Study of a High-Performance Chemoresistive Ethanol Gas Sensor Synthesized With Au Nanoparticles and an Amorphous IGZO Thin Film

Abstract

A new and interesting ethanol (C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> OH) 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 (S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</sub> /V) ratio, spill-over effect, and catalytic reactivity of Au metal. In our experiment, a high sensing response S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">R</sub> of 465.4 under 2400 ppm C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> OH/air gas with a response (recovery) time of 32 s (21 s) and an extremely low detection level of 100 ppb C <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sub> OH/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.