UV Irradiation Effect on the Surface KTaO₃ Crystals

Abstract

Abstract. The perovskite oxides property are wider band-gap semiconductors and are sensitive to visible light but opaque In this paper, we are interested in the resistance change of insulating KTaO 3 crystals could decrease as much as 3-4 orders of magnitudes under exposure to focused sunlight. But, these resistances under ambient pressure would change back quickly after light was off. And the resistances change in a similar way under exposure to synchrotron light but the increase resistance rate was much slower under vacuum condition. However, the large increase resistance rate by increasing the oxygen pressure. From the ARPES study, we found that the change in resistance occurred due to the oxygen vacancy induced by the exposure to ultraviolet light. These oxygen vacancies induce two-dimensional electron gas at the surface KTaO 3 . This indicates that the KTaO 3 could be used as a light sensing device.