The preparation and characterization of Fe2O3/FTO gas sensor

Fe2O3 thin film was successfully grown on fluorine doped tin oxide (FTO) coated glass substrate at 30 SILAR cycle at room temperature by the Successive Ionic Layer Adsorption and Reaction (SILAR) method. The structural, morphological, chemical composition and CO gas sensing properties of the thin film were investigated by XRD, SEM, EDAX and gas measurement system, respectively. XRD and SEM studies indicated that the thin film had polycrystalline nature and was crystallized in the hematite (α-Fe2O3) phase, there were dense coating and regional agglomerations of different sizes on the FTO substrate surface. EDAX analysis confirmed the presence of Fe and O elements and formation of iron oxide on the surface of the film. Static and dynamic CO gas detection measurements of the Fe2O3/FTO sensor were done. It was observed that the sensitivity of the sensor increased with the operating temperature up to 285 °C and the optimum operating temperature was 285 °C. At operating temperature of 285 °C, the sensitivity value of the sensor was determined as 10% for 5 ppm CO gas and 47.8% for 100 ppm CO gas. The response and recovery times of the sensor were calculated. In addition, the repeatability, stability and selectivity measurements for the control group gases were done.