Main Article Content
Double-walled carbon nanotubes (DWNTs) were synthesized by high-vacuum chemical vapor deposition (HVCVD) at 875-1000 °C using ethanol and ammonium iron (III) citrate as carbon source and metal catalyst, respectively. Synthesized DWNTs were purified by acid and thermal treatments to remove the metal catalyst and amorphous carbon. Transmission electron microscopy (TEM) and Raman spectroscopy were utilized for characterization of the structure, diameter, crystallinity and purity of DWNTs. By Raman spectroscopy analysis, we found that the optimized synthesis temperature for high quality DWNTs was 900 °C. After purification process, the purity of purified DWNTs was 2.1-fold higher than that of as-grown DWNTs. TEM images revealed the purified synthesized DWNTs at 900 °C with inner and outer diameters of 1.02±0.03 and 1.72±0.05 nm, respectively. These results imply that synthesis temperature and treatment process are key parameters that affect structure, crystallinity and purity of DWNTs.
2. S. Iijima, T. Ichihashi, Single-walled carbon nanotubes of 1-nm diameter, Nature, 1993, 363, 603-605.
3. M.S. Dresselhaus, G. Dresselhaus, J.C. Charlier, E. Hernandez, Electronic, thermal and mechanical properties of carbon nanotubes, Philos. Trans. R Soc. Lond. A, 2004, 362, 2065-2098.
4. L.F. Sun, S.S. Xie, J.M. Mao, Z.W. Pan, B.H. Chang, W.Y. Zhou, G. Wang, L.X. Qian, Effects of temperature oscillations on the growth of carbon nanotubes by chemical vapor deposition, Appl. Phys. Lett., 2000, 76, 828-830.
5. C.J. Lee, J. Park, Y. Huh, J.Y. Lee, Temperature effect on the growth of carbon nanotubes using thermal chemical vapor deposition, Chem. Phys. Lett., 2001, 343, 33-38.
6. W.Z. Li, J.G. Wen, Z.F. Ren, Effect of temperature on growth and structure of carbon nanotubes by chemical vapor deposition, Appl. Phys. A, 2002, 74, 397-402.
7. C. Du, N. Pan, CVD growth of carbon nanotubes directly on nickel substrate, Mater. Lett., 2005, 59, 1678-1682.
8. S. Maruyama, R. Kojima, Y. Miyauchi, S. Chiashi, M. Kohno, Low-temperature synthesis of high-purity single-walled carbon nanotubes from alcohol, Chem. Phys. Lett., 2002, 360, 229-234.
9. S. Maruyama, Y. Miyauchi, Y. Murakami, S. Chiashi, Optical characterization of single-walled carbon nanotubes synthesized by catalytic decomposition of alcohol, New. J. Phys., 2003, 5, 149.1-149.12.
10. Y. Murakami, Y. Miyauchi, S. Chiashi, S. Maruyama, Direct synthesis of high-quality single-walled carbon nanotubes on silicon and quartz substrates, Chem. Phys. Lett., 2003, 377, 49-54.
11. Y. Murakami, Y. Miyauchi, S. Chiashi, S. Maruyama, Characterization of sing-walled carbon nanotubes catalytically synthesized from alcohol, Chem. Phys. Lett., 2003, 374, 53-58.
12. A. GrÜneis, M.H. RÜmmel, C. Kramberger, A. Barreiro, T. Pichler, R. Pfeiffer, H. Kuzmany, T. Gemming, B. BÜchner, High quality double wall carbon nanotubes with a defined diameter distribution by chemical vapor deposition from alcohol, Carbon, 2006, 44, 3177-3182.
13. Y. Taki, K. Shinohara, M. Kikuchi, A. Tanaka, Selective growth of single-, double-, and triple-walled carbon nanotubes through precise control of catalyst diameter by radiation-heated chemical vapor deposition, Jpn. J. Appl. Phys., 47, 725-729.
14. L. Shi, M. Sauer, O. Domonov, P. Rohringer, P. Ayala. T. Pichler, Raman and XPS analyses of pristine and annealed N-doped double-walled carbon nanotubes, Phys. Status Solidi B, 2015, 252, 2558-2563 .
15. J. Arvanitidis, D. Christofilos, K. Papagelis, K.S. Andrikopoulos, T. Takenobu, Y. Iwasa, H. Kataura, S. Ves, G.A. Kourosklis, Pressure screening in the interior of primary shells in double-wall carbon nanotubes, Phys. Rev. B, 2005, 71, 125404(1-5).
16. J. Arvanitidis, D. Christofilos, K. Papagelis, T. Takenobu, Y. Iwasa, H. Kataura, S. Ves, G.A. Kourouklis, Double-wall carbon nanotubes under pressure: Probing the response of individuals tubes and their intratube correlation, Phys. Rev. B, 2005, 72, 193411(1-4).
17. M. Dresselhaus, G. Dresselhaus, R. Saito, Physics of carbon nanotubes, Carbon, 1995, 33, 883-891.
18. W. Ren, F. Li, J. Chen, S. Bai, H.-M. Cheng, Morphology , diameter distribution and Raman scattering measurements of double-walled carbon nanotubes synthesized by catalytic decomposition of methane, Chem. Phys. Lett., 2002, 359, 196-202.
19. T. Grace, L. Yu, C. Gibson, D. Tune, H. Alturaif, Z.A. Othman, J. Shapter, Investigating the effect of carbon nanotube diameter and wall number in carbon nanotube/silicon heterojunction solar cells, Nanomaterials (Basel), 2016, 6, 52(1-13).