Transparent Boron-Doped Carbon Nanotube Films

• Published in: Nano letters 2008-09, Vol.8 (9), p.2613-2619
• Main Authors: Liu, X. M, Romero, H. E, Gutierrez, H. R, Adu, K, Eklund, P. C
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Cross-disciplinary physics: materials science; rheology; Electronic structure and electrical properties of surfaces, interfaces, thin films and low-dimensional structures; Electronic structure of nanoscale materials : clusters, nanoparticles, nanotubes, and nanocrystals; Exact sciences and technology; Fullerenes and related materials; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Nanotubes; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics; Visible and ultraviolet spectra
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl0729734

We report results of studies on the sheet resistance and optical transmission of thin films of boron-doped single-walled carbon nanotubes (SWNTs). Boron doping was carried out by exposure of SWNTs to B2O3 and NH3 at 900 °C and 1−3 atom % boron was found in the SWNT bundles via electron energy loss spectroscopy (EELS). Boron doping was found to downshift the positions of the optical absorption bands associated with the van Hove singularities (E11 s E22 s and E11 m) by ∼30 meV relative to their positions in acid-treated and annealed SWNTs. Raman spectroscopy, EELS, and optical data are consistent with the picture that a few atom % boron has been substituted for carbon in the sp2 framework of SWNTs. Finally, our results show that boron doping does not significantly affect the optical transmittance in the visible region. However, boron doping lowers the sheet resistance by ∼30% relative to pristine SWNT films from the same batch. Boron-doped SWNT may provide a better approach to touch-screen technology.