Electron transport of nanotube-based gas sensors: An ab initio study

Abstract

The effect of physisorption of NO2 gas molecules on quantum transport properties of semiconducting carbon nanotubes is studied using ab initio calculations and Green function formalism. The results show that the conductance change is mainly due to the electric dipole moment of NO2. It is also shown that upon exposure of nanotube to different concentrations of gas, the common feature is the shift in conductance toward lower energies. This suggests that physisorption of NO2 will result in a decrease (increase) in conductance of p-type (n-type) nanotubes with Fermi energies close to the edge of valence and conduction band.