Design-Dependent Switching Mechanisms of Schottky-Barrier-Modulated Memristors based on 2D Semiconductor

For Schottky barrier-modulated memristors based on 2D semiconductors it has, to date, not been possible to achieved control over defect type and concentration as the measured switching characteristics vary considerably even under similar fabrication conditions. In this work, four distinct types of memristors are identified based on the combination of low and high resistance sequences, as well as volatile and nonvolatile characteristics. All these four types of memristors were previously observed experimentally by different research labs. It is found that the specific behavior of each memristor type can be explained by the Schottky barrier height modulation and current rectification arising from the concerted effects of the concentration, charge polarity and mobility of defects. The conditions required to realize the four types of 2D semiconductor-based memristors are analyzed and design guidelines for fabricating each of these four types of memristors are provided.