Photoluminescence scanning on InAs/InGaAs quantum dot structures

M. Dybiec, L. Borkovska, S. Ostapenko, T. V. Torchynska, J. L. Casas Espinola, A. Stintz, K. J. Malloy

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30 Scopus citations

Abstract

The photoluminescence spectra of InAs quantum dots (QDs) embedded into four types of In x Ga 1-x As/GaAs (x = 0.10, 0.15, 0.20 and 0.25) multi quantum well MBE structures have been investigated at 300 K in dependence on the QD position on the wafer. PL mapping was performed with 325 nm HeCd laser (35 mW) focused down to 200 μm (110 W/cm 2 ) as the excitation source. The structures with x = 0.15 In/Ga composition in the In x Ga 1-x As capping layer exhibited the maximum photoluminescence intensity. Strong inhomogeneity of the PL intensity is observed by mapping samples with the In/Ga composition of x ≥ 0.20-0.25. The reduction of the PL intensity is accompanied by a gradual "blue" shift of the luminescence maximum at 300 K as follows from the quantum dot PL mapping. The mechanism of this effect has been analyzed. PL peak shifts versus capping layer composition are discussed as well.

Original languageEnglish
Pages (from-to)5542-5545
Number of pages4
JournalApplied Surface Science
Volume252
Issue number15
DOIs
StatePublished - 30 May 2006

Keywords

  • InAs quantum dots
  • PL scanning spectroscopy

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