This activity provides experimental data and measurement techniques for the effective thermal conductivities of complex micro- and nano-fabricated structures. Many of my first graduate students focused on the thermal properties of silicon films, and the silicon work has been completed by a comprehensive review [a] and data for polysilicon and doped silicon [b,c]. More recently we have focused on the thermal properties of nanostructures and nanostructured materials, including arrays of carbon nanotubes with potential application as interface materials for electronic systems [d]. We have also developed a novel structure for measuring the thermal conductivity of unbundled, single wall carbon nanotubes, which show a large increase in conductance per nanotube [e]. Future work in this area will focus on further development of nanostructured interface materials as well as novel materials for phase-change memory applications.
Figure 1: Single wall carbon nanotubes suspended between parallel
polysilicon bridges in a thermal conductivity measurement structure.
a. McConnell and Goodson, 2005, “Thermal Conduction in Silicon Micro and Nanostructures,” Annual Review of Heat Transfer, Vol. 14, pp. 129-168. pdf
b. Asheghi et al., 2002, “Thermal conduction in doped single-crystal silicon films,” Journal of Applied Physics, Vol. 91, pp 5079-5088.
c. McConnell et al., 2001, “Thermal Conductivity of Doped Polysilicon," JMEMS, Vol. 10, pp. 360-369.
d. Hu et al., “3w Measurements of the Thermal Conductivity of Vertically Oriented Carbon Nanotubes on Silicon,” ASME Journal of Heat Transfer, in press.
e. McConnell and Goodson, “Measurement of the Thermal Properties of High-Resistance Nanostructures using Transient Electrical Thermometry,” submitted to the ASME Journal of Heat Transfer.