Electronic Transport Properties of Carbon-Nanotube Networks: The Effect of Nitrate Doping on Intratube and Intertube Conductances

Transparent, conductive thin films are essential to modern optoelectronic devices such as displays, touch screens, and solar cells. This study shows how networks of carbon nanotube can be used as such films, and how the main technical challenge regarding the high sheet resistance of present-day thin films can be solved. Using density functional theory plus the Green's function method for their transport calculations, the authors find that nitrate moieties from nitric acid adsorbed on the nanotubes yield $p$-type doping, and remarkably improve conductance both within and between tubes.