Emulation of Optoelectronic Synaptic Behavior in a MoS₂/WSe₂-Based p–n van der Waals Heterostructure Memtransistor

Memtransistors, which combine the advantages of memristors and transistors, are expected to be candidates for next-generation nonvolatile memories and synaptic devices due to their nanoscale size, nonlinearity, synaptic-like characteristics, and availability for logic operations. Here, an optoelectronic memtransistor based on two-dimensional (2D) van der Waals MoS2/WSe2 p–n heterostructures is proposed to mimic neural synaptic functions. In 30 cycles, the device demonstrates reversible bipolar resistance switching phenomena, alternating between a low resistance state and a high resistance state with a switching ratio of 103. Moreover, neuromimetic learning functions, such as excitatory postsynaptic current/inhibitory postsynaptic currents (EPSC/IPSC), short-term plasticity(STP) and long-term plasticity(LTP), paired-pulse facilitation (PPF), and spike rate-dependent plasticity (SRDP), are performed by controlling the electrical and optical inputs. In addition, simulation of the light-adaptive behavior of the biological visual system is realized successfully. This work provides a strategy for the application of p–n heterojunction memtransistors in the field of optoelectronic synapses.