Nonvolatile infrared memory in MoS₂/PbS van der Waals heterostructures

Optoelectronic devices for information storage and processing are at the heart of optical communication technology due to their significant applications in optical recording and computing. The infrared radiations of 850, 1310, and 1550 nm with low energy dissipation in optical fibers are typical optical communication wavebands. However, optoelectronic devices that could convert and store the infrared data into electrical signals, thereby enabling optical data communications, have not yet been realized. We report an infrared memory device using MoS₂/PbS van der Waals heterostructures, in which the infrared pulse intrigues a persistent resistance state that hardly relaxes within our experimental time scales (more than 10⁴ s). The device fully retrieves the memory state even after powering off for 3 hours, indicating its potential for nonvolatile storage devices. Furthermore, the device presents a reconfigurable switch of 2000 stable cycles. Supported by a theoretical model with quantitative analysis, we propose that the optical memory and the electrical erasing phenomenon, respectively, originate from the localization of infrared-induced holes in PbS and gate voltage pulse-enhanced tunneling of electrons from MoS₂ to PbS. The demonstrated MoS₂ heterostructure-based memory devices open up an exciting field for optoelectronic infrared memory and programmable logic devices.