Anisotropic artificial synapse based on 2D ReS2 field-effect transistor

Taking inspiration from the brain, neuromorphic systems are thought to be a potential computational platform to solve the problems of the "von-Neumann bottleneck. " Artificial synaptic devices hold the potential to emulate the multi-synapse system to perform complex functions by applying anisotropic materials. Here, we demonstrate a synaptic device based on a two-dimensional ReS2 material, exhibiting synaptic functions such as short-term plasticity, long-term plasticity, paired-pulse facilitation, and spike-rate dependent plasticity. More importantly, benefiting from the broken symmetry of the ReS2 crystal, the devices showed obvious anisotropy of response behavior to the same input signal. In addition, the synaptic performance can also be modulated by laser irradiation. Our results provide possibilities for two-dimensional materials to mimic the biological axon-multisynapse systems with additional optical modulation.