Wafer-scale monodomain films of spontaneously aligned single-walled carbon nanotubes

• Published in: Nature nanotechnology Vol. 11; no. 7; pp. 633 - 638
• Main Authors: He, Xiaowei, Gao, Weilu, Xie, Lijuan, Li, Bo, Zhang, Qi, Lei, Sidong, Robinson, John M., Hároz, Erik H., Doorn, Stephen K., Wang, Weipeng, Vajtai, Robert, Ajayan, Pulickel M., Adams, W. Wade, Hauge, Robert H., Kono, Junichiro
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.07.2016; Nature Publishing Group
• Subjects: 140/133; 147/135; 147/143; 639/301/1005/1007; 639/925/357/73; Alignment; Anisotropy; Carbon; Devices; Electronics; Electrons; Materials Science; Nanostructure; Nanotechnology; Nanotechnology and Microengineering; Nanotubes; Optical properties; Photoelectric effect; Single wall carbon nanotubes; Surfactants; Thin films; Vacuum filtration; United States > US; Texas
• ISSN: 1748-3387; 1748-3395
• DOI: 10.1038/nnano.2016.44

The one-dimensional character of electrons, phonons and excitons in individual single-walled carbon nanotubes leads to extremely anisotropic electronic, thermal and optical properties. However, despite significant efforts to develop ways to produce large-scale architectures of aligned nanotubes, macroscopic manifestations of such properties remain limited. Here, we show that large (>cm 2 ) monodomain films of aligned single-walled carbon nanotubes can be prepared using slow vacuum filtration. The produced films are globally aligned within ±1.5° (a nematic order parameter of ∼1) and are highly packed, containing 1 × 10 6 nanotubes in a cross-sectional area of 1 μm 2 . The method works for nanotubes synthesized by various methods, and film thickness is controllable from a few nanometres to ∼100 nm. We use the approach to create ideal polarizers in the terahertz frequency range and, by combining the method with recently developed sorting techniques, highly aligned and chirality-enriched nanotube thin-film devices. Semiconductor-enriched devices exhibit polarized light emission and polarization-dependent photocurrent, as well as anisotropic conductivities and transistor action with high on/off ratios. Large films of aligned and closely packed single-walled carbon nanotubes can be prepared through slow vacuum filtration, and used to create terahertz polarizers, thin-film transistors, polarized light emission devices, and polarization-sensitive detectors.