Electronic transport properties and electronic structure of InO1.5-doped CaZrO3

Simultaneous measurements of total conductivity and thermoelectric power have been made on 1 mol% InO1.5-doped CaZrO3 (CaZr0.99In0.01O0.995) in order to evaluate defect chemical parameters and both electronic and ionic transport properties. The concentrations of holes, protons, and oxygen vacancies and their mobility, in addition to the heat of transport of oxide ions and protons, have been estimated using defect chemical and irreversible thermochemical analyses. The present results show that the dissolution reaction of protons saturates below 1173 K and the concentration of holes decreases by the dissolution of protons, indicating the presence of direct substitution of protons with holes. Ols X-ray absorption spectroscopy has been employed to observe the electronic structure near the band gap, showing the presence of holes at the top of the valence band and the splitting of the hole state when protons dissolve. The decrease in the hole concentration observed under reducing conditions is consistent with the defect chemical analysis. (C) 2000 Elsevier Science B.V. All rights reserved.