Low voltage and robust InSe memristor using van der Waals electrodes integration

Memristors have attracted tremendous interest for high-density memory and neuromorphic computing. However, despite tremendous efforts devoted recent years, the high operation voltage, poor stability and large device variability remain key limitations for its practical application, and could be partially attributed to the un-optimized interfaces between electrodes and the channel material. Here, for the first time, we demonstrate a van der Waals memristor by physically sandwiching pre-fabricated metal electrodes on both sides of two-dimensional channel material. The atomically flat bottom electrode ensures the intimate contact between channel and electrode (hence low operation voltage), and the van der Waals integration of top electrode could avoid aggressive fabrication processes (e.g., sputtering, lithography) directly applied on channel material, improving device stability. Together, we demonstrate memristor arrays with high integration density of 1010/cm2, high stability, as well as lowest set/reset voltage of 0.12 V/0.04 V, which is a record low value in all 2D based memristors, as far as we know. Furthermore, detailed characterizations are conducted to confirm the improved memristor behavior is the result of optimized metal/channel interfaces. Our study not only demonstrates robust and low voltage memristor, but also provides a general electrodes integration approach for other memristors (such as oxide based) that are previously limited by non-ideal contact integration, high operation voltage and poor device stability.