Role of c-screw dislocations on indium segregation in InGaN and InAlN alloys

Abstract

Indium segregation induced by c-screw dislocations in wurtzite InGaN and InAlN alloys is investigated with molecular dynamics based on Stillinger–Weber potentials [Stillinger and Weber, Phys. Rev. B 31, 5262 (1985)]. Beginning with the analysis of atomic structures and energetic stability of c-screw dislocations in AlN, GaN, and InN compounds, their interaction with In atoms in GaN and AlN is explored. The results show that In atoms reduce the core energy of c-screw dislocation when they are located at the center of the core region. The distance dependence of the interaction energy indicates that In atoms will tend to gather around the dislocation line and form an In-rich region. These results agree with experimental observations in InGaN and should predict a similar behavior in InAlN.