Study of the chemical bonding of titanium with silicon and oxygen by AES and SEELS

Abstract

Auger electron Spectroscopy (AES) and slow electron energy loss Spectroscopy (SEELS) have been employed to study the electronic structure of Ti, TiSi 2 and TiO 2. The changes in the Auger and loss spectra when Ti chemically binds with silicon to form TiSi 2 and with oxygen to form TiO 2 have been understood as manifestations of changes in electronic participation. AES spectra show distinct changes in line shapes of transitions involving the Ti valence electrons. The SEELS spectra provide information regarding shallow core levels, valence band and the collective excitation energies of the volume and surface plasmons. By monitoring the changes in the Auger peak at 387 eV and the 3 p→ 3 d quasiatomic transition (at about 45 eV), the role of d-orbital occupancies are studied in Ti and its compounds. The SEELS studies in the 0-80 eV range have enabled the authors to observe the behaviour of the 3 p → 3 d quasiatomic transition in Ti, which persists after oxidation but almost disappears during TiSi 2 formation. The values of the plasmon losses are related to the collective behaviour of conduction electrons.