Defect evolution and interplay in n-type InN

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 x 10(20) 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 (V-In-V-N) are the dominant III-sublattice related vacancy defects. An increase in the number of V-N in these complexes toward the interface suggests high concentrations of additional isolated V-N and V-N-clusters near the GaN buffer layer and coincides with elevated dislocation densities in that area. (C) 2012 American Institute of Physics. [doi:10.1063/1.3688038]