Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

High-density integration of carbon nanotubes via chemical self-assembly


Carbon nanotubes have potential in the development of high-speed and power-efficient logic applications1,2,3,4,5,6,7. However, for such technologies to be viable, a high density of semiconducting nanotubes must be placed at precise locations on a substrate. Here, we show that ion-exchange chemistry can be used to fabricate arrays of individually positioned carbon nanotubes with a density as high as 1 × 109 cm−2—two orders of magnitude higher than previous reports8,9. With this approach, we assembled a high density of carbon-nanotube transistors in a conventional semiconductor fabrication line and then electrically tested more than 10,000 devices in a single chip. The ability to characterize such large distributions of nanotube devices is crucial for analysing transistor performance, yield and semiconducting nanotube purity.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Selective placement of carbon nanotubes by an ion-exchange process.
Figure 2: High density of individually positioned carbon nanotubes.
Figure 3: Demonstration of high-density carbon nanotube transistors (CNTs).


  1. Kreupl, F. Carbon nanotubes finally deliver. Nature 484, 321–322 (2012).

    Article  CAS  Google Scholar 

  2. Javey, A., Guo, J., Lundstrom, M. & Dai, H. Ballistic carbon nanotube field-effect transistors. Nature 424, 654–657 (2003).

    Article  CAS  Google Scholar 

  3. Appenzeller, J. Carbon nanotubes for high-performance electronics—progress and prospect. Proc. IEEE 96, 201–211 (2008).

    Article  CAS  Google Scholar 

  4. Avouris, P. & Martel, R. Progress in carbon nanotube electronics and photonics. Mater. Res. Soc. Bull. 35, 306–313 (2010).

    Article  CAS  Google Scholar 

  5. Franklin, A. D. & Chen, Z. Length scaling of carbon nanotube transistors. Nature Nanotech. 5, 858–862 (2010).

    Article  CAS  Google Scholar 

  6. Franklin, A. D. et al. Sub-10 nm carbon nanotube transistor. Nano Lett. 12, 758–762 (2012).

    Article  CAS  Google Scholar 

  7. Patil, N., Deng, J., Mitra, S. & Wong, H-S. P. Circuit-level performance benchmarking and scalability analysis of carbon nanotube transistor circuits. IEEE Trans. Nanotechnol. 8, 37–45 (2009).

    Article  Google Scholar 

  8. Rao, S. G., Huang, L., Setyawan, W. & Hong, S. Large-scale assembly of carbon nanotubes. Nature 425, 36–37 (2003).

    Article  CAS  Google Scholar 

  9. Vijayaraghavan, A. et al. Ultra-large-scale directed assembly of single-walled carbon nanotube devices. Nano Lett. 7, 1556–1560 (2007).

    Article  CAS  Google Scholar 

  10. Oh, B. S. et al. Fabrication of suspended single-walled carbon nanotubes via a direct lithographic route. J. Mater. Chem. 16, 174–178 (2006).

    Article  CAS  Google Scholar 

  11. Papadopoulos, C. & Omrane, B. Nanometer-scale catalyst patterning for controlled growth of individual single-walled carbon nanotubes. Adv. Mater. 20, 1344–1347 (2008).

    Article  CAS  Google Scholar 

  12. Wang, Y. et al. Controlling the shape, orientation, and linkage of carbon nanotube features with nano affinity templates. Proc. Natl Acad. Sci. USA 103, 2026–2031 (2006).

    Article  CAS  Google Scholar 

  13. Duchamp, M. et al. Controlled positioning of carbon nanotubes by dielectrophoresis: insights into the solvent and substrate role. ACS Nano 4, 279–284 (2010).

    Article  CAS  Google Scholar 

  14. Hannon, J. B., Afzali, A., Klinke, C. & Avouris, Ph. Selective placement of carbon nanotubes on metal-oxide surfaces. Langmuir 21, 8569–8571 (2005).

    Article  CAS  Google Scholar 

  15. Lee, M. et al. Linker-free directed assembly of high-performance integrated devices based on nanotubes and nanowires. Nature Nanotech. 1, 66–77 (2006).

    Article  CAS  Google Scholar 

  16. Bardeccker, J. A. et al. Directed assembly of single-walled carbon nanotubes via drop-casting onto a UV-patterned photosensitive monolayer. J. Am. Chem. Soc. 130, 7226–7227 (2008).

    Article  Google Scholar 

  17. Klinke, C., Hannon, J. B., Afzali, A. & Avouris, Ph. Field-effect transistors assembled from functionalized carbon nanotubes. Nano Lett. 6, 906–910 (2006).

    Article  CAS  Google Scholar 

  18. Tulevski, G. S. et al. Chemically assisted directed assembly of carbon nanotubes for the fabrication of large-scale device arrays. J. Am. Chem. Soc. 129, 11964–11968 (2007).

    Article  CAS  Google Scholar 

  19. Gomez, L. M. et al. Scalable light-induced metal to semiconductor conversion of carbon nanotubes. Nano Lett. 9, 3592–3598 (2009).

    Article  CAS  Google Scholar 

  20. Ono, Y., Kishimoto, S., Ohno, Y. & Mizutani, T. Thin film transistors using PECVD-grown carbon nanotubes. Nanotechnology 21, 205202 (2010).

    Article  Google Scholar 

  21. Arnold, M. S., Green, A. A., Hulvat, J. F., Stupp, S. I. & Hersam, M. C. Sorting carbon nanotubes by electronic structure using density differentiation. Nature Nanotech. 1, 60–65 (2006).

    Article  CAS  Google Scholar 

  22. Folkers, J. P., Gorman, C. B., Laibinis, P. E., Buchholz, S. & Whitesides, G. M. Self-assembled monolayers of long-chain hydroxamic acids on the native oxides of metals. Langmuir 11, 813–824 (1995).

    Article  CAS  Google Scholar 

  23. Franklin, A. D. et al. Variability in carbon nanotube transistors: improving device-to-device consistency. ACS Nano 6, 1109–1115 (2012).

    Article  CAS  Google Scholar 

  24. Engel, M. et al. Thin film nanotube transistors based on self-assembled, aligned, semiconducting carbon nanotube arrays. ACS Nano 2, 2445–2452 (2008).

    Article  CAS  Google Scholar 

  25. Stokes, P. & Khondaker, S. I. High quality solution processed carbon nanotube transistors assembled by dielectrophoresis. Appl. Phys. Lett. 96, 083110 (2010).

    Article  Google Scholar 

  26. Tseng, Y., Phoa, K., Carlton, D. & Bokor, J. Effect of diameter variation in a large set of carbon nanotube transistors. Nano Lett. 6, 1364–1368 (2006).

    Article  CAS  Google Scholar 

  27. Park, S. et al. Highly effective separation of semiconducting carbon nanotubes verified via short-channel devices fabricated using dip-pen nanolithography. ACS Nano 6, 2487–2496 (2012).

    Article  CAS  Google Scholar 

  28. Ho, C. Y., Strobel, E., Ralbovsky, J. & Galemmo, R. A. Jr Improved solution- and solid-phase preparation of hydroxamic acids from esters. J. Org. Chem. 70, 4873–4875 (2005).

    Article  CAS  Google Scholar 

  29. Moshammer, K., Hennrich, F. & Kappes, M. M. Selective suspension in aqueous sodium dodecyl sulfate according to electronic structure type allows simple separation of metallic from semiconducting single-walled carbon nanotubes. Nano Res. 2, 599–606 (2009).

    Article  CAS  Google Scholar 

Download references


The authors thank J. Bucchignano and G. Wright for their expert technical assistance with electron-beam lithography, and Q. Cao for helpful discussions.

Author information

Authors and Affiliations



H.P., A.A., G.S.T. and S.H. developed the carbon nanotube placement method. H.P., S.H. and A.D.F. fabricated and characterized the nanotube transistors. J.B.H., J.T. and W.H. developed the model and software for rapid assessment of the large sets of measured data. All authors contributed to discussing the results and writing manuscript.

Corresponding authors

Correspondence to Hongsik Park or Ali Afzali.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 850 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Park, H., Afzali, A., Han, SJ. et al. High-density integration of carbon nanotubes via chemical self-assembly. Nature Nanotech 7, 787–791 (2012).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Find nanotechnology articles, nanomaterial data and patents all in one place. Visit Nano by Nature Research