Highly sensitive NO2 sensor array based on undecorated single-walled carbon nanotube monolayer junctions

Using the surface-programmed assembly technique, we have fabricated a uniform array of NO2 sensors based on undecorated single-walled carbon nanotube (SWNT) monolayer junctions. The sensitivity of the SWNT monolayer network-based sensors to NO2 gas was investigated at room temperature. We have found that the response of the gas sensors is inversely proportional to the initial conductance of the SWNT network. This behavior is different from conventional gas sensors based on uniform films, and it may be critical for the calibration of sensors in practical applications. An analytical model based on standard percolation theory is proposed to explain this behavior.