Tin oxide and iron doped tin oxide thin films as gas sensors

Monitoring of toxic, inflammable and green house gases have become a major concern for present day industries. Detecting low concentrations of such gases has proven to prevent accidents that could occur due to leakage or ignition of gas. Thus gas sensing has grown into a field of research.There are many green house gases that need to be monitored, and carbon monoxide is one of the most important among them. Carbon monoxide (CO) is emitted largely by automobiles and industries that use fossil fuel. Many different materials have been studied as a potential for CO sensor out of which Tin oxide (SnO2) being one of the foremost. Both bulk and thin film form have been studied for gas sensing purposes. It has also been noted that adding certain metal oxides or metals into the SnO2 material enhances its gas sensing property.In this study both pure and Iron (Fe) doped SnO2 materials are studied for CO gas sensing. Thin films of these materials are prepared by RF magnetron sputtering. These films are used for CO gas sensing. The gas sensing property is also studied in relation to vacuum annealing of the sensor and varying CO gas concentration. The films are characterized using tools like X-ray diffraction, Optical and Raman spectroscopy, and Scanning electron microscopy, to obtain the physical properties of these sensors. A correlation has been made between the physical properties and the gas sensing property. The tests have been able to show that Fe doping improves the CO gas sensing properties of SnO2.