Spiral growth of GaAs by molecular beam epitaxy

Steps of monolayer height (0.28 nm) were observed by atomic force microscopy on a GaAs surface grown by molecular beam epitaxy. The monolayer terrace width between steps was found to be as large as 1000 nm in some areas. Surface reconstruction affects the surface diffusion process during growth and the shape of the step edges. Growth spirals were observed. Spirals originate from screw dislocations. The growth mechanism is according to the Burton–Cabrera–Frank theory.