Importance of Solvent Evaporation Temperature in Pre-Annealing Stage for Solution-Processed Zinc Tin Oxide Thin-Film Transistors

We focused on the importance of solvent evaporation governed by the temperature of the pre-annealing stage (T-S) in solution-processed zinc tin oxide (ZTO) thin-film transistors (TFTs). We controlled T-S based on the boiling point (B-P) of the solvent used. When T-S reaches the B-P, the field effect mobility is found to be about 1.03 cm2/V s, which is 10 times larger than the T-S < B-p case (0.13 cm(2)/V s). The reason is presumed to be that residual organic defects are effectively removed as T-S increases. In addition, when Ts is beyond B-p, the mobility is rather decreased due to structural defects such as pores and pinholes. Based on our results, it is noted that T-S plays a significant role in the enhancement of electrical performance and stability of solution-processed ZTO TFTs.