Large photoelectric-gating effect of two-dimensional van-der-Waals organic/tungsten diselenide heterointerface

Photo- or photoelectric-gating modulation is a promising strategy for high-performance photodetectors, which amplifies photoresponsivity by long-lived trapped charges at the interface. However, the performance is normally limited by the uncontrollable trapping process. Here, we develop a large photoelectric-gating, which enhances interfacial charge trapping process by a van-der-Waals interface with an electric-gating tunable energy barrier in the band alignment. By synergy of photo-gating and electric-gating effects, responsivity and detectivity of 1,4-bis(4-methylstyryl)benzene/tungsten diselenide (WSe2) increase by 25-fold and 3-fold to 3.6 × 106 A/W and 8.6 × 1014 Jones. High-quality two-dimensional van-der-Waals interface is of great importance. Sufficient supply of gas-phase molecules in physical vapor deposition is pivotal to obtain such interface between organic crystal and WSe2. As an application, an electric-gating switchable photodetector has been developed, showing great potential of this strategy not only in high-performance photodetectors but also in new photoelectrical devices.