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

Autor(es)

Couto, Jr., O. D. D. ; de Almeida, P. T. ; dos Santos, G. E. ; Balanta, M. A. G. ; Andriolo, H. F. ; Brum, J. A. ; Brasil, M. J. S. P. ; Iikawa, F. ; Liang, B. L. ; Huffaker, D. L.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Applied Physics; v. 120, n. 8 AUG 28 2016.
• Citações Web of Science: 1

Resumo

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 mu s for QDs depending on the spacer layer thickness. Published by AIP Publishing. (AU)

• Processo FAPESP: 14/17141-9 - EMU concedido no processo 2012/11382-9: espectrômetro (iHR550) mais detector tipo ICCD (SII-3LS-256-BR)-Horiba
• Beneficiário: Odilon Divino Damasceno Couto Júnior
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários
• Processo FAPESP: 12/11382-9 - Modulação ótica de sistemas nanoestruturados usando ondas acústicas de superfícies
• Beneficiário: Odilon Divino Damasceno Couto Júnior
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores