Growth mechanism of beam-induced lateral epitaxy on (0Â 0Â 1) GaAs substrate in molecular beam epitaxy

The mechanism of GaAs beam-induced lateral epitaxy (BILE) on (0 0 1) GaAs substrate by molecular beam epitaxy (MBE) was investigated by systematically varying the crystal orientation of ridges on the surface. In the growth sequence of BILE, a certain number of facets were first formed on the growth front in connection with the crystal orientation of the ridges. These facets competed with each other as they grew. As a result, the formation of the dominant facet determined the main shape. The crystal orientation of the ridge largely affected the formation of facets and their development. The cross-sectional images of the grown layers observed by a scanning electron microscope (SEM) indicates that the facets formed in the following order from first to last: (1 1 1)A facets, (1 1 0) facets, (1 1 1)B facets, and (0 0 1) facets. During the growth, facet formation was largely controlled by the intersurface diffusion of adatoms, although shadowing effects also influenced the grown shapes.