LAUSR

Abstract 100 MeV swift heavy silver (Ag+7) ion irradiation at normal incidence results in the formation of dense and ordered nanosized dots on molecular beam epitaxy (MBE) grown GaSb epitaxial layers. The shape, size and density of the nanodots are found to be strongly dependent on the ion fluence. Ripening of the dots with change in shape from cone to dome, and finally smoothening of the surface is observed with increasing ion fluence. The dot formation mechanism is explained on the basis of a surface instability introduced by combination of sputtering, step or kink Ehrlich-Schwoebel barrier effect and surface diffusion of mobile adatoms. Raman spectroscopy and high resolution X-ray diffraction results suggest preservation of crystallinity in the irradiated epilayers with presence of small tensile stress. Prevention of amorphisation in the irradiated samples is explained on the basis of a dynamic self annealing process during irradiation.