Near-infrared optoelectronic synapses based on a Te/α-In2Se3 heterojunction for neuromorphic computing

Neuromorphic computing based on artificial optoelectronic synapses has attracted considerable attention owing to its high time/power efficiency and parallel processing capability. However, existing devices are mainly suitable for only the visible range. Here, high-performance near-infrared optoelectronic memories and synapses were demonstrated using Te/alpha-In2Se3 heterostructures. Owing to the entangled ferroelectricity-semiconducting properties of alpha-In2Se3, whose ferroelectric polarizations can be switched by photocarriers that migrated from the Te near-infrared light absorber, the device could be set into a non-volatile high-resistance/low-resistance state through the application of positive gate voltages/near-infrared light pulses. Hence, the device could function as a high-performance photodetector, with a photoresponsive on/off ratio of 5.25 x 10(4)/8.3 x 10(3) and a specific detectivity of 2.6 x 10(11)/7.5 x 10(10) Jones at 1550/1940 nm. In addition, the device could function as a multi-state optoelectronic synapse with good stability and high linearity; moreover, using the device, we developed an optoelectronic artificial neural network with high recognition accuracies of 100% and 89.9% for a database composed of 64-pixel letters with 10% and 70% noise levels, respectively. Our work provides a feasible avenue for developing neuromorphic networks applicable in the infrared range.