Density-functional tight-binding calculations of electronic states associated with grain boundaries in GaN -: art. no. 125211

The electronic structure of the (3 (7) over bar 40) Σ=37 (θ=9.3°), (3 (5) over bar 20) Σ=19 (θ=13.4°), and (1 (3) over bar 20) Σ=7 (θ =21.6°) tilt grain boundaries has been investigated by means of atomic computer simulation within the density-functional-based tight-binding approach. Among the three possible atomic configurations of these boundaries, namely, the 5/7-, the 4-, and the 8 dislocation core interfaces, it is shown that the 4 or 8 interface introduces deep states in the very center and the upper half of the band gap whereas the 5/7 interface possesses only states close to the conduction band.