Enhanced Photoresponsive Properties of Perovskite Films on Metal Oxide LaAlO₃ Substrates

We report enhanced photoresponsive properties of planar-type perovskite films fabricated by spin-coating method on metal oxide LaAlO₃ substrates. The reliable I_light/I_dark ratio (>10⁴), responsivity (70 mA/W), detectivity (1.5 × 10¹⁰ Jones), and photoresponsive time (0.26 ms) of films on LaAlO₃ substrates are achieved. These results are caused by the abundant La vacancies at the surface of LaAlO₃ substrates after the plasma treatment, which would form the build-in electric field at the interface and meanwhile induce the sub-band gap photoluminescence. Thus, the photon-generated carrier separation and density are increased. Our results pave a way for promoting photoresponsive properties by the interface effect and create an opportunity for future high-performance photodetectors based on perovskites.