Effects of physical and chemical adsorption on the electric conductance of carbon nanotube films

We studied physical and chemical adsorption on carbon nanotube surfaces and measured the effect of adsorption on their electric conductance. The increase in capacitance at the carbon nanotube interface (due to physisorption) disturbed carrier transport, while chemisorption induced charge transfer and resulted in an increase or decrease in the electric conductance. The principle of carrier transport in carbon nanotube films could be clearly explained by applying a fluctuation-induced tunneling model. Our model proved that the surface coverage ratio and the electric conductance change ratio are closely correlated.