Sulfurization Engineering of One-Step Low-Temperature MoS₂ and WS₂ Thin Films for Memristor Device Applications

2D materials have been of considerable interest as new materials for device applications. Non-volatile resistive switching applications of MoS₂ and WS₂ have been previously demonstrated; however, these applications are dramatically limited by high temperatures and extended times needed for the large-area synthesis of 2D materials on crystalline substrates. The experimental results demonstrate a one-step sulfurization method to synthesize MoS₂ and WS₂ at 550 °C in 15 min on sapphire wafers. Furthermore, a large area transfer of the synthesized thin films to SiO₂/Si substrates is achieved. Following this, MoS₂ and WS₂ memristors are fabricated that exhibit stable non-volatile switching and a satisfactory large on/off current ratio (10³–10⁵) with good uniformity. Tuning the sulfurization parameters (temperature and metal precursor thickness) is found to be a straightforward and effective strategy to improve the performance of the memristors. The demonstration of large-scale MoS₂ and WS₂ memristors with a one-step low-temperature sulfurization method with simple strategy to tuning can lead to potential applications such as flexible memory and neuromorphic computing.