Solution-processed amorphous gallium-tin oxide thin film for low-voltage, high-performance transistors

Gallium-tin oxide (GTO) semiconductor thin films were prepared by spin-coating with 2-methoxyethanol as the solvent. Their crystal structures, optical transparency, chemical states and surface morphologies, along with the electrical properties, were dependent on Ga contents and annealing temperatures. The optimized GTO channel layer was applied in the high- k Al 2 O 3 thin film transistor (TFT) with a low operation voltage of 2 V, a maximum field-effect mobility of 69 cm 2 V −1 s −1 , a subthreshold swing (SS) of 76 mV dec −1 , a threshold voltage of 0.67 V and an on-off current ratio of 1.8×10 7 . The solution-processed amorphous- GTO-TFTs would promote the development of low-consumption, low-cost and high performance In-free TFT devices.