Influence of growth parameters on In-droplet-assisted growth of InAs nanowires on silicon

The influence of growth parameters on the morphology and density of InAs nanowires (NWs) grown on bare Si substrates using Indium (In) droplets as catalyst is investigated. By tuning the growth temperature, V/III flux ratio, and growth rate, the diameter and yield of as-grown NWs were controllably manipulated. It is demonstrated that the In-droplet-assisted growth of InAs NWs can only be realized on bare Si within a relatively narrow growth window of 420–475 °C. Below 420 °C, NWs’ growth is kinetically limited, while the highest yield of vertically aligned NWs was obtained at ~450 °C. It is shown that In-catalyzed InAs NWs nucleation can only be realized on Si at highly As-rich conditions (V/III flux ratio >50), while the axial growth rate was found to be strongly dependent on the V/III flux ratio. The nucleation and axial growth of In-catalyzed InAs NWs are promoted by a low growth rate, while a high growth rate favors the formation of unwanted parasitic islands