Nanopatterning of ZnS thin film surfaces by keV ion beam irradiation

The nanopatterning of crystalline ZnS thin film surfaces under 80 keV Ar+ ions irradiation at incident angles of 0°, 20°, and 40° is presented. Structural and morphological changes have been investigated by means of X-ray diffraction and atomic force microscopy respectively. The surface morphology mainly consists of nanograins of spherical shape in pristine and films irradiated at normal incidence. The irradiation at oblique angle (20° and 40°) leads to the formation of ripple structures on the surface with a wave vector parallel to the ion beam direction. The existing theories for the ripple formation are invoked to explain the observed surface structure.