Gate-tunable non-volatile photomemory effect in MoS2 transistors

© 2019 IOP Publishing Ltd. Non-volatile memory devices have been limited to flash architectures that are complex devices. Here, we present a unique photomemory effect in MoS2 transistors. The photomemory is based on a photodoping effect-a controlled way of manipulating the density of free charges in monolayer MoS2 using a combination of laser exposure and gate voltage application. The photodoping promotes changes on the conductance of MoS2 leading to photomemory states with high memory on/off ratio. Such memory states are non-volatile with an expectation of retaining up to 50% of the information for tens of years. Furthermore, we show that the photodoping is gate-tunable, enabling control of the recorded memory states. Finally, we propose a model to explain the photodoping, and we provide experimental evidence supporting such a phenomenon. In summary, our work includes the MoS2 phototransistors in the non-volatile memory devices and expands the possibilities of memory application beyond conventional memory architectures.