The lateral photovoltaic effect and its applications in light-based devices

Photoelectronic effects in nanostructures, such as the photovoltaic effect in solar cells and the photogating effect in photodetectors, represent both fundamental issues in solid state physics and promising application prospects. This review focuses on the progress and challenges of the lateral photovoltaic effect (LPE) in nanostructures. As a characteristic attribute in semiconductor-based materials, LPE originates from the lateral diffusion of photon-generated carriers under non-uniform illumination. A carrier concentration gradient between two lateral electrodes on the same side generates the lateral photovoltage (LPV) that varies linearly with light spot position. This linear relationship enables the LPE's primary application in position-sensitive detectors (PSDs) for high-precision displacement measurements and real-time trajectory tracking of light sources. The key parameter of LPE is position sensitivity, defined as the rate of LPV change per unit displacement. Pursuing a high LPE sensitivity under specific operational requirements has attracted substantial research attention. Herein, we systematically summarize the mechanisms of LPE and enhancement strategies of sensitivity including local surface plasmonic engineering and external field modulation techniques. We review some recent advancements across diverse nanostructures, such as nanofilms, quantum dots, nanowires, graphene, transition-metal chalcogenides, and so on. This review provides a comprehensive overview of LPE in semiconductor-based nanostructures while offering the future outlook on the development of PSDs.