Bendable thin-film transistors based on sol-gel derived amorphous Ga-doped In₂O₃ semiconductors

Bendable thin-film transistors (TFTs) are demonstrated based on sol-gel-derived amorphous Ga-doped In₂O₃ (GIO) that can be thermally converted into a device-quality semiconducting layer at 300 C, which is compatible with a plastic polyimide (PI) substrate. The device performance of the GIO TFTs is studied through the investigation on the electrical parameters (including mobility, threshold voltage, off-current, and subthreshold swing) of the devices as a function of Ga composition. With increasing Ga composition up to 36 mol%, the mobility decreases from 1.4 to 0.08 cm² V s ^-1 with sluggish reduction in the Ga compositional range between 0 and 12 mol%, and the threshold voltage shifts from -21.6 to 13.5 V. Both the off-current and subthreshold swing decreases with a dramatic variation at Ga composition of 12 mol%. From the overall analysis, it is concluded that the incorporation of 12 mol% Ga enables for the GIO semiconducting layer with the best electrical performance. In addition, the bending characteristics of GIO TFTs, prepared on a SiO₂/ITO/PI substrate, are analyzed with device performance variations depending on the bending radius. It is demonstrated that the device performance is maintained with acceptable electrical characteristics under a bending radius of 10 mm.