Hot-carrier dynamics in InAs/AlAsSb multiple-quantum wells

Herath P. Piyathilaka; Rishmali Sooriyagoda; Hamidreza Esmaielpour; Vincent R. Whiteside; Tetsuya D. Mishima; Michael B. Santos; Ian R. Sellers; Alan D. Bristow

arXiv · 2103.03839

Hot-carrier dynamics in InAs/AlAsSb multiple-quantum wells

Herath P. Piyathilaka·Rishmali Sooriyagoda·Hamidreza Esmaielpour·Vincent R. Whiteside·Tetsuya D. Mishima·Michael B. Santos·Ian R. Sellers·Alan D. Bristow

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Abstract

A type-II InAs/AlAs$_{0.16}$Sb$_{0.84}$ multiple-quantum well sample is investigated for the photoexcited carrier dynamics as a function of excitation photon energy and lattice temperature. Time-resolved measurements are performed using a near-infrared pump pulse, with photon energies near to and above the band gap, probed with a terahertz probe pulse. The transient terahertz absorption is characterized by a multi-rise, multi-decay function that captures long-lived decay times and a metastable state of for an excess-photon energy of $>100$ meV. For sufficient excess-photon energy, excitation of the metastable state is followed by a transition to the long-lived states. Excitation dependence of the long-lived states map onto a near-direct band gap ($E{_g}$) density of states with an Urbach tail below $E{_g}$. As temperature increases, the long-lived decay times increase $ E{_g}$. Additionally, Auger (and/or trap-assisted Auger) scattering above the onset of the plateau may also contribute to longer hot-carrier lifetimes. Meanwhile, the initial decay component shows strong dependence on excitation energy and temperature, reflecting the complicated initial transfer of energy between valence-band and defect states, indicating methods to further prolong hot carriers for technological applications.

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Herath P. Piyathilaka, Rishmali Sooriyagoda, Hamidreza Esmaielpour, Vincent R. Whiteside, Tetsuya D. Mishima, Michael B. Santos, Ian R. Sellers, Alan D. Bristow. 2021-03-05. Hot-carrier dynamics in InAs/AlAsSb multiple-quantum wells. https://arxiv.org/abs/2103.03839

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