Visible light-modulated photoelectric synaptic transistor based on ITO and IGZO bilayer channel

With the increasing computational demands faced by computing systems based on the von Neumann architecture, artificial synaptic devices that mimic the neural synapses of the human brain have emerged as a potential solution to this challenge. This study presents a photoelectric synaptic thin-film transistor (TFT) based on an ITO/IGZO composite active layer, aiming to enhance the device’s responsiveness to visible light and synaptic plasticity. Compared to traditional single-layer devices, the ITO/IGZO bilayer structure exhibits significantly improved visible light response, particularly in the red and green light bands. X-ray photoelectron spectroscopy (XPS) analysis revealed an increase in oxygen vacancies and sub-bandgap states at the ITO/IGZO interface, which facilitates the generation of carriers excited by low-energy photons, thereby further enhancing the photoelectric performance. The photoelectric synaptic device demonstrates good short-term and long-term plasticity (STP and LTP) in mimicking synaptic plasticity and achieved an accuracy rate of 93% in the Modified National Institute of Standards and Technology (MNIST) handwritten digit recognition experiment. The results indicate that ITO/IGZO TFTs not only enhance visible light response but also have the potential to simulate neural synaptic behavior, making them a promising component in neuromorphic computing and visual perception systems.