Roughening of a stepped GaN grain boundary with increasing driving force for migration

High-resolution transmission electron microscopy is applied to characterize the structure of a GaN grain boundary, which is subjected to the driving force for migration arising from the surface energy anisotropy during annealing at 500 degrees C in a transmission electron microscope. At a low driving force for migration, the grain boundary consists of atomically flat terrace regions interrupted by steps. As the driving force increases, grain-boundary steps become more frequent and undergo meandering, which is a typical attribute of kinetic roughening transition. Copyright (C) EPLA, 2017