Carbon nanowalls/diamond heterojunctions as novel photo-switching memory devices

We demonstrate in-situ growth of carbon nanowalls (CNWs) on diamond semiconductors by microwave plasma assisted chemical vapor deposition. The resulting CNW/diamond junctions behave as photomemristors having both photo-controllable multiple resistance states and nonvolatile memory functions. The resistance state (high or low resistance state) can be selected by light irradiation with the application of a bias voltage, giving a large resistance switching ratio of ∼10
⁶
. The photo-induced resistance switching behaviors are rarely observed and has only been observed in a few materials and/or heterostructures. These results indicate CNW/diamond (that is, carbon sp
²
-sp
³
) junctions could have applications in novel photo-controllable devices, which have photo-sensing, memory, and switching functions.