Indium Gallium Oxide Thin Film Transistor for Two-Stage UV Sensor Application

Abstract

In this work, indium gallium oxide (IGO) thin film transistor (TFT) was fabricated by radio-frequency (RF) sputtering. The transmittance of the TFT shows larger than 80% cross the visible light region. As a wide bandgap and high transparency semiconducting material, IGO is a potential candidate for UV-detection applications. Measured in the dark, the IGO TFT exhibits a threshold voltage of 0.9 V, mobility of 2.66 cm2/Vs, on-off ratio of 1.21 × 106, subthreshold swing of 0.41 V/dec. The TFT was then employed to detect UV light and the sensing properties are investigated. The IGO phototransistor has a high responsivity of 5.012 A/W and a rejection ratio of 1.65 × 105. The above results reveal that IGO phototransistor is a brilliant multi-functional device, which can serve as either a switch component or a UV sensor.