Photoluminescence study of type-II submonolayer quantum dots

Minseak Kim, Hyun Jun Jo, Mo Geun So, Jong Su Kim, Yeongho Kim, Sang Jun Lee, Seung Hyun Lee, Christiana Honsberg, Heedae Kim

Research output: Contribution to journalArticle

Abstract

We have studied the optical properties of InAs/GaAsSb submonolayer quantum dots (SML-QDs) through excitation intensity (Iex) and temperature dependent photoluminescence (PL) experiments. The SML-QDs with type-I (T-1) and type-II (T-2) band structures were grown using a GaAsSb spacer with a Sb composition of 0% and 15.8%. At 13 K, the PL signals from the T-1 and the T-2 samples were observed at 1.42 eV and 1.37 eV, respectively, when the Iex was 8.7 mW/cm2. The PL signal of the T-1 sample is due to the recombination of electrons and holes in the InAs SML-QDs. The PL signal of the T-2 sample is due to the recombination of electrons (in the GaAs electron band) and holes (in the GaAsSb spacer hole band) by type-II band alignment formed between GaAs and GaAsSb. The full widths at half maxima (FWHMs) of the T-1 and the T-2 samples were 7.09 meV and 24.6 meV, respectively, because the T-2 sample has a lower uniformity than the T-1 sample. As the excitation intensity was increased, the PL signals of the T-1 and the T-2 samples shifted to lower energy because of the quantum-confined Stark effect. As a result of these temperature-dependent PL experiments, the activation energy of the T-1 sample was found to be 30 meV.

Original languageEnglish (US)
Pages (from-to)794-799
Number of pages6
JournalNew Physics: Sae Mulli
Volume69
Issue number8
DOIs
StatePublished - Jan 1 2019

Keywords

  • III-V semiconductor
  • Photoluminescence
  • Quantum dot
  • Quasimonolayer
  • Submonolayer

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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