THE INFLUENCE OF OXYGEN DEFICIENCY AND SB DOPING ON INVERSE PHOTOEMISSION SPECTRA OF SNO2

The changes in the empty electronic states in SnO2 produced by ion-beam induced oxygen deficiency and by Sb doping have been studied by inverse photoemission spectroscopy. Inverse photoemission in SnO2 itself is dominated by peaks 4 and 12 eV above the Fermi level, the former associated with empty states of dominant Sn 5p atomic character. Sb doping populates states in the Sn 5s conduction band, shifting the empty state structure closer to the Fermi energy. By contrast oxygen deficiency introduces new states above the main Sn 5p peak. These are tentatively described as 5s 5p hybrids pushed up in energy from the 5p band by mixing between atomic orbitals of different parity in the non-centrosymmetric cation environment of oxygen deficient SnO2.