Optically controlled memristor based on ZrO2(Y) film with Au nanoparticles

We report on the fabrication and investigation of prototype optically controlled memristors based on ZrO₂(Y) (12% mol. Y₂O₃) with Au nanoparticles (NPs) of 2–3 nm in diameter formed by layer-by-layer magnetron deposition of ZrO₂(Y)/Au/ZrO₂(Y) stacks followed by annealing. The upper contacts of the memristor stacks were made from indium-tin oxide (ITO) to provide the access of photoexcitation to the active Au NP array. The crosspoint memristor devices with the active region sizes of 2020 μm2 were defined by standard photolithography with wet etching. A shift of the switching voltages from the high resistance state into the low resistance one and back has been observed under the photoexcitation at the wavelength of 650 nm corresponding to the collective plasmon resonance in the dense Au NP array. The effect was related to the charging of the Au NPs due to the internal photoemission of the electrons from the Au NPs into the ZrO₂(Y) matrix enhanced by the plasmon resonance. It leads to the redistribution of the electric field near the Au NPs that, in turn, stimulates the switching process. The optically-controlled  memristors investigated are promising for application in various fields of memristive photonics.