Improvement of the Elastic Modulus of Micromachined Structures using Carbon Nanotubes


Microelectromechanical flexural structures have been fabricated using sandwiched multi-layers consisting of bundled singled walled carbon nanotubes(SWNTs) incorporated into silicon nitride (Si3N4) films. The Si3N4-SWNT composite layer was patterned by reactive ion etching followed by release in XeF2 to create freestanding bridge structures. The mechanical stiffness of the micromechanical bridges was monitored via force-displacement (F-D) curves obtained using an Atomic Force Microscope (AFM). Inclusion of SWNTs resulted in an increase in the spring constant of the bridge by as much as 64%, with an average increase of 25%. In a second experiment, micromachined bridges fabricated using dissolved wafer process were coated with debundled SWNTs. The SWNTs suspended in N-methyl-2-pyrrolidinone (NMP) solvent were sprayed locally on each bridge using a piezoelectric print head. Resonance frequency measurements were done in vacuum (∼10-4 Torr) on the bridges after successive SWNT depositions. A 20% increase in the resonance frequency of the bridges was observed. The observed increase in stiffness in the first set of experiments as well as the observed increase in the frequency in the second set of experiments can be attributed to the high axial modulus of elasticity (∼1 TPa) of the carbon nanotubes.

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


  1. 1.

    K.M. Lakin G.R. Kline, and K.T. McCarron, Development of miniature filters for wireless applications. IEEE Transactions on Microwave Theory and Techniques 1995. 43 (12, pt.2): p. 2933–9.

    Article  Google Scholar 

  2. 2.

    K. Wang A.-C. Wong, and C.T.-C. Nguyen, VHF free-free beam high-Q micromechanical resonators. Journal of Microelectromechanical Systems. 2000, 9(3): p. 347–60.

    Article  Google Scholar 

  3. 3.

    J. Wang Z. Ren, and C.T.-C. Nguyen . 1.14-GHz self-aligned vibrating micromechanical disk resonator. in IEEE Radio Frequency Integrated Circuits Symposium (RFIC), 8-10 June 2003. 2003. Philadelphia, PA, USA: IEEE.

    Google Scholar 

  4. 4.

    V.N. Popov Carbon nanotubes: properties and application. Materials Science & Engineering R: Reports, 2004. R43(3): p. 61–102.

    CAS  Article  Google Scholar 

  5. 5.

    S. Tadigadapa and S.M. Ansari . Applications of high-performance MEMS pressure sensors based on dissolved wafer process. in Proceedings SENSORS EXPO Baltimore. 1999. Baltimore, MD, USA: Helmers Publishing.

    Google Scholar 

  6. 6.

    J. Wei et al., Low temperature wafer anodic bonding. Journal of Micromechanics and Microengineering, 2003. 13(2): p. 217–222.

    CAS  Article  Google Scholar 

  7. 7.

    A. Goyal J. Cheong, and S. Tadigadapa, Tin-based solder bonding for MEMS fabrication and packaging applications. Journal of Micromechanics and Microengineering, 2004. 14(6): p. 819–825.

    CAS  Article  Google Scholar 

  8. 8.

    J. Li et al., Carbon nanotube sensors for gas and organic vapor detection. Nano Letters, 2003. 3(7): p. 929–933.

    CAS  Article  Google Scholar 

  9. 9.

    G.U. Sumanasekera et al. Thermoelectric study of hydrogen storage in carbon nanotubes. in Making Functional Materials with Nanotubes. Symposium, 26-29 Nov. 2001. 2002. Boston, MA, USA: Mater. Res. Soc.

    Google Scholar 

  10. 10.

    A.C. Dillon et al., Storage of hydrogen in single-walled carbon nanotubes. Nature, 1997. 386(6623): p. 377–9.

    CAS  Article  Google Scholar 

  11. 11.

    E. Dujardin et al., Capillarity and wetting of carbon nanotubes. Science, 1994. 265(5180): p. 1850–2.

    CAS  Article  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Prasoon Joshi.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Joshi, P., Duarte, N.B., Goyal, A. et al. Improvement of the Elastic Modulus of Micromachined Structures using Carbon Nanotubes. MRS Online Proceedings Library 875, 15 (2005).

Download citation