This paper discusses the design, fabrication and testing of a novel thermoelectric device comprised of arrays of silicon nanowires embedded in a polymer matrix. By exploiting the low-thermal conductivity of the composite and presumably high-power factor of the nanowires, a thermoelectric figure of merit, higher than the corresponding bulk value, should result. Arrays were first synthesized using a vapor-liquid-solid (VLS) process leading to one-dimensional (1-D) growth of single-crystalline nanowires. To provide structural support while maintaining thermal isolation between nanowires, parylene, a low thermal conductivity and extremely conformal polymer, was embedded within the arrays. Mechanical polishing and oxygen plasma etching techniques were used to expose the nanowire tips and a metal contact was deposited on the top surface. Scanning electron micrographs (SEMs) illustrate the results of the fabrication processes. Using a modification of the 3ω technique, the effective thermal conductivity of the nanowire matrix was measured and 1 V characteristics were also demonstrated. An assessment of the suitability of this nanocomposite for high thermoelectric performance devices is given.
Bibliographical noteFunding Information:
Manuscript received March 10, 2003; revised December 10, 2003. This work was supported by the National Science Foundation, Nanoscale Interdisciplinary Research Team Grant Program. Subject Editor H. Fujita. A. R. Abramson is with the Mechanical and Aerospace Engineering Department, Case Western Reserve University, Cleveland, OH 44106-7222 USA (e-mail: firstname.lastname@example.org). W. C. Kim and A. Majumdar are with the Department of Mechanical Engineering, University of California, Berkeley, CA 94720-1740 USA. S. T. Huxtable is with the Department of Mechanical Engineering, Virginia Tech, Blacksburg, VA 24061 USA. H. Yan and P. Yang are with the Department of Chemistry, University of California, Berkeley, CA 94720-1460 USA. Y. Wu is with the Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106-9510 USA. C.-L. Tien, deceased, was with the Department of Mechanical Engineering, University of California, Berkeley, CA 94720-1740 USA. Digital Object Identifier 10.1109/JMEMS.2004.828742
All Science Journal Classification (ASJC) codes
- Mechanical Engineering
- Electrical and Electronic Engineering