Fabrication and Operating Mechanism of Deep-UV Transparent Semiconducting SrSnO 3 -based Thin Film Transistor

Thin film transistor (TFT) with deep-UV transparency is a promising component for the next generation optoelectronics such as biosensor. Among several deep-UV transparent oxide semiconductors, SrSnO 3 is an excellent candidate material owing to its wide bandgap (∼4.6 eV) and rather high carrier electron mobility. Here we show fabrication and operating mechanism of the SrSnO 3 -based TFT. We fabricated metal-insulator-semiconductor TFT structure on the 28-nm-thick SrSnO 3 film. The resultant TFT showed clear transistor characteristics; the on-to-off current ratio was ∼102, the threshold voltage was ∼ -18 V, and the field effect mobility was ∼14 cm2 V−1 s−1. The effective thickness of the electron channel gradually increased with gate voltage and saturated at ∼5 nm, which was evaluated by the thermopower modulation.