Role of surface diffusion in chemical beam epitaxy of InAs nanowires

We present growth studies of InAs nanowires nucleated from lithographically positioned Au seeds on InAs (111)B substrates. The nanowires are grown in a chemical beam epitaxy system and exhibit high aspect ratios and high homogeneity in length and width. Investigations of wire growth rate as a function of diameter, density, and time were performed and the results indicate that 80% of the growth is due to In species diffusing from the (111)B substrate surface. Furthermore, we have established that the diffusion length on the {110} wire side surfaces exceeds 10 mum. We also observe a decreasing length growth rate with increasing wire diameter.