Novel processing of NASICON and sodium carbonate/barium carbonate thin and thick films for a CO₂ microsensor

Abstract

The use of chemical microsensors can be advantageous for the monitoring of gas species in efforts to accurately monitor environmental conditions, detect fires, and determine emissions. The microsensor described herein shows promise for use as a carbon dioxide sensor. Carbon dioxide levels are of particular concern for passenger environments, as a chemical signature of a fire, and as a combustion product.

This amperometric carbon dioxide microsensor was produced using microfabrication and micromachining techniques. Electron beam evaporation, sputtering, and thick film printing were used for deposition of the chemically active layers of the device—Na₃Zr₂Si₂PO₁₂ (NASICON) and Na₂CO₃/Ba₂CO₃. The deposition techniques used to deposit these materials were an important processing advance in this development endeavor. The films were incorporated into an amperometric, limiting current type sensor design with overall dimensions of 1.4 mm × 1.5 mm. The inclusion of this type of sensor in an array of differing sensors offers an advantage of high selectivity to analytes of interest.