Evolution of the optical properties of InAs/GaAs quantum dots for increasing InAs coverages

A. Patanè, M. Grassi Alessi, F. Intonti, A. Polimeni, M. Capizzi, F. Martelli, M. Geddo, A. Bosacchi, S. Franchi

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20 Citations (Scopus)


The photoluminescence (PL) of InAs/GaAs heterostructures is investigated for InAs coverages, L, ranging from 0.6 to 3 monolayers (ML). For thin coverages (L ≤ 1.6 ML), we observe the recombination of heavy-hole excitons in InAs quantum dots (QDs) and in a 2D-InAs layer. The two PL bands shift toward low energy for increasing L. For L ≥ 1.6ML. the QD band shifts faster, while the exciton recombination in the 2D-layer vanishes. These results, confirmed by PL excitation and photoreflectivity, indicate that: a) QDs are interconnected by a two-dimensional InAs layer which allows an efficient carrier capture into the dots; b) the dot size increases with L, faster for L≥ 1.6 ML, at the expense of the 2D-layer. The peculiar temperature dependence of lizneshape and peak energy of the QD band is explained in terms of exciton thermal escape and relaxation mechanisms.

Original languageEnglish
Pages (from-to)493-497
Number of pages5
JournalPhysica Status Solidi (A) Applied Research
Issue number1
Publication statusPublished - Jan 1 1997

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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