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Modified fermi-level pinning of the (100) GaAs surface through InAs quantum dots in different stages of overgrowth

Authors
  • Walther, C.1
  • Blum, R. P.1
  • Niehus, H.1
  • Thamm, A.2
  • Masselink, W. T.1
  • 1 Humboldt Universität zu Berlin, Department of Physics, Invalidenstrasse 110, Berlin, 10115, Germany , Berlin
  • 2 Paul-Drude-Institut, Hausvogteiplatz 5-7, Berlin, 10117, Germany , Berlin
Type
Published Article
Journal
Journal of Electronic Materials
Publisher
Springer-Verlag
Publication Date
May 01, 2000
Volume
29
Issue
5
Pages
504–509
Identifiers
DOI: 10.1007/s11664-000-0035-2
Source
Springer Nature
Keywords
License
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Abstract

The presence of InAs quantum dots on a {100} GaAs surface results in a pronounced increase of the Fermi level pinning energy. Using room-temperature photo-reflectance measurements combined with atomic force microscopy, we find that the presence of the quantum dots results in the Fermi level being pinned approximately ∼250 meV deeper in the bandgap, an effect which is reversed by either removing or overgrowing the dots. Both overgrowth and complete etching of quantum dots results in the disappearance of the polar InAs facets; we explain the change in Fermi level in terms of such facets. We also discuss the phase delay for the InAs related feature of the photoreflectance experiment as a detrapping of photo-generated electron-hole pairs in the dots.

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