CuI: An Attractive Material for Constructing Transparent and Metal-electrode-free Optoelectronic Synapse

Fabricating devices with functions of biosynapses is one of attractive highlights in the field of artificial intelligence. Optoelectronic synapses are believed to be an important cornerstone of neuromorphic intelligent systems because they can directly process visual input signals. In this work, a transparent and metal-electrode-free optoelectronic synapse with a structure of CuI/ITO is prepared, in which the CuI layer acts as both an active layer and electrode. Some basic functions of biosynapses are realized by this device, including paired-pulse facilitation (PPF), spike-number-dependent plasticity (SNDP), spike-width-dependent plasticity (SWDP), and ″learning-experience″ behavior. Furthermore, this device exhibits the capability of detecting and processing the integrated optical information, and image recognition and memory. This work illustrates the great application potential of CuI in transparent optoelectronic synapse due to its unique properties.