  Guided growth of semiconductor nanowires in nanotube templates has been
considered as a potential platform for reproducible integration of III-Vs on
silicon or other mismatched substrates. Herein, we report on the challenges and
prospects of molecular beam epitaxy of InAs nanowires on SiO2/Si nanotube
templates. We show how and under which conditions the nanowire growth is
initiated by In-assisted vapor-liquid-solid growth enabled by the local
conditions inside the nanotube template. The conditions for high yield of
vertical nanowires are investigated in terms of the nanotube depth, diameter
and V/III flux ratios. We present a model that further substantiates our
findings. This work opens new perspectives for monolithic integration of III-Vs
on the silicon platform enabling new applications in the electronics,
optoelectronics and energy harvesting arena.
