Artificial Optoelectronic Synapses Based on TiN_xO_2–x/MoS₂ Heterojunction for Neuromorphic Computing and Visual System

Being capable of dealing with both electrical signals and light, artificial optoelectronic synapses are of great importance for neuromorphic computing and are receiving a burgeoning amount of interest in visual information processing. In this work, an artificial optoelectronic synapse composed of Al/TiN_xO_2–x/MoS₂/ITO (H-OSD) is proposed and experimentally realized. The H-OSD can enable basic electrical voltage-induced synaptic functions such as the long/short-term plasticity and moreover the synaptic plasticity can be electrically adjusted. In response to the light stimuli, versatile advanced synaptic functions including long/short-term memory, and learning-forgetting-relearning are successfully demonstrated, which could enhance the information processing capability for neuromorphic computing. Most importantly, based on these light-induced salient features, a 4 × 4 synapse array is developed to show the potential application of the proposed H-OSD in constructing artificial visual system. It is shown that the perceiving and memorizing of the light information that are respectively relevant to the visual perception and visual memory functions, can be readily attained through tuning of the light intensity and the number of illuminations. As such, the proposed optoelectronic synapse shows great potentials in both neuromorphic computing and visual information processing and will facilitate the applications such as electronic eyes and light-driven neurorobotics.