Metal oxide semiconductor nanowires enabled air-stable ultraviolet-driven synaptic transistors for artificial vision

Abstract

The multi-terminal transistor can provide reliable platform to construct artificial synapses with various benefits. In particular, synaptic transistors based on wide-bandgap metal oxide semiconductors (MOSs) offer opportunities to realize ultraviolet (UV) artificial vision. In this work, via a low-cost electrospinning technique, we have fabricated bio-inspired synaptic transistors based on zinc tin oxide (ZnSnO) nanowires, which can be effectively tuned by UV laser to achieve air-stable synaptic characteristics, such as excitatory post-synaptic current, paired-pulse facilitation, and learning-forgetting process based on long-term potentiation. The adsorption/desorption of oxygen molecules governs the generation of free charge carriers in the ZnSnO nanowires. Via the combination of transmission electron microscopy and X-ray diffraction measurements, we found that the revealed SnO2/ZnO heterostructures can effectively mitigate the recombination of UV-induced free carriers in the ZnSnO nanowires. Furthermore, based on the synaptic characteristics obtained from ZnSnO nanowires, we present several applications relevant to the UV artificial vision. We believe this study can provide insights into importance of heterostructures in synaptic transistors based on low-dimension MOSs with superior environmental stability and various applications.