Polyoxometalates‐Modulated Reduced Graphene Oxide Flash Memory with Ambipolar Trapping as Bidirectional Artificial Synapse

Abstract

AbstractEmploying flash memories that function as the analogue synapse cleft for implementation of neural systems is a popular approach. For practical application in synapse mimicking, ambipolar trapping of both holes and electrons enables the weight updated linearity, symmetric conductivity variation, and desired variation margin, which are consistent with biological synapse. Nevertheless, most of the flash memory exhibits unipolar charge trapping behavior. Here, the first polyoxometalates (POMs)‐modulated reduced graphene oxide (RGO)‐based flash memory with ambipolar charge trapping characteristics is reported. Keggin type [PW12O40]3− (PW) is selected to function as both catalyst for in situ photoreduction of the graphene oxide (GO) into RGO under UV illumination and electron trapping sites. The electrons accepting property of PW induces energy level realignment between the PW/RGO interface and the subsequent ambipolar charge trapping. Furthermore, the selected features of biological synaptic behavior, including short‐term plasticity and long‐term plasticity as well as paired pulse facilitation and depression, are mimicked. It is worth noting that almost symmetrical potentiation and depression synaptic behavior is obtained. This work provides new opportunities to realize reconfigurable characteristics of electronic devices via engineering of POMs, which is significantly meaningful to emerging artificial intelligence.