  Networks of vertically c-oriented prism shaped InN nanowalls, are grown on
c-GaN/sapphire templates using a CVD technique, where pure indium and ammonia
are used as metal and nitrogen precursors. A systematic study of the growth,
structural and electronic properties of these samples shows a preferential
growth of the islands along [11-20] and [0001] directions leading to the
formation of such a network structure, where the vertically [0001] oriented
tapered walls are laterally align along one of the three [11-20] directions.
Inclined facets of these walls are identified as r-planes [(1-102)-planes] of
wurtzite InN. Onset of absorption for these samples is observed to be higher
than the band gap of InN suggesting a high background carrier concentration in
this material. Study of the valence band edge through XPS indicates the
formation of positive depletion regions below the r-plane side facets of the
walls. This is in contrast with the observation for c-plane InN epilayers,
where electron accumulation is often reported below the top surface.
