Abstract
N-type GaN films bombarded with different highly charged Xe-126(q+)-ions(9 <= q <= 30) at room temperature was studied by atomic force microscopy. The experimental results show that when q exceeds the threshold value 18, remarkable swelling turns into obvious erosion in the irradiated area. On the other hand, surface disorder of GaN films strongly depends on the charge state q of ions, incident angle and ion influence, and the damage behavior of films is unrelated to the kinetic energy within the scope of experimental parameters (180 keV <= E-k <= 600 keV). For q = 18, the surface morphology of the films almost does hot change at normal incidence, and at incidence angle of 30 degrees relative to the film surface, there appears small-scale swelling in irradiated region and a low step forms between the irradiated and un-irradiated regions. For q < 18, the film surface is capped with an amorphous layer, with increased roughness, distinct swelling. Moreover, especially at and near the boundaries, a series of rema