Thermal spike effect in sputtering of porous germanium to form surface pattern by high energy heavy ions irradiation

Abstract

Germanium exhibits a remarkable effect when subjected to high energy heavy ions irradiation. A synergic effect of high electronic energy loss (Se = 16.4 keV nm−1) and nuclear energy loss (Sn = 0.1 keV nm−1) of 100 MeV Ag ions irradiation in Ge is presented. The results show that crystalline Ge is insensitive to the ionizing part of energy loss whereas thermal spike generated in the damaged Ge leads to the formation of porous structure. Further, an unusual high sputtering of the porous structure opens up the sub-surface voids to show the surface pattern. We explore the role of electron and phonon confinement to explain this effect.