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Optical properties of bimodally distributed InAs quantum dots grown on digital AlAs0.56Sb0.44 matrix for use in intermediate band solar cells

Debnath, Mukul C., Liang, Baolai, Laghumavarapu, Ramesh B., Wang, Guodong, Das, Aparna, Juang, Bor-Chau and Huffaker, Diana 2017. Optical properties of bimodally distributed InAs quantum dots grown on digital AlAs0.56Sb0.44 matrix for use in intermediate band solar cells. Journal of Applied Physics 121 (21) , 214304. 10.1063/1.4984832

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Abstract

High-quality InAs quantum dots (QDs) with nominal thicknesses of 5.0–8.0 monolayers were grown on a digital AlAs0.56Sb0.44 matrix lattice-matched to the InP(001) substrate. All QDs showed bimodal size distribution, and their optical properties were investigated by photoluminescence (PL) and time-resolved PL measurements. Power dependent PL exhibited a linear relationship between the peak energy and the cube root of the excitation power for both the small QD family (SQDF) and the large QD family (LQDF), which is attributed to the type-II transition. The PL intensity, peak energy, and carrier lifetime of SQDF and LQDF showed very sensitive at high temperature. Above 125 K, the PL intensity ratio increased continuously between LQDF and SQDF, the peak energy shifted anomalously in SQDF, and the longer carrier radiative lifetime (≥3.0 ns at 77 K) reduced rapidly in SQDF and slowly in LQDF. These results are ascribed to thermally activated carrier escape from SQDF into the wetting layer, which then relaxed into LQDF with low-localized energy states.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Subjects: Q Science > QC Physics
Publisher: AIP Publishing
ISSN: 00218979
Date of First Compliant Deposit: 24 October 2017
Date of Acceptance: 19 May 2017
Last Modified: 06 Jun 2018 01:30
URI: http://orca.cf.ac.uk/id/eprint/105850

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