Self-powered broadband photodetection and bias-tunable infrared optoelectronic synapses: Dual-functional device based on asymmetric Schottky contact Au/WSe2/1T'-MoTe2 heterojunction

The dual-functional devices integrating high-sensitivity photodetection and optoelectronic synapse characteristics deliver distinct advantages of low power consumption and miniaturized size. Notably, optoelectronic synapses with near-infrared sensitivity and synaptic plasticity exhibit promising prospects in high-precision infrared sensing, autopilot systems, optical communication networks, and robotic vision perception. Herein, we present a vertical asymmetric Schottky contact Au/WSe2/1T'-MoTe2 heterojunction, which exhibits broadband photodetection and near-infrared optoelectronic synaptic plasticity. The heterojunction enables broadband self-powered photodetection spanning from 405 to 1550 nm. Under 660 nm light illumination, it achieves a responsivity (R) of 72.7 mA/W, an external quantum efficiency of 13.7%, a specific detectivity (D*) of 1.84 × 1012 Jones, and an On/Off ratio of 1.83 × 106. By tuning the power, pulse width, and pulse number of the input light stimulation, the bias-tunable heterojunction can simulate synaptic plasticity behaviors, including paired-pulse facilitation (PPF), paired-pulse depression, short-term plasticity, long-term plasticity, and learning-experience behavior, under 1064 and 1550 nm light illumination. Notably, it exhibits a peak PPF of 156.25% and a power consumption as low as 5.17 pJ. This dual functionality paves the way for integrating neuromorphic computing with optoelectronics and provides potential approaches for developing advanced intelligent sensing and neuromorphic computing.