Dislocation relaxation in InAs y P1− y films deposited onto (001) InP by gas-source molecular beam epitaxy

The strain relaxation of InAsyP1−y layers grown on (001) InP substrates by gas-source molecular beam epitaxy was examined using transmission electron microscopy (TEM) and cathodoluminescence (CL) imaging. InAsyP1−y films with a thickness of 190 Å were prepared, systematically varying the As content from y=0.30 and 0.77, corresponding to a lattice mismatch between 0.97% and 2.5%. Relaxation was anisotropic, with 60° misfit dislocations lying …