A total current spectroscopy study of metal oxide surfaces: II. Unoccupied electronic states on TiO2(110) and SrTiO3(100) surfaces

摘要

Unoccupied densities of states (DOS) for the ordered and atomically clean TiO2(110) and SrTiO3(100) surfaces were studied using the total current spectroscopy (TCS) technique. Obtained TC spectra reveal the Ti-derived (Ti 3d(e(g))-5.2 eV, Ti 4s-23.5 eV) and Sr-derived (Sr 3d-triplet: 7.3, 9.0 and 10.5 eV; Sr 5p/O 2p-15 eV) maxima of unoccupied DOS. Main oxygen-derived maxima are located at 11.2 and 15.0 eV for TiO2 and at 11.8, 18.0 and 19.6 eV for SrTiO3. The results are discussed in comparison with the previously reported data on DOS of these materials and they provide additional detailed information on the energy structure of unoccupied DOS on TiO2(110) and SrTiO3(100) surfaces in the 4-25 eV range above the Fermi level. [References: 28]