Experimental Evidence of Non-Diffusive Thermal Transport in Si and GaAs
Author(s)Johnson, Jeremy A.; Maznev, Alexei; Eliason, Jeffrey Kristian; Minnich, Austin Jerome; Collins, Kimberlee C.; Chen, Gang; Cuffe, John; Kehoe, Timothy; Sotomayor Torres, Clivia M.; Nelson, Keith Adam; ... Show more Show less
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The length-scales at which thermal transport crosses from the diffusive to ballistic regime are of much interest particularly in the design and improvement of nano-structured materials. In this work, we demonstrate that the departure from diffusive transport has been observed in Si and GaAs using an optical transient thermal grating technique where an arbitrary, experimentally set length scale can be imposed on a material. In a transient thermal grating experiment, crossed laser pulses interfere creating a well-defined periodic absorption and temperature profile. A probe beam is diffracted from this transient grating and length-scale dependent thermal transport properties can be determined from the signal decay. As the length scale is decreased to lengths shorter than the mean free paths of heat carrying phonons, quasi-ballistic heat transport effects become apparent allowing us to map out length scales and mean free paths relevant to nondiffusive thermal transport in Si and GaAs.
DepartmentMassachusetts Institute of Technology. Department of Chemistry; Massachusetts Institute of Technology. Department of Mechanical Engineering
Cambridge University Press/Materials Research Society
Johnson, Jeremy A., Alexei A. Maznev, Jeffrey K. Eliason, Austin Minnich, Kimberlee Collins, Gang Chen, John Cuffe, Timothy Kehoe, Clivia M. Sotomayor Torres, and Keith A. Nelson. “Experimental Evidence of Non-Diffusive Thermal Transport in Si and GaAs.” MRS Proceedings 1347 (January 23, 2011).© 2011 Materials Research Society.
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