Nanoscale Research Letters (Jan 2006)

Guided self-assembly of lateral InAs/GaAs quantum-dot molecules for single molecule spectroscopy

  • Krause B,
  • Metzger TH,
  • Wang L,
  • Rastelli A,
  • Kiravittaya S,
  • Songmuang R,
  • Schmidt OG

Journal volume & issue
Vol. 1, no. 1
pp. 74 – 78

Abstract

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Abstract We report on the growth and characterization of lateral InAs/GaAs (001) quantum-dot molecules (QDMs) suitable for single QDM optical spectroscopy. The QDMs, forming by depositing InAs on GaAs surfaces with self-assembled nanoholes, are aligned along the [] direction. The relative number of isolated single quantum dots (QDs) is substantially reduced by performing the growth on GaAs surfaces containing stepped mounds. Surface morphology and X-ray measurements suggest that the strain produced by InGaAs-filled nanoholes superimposed to the strain relaxation at the step edges are responsible for the improved QDM properties. QDMs are Ga-richer compared to single QDs, consistent with strain- enhanced intermixing. The high optical quality of single QDMs is probed by micro-photoluminescence spectroscopy in samples with QDM densities lower than 108 cm−2.

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