Defect evolution and interplay in n-type InN

TL;DR

This study investigates the types and interactions of defects in highly n-type Si-doped InN epilayers, revealing complex vacancy defect behaviors and their correlation with dislocation densities using advanced microscopy techniques.

Contribution

It provides new insights into defect evolution and interactions in highly doped InN, highlighting the formation of vacancy complexes and their spatial distribution.

Findings

V_In-V_N complexes dominate in as-grown samples

Larger V_In-mV_N clusters form at the interface

Higher dislocation densities correlate with vacancy clusters

Abstract

The nature and interplay of intrinsic point and extended defects in n-type Si-doped InN epilayers with free carrier concentrations up to 6.6x10E20cm-3 are studied using positron annihilation spectroscopy and transmission electron microscopy and compared to results from undoped irradiated films. In as-grown Si-doped samples, V_In-V_N complexes are the dominant III-sublattice related vacancy defects. Enhanced formation of larger V_In-mV_N clusters is observed at the interface, which speaks for high concentrations of additional V_N in the near-interface region and coincides with an increase in the density of screw and edge type dislocations in that area.