Three-terminal CNTs gas sensor for N2 detection

A novel three-terminal gas sensor was fulfilled by utilizing the vertically aligned carbon nanotubes (CNTs) mat. Carbon nanotubes were synthesized by thermal chemical vapor deposition (thermal CVD) at 700 degrees C under C2H2 gas flow rate of 30 sccm. Upon exposure to a with and without N-2 environment at the room temperature of 25 degrees C, the electrical resistance of as-made devices was found to increase and to return back, respectively. Compared to a low bias one, the sensitivity increased when applying a high source drain bias voltage. Furthermore, the device became more sensitive for N, detection by applying a negative gate voltage. It was concluded that the alteration of free holes concentration in the CNTs mat played the major mechanism for the N, gas detection. (c) 2005 Elsevier B.V All rights reserved.