Abstract
The structure and atomic-scale morphology of GaAs surfaces and the use of reflection high-energy electron diffraction to control their evolution during molecular beam epitaxy are reviewed. Results on the terrace-step structure of the singular (001) surface, on step arrays on vicinal (001) surfaces and on facet arrays on high-index surfaces are presented. Implications for interface formation and modifications by incorporation of impurities are pointed out. New approaches toward a direct synthesis of one-dimensional structures are considered, including the attachment of impurity atoms at edges of misorientation steps and GaAs-AlAs multilayer growth on corrugated high-index surfaces.