The effects of Au surface diffusion to formation of Au droplets/clusters and nanowire growth on GaAs substrate using VLS method

Abstract

Using VLS method with the separated 220 nm thick Au catalyst circles/stripes configurations sputtered onto GaAs substrate surface, this paper investigated the effects of the Au droplets/clusters formation as well as the nanowires growth process inside and outside the Au circles/stripes configurations. The Au surface outward diffusion from the Au layer edge up to several tens of micrometers has strongly dominated. The effects of Au surface diffusion to formation of Au droplets/cluster and to the nanowires growth on GaAs semiconductor substrate in the region outside the Au layers have been shown. The mechanism of the droplets/clusters formation outside the Au layer could explained by the surface cluster diffusion, meanwhile the nanowires have grown simultaneously during the Au outward diffusion. The growth could explain by the diffusion of Ga and As atoms into the diffusing Au droplets/clusters via dissociative mechanism to form nanowire seeds inside for nanowires growth. The Au droplets/clusters formation and nanowires growth on GaAs substrate outside Au layer could be applied for making nanodevices blocks outside the Au layer. Unfortunately if this Au surface diffusion phenomenon is occurring on the GaAs semiconductor containing the Au stripes interconnections in micro/nanocircuits this could also cause the short-circuits phenomenon, even at thin Au layer.