Synaptic properties of monolayer CuOx-based optoelectronic devices

Abstract

Recently, the interest in neuromorphic computing that can mimic the human brain to combine computation and storage with energy efficiency into a compact space, has created a new artificial computing architecture distinguished from the traditional von Neumann ones. As one of the key components in artificial computing architectures, synaptic devices play very important roles in detecting and processing the environmental information. Copper oxide is one of the transition metal oxides with unique electronic, mechanical, magnetic and optical properties. However, there have been few reports on the investigation of synaptic devices based on copper oxide semiconductors. Most of the reported synaptic devices respond to electrical excitation but few of them can work under light excitation. Here, we report the fabrication of an optoelectronic synaptic device structured as ITO/CuOx/Pt that is based on monolayer copper oxide film only, and demonstrate the multiple synaptic properties. It is found that the device could effectively absorb and respond to the stimulating light at 450 nm and 520 nm, and the generated photocurrent could be modulated by regulating the defects and the composition of the memristive film inside the device. Additionally, a series of important synaptic functions, including excitatory postsynaptic current (EPSC), paired-pulse facilitation (PPF), short-term potentiation (STP) to long-term potentiation (LTP) transition, have been successfully simulated on the device. Our newly fabricated optoelectronic synaptic device shows a great potential in neuromorphic computing.