Evaluation of dynamics of charge accumulation and dissipation processes in Ge15Se85 thin film under electron beam irradiation by mapping surface potential distribution

Abstract

The interaction of Ge15Se85 amorphous chalcogenide films with an electron beam has been studied. Three ranges of electron irradiation doses, in which a surface relief of various shapes is formed, are found. The presence and persistence of the surface potential for a long time after film irradiation have been established using the Kelvin probe force microscopy (KPFM). It is shown that the formation of surface relief is result of the charge accumulation in the interaction region. Based on the mapping of surface potential distribution in irradiated regions using KPFM we propose models of electric field distribution in the irradiated spots and suggest mechanism of electron-induced mass transfer. It has been suggested that the formation of a high surface relief structures is due to the electron-induced plastic effect. It is shown that the appearance of asymptotically sharp Taylor cones in chalcogenide films is due to charge collapse in the interaction region when the volume charge density and internal electric field strength exceed their critical values.