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

摘要

Graphical abstractDisplay OmittedHighlights•An etching method is developed to increase adsorption sites for gas molecules.•The method increases the individual ZnO MW gas sensor’s sensitivity by 20-fold.•Room temperature NO2-sensing is realized with the individual ZnO MW gas sensor.AbstractEnhancing the performance of individual microanowires 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−2of 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.