Formation and Optical Characteristics of Type-II Strain-Relieved GaSb/GaAs Quantum Dots by Using an Interfacial Misfit Growth Mode

Author

Tatebayashi, Jun ; Liang, Baolai ; Bussian, David A. ; Htoon, Han ; Huang, Shenghong ; Balakrishnan, Ganesh ; Klimov, Victor ; Dawson, L. Ralph ; Huffaker, Diana L.

Author_Institution

Electr. Eng. Dept., Univ. of California Los Angeles, Los Angeles, CA

Volume

8

Issue

2

fYear

2009

fDate

3/1/2009 12:00:00 AM

Firstpage

269

Lastpage

274

Abstract

We report the formation and optical characteristics of GaSb/GaAs type-II quantum dots (QDs) by using an interfacial misfit (IMF) growth mode. A V/III ratio during the growth of GaSb QDs determines the selectivity of IMF and conventional Stranski-Krastanov (SK) growth modes. This transition between SK and optimized IMF QDs is rather abrupt and occurs within a factor-of-2 variations in V/III ratio. The IMF QDs emit at longer wavelength (cong1.1 mum) compared to the SK QD peak emission at cong1.02 mum at low temperature (LT) (4 K) because of their strain-free nature of the IMF growth mode. A blueshift of the photoluminescence (PL) peak is observed with increased excitation densities due to the Coulomb interaction between physically separated electrons and holes characteristics of the type-II band alignment. LT time-resolved PL measurements show a long decay time of cong20-40 ns from the transition between GaSb IMF QDs and GaAs 2-D electron gas, which is characteristic of the type-II band alignment.

Keywords

III-V semiconductors; gallium arsenide; gallium compounds; photoluminescence; semiconductor growth; semiconductor quantum dots; time resolved spectra; two-dimensional electron gas; 2D electron gas; Coulomb interaction; GaSb-GaAs; blueshift; conventional Stranski-Krastanov growth mode; excitation densities; interfacial misfit growth mode; long decay time; optical characteristics; quantum dot growth; time-resolved photoluminescence; type-II band alignment; type-II strain-relieved quantum dot formation; GaSb/GaAs; interfacial misfit (IMF); quantum dots (QDs); strain-relieved; time-resolved photoluminescence (TRPL); type-II;

fLanguage

English

Journal_Title

Nanotechnology, IEEE Transactions on

Publisher

ieee

ISSN

1536-125X

Type

jour

DOI

10.1109/TNANO.2008.2008717

Filename

4667660