Nanorippling of ion irradiated GaAs (001) surface near the sputter-threshold energy

Ripple formation driven by Ehrlich–Schwoebel barrier is evidenced for normal incidence 30 eV Ar+ bombardment of GaAs (001) surface at elevated target temperature. The pattern follows the twofold symmetry of the bombarded crystal surface. The ridges of the ripples are found to align along the direction. The results are described by a non-linear continuum equation based on biased diffusion of adspecies created by ion impact. Ripple topography on ion bombarded GaAs (001) surface: AFM image (left panel) and XTEM image (right panel).