Patterned gold-assisted growth of GaP nanowires on Si
The patterning of metal seed particles for the vapor–liquid–solid (VLS) growth of semiconductor nanowires is examined. We report the challenges of obtaining GaP nanowires grown by molecular beam epitaxy (MBE) from a patterned array of Au seed particles created by electron beam lithography. Transmission electron microscopy studies revealed the presence of a thin silicon oxide layer over the patterned Au seed particles. Au acted as a catalyst for silicon oxide growth at even moderate temperatures. In particular, the annealing of Au-patterned Si (1 1 1) substrates at low temperatures required for indium mounting (200–300 °C) was responsible for the formation of an oxide layer that was detrimental to Au-assisted growth. Removal of the oxide layer by a buffered HF etch prior to MBE sample loading enabled patterned VLS growth.