Comparative photoemission study of the electronic properties of L-CVD SnO2 thin films

In this work we present the results of comparative XPS and PYS studies of electronic properties of the space charge layer of the L-CVD SnO2 thin films after air exposure and subsequent UHV annealing at 400 8C, with a special emphasis on the interface Fermi level position. From the centre of gravity of binding energy of the main XPS Sn 3d5/2 line the interface Fermi level position EF Ev in the band gap has been determined. It was in a good correlation with the value estimated from the offset of valence band region of the XPS spectrum, as well as from the photoemission yield spectroscopy (PYS) measurements. Moreover, from the valence band region of the XPS spectrum and PYS spectrum two different types of filled electronic band gap states of the L-CVD SnO2 thin films have been derived, located at 6 and 3 eV with respect to the Fermi level.