We report on the evolution of the growth front during molecular-beam epitaxy on GaAs (3 1 1)A substrates stripe patterned along the [ ] direction as a function of the mesa height. During growth (1 0 0) and (2 1 1)A facets are formed and expand at the corners near the two opposite lying ( )A and (1 1 1)A mesa sidewalls, respectively. After covering the ( )A facet completely, the (1 0 0) facet shrinks away, leaving behind a convex surface profile. For shallow mesa height of several ten nanometers, the growth develops a fast-growing microscopic slope tilted several degrees to (3 1 1)A, which is identified as the basis for quantum wire formation.
Gong, Q., Nötzel, R., Schönherr, H-P., & Ploog, K. (2000). Study of molecular-beam epitaxy growth on patterned GaAs (311)A substrates with different mesa height. Journal of Crystal Growth, 220(1-2), 23-29. https://doi.org/10.1016/S0022-0248(00)00745-4