Tailoring resistive switching in ultra-thin tellurium films by interface engineering

The use of two-dimensional or nanoscaled materials as active medium in resistive switching (RS) is becoming more and more frequent in the neuromorphic and in-memory computing. Although many works have focused their attention on the RS mechanism of the materials, less attention is devoted to understanding the role of the interfaces with the metallic electrodes, especially when the electrode is also used as substrate for the growth of the material. Indeed, a low temperature growth of the active material on the largest possible metallic substrate would greatly improve the scalability and compatibility with back-end-of-line processing of the resulting memristive devices. Here, we report that tellurium grown by vapour transport deposition at 100 °C on gold substrate improves its RS when the surface of the Au(111) shows the well-known herringbone reconstruction. Indeed, the morphology of the nanoscaled tellurium is influenced by the gold surface reconstruction and, in turn, its RS probed by conductive atomic force microscopy. By comparison with the un-reconstructed surface, a non-negligible reduction of the set and reset voltages is observed. These results demonstrate that proper interface engineering between the material and electrodes might turn out to be as important as the material itself for the memristive performance.