Network of vertically c-oriented prism shaped InN nanowalls grown on c-GaN/sapphire template by chemical vapor deposition technique

TL;DR

This study reports the growth and characterization of vertically oriented prism-shaped InN nanowalls on c-GaN/sapphire templates using CVD, revealing their structural, electronic properties, and growth directions.

Contribution

It presents a systematic analysis of the growth, structure, and electronic properties of InN nanowalls, highlighting their preferential growth directions and unique electronic behavior.

Findings

Preferential growth along [11-20] and [0001] directions.

Inclined facets identified as r-planes of wurtzite InN.

High background carrier concentration indicated by absorption onset.

Abstract

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.