A theoretical model of nanowire formation was presented which accounted for adatom diffusion from the side-walls and from the substrate surface to the wire top. Exact solution for the adatom diffusion flux from the surface to the wires was analyzed in different growth regimes. It was shown theoretically that, within the range of growth conditions, the growth rate depends on wire radius R approximately as 1/R2, which was principally different from the conventional 1/R performance. The effect was verified experimentally for the MBE grown GaAs and AlGaAs wires. The dependences of wire length on the drop density, surface temperature and deposition flux during vapor pressure deposition and high vacuum deposition were analyzed and the differences between these two growth techniques were discussed.

Diffusion-Controlled Growth of Semiconductor Nanowires - Vapor Pressure versus High Vacuum Deposition. V.G.Dubrovskii, N.V.Sibirev, R.A.Suris, G.E.Cirlin, J.C.Harmand, V.M.Ustinov: Surface Science, 2007, 601[18], 4395-401