Multifunction realization in MoS2/WS2/h-BN heterojunction: Integrated self-powered high-performance photodetection, visualization, nonvolatile memory, and synaptic simulation

Abstract

Nowadays, efficient performance, functional diversification, device miniaturization and systematic integration are the trends for developing new electronic information technology. However, photodetectors with only optoelectronic detection functions cannot satisfy the growing demands of the multifunction required in single devices. This paper presents a MoS2/WS2/h-BN van der Waals heterojunction device realizing multifunctional applications which integrated self-powered high-performance photodetection, visualization, nonvolatile memory, and synaptic simulation. The heterojunction achieves a high responsivity of 9.28 A/W, an excellent specific detectivity of 6.1×1012 Jones, a large external quantum efficiency of 2358 %, a considerable on/off ratio of 7×105 and an ultrafast response time of 0.6 μs at 1 V bias under 488 nm laser irradiation. Besides, the photodetector shows excellent photovoltaic characteristics with a short-circuit current of 0.22 μA and an open-circuit voltage of 0.34 V. Moreover, the device also shows a favorable optical response to 532 and 633 nm lasers. The device also realizes visualization and can be used as an imaging sensor. In addition, the device integrates nonvolatile memory function due to the charge storage effect of h-BN and h-BN/SiO2 interface. Furthermore, biological synaptic functions, such as the memory process, short- and long-term plasticity, and double pulse facilitation, are also successfully simulated. This work realizes the high-performance and multifunctional applications of MoS2/WS2/h-BN device based on a new strategy of utilizing h-BN as a heterojunction substrate.