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Title: Near-surface depletion of antimony during the growth of GaAsSb and GaAs/GaAsSb nanowires

The near-surface reduction of the Sb mole fraction during the growth of GaAsSb nanowires (NWs) and GaAs NWs with GaAsSb inserts has been studied using quantitative high-angle annular dark field scanning transmission electron microscopy (STEM). A model for diffusion of Sb in the hexagonal NWs was developed and employed in combination with the quantitative STEM analysis. GaAsSb NWs grown by Ga-assisted molecular beam epitaxy (MBE) and GaAs/GaAsSb NWs grown by Ga- and Au-assisted MBE were investigated. At the high temperatures employed in the NW growth, As-Sb exchange at and outward diffusion of Sb towards the surface take place, resulting in reduction of the Sb concentration at and near the surface in the GaAsSb NWs and the GaAsSb inserts. In GaAsSb NWs, an increasing near-surface depletion of Sb was observed towards the bottom of the NW due to longer exposure to the As beam flux. In GaAsSb inserts, an increasing change in the Sb concentration profile was observed with increasing post-insert axial GaAs growth time, resulting from a combined effect of radial GaAs overgrowth and diffusion of Sb. The effect of growth temperature on the diffusion of Sb in the GaAsSb inserts was identified. The consequences of these findings for growthmore » optimization and the optoelectronic properties of GaAsSb are discussed.« less
Authors:
;  [1] ; ;  [2] ; ; ;  [3]
  1. Department of Physics, Norwegian University of Science and Technology (NTNU), Trondheim (Norway)
  2. Department of Electronics and Telecommunications, NTNU, Trondheim (Norway)
  3. Institut für Festkörperphysik, Universität Bremen, Bremen (Germany)
Publication Date:
OSTI Identifier:
22305799
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 14; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ANTIMONY COMPOUNDS; BEAMS; CONCENTRATION RATIO; CRYSTAL GROWTH; DIFFUSION; GALLIUM ARSENIDES; MOLECULAR BEAM EPITAXY; NANOWIRES; OPTIMIZATION; QUANTUM WIRES; SPATIAL DISTRIBUTION; SURFACES; TRANSMISSION ELECTRON MICROSCOPY