Stability and interaction of cation Frenkel pair in wurtzite semiconductor materials

Abstract

The understanding of defects is an important issue in the development of semiconductor materials. Using ab initio calculations and ab initio molecular dynamics, the stability and interaction of cation Frenkel pairs were investigated in four wurtzite semiconductor materials, GaN, AlN, InN and ZnO. With regard to GaN material, an interesting phenomenon was found that the recombination path of Ga Frenkel pair is a kick-out mechanism which is similar to the migration of Ga interstitial. Based on the obtained path, the recombination energy barriers of different positions of Frenkel pairs were calculated respectively. The calculation results demonstrated that the recombination behavior of Ga Frenkel pair is not only determined by the distance but also the relative position of vacancy and interstitial. Meanwhile, the value of the projected interaction radius was observed to be about 7.5 Å. Compared with the small interaction range of N Frenkel pair, Ga Frenkel pair was found to be unstable, which is consistent with previous radiation experiments. Furthermore, the same phenomenon in GaN material was also found in the other three wurtzite materials and the projected interaction radius of wurtzite materials was concluded as 7/3 lattice parameter. In general, this theoretical study provides an insight of the stability of cation Frenkel pair and improves our understanding of defects in wurtzite semiconductors.