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Title: Effect of interwire separation on growth kinetics and properties of site-selective GaAs nanowires

We report tuning of the growth kinetics, geometry, and properties of autocatalytic GaAs nanowires (NW) by precisely controlling their density on SiO{sub 2}-mask patterned Si (111) substrates using selective area molecular beam epitaxy. Using patterned substrates with different mask opening size (40–120 nm) and pitch (0.25–3 μm), we find that the NW geometry (length, diameter) is independent of the opening size, in contrast to non-catalytic GaAs NWs, whereas the NW geometry strongly depends on pitch, i.e., interwire separation and NW density. In particular, two distinct growth regimes are identified: a diffusion-limited regime for large pitches (low NW density) and a competitive growth regime for smaller pitches (high NW density), where axial and radial NW growth rates are reduced. The transition between these two regimes is significantly influenced by the growth conditions and shifts to smaller pitches with increasing As/Ga flux ratio. Ultimately, the pitch-dependent changes in growth kinetics lead to distinctly different photoluminescence properties, highlighting that mask template design is a very critical parameter for tuning intrinsic NW properties.
Authors:
; ; ; ; ; ; ; ;  [1] ;  [1] ;  [2]
  1. Walter Schottky Institut and Physik Department, Technische Universität München, Garching 85748 (Germany)
  2. (Germany)
Publication Date:
OSTI Identifier:
22311158
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 3; 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; CRYSTAL GROWTH; DIFFUSION; GALLIUM ARSENIDES; MOLECULAR BEAM EPITAXY; NANOWIRES; PHOTOLUMINESCENCE; QUANTUM WIRES; SILICA; SILICON OXIDES; SUBSTRATES