N:ZnO/MoS2-heterostructured flexible synaptic devices enabling optoelectronic co-modulation for robust artificial visual systems

With the merits of non-contact, highly efficient, and parallel computing, optoelectronic synaptic devices combining sensing and memory in a single unit are promising for constructing neuromorphic computing and artificial visual chip. Based on this, a N:ZnO/MoS2-heterostructured flexible optoelectronic synaptic device is developed in this work, and its capability in mimicking the synaptic behaviors is systemically investigated under the electrical and light signals. Versatile synaptic functions, including synaptic plasticity, long-term/short-term memory, and learning-forgetting-relearning property, have been achieved in this synaptic device. Further, an artificial visual memory system integrating sense and memory is emulated with the device array, and the visual memory behavior can be regulated by varying the light parameters. Moreover, the optoelectronic co-modulation behavior is verified by applying mixed electric and light signals to the array. In detail, a transient recovery property is discovered when the electric signals are applied in synergy during the decay of the light response, of which property facilitates the development of robust artificial visual systems. Furthermore, by superimposing electrical signals during the light response process, a differentiated response of the array is achieved, which can be used as a proof of concept for the color perception of the artificial visual system.