Pre-Annealing Effect for Low-Temperature, Solution-Processed Indium Oxide Thin-Film Transistors

In this study, we improved the electrical performance of low-temperature, solution-processed indium oxide thin-film transistors (fabricated at 200 degrees C) by employing a pre-annealing process. The pre-annealed films exhibit dense and smooth surfaces in contrast to the rough and large grains found on films without pre-annealing, as determined using atomic force microscopy and transmission electron microscopy. The O 1s peak in X-ray photoelectron spectroscopy shows a higher metal oxide lattice peak obtained by employing the pre-annealing process, which implies stronger electrical transport behavior. Therefore, the overall electrical characteristics of the thin-film transistors are improved by pre-annealing in terms of mobility, on/off ratio, subthreshold swing, and hysteresis.