Terahertz Conductivity Assessment of Doped and Aligned Carbon Nanotubes
Master of Science
Carbon nanotubes (CNTs) have captured the interest of scientist due to their large aspect ratios, remarkable optical, electrical and mechanical properties. A recent breakthrough has produced highly aligned nanotube films. Although these films are tightly packed, mono-domain and wafer-scale, their conductivity is lower than that of the theoretical maximum of single-wall CNTs or CNT fibers produced by wet spinning. Conductivity can be enhanced in these films via chemical doping. Chemical doping increases conductivity by decreasing the the resistance across tube-tube junctions and increasing intra-tube conductivity. In this study, we investigated the potency and stability of six different dopants using terahertz time-domain spectroscopy. The results show that common high-redox potential acid dopants, such as nitric acid, are potent but volatile in stability. Dopants such as AuCl 3 (gold chloride) and F4-CNTQ (a popular p-type dopant for hole-only devices) are more effective and stable when used with CNT films.
carbon; nanotubes; terahertz; films; doping