Weak Light‐Stimulated Synaptic Transistors Based on MoS2/Organic Semiconductor Heterojunction for Neuromorphic Computing

Abstract

Photonic synapses are expected to play an important role in implementing brain‐like computing owing to the wide bandwidth and low mutual interference of optical signals. Herein, photonic synaptic transistors based on inorganic semiconductor molybdenum disulfide (MoS2) and organic semiconductor heterojunction with adjustable short‐term/long‐term plasticity are proposed. Benefitting from the outstanding photosensitive characteristics originating from the heterojunction, the devices have the capability of weak light detection and can exhibit distinct synaptic responses even under an ultraweak light intensity of 40 nW cm−2, which is considerably lower than that of most previously reported photonic synaptic transistors. Furthermore, a low energy consumption of 0.4 fJ per synaptic event can be obtained at a low operating voltage of 0.001 V, lower than that required for a single synaptic event observed in human brains. In addition, the devices can implement high‐pass filtering function and illustrate the potential in image sharpening processing. More significantly, logic functions as well as associative learning behavior are dramatically simulated through all‐optical stimulation. This work demonstrates a feasible approach to developing multifunctional photonic synaptic transistors based on inorganic/organic semiconductor heterojunction for neuromorphic computing.