The crystalline quality of GaN thin films grown on foreign substrates for opto- and micro-electronics applications depends strongly on the growth conditions. Among a variety of microstructural defects that appear in GaN epilayers, grain boundaries were extended defects that may be formed during the growth process under certain circumstances. The atomic structures of symmetrical and asymmetrical 70.53° <1¯2▪0> Σ18 tilt boundaries were investigated here by combining large scale energetic calculations, using a modified Stillinger-Weber interatomic potential, with high resolution transmission electron microscopy observations. The energetically favourable short-period asymmetric interface was matched to the experimental observations.

Atomic Simulations and HRTEM Observations of a Σ18 Tilt Grain Boundary in GaN. J.Kioseoglou, A.Béré, P.Komninou, G.P.Dimitrakopulos, G.Nouet, E.Iliopoulos, A.Serra, T.Karakostas: Physica Status Solidi A, 2005, 202[5], 799-803