Electron energy-loss spectroscopy of molybdenum disilicide

Thin films of molybdenum disilicide prepared by solid-state diffusion of Mo/Si(111) have been investigated by electron energy-loss spectroscopy for their valence level and core level electron excitations. In the valence band, interband transitions around 2.2, 3.9, and 5.3 eV have been observed. These transitions have been interpreted as electron excitations of the metal d band and Mo(4d)–Si(3p) levels. These transitions are in excellent agreement with the available experimental and theoretical data on MoSi2 electronic band structure. In the core levels, the electron excitations corresponding to the Si(2p) core level are shifted towards higher energy while that of the Mo(3d) are shifted towards lower energy. These shifts indicate a change in the bonding nature of Mo–Si during silicidation.