Theoretical and experimental investigations of enhanced carbon nanotube-gold interface conductivity through nitrogen doping

It is necessary to establish high-quality contact between carbon nanotubes and metals in carbon-based devices. However, how to control and reduce contact resistance still remains unsolved. In this study, the effect of N doping in single-walled carbon nanotubes on the contact resistance with gold was studied by combining theoretical calculation with experimental methods. The theoretical results indicate that nitrogen doping in carbon nanotubes can control the bottom of the carbon nanotube conduction band downward, the Fermi level enters the conduction band, the height of the Schottky barrier between the bottom of the carbon nanotube conduction band and the gold Fermi level decreases, and the increase in doping concentration leads to the decrease of Schottky barrier width. As a result, the conductivity between the gold and carbon nanotube interface is enhanced. During experiments, the carrier density and the current of the gold and carbon nanotube device increase gradually with the increase in N doping concentration and a good electron transport channel is established between the gold and carbon nanotubes. The high-quality contact is crucial to reducing the size, improving the performance, and reducing the power consumption of carbon-based devices. With the introduction of nitrogen, the Schottky barrier and contact resistance between the carbon nanotubes and the gold electrode are reduced, and the device performance is improved.