Light-Enhanced Negative Differential Resistance and Multi-Level Resistive Switching in Glutamine-Functionalized MoS2 Quantum Dots for Resistive Random-Access Memory Devices

Abstract

Negative differential resistance (NDR) with multi-level resistive switching has been investigated for realizing multi-level memory devices. However, achieving a high peak-to-valley ratio of NDR is a formidable challenge for a reliable multi-level switch. Here, a new type of a light-enhanced NDR device accompanied with resistive switching based on glutamine-functionalized MoS2 quantum dots has been demonstrated. By increasing the illuminated light power on the device, the NDR effect can be greatly enhanced and a peak-to-valley ratio as high as 15.5 has been achieved. The tunneling transport and carrier trapping of the interface states are responsible for the mechanism of the light-enhanced NDR. Multi-level resistive switching can be realized in the same device by adjusting the illuminated light power. A high on/off resistance ratio of ≈103 and good endurance in multi-valued switching have been achieved, exhibiting potential applications in multi-level memory devices.