Demonstration of asymmetric Hebbian learning based on analog resistive switching in Ag/Co3O4/p-Si memristor

In this work, brain-like experiential learning/forgetting ability is demonstrated with the help of various synaptic adaptation rules, namely, short-term potentiation/short-term depression, long-term potentiation/long-term depression, spike rate-dependent plasticity, and spike-time-dependent plasticity in a thin-film device. The model device used here is a unidirectional thin film of nanocrystalline Co3O4, grown on a p-Si (100) substrate using the pulsed laser deposition technique to fabricate a metal–insulator–semiconductor type memristor. Along with this, we found an analog bipolar-type switching behavior with excellent resistive switching properties in terms of endurance, retention, and ON–OFF ratio suitable for CMOS-based memory applications. The conduction and resistive switching mechanisms are elucidated using a speculative band diagram formulated from the UV-visible spectroscopy data.