Optoelectronic synaptic devices based on TMD alloys for image memory and processing

Abstract

Optoelectronic synaptic devices emulate the parallel processing and low-power characteristics of biological neural systems, enabling real-time image processing and dynamic object tracking. These advancements address the limitations of conventional von Neumann architectures. Transition metal dichalcogenides (TMDs) have become important candidate materials for synaptic devices due to their excellent optoelectronic properties, and the trapping effect of defects in TMDs on photogenerated carriers enables this possibility. However, current synaptic devices based on TMDs face the challenges associated with unstable defect effects, relying on complex heterojunctions and device structures to achieve neural synapse function, which limits their widespread application. In this work, the alloying strategy of TMDs is adopted to address this issue. The large-scale growth and composition gradient control of monolayer MoS2(1−x)Se2x are achieved under the guidance of ab initio molecular dynamics. Based on the defect effect in MoS2(1−x)Se2x through the synergistic effect of S atom vacancies and substitutions, synaptic devices with dual-terminal structure are constructed, which have photoresponsivity of 0.23 A/W and pair-pulse facilitation ratio of 147%. An imaging system is also built to demonstrate the imaging memory and processing functions of the devices. The defect effect engineered through alloying offers a promising pathway for the development of synaptic devices.