Revealing the potential of 2D WS2 memristors as an artificial synapse with resilient gradual behavior at high temperatures for neuromorphic applications

Abstract

The increasing demand for future digital technologies and high-temperature neuromorphic hardware will rely on non-volatile behavior and power efficiency. High-temperature devices are crucial for space exploration and function in severe environments, such as industrial units. Two-dimensional transition metal dichalcogenides (TMDs) are known for their strong mechanical properties, which make them frontrunners for next-generation device fabrication. This paper presents an Ag/WS₂/W memristive device deposited onto a silicon substrate utilizing a direct current (DC) magnetron sputtering technique that can operate at high temperatures. The device displays steady and reliable gradual resistive switching characteristics with low set/reset switching voltages (+0.65 V/−0.55 V). Device also exhibits an excellent electrical endurance (>2500 cycles), retention time (>10⁴ s), and good cycle-to-cycle variability with low variation coefficient, confirming its consistency and robustness. Temperature-dependent current–voltage measurements were utilized to investigate the conduction behavior of the developed memristive device. The measured electrical characteristics highlighted a thermally assisted conduction process, thereby justifying the proposed switching model. Furthermore, the memristor device emulated fundamental synaptic plasticity functionalities, including long-term potentiation (LTP), long-term depression (LTD), paired-pulse facilitation (PPF), and paired-pulse depression (PPD). This study highlights 2D WS₂ as an emerging material that can serve effectively as an artificial synapse and also maintains steady operation at elevated temperatures. These findings pave the way for the realization of state-of-the-art neuromorphic computing platforms.