Crossref journal-article
American Association for the Advancement of Science (AAAS)
Science (221)
Abstract

We describe a simple process for the fabrication of ultrathin, transparent, optically homogeneous, electrically conducting films of pure single-walled carbon nanotubes and the transfer of those films to various substrates. For equivalent sheet resistance, the films exhibit optical transmittance comparable to that of commercial indium tin oxide in the visible spectrum, but far superior transmittance in the technologically relevant 2- to 5-micrometer infrared spectral band. These characteristics indicate broad applicability of the films for electrical coupling in photonic devices. In an example application, the films are used to construct an electric field–activated optical modulator, which constitutes an optical analog to the nanotube-based field effect transistor.

Bibliography

Wu, Z., Chen, Z., Du, X., Logan, J. M., Sippel, J., Nikolou, M., Kamaras, K., Reynolds, J. R., Tanner, D. B., Hebard, A. F., & Rinzler, A. G. (2004). Transparent, Conductive Carbon Nanotube Films. Science, 305(5688), 1273–1276.

Authors 11
  1. Zhuangchun Wu (first)
  2. Zhihong Chen (additional)
  3. Xu Du (additional)
  4. Jonathan M. Logan (additional)
  5. Jennifer Sippel (additional)
  6. Maria Nikolou (additional)
  7. Katalin Kamaras (additional)
  8. John R. Reynolds (additional)
  9. David B. Tanner (additional)
  10. Arthur F. Hebard (additional)
  11. Andrew G. Rinzler (additional)
References 27 Referenced 2,720
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  2. R. G. Gordon, MRS Bull.25, 52 (2000). / MRS Bull. (2000)
  3. K. Leeet al., Nano Lett.4, 911 (2004). (10.1021/nl0496522) / Nano Lett. (2004)
  4. See supporting text on Science Online.
  5. Others have also used vacuum filtration as the initial step to fabricate free-standing SWNT films ( 6 ). However their transfer process involved cutting a rectangular hole in adhesive tape laying this tape onto the nanotube layer on the membrane and peeling up the tape to obtain the free-standing film within the hole in the tape. This gives comparatively little control over the film thickness and is not amenable to film deposition over large areas compatible with microelectronic processing.
  6. F. Hennrichet al., Phys. Chem. Chem. Phys.4, 2273 (2002). (10.1039/b201570f) / Phys. Chem. Chem. Phys. (2002)
  7. 10.1021/nl0156639
  8. F. Hennrich, R. Wellmann, S. Malik, S. Lebedkin, M. M. Kappes, Phys. Chem. Chem. Phys.5, 178 (2003). (10.1039/b208270e) / Phys. Chem. Chem. Phys. (2003)
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  11. 10.1038/29954
  12. Work over recent years has shown that this simple picture for NFET operation is by no means complete and ignores Schottky barriers that develop at the nanotube-metal contact junctions which are also modulated by the gate fields ( 13 ). Nonetheless carrier concentration modulation contributes to the effect and under some conditions dominates ( 14 ).
  13. S. Heinzeet al., Phys. Rev. Lett.89, 106801 (2002). (10.1103/PhysRevLett.89.106801) / Phys. Rev. Lett. (2002)
  14. 10.1038/nature01797
  15. 10.1063/1.1350427
  16. 10.1021/nl025639a
  17. We have also fabricated entirely solid-state devices consisting of a transparent ITO counterelectrode separated from the t-SWNT film by a thin AlO x dielectric layer.
  18. 10.1038/nature01797
  19. Modulation of the three principal SWNT absorption bands in a three-terminal electrochemical cell has been reported ( 20 21 ). There the effect was ascribed to nanotube Fermi level shifts associated with intercalated species generated by electrochemical redox reactions in the electrolyte. The SWNT film (produced by airbrushing) used in those experiments evidently did not have sufficient intrinsic conductivity to be used without a thin transparent platinum electrode ( 20 ) or ITO electrode ( 21 ) onto which the nanotubes were sprayed. The ionic liquid in our experiments acts merely as a near-lying gate electrode undergoing no complicating redox reactions. It also yields substantially cleaner SWNT spectra over broader voltage and spectral ranges. The spectra we show are raw data.
  20. 10.1063/1.1372208
  21. L. Kavanet al., J. Phys. Chem. B105, 10764 (2001). (10.1021/jp011709a) / J. Phys. Chem. B (2001)
  22. Although the S1 band overlaps the 1.55-μm wavelength important in optical communications the ionic liquid–gated device (or any electrolyte-gated device) is far too slow to be useful for modulation at the rates needed in communication devices. Because of the high viscosity of the ionic liquid the time scale for electrostatic gate equilibration is on the order of minutes.
  23. Our all–solid-state device has similar spectral behavior with “gate” voltage; however the magnitude of the modulation is much smaller (0.2% over ±6 V at the peak of S1) because electrostatic screening allows only the layer of nanotubes nearest the ITO counterelectrode to participate. Because gating is all electronic (as opposed to ionic) however the response time is much faster than the ionic liquid device.
  24. With the spectrophotometer in a mode that records the transmittance at fixed wavelength as a function of time we sat on the peak of the S1 absorption band while driving the O-NFET with a square wave potential. No systematic changes in the amplitude of the modulation were observed over multiple measurements totaling several hundred cycles. Only small changes (a few percent) in the average transmittance both up and down were seen—entirely consistent with spectrometer drift over the long time scale of these measurements.
  25. Four-probe measurements were performed with a Linear Research 700 resistance bridge using 2-mV excitation at 16 Hz.
  26. P. Chandrasekharet al., Synth. Metals135–136, 23 (2003). / Synth. Metals (2003)
  27. Supported by the U.S. Army through Center for Materials in Sensors and Actuators grant DAAD19-00-1-0002 (J.R.R. D.B.T. A.F.H. A.G.R.) NSF grants DMR 0101856 (A.F.H.) and ECS-0210574 (A.G.R.) and NSF-MTA-OTKA international grants 021 N31622 (D.B.T. K.K.) NSF-INT-9902050 (D.B.T. K.K.) and OTKA 034198 (K.K.).
Dates
Type When
Created 21 years ago (Aug. 26, 2004, 5:14 p.m.)
Deposited 1 year, 7 months ago (Jan. 9, 2024, 10:23 p.m.)
Indexed 1 day, 10 hours ago (Aug. 27, 2025, 12:17 p.m.)
Issued 21 years ago (Aug. 27, 2004)
Published 21 years ago (Aug. 27, 2004)
Published Print 21 years ago (Aug. 27, 2004)
Funders 0

None

@article{Wu_2004, title={Transparent, Conductive Carbon Nanotube Films}, volume={305}, ISSN={1095-9203}, url={http://dx.doi.org/10.1126/science.1101243}, DOI={10.1126/science.1101243}, number={5688}, journal={Science}, publisher={American Association for the Advancement of Science (AAAS)}, author={Wu, Zhuangchun and Chen, Zhihong and Du, Xu and Logan, Jonathan M. and Sippel, Jennifer and Nikolou, Maria and Kamaras, Katalin and Reynolds, John R. and Tanner, David B. and Hebard, Arthur F. and Rinzler, Andrew G.}, year={2004}, month=aug, pages={1273–1276} }