Delicate construction of Bi2Te3 nanosheets for striking artificial synapses and broadband photodetecting

Neuromorphic devices have gained considerable attention in mimicking the perception and memory of brains. As a type of neuromorphic device, broadband responsive optical synapses are urgently needed. In this work, an artificial optical synapse based on topological insulator Bi2Te3 nanosheets is constructed by a simple solvothermal method, which can be sensitively modulated by wide spectral light from visible to near-infrared. The Bi2Te3 nanosheets were fabricated as a photodetector through a spin-coating route, which exhibits a remarkable photoresponse with a maximum responsivity of 27.4 mA W-1 and a maximum detectivity of 4.21×1010 Jones. The Bi2Te3 photodetector showed a unique memory effect for light sources with different wavelengths, confirming its potential as an artificial optical synapse. Its photoresponse to infrared light showed no significant difference compared to visible light with higher energy, which lights up the future of developing broadband-responsive optical synaptic devices.