Photovoltaic and resistance switching properties of NiO/Pb0.92La0.08(Zr0.52Ti0.48)O3/LaNiO3

Abstract

Due to its excellent ferroelectricity and photovoltaic effect (PE), Pb0.92La0.08(Zr0.52Ti0.48)O3 (PLZT) has considerable application potential in the field of multifunctional electronic devices. In this study, an Ag/NiO/PLZT/LaNiO3 structure is prepared on a Si substrate via a combination of sol–gel and pulsed laser deposition methods, and its ferroelectricity, PE and resistance switching (RS) properties are studied in detail. With decrease in temperature, coercive field of PLZT increases, and its residual polarization initially remains constant and then decreases. The results of ultraviolet-irradiation experiments show that the photogenerated open-circuit voltage (Vo) of PLZT first increases slightly and then decreases slightly as the temperature decreases. By changing the direction of PLZT polarization, the polarization field can be oriented in the same direction or opposite to the built-in electric field formed by p–n junction at NiO/PLZT interface. Thus, the total electric field required to drive the photogenerated carriers inside the structure can be tuned, which results in different Vo values. Furthermore, current–voltage characteristics of the structure are tested. It is found that as different polarization charges are generated at the NiO/PLZT interface for different PLZT polarization directions, the holes in NiO can be attracted or repelled by these polarization charges. Thereby, the interface barrier height of the p–n junction can be varied. Consequently, the structure exhibits a pronounced RS effect suitable for multilevel storage applications. These results represent an important experimental basis for the development and application of multifunctional electronic devices for optoelectronics and RS-based memories.