Morphological instabilities during homoepitaxy on vicinal GaAs(110) surfaces

Growth of GaAs by molecular beam epitaxy on (110) substrates vicinal to (11 1)A has been systematically studied by atomic force and Nomarski microscopy at different As/Ga flux ratios, substrate temperatures and growth rates. D epending on the growth conditions, a striking variety of morphological inst abilities have been found that range from step bunching in the Ga-supply li mited regime to creation of long-range, well-ordered patterns of three-dime nsional pyramidal features on the surface under As-deficient conditions. We discuss the microscopic origin of the morphological instabilities and self -organization of the surface features in terms of growth modes, relative ad atom populations and step-attachment probabilities. (C) 1999 Elsevier Scien ce Ltd. All rights reserved.