Temperature and polarity dependence of electrical properties of ZnO film on pyroelectric LiNbO₃single crystal

Abstract

Effects of polarity and pyroelectricity of LiNbO 3 (LN) on electrical properties of ZnO film were investigated. The ZnO films were annealed at 500 °C and 900 °C under an oxygen atmosphere to reduce the interface defects. Current-voltage (I-V ) and surface potential measurements showed that the as deposited ZnO did not show polarity dependence. The ZnO annealed at 500 °C on +LN and −LN showed semiconducting and metallic behaviors at low temperature, respectively. X-ray photoelectron spectroscopy revealed that the polarization of LN changed the band alignment of ZnO/LN interface. In addition, the pyroelectricity increased the band bending, resulting in the enhancement of semiconducting and metallic properties for +LN and −LN, respectively. Especially, the resistivity of ZnO annealed at 500 °C changed by 5-digit from 80 to 500 K. The pyroelectricity and polarity of LN should contribute to modulating the electrical properties of ZnO for environment sensing devices.