PHOTOEMISSION-STUDY ON PROTONIC CONDUCTOR P-TYPE SRTIO3

The electronic structure of Sc-doped p-type SrTiO3 has been studied by photoemission spectroscopy. Comparing the results with those of Nb-do ped n-type SrTiO3, the Fermi level of p-type is shifted to the low bin ding energy. As Sc dopant increases, the top of the valence band is sh ifted to the low binding energy in accord with the rigid-band model. T he Ti 3d component in the O 2p band of p-type SrTiO3 increases compare d with that of the n-type one. It was also found that the satellite in tensities of Ti core levels drastically increase. The covalency of p-t ype SrTiO3 increases by the doping of the Sc ions. The dopant concentr ation dependence shows that the covalency is strongest when the Sc con centration is 2 mol%. These facts suggest that the covalency is relate d to the protonic conduction. reserved. (C) 1998 Elsevier Science B.V. All rights reserved.