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Title: Enhancement of carrier lifetimes in type-II quantum dot/quantum well hybrid structures

Abstract

We investigate optical transitions and carrier dynamics in hybrid structures containing type-I GaAs/AlGaAs quantum wells (QWs) and type-II GaSb/AlGaAs quantum dots (QDs). We show that the optical recombination of photocreated electrons confined in the QWs with holes in the QDs and wetting layer can be modified according to the QW/QD spatial separation. In particular, for low spacer thicknesses, the QW optical emission can be suppressed due to the transference of holes from the QW to the GaSb layer, favoring the optical recombination of spatially separated carriers, which can be useful for optical memory and solar cell applications. Time-resolved photoluminescence (PL) measurements reveal non-exponential recombination dynamics. We demonstrate that the PL transients can only be quantitatively described by considering both linear and quadratic terms of the carrier density in the bimolecular recombination approximation for type-II semiconductor nanostructures. We extract long exciton lifetimes from 700 ns to 5 μs for QDs depending on the spacer layer thickness.

Authors:
; ; ; ; ; ; ;  [1]; ;  [2]
  1. Instituto de Física “Gleb Wataghin,” Universidade Estadual de Campinas, 13083-859 Campinas, São Paulo (Brazil)
  2. California NanoSystems Institute, UCLA, Los Angeles, California 90095 (United States)
Publication Date:
OSTI Identifier:
22598834
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 120; Journal Issue: 8; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALUMINIUM ARSENIDES; CARRIER DENSITY; CARRIER LIFETIME; ELECTRONS; GALLIUM ANTIMONIDES; GALLIUM ARSENIDES; LAYERS; PHOTOLUMINESCENCE; QUANTUM DOTS; QUANTUM WELLS; RECOMBINATION; SEMICONDUCTOR MATERIALS; THICKNESS; TIME RESOLUTION; TRANSIENTS

Citation Formats

Couto, O. D. D., E-mail: odilon@ifi.unicamp.br, Almeida, P. T. de, Santos, G. E. dos, Balanta, M. A. G., Andriolo, H. F., Brum, J. A., Brasil, M. J. S. P., Iikawa, F., Liang, B. L., E-mail: bliang@cnsi.ucla.edu, and Huffaker, D. L.. Enhancement of carrier lifetimes in type-II quantum dot/quantum well hybrid structures. United States: N. p., 2016. Web. doi:10.1063/1.4961534.
Couto, O. D. D., E-mail: odilon@ifi.unicamp.br, Almeida, P. T. de, Santos, G. E. dos, Balanta, M. A. G., Andriolo, H. F., Brum, J. A., Brasil, M. J. S. P., Iikawa, F., Liang, B. L., E-mail: bliang@cnsi.ucla.edu, & Huffaker, D. L.. Enhancement of carrier lifetimes in type-II quantum dot/quantum well hybrid structures. United States. doi:10.1063/1.4961534.
Couto, O. D. D., E-mail: odilon@ifi.unicamp.br, Almeida, P. T. de, Santos, G. E. dos, Balanta, M. A. G., Andriolo, H. F., Brum, J. A., Brasil, M. J. S. P., Iikawa, F., Liang, B. L., E-mail: bliang@cnsi.ucla.edu, and Huffaker, D. L.. Sun . "Enhancement of carrier lifetimes in type-II quantum dot/quantum well hybrid structures". United States. doi:10.1063/1.4961534.
@article{osti_22598834,
title = {Enhancement of carrier lifetimes in type-II quantum dot/quantum well hybrid structures},
author = {Couto, O. D. D., E-mail: odilon@ifi.unicamp.br and Almeida, P. T. de and Santos, G. E. dos and Balanta, M. A. G. and Andriolo, H. F. and Brum, J. A. and Brasil, M. J. S. P. and Iikawa, F. and Liang, B. L., E-mail: bliang@cnsi.ucla.edu and Huffaker, D. L.},
abstractNote = {We investigate optical transitions and carrier dynamics in hybrid structures containing type-I GaAs/AlGaAs quantum wells (QWs) and type-II GaSb/AlGaAs quantum dots (QDs). We show that the optical recombination of photocreated electrons confined in the QWs with holes in the QDs and wetting layer can be modified according to the QW/QD spatial separation. In particular, for low spacer thicknesses, the QW optical emission can be suppressed due to the transference of holes from the QW to the GaSb layer, favoring the optical recombination of spatially separated carriers, which can be useful for optical memory and solar cell applications. Time-resolved photoluminescence (PL) measurements reveal non-exponential recombination dynamics. We demonstrate that the PL transients can only be quantitatively described by considering both linear and quadratic terms of the carrier density in the bimolecular recombination approximation for type-II semiconductor nanostructures. We extract long exciton lifetimes from 700 ns to 5 μs for QDs depending on the spacer layer thickness.},
doi = {10.1063/1.4961534},
journal = {Journal of Applied Physics},
number = 8,
volume = 120,
place = {United States},
year = {Sun Aug 28 00:00:00 EDT 2016},
month = {Sun Aug 28 00:00:00 EDT 2016}
}