CuS nanosheets with controllable morphology and alignment for memristor devices

In electrochemical metallization memristor, the performance of resistive switching (RS) is influenced by the forming and fusing of conductive filaments within the dielectric layer. However, the growth of filaments, mostly, is unpredictable and uncontrollable. For this reason, to optimize ions migration paths in the dielectric layer itself in the Al/CuS/Cu structure, uniform CuS nanosheets films have been synthesized using anodization for various time spans. And the Al/CuS/Cu devices show a low operating voltage of less than 0.3 V and stable RS performance. At the same time, a reversible negative differential resistance (NDR) behavior is also demonstrated. And then, the mechanism of repeatable coexistence of RS effect and NDR phenomenon is investigated exhaustively. Analyses suggest that the combined physical model of space-charge limited conduction mechanism and conductive filaments bias-induced migration of Cu ions within the CuS dielectric layer is responsible for the RS operation, meanwhile, a Schottky barrier caused by copper vacancy at the CuS/Cu interface is demonstrated to explain the NDR phenomenon. This work will develop a new way to optimize the performance of non-volatile memory with multiple physical attributes in the future.