This Small Business Innovation Research Phase I project is focused on the development of highly stable and sensitive metal oxide semiconductor sensors for high-temperature applications. Currently available semiconductor sensors are typically restricted to the 200 C to 500 C range in order to have adequate response times and the necessary selectivity. In order to operate in the 600 C to 900 C range, stability of the porous sensing materials has to be enhanced in order to have a fast responding, sensitive sensor. In the project, the unique nanocomposite sensor materials will be developed first, followed by preparation of the substrate with high temperature electrodes, on to which the sensor film is deposited and then evaluated for sensitivity, response time and stability. The sensors to be developed will be applicable to high temperature engine control and monitoring, combustion system control for fossil-fueled power plants and incinerators, and monitoring of product gases from chemical process reactors.