Radiation Effects on LiNbO2 Memristors for Neuromorphic Computing Applications

The effects of X-ray and proton radiation on a LiNbO2 analog memristor are investigated by I-V hysteresis, Electrochemical Impedance Spectroscopy, low-frequency AC voltage, and X-ray diffraction analysis. Both electrical and structural characterization of an irradiated memristor show that irradiation leads to an increased level of defects in the LiNbO2 crystalline lattice. These radiation-induced defects facilitate faster lithium movement as shown by electrochemical impedance spectroscopy measurements on the as-grown and irradiated memristor. X-ray radiation improves ionic motion in the bulk of the device and increases the ionic resistance at the LiNbO2-metal interface. In the case of proton radiation, the memristance response improves due to an increase in ionic motion in the bulk and at the interfaces. It is also shown by Monte Carlo simulations that proton irradiation of LiNbO2 results in structural damage, which was verified experimentally by an X-ray diffraction study.