Thesis Defense

Lithography-free oxide isolation of GaAs nanowires using the VLS growth method

Wednesday, 28 June 2017 12:00PM PDT
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Thesis Defense
 
David Dvorak
SFU Physics
 
Lithography-free oxide isolation of GaAs nanowires using the VLS growth method
 
Jun 28, 2017 at 12PM
 

Synopsis

Semiconductor nanowires show significant potential for incorporation into next generation technologies due to their unique electronic, optical and mechanical properties. In order to keep pace with the rapid development of new semiconductor technologies, quick and efficient device prototyping methods are required. In this work, a lithography-free approach for the fabrication of oxide-isolated nanowire devices is developed using a combination of atomic layer deposition and the vapour-liquid-solid method. Axial growth of Al2O3 and Ga2O3-coated GaAs nanowires is restarted using an annealing step which fractures the oxide surrounding the gold nanoparticle. The oxide fracture is observed to depend on the oxide composition and thickness, annealing temperature and nanoparticle radius. The compositional and electronic properties of the regrown nanowires are investigated and a thermal expansion mismatch model is presented to describe the observed results.