Mechanisms for the enhancement of the lateral photovoltage in perovskite heterostructures

The mechanisms for the greatly enhanced lateral photovoltaic effect in the perovskite oxide heterostructures are studied by solving time-dependent   two-dimensional drift-diffusion equations self-consistently. By our calculations, we find that the lateral photovoltage of pp-type material is larger than that of nn-type material owing to the larger drift electric field induced in the pp-type material than that in the nn-type material. Moreover, the built-in electric field at the interface between the thin film and substrate can also enhance the lateral photovoltage. The above two mechanisms can well explain one-order-of-magnitude enhancement of the lateral photovoltaic effect in the perovskite heterostructures. In addition, we find that the materials with larger mobility ratio have a stronger Dember effect. Such an understanding of the mechanisms for the enhancement of lateral photovoltage in oxide heterostructures should be useful in further designing of the structures of position-sensitive detectors and new THz sources.