Theoretical modeling of the self-catalyzed nanowire growth: nucleation- and adsorption-limited regimes

In this paper we study theoretically influence of group 3 and group 5 deposition rates on A3B5 nanowires (NWs) self-catalyzed vapor–liquid–solid (VLS) growth. Our self-consistent approach allows numerical calculation of chemical potential difference of the growth species, group 5 atomic concentration in the droplet and NW elongation rate for two-component system depending on deposition rates. It is found that chemical potential difference tends to saturation with increasing group 5 deposition rate (J 5), while increase of group 3 deposition rate (J 3) leads to its logarithmic growth. Two growth regimes are distinguished depending on relation between the deposition rates: high J 3 and low J 5 leads to adsorption-limited NW growth and in the opposite case nucleation-limited regime occurs. Nanowire elongation rate increases linearly with group 3 deposition rate in nucleation-limited regime. Further increase of the deposition rate leads to saturation of the growth rate in adsorption-limited regime. On the contrary, elongation rate grows linearly with group 5 deposition rate in adsorption-limited regime with slower linear growth in nucleation-limited regime.