Artificial optoelectronic synapses based on Ga2O3 metal–semiconductor–metal solar-blind ultraviolet photodetectors withasymmetric electrodes for neuromorphic computing

Abstract

Research on optoelectronic synapses that can integrate both detection and pro-cessing functions is essential for the development of efficient neuromorphiccomputing. Here, we experimentally demonstrated an Ga2O3-based metal–semiconductor–metal (MSM) solar-blind ultraviolet (UV) photodetector (PD)with asymmetric interdigital electrodes. The Ga2O3 PD exhibits a responsivity of732 A/W under a forward bias of 6 V. The tunable conductance properties of PDsprovide a novel approach to synaptic performance. The proposed PDs as artificialsynapse realized several essential synaptic function, including excitatory post-synaptic current, paired-pulse facilitation, long-term potentiation, the transitionfrom short-term memory to long-term memory, and learning experience behaviorssuccessfully. At a reverse bias, an ultra-low energy consumption of 140 fJ wasachieved. In addition, the optoelectronic synapses demonstrated a recognitionaccuracy of over 95% in the MNIST handwritten number recognition task. Theseresults suggest that Ga2O3 MSM solar-blind UV PDs have high potential forefficient optoelectronic neuromorphic computing applications.