Structural studies of (331) GaAs surface

The atomic structures of (331)-A and (331)-B GaAs surfaces, prepared by ion bombardment and annealing (IBA) or by molecular-beam epitaxy, are investigated with low-energy electron diffraction, electron energy-loss spectroscopy, and Auger electron spectroscopy. The IBA (331)-Asurface exhibits double-layer steps at rather low temperature, and develops large (110) and (111) facets after further annealing at ~420 °C; the (331)-B surface is flat up to annealing temperatures ~600 °C, and exhibits large {110} and (111) facets after further annealing. When prepared by molecular-beam epitaxy, the (331)-A surface exhibits double-layer steps after annealing up to ~550 °C, and develop (110) and (111) facets after further annealing; the (331)-B surface is flat up to annealing at 550 °C, and exhibits double-layer steps after further annealing at 600 °C; it then develops large {110} and (111) facets after further annealing.