Multi-wavelength optoelectronic synapse based on MoS₂/WS₂ van der waals heterostructures

Abstract The utilization of two-dimensional van der waals heterostructures in optoelectronic synapses allows for the integration of information processing and memory, thereby providing novel operating platforms for simulating the perceptual visual systems and developing the neuromorphic computing systems due to its contactless, highly efficient and parallel computing. Herein, we have constructed a straightforward MoS 2 /WS 2 heterostructure optoelectronic synapse and examined its capacity to imitate synaptic behaviors under optical stimulus. The MoS 2 /WS 2 device demonstrated several synaptic functions, such as the excitatory postsynaptic current, short-term plasticity, long-term plasticity, pairs-pulse facilitation and ‘learning-experience’ behavior. Moreover, the MoS 2 /WS 2 synaptic device can achieve a wide range of photo response wavelengths, spanning from UV to visible light, as well as the conversion from short-term plasticity to long-term plasticity. Furthermore, light-induced charge transfer due to adsorption and desorption of oxygen molecules in MoS 2 /WS 2 heterostructure can be used to explain its working mechanism. Additionally, the synaptic plasticity of MoS 2 /WS 2 device can be controlled by adjusting the duration, power and number of the optical pulses, which renders the MoS 2 /WS 2 -based optoelectronic synaptic device extremely favorable for implementation in the perceptual visual system.