Energy dependence of quantum dot formation by ion sputtering

Ordered quantum dot patterns are generated on GaSb and InSb surfaces due to a
surface instability induced by Ar+ ion sputtering under normal incidence.
The characteristic length of the generated patterns scales with the square
root of the ion energy over the energy range of 75 - 1800 eV. This energy
dependence is compared to the solutions of the isotropic Kuramoto-Sivashinsky
equation and allows the determination of the lateral width of the energy
distribution deposited by the incident ions in the very low energy range. We
show that the observed energy dependence is in agreement with the linear
continuum theory under the assumption that the dominant smoothing process is
due to effective ion induced diffusion without mass transport on the surface.