Study of Ethanol Gas Sensing Characteristics of An Al-Doped SnO₂ Thin Film Decorated With Gold Nanoparticles

The ethanol ( $\text{C}_{{2}}\text{H}_{{5}}$ OH) gas sensing characteristics of an interesting sensor have been studied and reported. The studied sensor is manufactured by the deposition of an Al-doped SnO2(ATO) thin film via sputtering, followed by the addition of evaporated gold nanoparticles (Au NPs) on a sapphire (Al2O3) substrate. The utilization of Au NPs is found to significantly enhance the sensor’s ethanol gas sensing capabilities, attributed to the augmented specific surface area and catalytic capability of the Au metal. In-depth characterization of the intrinsic material properties is achieved through compositional, morphological, and structural analyses. Experimentally, the proposed sensor demonstrates a higher sensing response of 1436, accompanied by a response time of 23 s and a recovery time of 17 s when exposed to 1000 ppm $\text{C}_{{2}}\text{H}_{{5}}$ OH/air gas at 275 °C. Notably, the sensor exhibits an exceptionally lower detectable content of 40 ppb $\text{C}_{{2}}\text{H}_{{5}}$ OH/air. The research further delves into the replicable and long-term (90 days) sensing properties concerning ethanol gas. In addition, the proposed sensor has the advantages including a simplistic sensor structure, cost-effectiveness, and a relatively straightforward fabrication process.

I. Introduction

As an important volatile organic compound (VOC), ethanol (C2H5OH), or ethyl alcohol has been widespread utilized in the fabrication of flavors, acetic acid, fuels, dyes, beverages, and medical disinfectants and commonly applied in chemical, bio-chemical, pharmacology, medical, health, hygienic and cosmetic, and food industries [1], [2]. Moreover, ethanol consumption is recognized as a significant contributor to car accidents globally. Nowadays, the assessment of intoxication levels among drivers primarily relies on measuring breath alcohol concentration (BAC). The BAC values serve as a prevalent method for gauging levels of haziness, slight drunkenness, and drunkenness [3].