Light-induced tunable threshold voltage and synaptic behavior of a solution-processed indium oxide thin film...

Oxygen vacancies (V_O) 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 V_O in solution-processed amorphous indium oxide thin-film transistors (TFTs), resulting in the precise regulation of the threshold voltage (V_TH) 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 V_O-related carrier trapping and detrapping processes. With the precise regulation of V_TH 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.