Abstract
Femtosecond thermoreflectance data for thin films and bulk quantities of Au, Cr, and Al are compared with the parabolic two-step thermal diffusion model for the purpose of determining the electron-phonon coupling factor. The thin films were evaporated and sputtered onto different substrates to produce films that vary structurally. The measurement of the electron-phonon coupling factor is shown to be sensitive to grain size and film thickness. The thin-film thermoreflectance data are compared with that of the corresponding bulk material and to a theoretical model relating the coupling rate to the grain-boundary scattering and size effects on the mean free path of the relevant energy carrier.
© 1999 Optical Society of America
Full Article | PDF ArticleMore Like This
Patrick E. Hopkins, J. Michael Klopf, and Pamela M. Norris
Appl. Opt. 46(11) 2076-2083 (2007)
J. P. Lehan
Appl. Opt. 35(25) 5048-5051 (1996)
K. L. Moore and T. D. Donnelly
Opt. Lett. 24(14) 990-992 (1999)