Effect of Post-Annealing on Low-Temperature Solution-Processed High-Performance Indium Oxide Thin Film Transistors

In this study, we analyzed the effect of post-annealing on solution-processed indium oxide thin-film transistors (TFT) with the aim of achieving high performance while taking advantage of the low processing temperatures. Before post-annealing, the indium oxide film does not show TFT channel characteristics and has no on/off ratio. However, after post-annealing, the device has the characteristics of high-performance TFTs, namely a high mobility (18.01 cm(2)V(-1)s(-1)), an on/off current ratio of similar to 10(5), and a threshold voltage of -1.91 V. The post-annealing effect was assessed by combining analytical methods such as X-ray photoemission spectroscopy and current-voltage measurements on films with different contact metals and post-annealed under different atmospheric conditions. Based on our experimental results, we suggest that the post-annealing effect, which involves a reduction in carrier concentration, originates with the loss of oxygen vacancies in the contact region by absorbing the oxygen present in the annealing atmosphere.