Weak UV-Stimulated Synaptic Transistors Based on Precise Tuning of Gallium-Doped Indium Zinc Oxide Nanofibers

In this work, a light-stimulated artificial synaptic transistor based on one-dimensional nanofibers of gallium-doped indium zinc oxides (IGZO) is demonstrated. The introduction of gallium into the nanofiber lattice can effectively alter the morphology and crystallinity, leading to a wider regulatory range of synaptic plasticity. The fabricated IGZO synaptic transistor with the optimal gallium concentration and low surface defects exhibits a superior photoresponsivity of 4300 A·W⁻¹ and excellent photosensitivity, which can detect light signals as weak as 0.03 mW·cm⁻². In particular, the paired-pulse facilitation index reaches up to 252% with over 2 h of enhanced memory retention exhibiting the long-term potentiation. Furthermore, the simulated image contrast and image recognition accuracy based on the newly designed IGZO synaptic transistors are successfully enhanced. These remarkable behaviors of light-stimulated synapses utilizing low-cost electrospun nanofibers have potential for ultraweak light applications in future artificial systems.

Graphical Abstract