Dual-Mode Photoresponse of the Gr/MoS₂/VO₂ Heterostructure toward Multifunctional Optoelectronic Applications

The advent of two-dimensional materials with diverse structures and exceptional properties has emerged as highly promising candidates for next-generational optoelectronic devices. In particular, there is a pressing need for integrating both photodetection and processing abilities in a single device. Here, a multifunctional optoelectronic device based on the MoS2/VO2 heterostructure is presented, with multilayer graphene (Gr) and gold serving as electrodes contacted with MoS2 and VO2, respectively. The energy band is electrically modulated to realize a switchable photoresponse between the photovoltaic device and photoconductor. In photovoltaic mode, the device exhibits self-powered photoresponse in a broadband spectrum range with a rapid response speed based on the built-in field of the MoS2/VO2 interface, which is suitable for high-speed infrared optical communication. Moreover, the phase transition property of VO2 enabled high-temperature photodetection. In photoconductive mode, the device owns a long-term memory characteristic effectively modulated by light intensity and pulse, essential for realizing an optoelectronic synapse. This work provides a strategy for implementing intelligent sensing and integrated optoelectronic devices.