Light-induced tunable threshold voltage and synaptic behavior of solution-processed indium oxide thin film transistor for logic computing and image denoising

Oxygen vacancies (VO) play a crucial role in promising amorphous metal oxide films for next-generation logic and synaptic computing. Here, a simple and reversible annealing-illumination method is introduced to control the concentration of VO in solution-processed amorphous indium oxide thin-film transistors (TFTs), resulting in the precise regulation of the threshold voltage (VTH) in a large range from 1.6 V to -21.7 V. Meanwhile, clear photo-synaptic behaviors are observed. These impressive behaviors result from the VO-related carrier trapping and detrapping processes. With the precise regulation of VTH by illumination, the TFTs are constructed as inverters, displaying tunable voltage gains from 5.7 to 10.6. Owing to the excellent photo-synaptic behavior, the TFTs are employed to demonstrate the optoelectronic logic functions of "OR", "AND", "NOR", and "NAND". Moreover, a 5 × 5 TFTs array is employed to demonstrate the real-time image preprocessing and image denoising functions, displaying an impressive accuracy of 96%. Furthermore, the improvement of the recognition accuracy will increase to a maximum value of 88%. This work shows the potential of amorphous indium oxide TFTs in future multifunctional logic circuits and efficient, all-optical neuromorphic vision systems.