Improved dynamic responses of room-temperature operable field-effect-transistor gas sensors enabled by programmable multi-spectral ultraviolet illumination

Abstract

Recently, with the increased importance of low-power human-based wearable technology incorporating multiple sensory systems, room-temperature operating sensory devices are of significant interest. In this work, we demonstrate a versatile approach to realize room-temperature operable and fast recovery amorphous oxide semiconductor (AOS)-based gas sensors using multi-wavelength ultraviolet (UV) illumination. Particularly, illumination of UV light with different wavelengths enabled an amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistor (FET)-based gas sensor to monitor the sensing behaviours of nitrogen dioxide (NO2) at various concentrations down to sub-ppm level. Our systematic investigation exhibited that time period taken for reacting and detaching the NO2 gas from the surface of AOS could be significantly controlled down to 32 s and several minutes, respectively, without any thermal energy. The key point of the variable properties of NO2 sensing performances in the a-IGZO FET is the generation of diverse electron-hole-pairs owing to the difference of the photonic energy applied to the sensor. Our work introduced in this research may provide a simple and efficient way for enhancing gas-sensing properties of AOS FET gas sensors by enabling programmable multi-spectral UV illumination approaches. © 2021 Elsevier B.V.