Misfit dislocations and the morphology of gallium aluminum arsenide epitaxial layers grown on gallium arsenide

Linear morphological features which are readily revealed using Nomarski interference contrast microscopy have been observed on the surfaces of Ga xAl1-xAs epitaxial layers grown by liquid phase epitaxy LPE on GaAs substrates at 950°C. These features are introduced along one <110≳ direction in the (001) growth surface only. Annealing at the growth temperature produces a similar set of features in the perpendicular <110≳ direction. Photoluminescence topographs reveal dark lines in the substrates that are directed parallel to the sets of surface features in both annealed and unannealed crystals.