Misfit dislocations in GaAsN/GaAs interface

Highly strained GaAsN layers were grown on GaAs by metal-organic vapor phase epitaxy and studied by synchrotron X-ray topography and X-ray diffraction. The critical thickness for misfit dislocation formation of the GaAs0.965N0.035 epitaxial layer on GaAs was found to be between 50 and 80 nm. In layers thicker than the critical thickness a misfit dislocation network was observed. The network was found to be isotropic and uniform. The relaxation of the strained epilayer begins through the misfit-dislocation generation and continues via formation of cracks. The cracks are not distributed as uniformly as misfit dislocations. (C) 2003 Kluwer Academic Publishers.