Vacancy kinetics and sputtering of GaAs(110)

Bombardment of GaAs(110) at 300≤T≤775 K with ${\mathrm{Ar}}^{+}$ ions at normal incidence creates surface-layer defects that generally span one or two unit cells, as shown by scanning tunneling microscopy. Vacancies produced in this way diffuse via thermal activation to form single-layer vacancy islands. The diffusion of divacancies favors [11¯0] and accommodation at islands produces roughly isotropic islands. Modeling of growth showed an overall Arrhenius behavior for diffusion with an activation energy of 1.3±0.2 eV. Investigations of the surface morphology during multilayer erosion revealed deviation from layer-by-layer removal with scaling exponents between 0.4 and 0.5 for 626≤T≤775 K.