Enhancing the performance of room temperature ZnO microwire gas sensor through a combined technology of surface etching and UV illumination

Abstract

Enhancing the performance of individual micro/nanowires based room temperature gas sensors is a big challenge for real-time detection of toxic gases. In this work, we developed a surface etching method to increase the sensitivity of individual ZnO microwire (MW) based gas sensor. The etching of the MW increases the adsorption sites for gas molecules on it by increasing the specific surface area and the surface density of single ionized oxygen vacancies. This leads to a ∼20-fold increase of the gas sensor’s sensitivity. When working under 148.8 μW cm−2 of UV light, the sensitivity is further increased to 411%. Meanwhile, the response and the recovery time decreases to ∼20% and ∼2% of the values in dark condition, respectively. As a result, the individual ZnO microwire based gas sensor’s performance was greatly enhanced, and it has great potential to be used as a room temperature gas sensor towards NO2.