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Kinetics of Au-Ga Droplet Mediated Decomposition of GaAs Nanowires

Tornberg, Marcus LU ; Jacobsson, Daniel LU ; Persson, Axel R. LU ; Wallenberg, Reine LU ; DIck, Kimberly A. LU and Kodambaka, Suneel LU (2019) In Nano Letters p.3498-3504
Abstract

Particle-assisted III-V semiconductor nanowire growth and applications thereof have been studied extensively. However, the stability of nanowires in contact with the particle and the particle chemical composition as a function of temperature remain largely unknown. In this work, we use in situ transmission electron microscopy to investigate the interface between a Au-Ga particle and the top facet of an ?1 1 1 ?-oriented GaAs nanowire grown via the vapor-liquid-solid process. We observed a thermally activated bilayer-by-bilayer removal of the GaAs facet in contact with the liquid particle during annealing between 300 and 420 °C in vacuum. Interestingly, the GaAs-removal rates initially depend on the thermal history of the sample and are... (More)

Particle-assisted III-V semiconductor nanowire growth and applications thereof have been studied extensively. However, the stability of nanowires in contact with the particle and the particle chemical composition as a function of temperature remain largely unknown. In this work, we use in situ transmission electron microscopy to investigate the interface between a Au-Ga particle and the top facet of an ?1 1 1 ?-oriented GaAs nanowire grown via the vapor-liquid-solid process. We observed a thermally activated bilayer-by-bilayer removal of the GaAs facet in contact with the liquid particle during annealing between 300 and 420 °C in vacuum. Interestingly, the GaAs-removal rates initially depend on the thermal history of the sample and are time-invariant at later times. In situ X-ray energy dispersive spectroscopy was also used to determine that the Ga content in the particle at any given temperature remains constant over extended periods of time and increases with increasing temperature from 300 to 400 °C. We attribute the observed phenomena to droplet-assisted decomposition of GaAs at a rate that is controlled by the amount of Ga in the droplet. We suggest that the observed transients in removal rates are a direct consequence of time-dependent changes in the Ga content. Our results provide new insights into the role of droplet composition on the thermal stability of GaAs nanowires and complement the existing knowledge on the factors influencing nanowire growth. Moreover, understanding the nanowire stability and decomposition is important for improving processing protocols for the successful fabrication and sustained operation of nanowire-based devices.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
annealing, GaAs, in situ, Nanowire, transmission electron microscopy, X-ray energy-dispersive spectroscopy
in
Nano Letters
pages
3498 - 3504
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85066150027
ISSN
1530-6984
DOI
10.1021/acs.nanolett.9b00321
language
English
LU publication?
yes
id
1d5e7658-3d85-4410-a418-5bfd0de72e20
date added to LUP
2019-06-13 12:42:09
date last changed
2019-11-13 05:35:55
@article{1d5e7658-3d85-4410-a418-5bfd0de72e20,
  abstract     = {<p>Particle-assisted III-V semiconductor nanowire growth and applications thereof have been studied extensively. However, the stability of nanowires in contact with the particle and the particle chemical composition as a function of temperature remain largely unknown. In this work, we use in situ transmission electron microscopy to investigate the interface between a Au-Ga particle and the top facet of an ?1 1 1 ?-oriented GaAs nanowire grown via the vapor-liquid-solid process. We observed a thermally activated bilayer-by-bilayer removal of the GaAs facet in contact with the liquid particle during annealing between 300 and 420 °C in vacuum. Interestingly, the GaAs-removal rates initially depend on the thermal history of the sample and are time-invariant at later times. In situ X-ray energy dispersive spectroscopy was also used to determine that the Ga content in the particle at any given temperature remains constant over extended periods of time and increases with increasing temperature from 300 to 400 °C. We attribute the observed phenomena to droplet-assisted decomposition of GaAs at a rate that is controlled by the amount of Ga in the droplet. We suggest that the observed transients in removal rates are a direct consequence of time-dependent changes in the Ga content. Our results provide new insights into the role of droplet composition on the thermal stability of GaAs nanowires and complement the existing knowledge on the factors influencing nanowire growth. Moreover, understanding the nanowire stability and decomposition is important for improving processing protocols for the successful fabrication and sustained operation of nanowire-based devices.</p>},
  author       = {Tornberg, Marcus and Jacobsson, Daniel and Persson, Axel R. and Wallenberg, Reine and DIck, Kimberly A. and Kodambaka, Suneel},
  issn         = {1530-6984},
  keyword      = {annealing,GaAs,in situ,Nanowire,transmission electron microscopy,X-ray energy-dispersive spectroscopy},
  language     = {eng},
  pages        = {3498--3504},
  publisher    = {The American Chemical Society (ACS)},
  series       = {Nano Letters},
  title        = {Kinetics of Au-Ga Droplet Mediated Decomposition of GaAs Nanowires},
  url          = {http://dx.doi.org/10.1021/acs.nanolett.9b00321},
  year         = {2019},
}