Solution-processed gallium-tin-oxide as a new choice for indium-free active layers in TFTs

We report a newly developed solution-processed amorphous oxide semiconductor, gallium-tin-oxide (GTO), for the active layer of thin-film transistors (TFTs). The transparent GTO thin film was fabricated by sol-gel process and patterned by photo-lithography into isolated arrays. The resulting TFTs exhibit a threshold voltage around zero-volgate, an on-off ratio as 106, and the field-effect mobility as 4.1 cm2/Vs. The electrical properties is readily higher than that of ZnO and comparable to solution-processed InGaZnO. Moreover, the un-capsulated TFTs exhibit better stablility in gate-bias stressing then solution-processed IGZO TFTs as measured in ambient conditions. The study may provide a new choice for the active layers for oxide-based TFTs and display technology.