Elimination of Response to Relative Humidity Changes in Chemical-Sensitive Field Effect Transistors.

Detecting accurate concentrations of gas in environments with dynamically changing relative humidity conditions has been a challenge in gas sensing technology. We report a method to eliminate effects of humidity response in chemical sensitive field effect transistors using microheaters. Using hydrogen gas sensor with Pt/FOTS active material as a test case, we demonstrate that a sensor response of 3844% to a relative humidity change of 50% to 90% at 25 °C can be reduced to a negligible response of 11.6% by utilizing microheaters. We also show the advantage of this technique in maintaining same sensitivity in changing ambient temperatures and its application to the nitrogen dioxide gas sensors.