Branched treelike carbon nanotubes were grown by plasma enhanced chemical
vapor deposition method on a silicon wafer. Patterned structures of as grown
nanostructures were used for the fabrication of a gas sensor, which operates
based on the field ionization of various gases. The variations in the
electrical resistivity and the emission current of the fabricated device are
related to the chemisorption and field ionization mechanisms, respectively.
The sensor is capable of gas detection at room temperature and at low
pressures with working at low voltages. Different gases such as H2,
O2, C2H2 and Ar have been used to examine the gas sensitivity
characteristics of the fabricated sensors.