Surface Electronic Structure of BaZr_1-xY_xO_3-δ by Soft-X-Ray Spectroscopy

Abstract

The electronic structures in the surface and bulk states of Y³⁺-doped BaZrO₃ (BaZr_1-xY_xO_3-δ) have been studied by X-ray absorption spectroscopy and soft-X-ray emission spectroscopy. The valence band is mainly composed of the O 2p state hybridized with the Zr 4d state. The conduction band consists of Zr 4d state. The band gap increases with increasing Y³⁺ concentration, indicating the existence of hole at the top of valence band. Although the Fermi level (E_F) of bulk locates at the valence band side, E_F of surface locates at intermediate of band gap. These findings may indicate that the band bending effect exists at the surface of BaZr_1-xY_xO_3-δ.