Optoelectronic synaptic plasticity mimicked in ZnO-based artificial synapse for neuromorphic image sensing application

Memristor-based optoelectronic artificial synapse enables future neuromorphic computing to be more efficient. Hence the development of better optoelectronic artificial synapses becomes considerably important for the era of next-generation neuromorphic computing and neuromorphic visual systems. Optoelectronic artificial synapses can empower neuromorphic visual systems even beyond the visible light region, which has substantial potential to mimic the essential functions of the human visual system. This paper demonstrates a better optoelectronic artificial synapse that shows many fundamental bio-synaptic characteristics. Fabricated devices exhibit excellent paired-pulse facilitation with both electrical and optical input stimuli. The transition from short-term memory to long-term memory was observed for the frequent and high number of input stimuli similar to bio-synapse. Essential Hebbian learning protocols, such as spike-timing-dependent plasticity and spike-rate-dependent plas-ticity, were successfully emulated in this artificial synapse. It also possesses light-tunable synaptic plasticity, which enables real-time neuromorphic visual pre-processing for realizing neuromorphic visual systems.