Defect evolution and interplay in n-type InN

Abstract

The nature and interplay of intrinsic point and extended defects in n-type Si-doped InN epilayers with free carrier concentrations up to 6.6×1020 cm−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, mixed In-N vacancy complexes (VIn-VN) are the dominant III-sublattice related vacancy defects. An increase in the number of VN in these complexes toward the interface suggests high concentrations of additional isolated VN and VN-clusters near the GaN buffer layer and coincides with elevated dislocation densities in that area.