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AC photoconductivity of type-II InAs/AlAs<sub>1-x</sub>Sb<sub>x</sub> multi-quantum well structure

ORAL

Abstract

InAs/AlAs1-xSbx multi-quantum wells (MQW) are a promising way to understand solar cells design through engineering of long excited-state lifetime and inhibition of phonon interactions. A type-II MQW structure is investigated using time-resolved terahertz spectroscopy as a function of lattice temperature to determine the dynamics of hot carriers. For hot-carrier densities above the Mott density and at low-to-intermediate temperatures, metastability is observed during early times of the transient absorption signal, which exhibits a plateau in the excitation-photon-energy dependence. Meanwhile, AC photoconductivity spectra, analyzed using the Drude-Smith model, shows that the mobility of hot-carriers remains constant above the Mott density and increases with increased carrier recombination. Under the latter excitation conditions, the mobility is consistent with higher scattering rates, attributed to a contribution of L-valley scattering. Finally, the carrier mobility reduces with increasing lattice temperature, inhibited by a phonon bottleneck that keeping both hot carrier and phonon densities high. Therefore, understanding AC photoconductivity of type-II InAs/AlAsSb MQW structures will reveal potential pathways for the development of efficient hot-carrier-based solar cells.

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Presenters

  • Herath Piyathilaka

    Department of Physics and Astronomy, West Virginia University, West Virginia University

Authors

  • Herath Piyathilaka

    Department of Physics and Astronomy, West Virginia University, West Virginia University

  • Rishmali Sooriyagoda

    Department of Physics and Astronomy, West Virginia University, West Virginia University

  • Hamidreza Esmaielpour

    Institut du Photovoltaïque d'Ile de France, Department of Physics and Astronomy, University of Oklahoma

  • Vincent R. Whiteside

    Homer L. Dodge Department of Physics & Astronomy, University of Oklahoma, Department of Physics and Astronomy, University of Oklahoma

  • Tetsuya D Mishima

    Homer L. Dodge Department of Physics & Astronomy, University of Oklahoma, Department of Physics and Astronomy, University of Oklahoma

  • Michael B Santos

    Homer L. Dodge Department of Physics & Astronomy, University of Oklahoma, Department of Physics and Astronomy, University of Oklahoma

  • Ian R Sellers

    Homer L. Dodge Department of Physics & Astronomy, University of Oklahoma, Department of Physics and Astronomy, University of Oklahoma

  • Alan D Bristow

    Department of Physics and Astronomy, West Virginia University, West Virginia University, Physics and Astronomy, West Virginia University