Amine-Functionalized Capacitive Carbon Dioxide Sensor Performance as a Function of Temperature and Sensing Film Thickness

초록

This paper systematically investigates sensor performance of amine-functionalized, microfabricated capacitive carbon dioxide (CO2) sensors as a function of sensor temperature and sensing film thickness. The sensor comprises a 1 mm by 1 mm interdigitated electrode structure with 2 mu m line width and 2 mu m line spacing, surrounded by a resistive temperature sensor and a resistive heater. A mixture of 3-aminopropyltrimethoxysilane and propyltrimethoxysilane was spray-coated onto the sensors and the CO2 response was measured in a gas mixing system. Using a 100 nm thick sensing film, a maximum sensor sensitivity of -1.2%/1,000ppm CO2 concentration was obtained with response times of 5-10 minutes at a sensor temperature of 85 degrees C. The sensor sensitivity decreases for higher and lower temperatures while the sensor response time monotonically decreases with increasing sensor temperature. Thicker sensing films improve sensor sensitivity at the expense of a longer response time.

키워드