Solvent-assisted sulfur vacancy engineering method in MoS2 for neuromorphic synaptic memristor

Recently, two-dimensional transition metal dichalcogenides (TMDs) such as molybdenum disulfide (MoS2) have attracted great attention due to their unique properties. To modulate electronic properties and structure of TMDs, it is crucial to precisely control chalcogenide vacancies and several methods have been already suggested. However, they have several limitations such as plasma damage by ion bombardment. Herein, we introduced a novel solvent-assisted vacancy engineering (SAVE) method to modulate sulfur vacancies in MoS2. Considering polarity and Hansen solubility parameter (HSP), three solvents were selected. Sulfur vacancies can be modulated by immersing MoS2 in each solvent, supported by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy analyses. SAVE method can further expand its application in memory devices representing memristive performance and synaptic behaviors. We represented the charge transport mechanism of sulfur vacancies forming and breaking conductive links. The non-destructive, scalable, and novel SAVE method controlling sulfur vacancies is expected to be a guideline for constructing a vacancy engineering system of TMDs.