A micro gas sensor based on a WO3 thin film for aromatic hydrocarbon detection

In the study, a novel gas sensor is presented for detection of aromatic hydrocarbons (benzene, toluene and xylene), consisting of a quartz substrate, Pt electrodes and a WO3 thin film. Oxidation occurs on the heated WO3 sensing layer as an aromatic hydrocarbon is present in the atmosphere, which causes a resistance variation of the WO3 thin film. From the measured resistance change, the aromatic hydrocarbon concentration is then computed. It is found that the crystalline structure is more perfect as the as-sputtering substrate temperature is 300°C, the WO3 thin film is annealed and the sputtering time is more than 6 hrs. At the optimal working temperature of 300°C, the experimental results show that the sensor has a rapid response time and a high degree of sensitivity for detection of benzene, toluene and xylene.