Equalizing Excitation‐Inhibition via the Ambipolar Photoresponse of Al2O3/graphene Hybrid Neuromorphic Devices

Abstract Intrigued by the artificial intelligence and brain‐like neural networks, the photoelectronic neuromorphic devices that can simulate synaptic functions have been attracting wide attention. However, equalizing excitation‐inhibition has been seldom artificially realized despite its fundamental feature in a biological system. In this work, an artificial synapse is proposed based on a sandwiched Ag/Al 2 O 3 /graphene/ITO photodetector. The device exhibits a special ambipolar photoresponse at the millivoltage as a result of the interfacial trapping effects. Under the coupled light and electrical stimulus, the synaptic excitatory, inhibitory signals and their recovery are emulated on a single device via the positive and negative photoresponse, respectively. Further, the biologically dynamic balance of excitation and inhibition is reproduced on a simple analogous system integrating multiple photoelectronic synaptic cells. These remarkable results provide a potential foundation for building hardware units with neuromorphic architecture to mimic the complex human brain functionalities.