Highly Strained Metastable Heterojunction between Wurtzite GaN(0001) and Cubic CrN(111)

Abstract

We present first-principles calculations on the heterojunction between a wurtzite GaN(0001) film and a cubic CrN(111) substrate. Atomic and electronic structures of the interface in our heteroepitaxial compound semiconductor models are investigated with the use of four models with fixed stoichiometry Cr(16)N(16)Ga(12)N(12). The relative stability of different models of the GaN(0001)/CrN(111) interface is examined as a function of the chemical potentials of Ga and Cr, and the most favorable interface consists of sixfold-coordinated Ga with three Ga-N and three Ga-Cr bonds. This interface structure gives rise to N-polarity in the GaN(0001) epitaxial film. The findings agree with previously reported experimental results. A detailed analysis of the bonding arrangements of the lowest energy interface indicates that hexagonal Cr(2)GaN "bulklike" interatomic distances relax this highly strained meta-stable interface. (c) 2010 The Electrochemical Society. [DOI: 10.1149/1.3489369] All rights reserved.