A general approach for sharp crystal phase switching in InAs, GaAs, InP, and GaP nanowires using only group V flow.

Abstract

III-V-based nanowires usually exhibit random mixtures of wurtzite (WZ) and zinc blende (ZB) crystal structure, and pure crystal phase wires represent the exception rather than the rule. In this work, the effective group V hydride flow was the only growth parameter which was changed during MOVPE growth to promote transitions from WZ to ZB and from ZB to WZ. Our technique works in the same way for all investigated III-Vs (GaP, GaAs, InP, and InAs), with low group V flow for WZ and high group V flow for ZB conditions. This strongly suggests a common underlying mechanism. It displays to our best knowledge the simplest changes of the growth condition to control the nanowire crystal structure. The inherent reduction of growth variables is a crucial requirement for the interpretation in the frame of existing understanding of polytypism in III-V nanowires. We show that the change in surface energetics of the vapor-liquid-solid system at the vapor-liquid and liquid-solid interface is likely to control the crystal structure in our nanowires.