A new and interesting ethanol (C2H5OH) gas sensor, synthesized by a radio frequency (RF) sputtered amorphous In-Ga-Zn-O (a-IGZO) thin film and rapid thermal evaporated Au nanoparticles (NPs), is fabricated and studied herein. The employed Au NPs substantially increase the surface area/volume (SA/V) ratio, spill-over effect, and catalytic reactivity of Au metal. In our experiment, a high sensing response SR of 465.4 under 2400 ppm C2H5OH/air gas with a response (recovery) time of 32 s (21 s) and an extremely low detection level of 100 ppb C2H5OH/air were obtained at the optimal operating temperature of 250°C. The related ethanol gas sensing mechanism is elucidated in this work. In addition, a thermodynamic analysis is reported on studying the surface coverage of ethanol molecules. The studied Au NP/a-IGZO sensor device also shows the advantages of a simple structure, relatively easy fabrication process, and low cost. Therefore, the studied device is a good candidate for high-performance ethanol gas sensing applications.
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