Gas adsorption effects on the electrical conductivity of semiconducting carbon nanotubes

We study the effect of diatomic (X2) and triatomic (XY2) gas molecule adsorption on the electrical conductivity of (8,0), (10,0) and (14,0) semiconducting zigzag single-walled carbon nanotubes. We use Greenʹs function method and coherent potential approximation. We find that the electrical conductivity of semiconducting carbon nanotubes is sensitive to the adsorption of these gases, when X2 and XY2 are identified as charge acceptors. While X2 and XY2 molecules adsorb weakly on nanotubes and act as charge donors, the electrical conductivity of the nanotubes shows no noticeable change.