Nanostructuring of sapphire by ion-induced plasma

Sapphire single crystals were irradiated with slow highly charged xenon ions from electron beam ion trap (EBIT) facility. Scanning electron microscopic measurements showed the ability of the used ions in creating surface nanohillocks by single ion impacts. A test charge approach is used to provide an explanation for the mechanism of nanostructure formation in the sapphire surface. The model shows an increase of the height of the created nanostructure by increasing of the ionic density and electron temperature. This is in agreement with the dependence of the size of the induced nanostructures as a function of the deposited ion energy. The influence of the test charge speed and the relevance of an attractive wakefield potential are discussed in terms of plasma parameters.