Fabrication and Operating Mechanism of Deep‐UV Transparent Semiconducting SrSnO3‐Based Thin Film Transistor

Thin film transistors (TFT) with deep‐UV transparency are a promising component for next‐generation optoelectronics such as biosensors. Among several deep‐UV transparent oxide semiconductors, SrSnO3 is an excellent candidate material owing to its wide band gap (≈4.6 eV) and rather high carrier electron mobility. Herein, fabrication and operation mechanism of the SrSnO3‐TFT is shown. A metal–insulator‐semiconductor structure is fabricated on a 28 nm‐thick SrSnO3 film. The resultant TFT shows clear transistor characteristics; the on‐to‐off current ratio is ≈102, the threshold voltage is ≈−18 V, and the field‐effect mobility is ≈14 cm2 V−1 s−1. The effective thickness of the electron channel gradually increases with gate voltage and saturates at ≈5 nm, which is evaluated by the thermopower modulation. The present results will be helpful for utilizing deep‐UV transparent TFTs for biosensing applications. Deep‐UV (DUV, 200−300 nm in wavelength) transparent oxide semiconductor, SrSnO3‐based thin film transistor (TFT) are realized. The resultant transistors shows clear transistor characteristics and the effective thickness of the conducting channel is clarified by the electric field thermopower modulation measurements. The present results are the pioneering steps for utilizing DUV transparent TFTs for biosensor applications.