Date of Award

Winter 2011

Project Type


Program or Major

Mechanical Engineering

Degree Name

Master of Science

First Advisor

Todd S Gross


Solid state gas sensors (SSGS) offer advantages over current technologies because they are small, require low power and are relatively inexpensive to manufacture compared to other technologies. We evaluated a thin film tungsten trioxide solid state carbon monoxide sensor based on an aluminum oxide crystal substrate. The sensor response was characterized as a function of temperature, flow rate and water vapor. The apparent CO resolution was measured to be one part per million. Temperature sensitivity was measured with a DeltaR/R o of 3% per °C. Response to water vapor resulted in a DeltaR/R o of 15% per kPa. Flow rate variation resulted in a DeltaR/R o of 0.06% per ccm. An asymptotic drift in sensor resistance in pure air was also observed.

Resulting temperature sensitivity data suggests temperature control of 3e-3 °C of the sensor surface would be required to achieve a carbon monoxide sensitivity goal of 0.1 ppm required for atmospheric measurements.