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

Journal Article · Tue Oct 14 04:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4896904· OSTI ID:22305799

Kauko, H.; Fimland, B. O.; Munshi, A. M. ^[1]; Grieb, T.; Müller, K.; Rosenauer, A. ^[2]

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1. Department of Electronics and Telecommunications, NTNU, Trondheim (Norway)
2. Institut für Festkörperphysik, Universität Bremen, Bremen (Germany)

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 growth optimization and the optoelectronic properties of GaAsSb are discussed.

• OSTI ID: 22305799
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 14 Vol. 116; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

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