Aerotaxy-grown GaAs nanowires using Ga seed particles

Abstract: Aerotaxy offers an alternative method for the manufacturing of semiconductor nanowires. Instead of seeding growth on an expensive substrate, aerosol seed particles act as the catalyst for the Vapor–Liquid–Solid growth in a hot flow through reactor. This thesis investigates the possibility of self-seeded GaAs nanowires grown from Ga seed particles replacing the regularly employed Au, hence eliminating potential impurities in the nanowire crystal lattice caused by the foreign seed particle material and not least dramatically reducing production costs. The influence of reactor temperature, seed particle diameter and precursor flows on the morphology of the nanowires was investigated. It is found that a strongly tapered morphology is unavoidable despite extensive parameter exploration. The seed particle size is discovered to strongly impact the nanowires’ morphology, causing prominent kinking for seed particles diameters less than 50 nm in diameter and strongly affecting the wires length. The nanowires diameter is found to increase with the reactor temperature, while the length remains constant. Different precursor flows and V/III ratios were extensively explored, and their effect on the nanowires’ morphology is discussed in detail. Preliminary results on Ga(As)P nanowires grown from Ga seed particles are also presented. This explorative study presents a successful investigation of self-seeded nanowire growth using aerotaxy, potentially paving the way for future self-seeded growth techniques.