In this work, we examine Fermi relaxation in 20 nm Au films with pump-probe themoreflectance using a thin film, intraband thermoreflectance model. Our results indicate that the Fermi relaxation of a perturbed electron system occurs approximately after absorption of a 785 nm, 185 fs laser pulse. This is in agreement with reported values from electron emission experiments but is higher than the Fermi relaxation time determined from previous thermoreflectance measurements. This discrepancy arises due to thermoreflectance modeling and elucidates the importance of the use of a proper thermoreflectance model for thermophysical property determination in pump-probe experiments.
Issue Section:
Technical Briefs
1.
Groeneveld
, R. H. M.
, Sprik
, R.
, and Lagendijk
, A.
, 1992, “Effect of a Nonthermal Electron Distribution on the Electron-Phonon Energy Relaxation Process in Noble Metals
,” Phys. Rev. B
0556-2805, 45
, pp. 5079
–5082
.2.
Groeneveld
, R. H. M.
, Sprik
, R.
, and Lagendijk
, A.
, 1995, “Femtosecond Spectroscopy of Electron-Electron and Electron-Phonon Energy Relaxation in Ag and Au
,” Phys. Rev. B
0556-2805, 51
, pp. 11433
–11445
.3.
Sun
, C. K.
, Vallee
, F.
, Acioli
, L. H.
, Ippen
, E. P.
, and Fujimoto
, J. G.
, 1993, “Femtosecond Investigation of Electron Thermalization in Gold
,” Phys. Rev. B
0556-2805, 48
, pp. 12365
–12368
.4.
Sun
, C. K.
, Vallee
, F.
, Acioli
, L. H.
, Ippen
, E. P.
, and Fujimoto
, J. G.
, 1994, “Femtosecond-Tunable Measurement of Electron Thermalization in Gold
,” Phys. Rev. B
0556-2805, 50
, pp. 15337
–15348
.5.
Eesley
, G. L.
, 1983, “Observation of Nonequilibrium Electron Heating in Copper
,” Phys. Rev. Lett.
0031-9007, 51
, pp. 2140
–2143
.6.
Eesley
, G. L.
, 1986, “Generation of Nonequlibrium Electron and Lattice Temperatures in Copper by Picosecond Laser Pulses
,” Phys. Rev. B
0556-2805, 33
, pp. 2144
–2151
.7.
Del Fatti
, N.
, Voisin
, C.
, Achermann
, M.
, Tzortzakis
, S.
, Christofilos
, D.
, and Vallée
, F.
, 2000, “Noneqilibrium Electron Dynamics in Noble Metals
,” Phys. Rev. B
0556-2805, 61
, pp. 16956
–16966
.8.
Hohlfeld
, J.
, Wellershoff
, S. S.
, Gudde
, J.
, Conrad
, U.
, Jahnke
, V.
, and Matthias
, E.
, 2000, “Electron and Lattice Dynamics Following Optical Excitation of Metals
,” Chem. Phys.
0301-0104, 251
, pp. 237
–258
.9.
Hopkins
, P. E.
, Kassebaum
, J. L.
, and Norris
, P. M.
, 2009, “Effects of Electron Scattering at Metal-Nonmetal Interfaces on Electron-Phonon Equilibration in Gold Films
,” J. Appl. Phys.
0021-8979, 105
, p. 023710
.10.
Hopkins
, P. E.
, and Norris
, P. M.
, 2007, “Substrate Influence in Electron-Phonon Coupling Measurements in Thin Au Films
,” Appl. Surf. Sci.
0169-4332, 253
, pp. 6289
–6294
.11.
Smith
, A. N.
, and Norris
, P. M.
, 2001, “Influence of Intraband Transitions on the Electron Thermoreflectance Response of Metals
,” Appl. Phys. Lett.
0003-6951, 78
, pp. 1240
–1242
.12.
Kaganov
, M. I.
, Lifshitz
, I. M.
, and Tanatarov
, L. V.
, 1957, “Relaxation Between Electrons and the Crystalline Lattice
,” Sov. Phys. JETP
0038-5646, 4
, pp. 173
–178
.13.
Anisimov
, S. I.
, Kapeliovich
, B. L.
, and Perel’man
, T. L.
, 1974, “Electron Emission From Metal Surfaces Exposed to Ultrashort Laser Pulses
,” Sov. Phys. JETP
0038-5646, 39
, pp. 375
–377
.14.
Brorson
, S. D.
, Kazeroonian
, A.
, Moodera
, J. S.
, Face
, D. W.
, Cheng
, T. K.
, Ippen
, E. P.
, Dresselhaus
, M. S.
, and Dresselhaus
, G.
, 1990, “Femtosecond Room-Temperature Measurement of the Electron-Phonon Coupling Constant l in Metallic Superconductors
,” Phys. Rev. Lett.
0031-9007, 64
, pp. 2172
–2175
.15.
Hopkins
, P. E.
, 2009, “Effects of Electron-Boundary Scattering on Changes in Thermoreflectance in Thin Metal Films Undergoing Intraband Transitions
,” J. Appl. Phys.
0021-8979, 105
, p. 093517
.16.
Qiu
, T. Q.
, and Tien
, C. L.
, 1993, “Heat Transfer Mechanisms During Short-Pulse Laser Heating of Metals
,” ASME J. Heat Transfer
0022-1481, 115
, pp. 835
–841
.17.
Fann
, W. S.
, Storz
, R.
, Tom
, H. W. K.
, and Bokor
, J.
, 1992, “Direct Measurement of Nonequilibrium Electron-Energy Distributions in Subpicosecond Laser-Heated Gold Films
,” Phys. Rev. Lett.
0031-9007, 68
, pp. 2834
–2837
.18.
Fann
, W. S.
, Storz
, R.
, Tom
, H. W. K.
, and Bokor
, J.
, 1992, “Electron Thermalization in Gold
,” Phys. Rev. B
0556-2805, 46
, pp. 13592
–13595
.19.
Hopkins
, P. E.
, Serrano
, J. R.
, Phinney
, L. M.
, Kearney
, S. P.
, Grasser
, T. W.
, and Harris
, C. T.
, 2010, “Criteria for Cross-Plane Dominated Thermal Transport in Multilayer Thin Film Systems During Modulated Laser Heating
,” ASME J. Heat Transfer
0022-1481, 132
, p. 081302
.20.
Schmidt
, A. J.
, Cheaito
, R.
, and Chiesa
, M.
, 2009, “A Frequency-Domain Thermoreflectance Method for the Characterization of Thermal Properties
,” Rev. Sci. Instrum.
0034-6748, 80
, p. 094901
.21.
Stevens
, R. J.
, Smith
, A. N.
, and Norris
, P. M.
, 2006, “Signal Analysis and Characterization of Experimental Setup for the Transient Thermoreflectance Technique
,” Rev. Sci. Instrum.
0034-6748, 77
, p. 084901
.22.
Kittel
, C.
, 1996, Introduction to Solid State Physics
, Wiley
, New York
.23.
Chen
, J. K.
, Tzou
, D. Y.
, and Beraun
, J. E.
, 2006, “A Semiclassical Two-Temperature Model for Ultrafast Laser Heating
,” Int. J. Heat Mass Transfer
0017-9310, 49
, pp. 307
–316
.24.
Brorson
, S. D.
, Fujimoto
, J. G.
, and Ippen
, E. P.
, 1987, “Femtosecond Electronic Heat-Transport Dynamics in Thin Gold Films
,” Phys. Rev. Lett.
0031-9007, 59
, pp. 1962
–1965
.25.
Hopkins
, P. E.
, 2010, “Influence of Electron-Boundary Scattering on Thermoreflectance Calculations After Intra- and Interband Transitions Induced by Short-Pulsed Laser Absorption
,” Phys. Rev. B
0556-2805, 81
, pp. 035413
.26.
Hummel
, R.
, 2001, Electronic Properties of Materials
, Springer
, New York
.27.
Abeles
, F.
, 1967, “Advanced Optical Techniques
,” Optics of Thin Films
, North-Holland
, Amsterdam
.28.
Macleod
, H. A.
, 2001, Thin-Film Optical Filters
, Institute of Physics
, Bristol, UK
.29.
Hostetler
, J. L.
, Smith
, A. N.
, Czajkowsky
, D. M.
, and Norris
, P. M.
, 1999, “Measurement of the Electron-Phonon Coupling Factor Dependence on Film Thickness and Grain Size in Au, Cr, and Al
,” Appl. Opt.
0003-6935, 38
, pp. 3614
–3620
.30.
Qiu
, T. Q.
, and Tien
, C. L.
, 1993, “Size Effects on nonequilibrium Laser Heating of Metal Films
,” ASME J. Heat Transfer
0022-1481, 115
, pp. 842
–847
.31.
Pines
, D.
, and Nozieres
, P.
, 1999, The Theory of Quantum Liquids
, Benjamin-Cummings
, New York
.Copyright © 2011
by American Society of Mechanical Engineers
You do not currently have access to this content.
