High Resolution Electron-Energy-Loss Spectroscopy of Amorphous Germanium and Silicon Films

Abstract

The energy loss spectra of monoenergetic 25 keV electrons having passed thin amorphous Ge and Si films are characterized by discrete and continuous energy losses. High energy resolution (0.005 eV) enables the observation of phonon excitation between 0.025 and 0.15 eV. In the region of the gap (0.15 to 0.5 eV) numerous peaks, corresponding to excitation of localized states were found. The principal maxima of localized states are located in a‐Ge at 0.210 and 0.365 eV and in a‐Si at 0.200, 0.255, and 0.360 eV. Interband transitions of a‐Ge were studied up to 3.0 eV.