posted on 2016-02-18, 22:18authored bySebastian Lehmann, Jesper Wallentin, Daniel Jacobsson, Knut Deppert, Kimberly
A. Dick
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.