletion Region to over 500 nm, thus leading to very efficient charge carrier separation and high quantum efficiency (>70%) for the weak indirect transition. As a result, this simultaneous optimization of the light absorption, minority carrier (hole) delivery, and majority carrier (electron) transport by means of a graded doping architecture may be useful for other indirect band gap photocatalysts that suffer from a similar problem of weak optical absorption.

A Frey - One of the best experts on this subject based on the ideXlab platform.

  • large Depletion Region at the epitaxial n znse gaas heterointerface
    Semiconductor Science and Technology, 2009
    Co-Authors: A Frey, F. Lehmann, P. Grabs, C. Gould, Georg Schmidt, K Brunner, Laurens W. Molenkamp
    Abstract:

    The extent of the Depletion Region at an n-ZnSe/GaAs heterointerface in MBE grown epilayers has been investigated by thickness-dependent Hall measurements. Exceptionally large Depletion widths of up to 110 nm have been found on the ZnSe side. The Depletion cannot be caused by charge transfer or interface states alone, but is attributed to compensation due to large scale atomic interdiffusion across the heterointerface. A II?VI buffer layer structure is demonstrated to shield the effects of the Depletion from sensitive device layers grown on top, and to prevent parallel conduction by lateral and vertical transport through the substrate and the lower-lying buffer layers.

  • Large Depletion Region at the epitaxial n-ZnSe/GaAs heterointerface
    Semiconductor Science and Technology, 2009
    Co-Authors: A Frey, F. Lehmann, P. Grabs, C. Gould, Georg Schmidt, K Brunner, Laurens W. Molenkamp
    Abstract:

    The extent of the Depletion Region at an n-ZnSe/GaAs heterointerface in MBE grown epilayers has been investigated by thickness-dependent Hall measurements. Exceptionally large Depletion widths of up to 110 nm have been found on the ZnSe side. The Depletion cannot be caused by charge transfer or interface states alone, but is attributed to compensation due to large scale atomic interdiffusion across the heterointerface. A II?VI buffer layer structure is demonstrated to shield the effects of the Depletion from sensitive device layers grown on top, and to prevent parallel conduction by lateral and vertical transport through the substrate and the lower-lying buffer layers.