Kinetics of Au-Ga Droplet Mediated Decomposition of GaAs Nanowires

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Kinetics of Au-Ga Droplet Mediated Decomposition of GaAs Nanowires. / Tornberg, Marcus; Jacobsson, Daniel; Persson, Axel R.; Wallenberg, Reine; DIck, Kimberly A.; Kodambaka, Suneel.

In: Nano Letters, 2019, p. 3498-3504.

Research output: Contribution to journalArticle

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TY - JOUR

T1 - Kinetics of Au-Ga Droplet Mediated Decomposition of GaAs Nanowires

AU - Tornberg, Marcus

AU - Jacobsson, Daniel

AU - Persson, Axel R.

AU - Wallenberg, Reine

AU - DIck, Kimberly A.

AU - Kodambaka, Suneel

PY - 2019

Y1 - 2019

N2 - 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.

AB - 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.

KW - annealing

KW - GaAs

KW - in situ

KW - Nanowire

KW - transmission electron microscopy

KW - X-ray energy-dispersive spectroscopy

U2 - 10.1021/acs.nanolett.9b00321

DO - 10.1021/acs.nanolett.9b00321

M3 - Article

SP - 3498

EP - 3504

JO - Nano Letters

T2 - Nano Letters

JF - Nano Letters

SN - 1530-6992

ER -