AuCl₃ Doping for Reducing the Contact Resistance of the Aligned Carbon Nanotube–Au Heterojunction: Experimental Research and First-Principles Calculation

The contact resistance between carbon nanotubes (CNTs) and metals is a key factor affecting their application. Traditional optimization methods are often destructive in which it is difficult to achieve quantitative control. In this study, through in situ growth and directional rolling, CNT arrays arranged in parallel are obtained and formed side contact structures with Au, selective doping of CNT–metal contact regions using 15 mM AuCl3 resulted in a 43% decrease in contact resistance, and the doping effect has good stability. Furthermore, the band structure and projected density of states (PDOS) obtained by using density functional theory (DFT) are consistent with the experimental phenomenon. The method of reducing the contact resistance by doping does not destroy the structure of the material and can achieve quantitative control. In addition, different combinations of dopants and metals should be investigated to establish system schemes for the doping of heterojunctions.