Photocurrent properties of KTa0.65Nb0.35O3 crystal grown by Czochralski method

The absorption and photocurrent properties of KTa0.65Nb0.35O3 crystal were studied experimentally and theoretically at room temperature. By modeling the crystal absorption with the density of states and the Urbach rule, it is shown that excitonic transitions contribute no effect on the absorption of the wafer. The spectra shift to lower energy when there is applied electric field. According to density of states and Urbach rule, the fundamental absorption determines the shape of the photocurrent spectrum. The photocurrent spectra have been studied by applying electric fields up to 25 V/mm. Photocurrent measurements indicate that KTa0.65Nb0.35O3 crystal exhibits excellent physical properties around its Curie point.