The effect of annealing temperature on gold catalyst and substrate surface in the growth of GaAs nanowire

Abstract

Annealing temperature plays an important role in the formation of Au-Ga alloy eutectic. Effect of annealing temperature on gold catalyst and substrate surface were studied using AFM, FE-SEM and TEM. With a temperature of 600 °C, the layer of gold colloids particle formed an islands in the state of molten eutectic alloy and absorbed evaporated metal-organics to formed nanowire underneath the alloy. Pit formed on the substrate surface due to the chemical reactions during the pre-annealing process have an impact on the direction of nanowire growth. Without pre-annealing temperature, the nanowire formed vertically on the GaAs (100) surface, meanwhile the growth direction depends on the intact nucleation facets and surface energy, when annealing is applied. With pre-annealing temperature, the wire base is large and curve due to the migration of Ga atoms on the substrate surface towards the tip of the wire and line tension between the substrate surface and gold particle.