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Title: Ge quantum dots encapsulated by AlAs grown by molecular beam epitaxy on GaAs without extended defects

We demonstrate nearly spherical, strain-free, self-assembled Ge quantum dots (QDs) fully encapsulated by AlAs, grown on (100) GaAs by molecular beam epitaxy. The QDs were formed without a wetting layer using a high temperature, in situ anneal. Subsequent AlAs overgrowth was free from anti-phase domains and threading dislocations in cross section transmission electron microscopy. The straddling band alignment for Ge in AlAs promises strong and tunable confinement for both electrons and holes. The reflection high-energy electron diffraction pattern changed from 2 × 3 to 2 × 5 with anneal, which can be explained by surface reconstructions based on the electron-counting model.
Authors:
; ; ; ; ; ;  [1]
  1. Electrical Engineering, University of Notre Dame, Notre Dame, Indiana 46556 (United States)
Publication Date:
OSTI Identifier:
22283088
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ALUMINIUM ARSENIDES; CROSS SECTIONS; CRYSTAL GROWTH; DISLOCATIONS; ELECTRON DIFFRACTION; ELECTRONS; GALLIUM ARSENIDES; GERMANIUM; HOLES; LAYERS; MOLECULAR BEAM EPITAXY; QUANTUM DOTS; REFLECTION; STRAINS; SURFACES; TRANSMISSION ELECTRON MICROSCOPY