Transmission electron microscopic studies of the strain relaxation driven by lattice mismatch between a film and substrate was carried out on GaAsN films grown onto (100) GaAs by molecular beam epitaxy. The nature of the defects produced was shown to be directly related to the nature of the surface which developed during the growth of these compounds. In general, when the surface of the film was smooth, strain relaxation occurred by cracking while, in films with a rough surface, relaxation occurred via twinning or by the formation of perfect dislocations. The results were considered within the context of available models for strain relaxation in epitaxial films.

TEM Studies of Stress Relaxation in GaAsN and GaP Thin Films. Y.Li, G.C.Weatherly, M.Niewczas: Philosophical Magazine, 2005, 85[26-27], 3073-90