LAUSR

Copper chalcogenides represent a class of materials with unique crystal structures, high electrical conductivity, and earth abundance, and are recognized as promising candidates for next‐generation green electronics. However, their 2D structures and the corresponding electronic properties have rarely been touched. Herein, a series of ultrathin copper chalcogenide nanosheets with thicknesses down to two unit cells are successfully synthesized, including layered Cu2Te, as well as nonlayered CuSe and Cu9S5, via van der Waals epitaxy, and their nonvolatile memristive behavior is investigated for the first time. Benefiting from the highly active Cu ions with low migration barriers, the memristors based on ultrathin 2D copper chalcogenide crystals exhibit relatively small switching voltage (≈0.4 V), fast switching speed, high switching uniformity, and wide operating temperature range (from 80 to 420 K), as well as stable retention and good cyclic endurance. These results demonstrate their tangible applications in future low‐power, cryogenic, and high temperature harsh electronics.