Perovskite colloidal quantum-dot enhanced graphene/silicon heterojunction with improved ultraviolet response

Abstract

Silicon (Si) is a mature semiconductor detection material because of its appropriate bandgap, high reliability, and low-cost manufacturing process. However, the detection range of Si-based photodetectors is mainly restricted to visible and near-infrared (NIR) ranges. Broadening the detection range of Si-based detectors to ultraviolet (UV) could ignite numerous applications, including flame detection, defense safety, and environmental monitoring. Here, the obtained perovskite colloidal quantum dots (QDs) with high quality are integrated with a Si/graphene heterojunction to broaden and improve response. By the electrical coupling mechanism between graphene and QDs, the built-in potential in detectors is maximized. As a result, the devices exhibit a high UV responsivity of 0.33 A W−1 at 210 nm, 0.73 A W−1 at 400 nm, and a superior detectivity of nearly 1012 Jones under the UV region. Aside from that, the performance of devices under visible and NIR ranges is also dramatically improved compared to that of the one without perovskite QDs.