Sensing with Nafion Coated Carbon Nanotube Field‐Effect Transistors

Sequential CVD and CMOS processes were used to make a FET that has single walled carbon nanotubes to serve as the conducting source to drain channel. This structure can be decorated to provide gas and liquid responses and herein is evaluated as a humdity sensor. The Na + , K + , and Ca 2+ ion‐exchanged Nafion polymer acts as the chemically sensitive layer in this electrochemical sensor. The effect of gate voltage on the charge‐sensitive NT structure was found to be RH dependent over the range of 12–93% RH with msec response time.