Date of Award

Winter 2011

Project Type

Thesis

Program or Major

Mechanical Engineering

Degree Name

Master of Science

First Advisor

Todd S Gross

Abstract

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.

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