Polytype formation in GaAs/GaP axial nanowire heterostructures

Transmission electron microscopy (TEM) studies are presented for Au-assisted vapor–liquid–solid (VLS) nanowire growth of gallium arsenide/gallium phosphide (GaAs/GaP) axial heterostructures. The supersaturation of the liquid Au-III–V alloy droplet during MBE growth was found to have a profound impact on both the crystal phase and growth rate of the nanowire heterostructures. Among these effects was the appearance of a previously unreported 4H GaP crystal phase. 4H GaP occurred at low Au-III–V droplet supersaturation following the transition from GaAs to GaP growth. Both crystal phase and growth rate were different for GaAs and GaP, underlining the importance of group V elements in Au-III–V droplet supersaturation and thus VLS nanowire growth.

► GaAs/GaP axial heterostructure nanowires were grown via Au-assisted VLS process.
► Polytype formation in GaP was observed including zincblende, wurtzite, and 4H.
► The first report of 4H GaP.
► The growth rate and crystal phase behavior in GaAs and GaP differed.
► The importance of group V elements in VLS growth is demonstrated.