Study on Impurity Levels in a Cr-Doped Y₂O₃ Thin Film

Abstract

We fabricated a sample having the structure of electrode-Cr doped Y₂O₃ thin film-electrode by the RF sputtering technique, and applied the photocurrent method to the sample. The photocurrent observed at wavelengths shorter than 450 nm is attributed to the charge transfer from the valence band to Cr⁵⁺, and a peak of the photocurrent at 370 nm is assigned to the electron transfer from the excited states of Cr⁵⁺ to the conduction band. By means of double source photocurrent measurements, the energy level of the oxygen vacancy states is estimated to be located at ca. 2eV below the conduction band.