Interface-Induced WSe(2) In-plane Homojunction for High-Performance Photodetection

2D transition metal dichalcogenides (TMDCs) have been extensively attractive for nano-electronics and nano-optoelectronics due to their unique properties. Especially, WSe(2), having bipolar carrier transport ability and sizable bandgap, is a promising candidate for future photodetectors. Here, we report an in-plane WSe(2) homojunction formed by the interface gate of the substrate. In this architecture, an insulated h-BN flake was used to make only part of WSe(2) flake contact substrate directly. Finally, the structures of WSe(2)/substrate and WSe(2)/h-BN/substrate construct an in-plane homojunction. Interestingly, the device can operate in both photovoltaic and photoconductive modes at different biases. As a result, a responsivity of 1.07 A W(−1) with a superior detectivity of over 10(12) jones and a fast response time of 106 μs are obtained simultaneously. Compared with previously reported methods adopted by chemical doping or electrostatic gating with extra bias voltages, our design provides a more facile and efficient way for the development of high-performance WSe(2)-based photodetectors.