Ultrafast and steady-state laser heating effects on electron relaxation and phonon coupling mechanisms in thin gold films
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States)
- Advanced Materials Laboratory, Sandia National Laboratories, Albuquerque, New Mexico 87106 (United States)
- Sandia National Laboratories, Livermore, California 94550 (United States)
We study the scattering mechanisms driving electron-phonon relaxation in thin gold films via pump-probe time-domain thermoreflectance. Electron-electron scattering can enhance the effective rate of electron-phonon relaxation when the electrons are out of equilibrium with the phonons. In order to correctly and consistently infer electron-phonon coupling factors in films on different substrates, we must account for the increase in steady-state lattice temperature due to laser heating. Our data provide evidence that a thermalized electron population will not directly exchange energy with the substrate during electron-phonon relaxation, whereas this pathway can exist between a non-equilibrium distribution of electrons and a non-metallic substrate.
- OSTI ID:
- 22253917
- Journal Information:
- Applied Physics Letters, Vol. 103, Issue 21; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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Publisher's Note: “Ultrafast and steady-state laser heating effects on electron relaxation and phonon coupling mechanisms in thin gold films” [Appl. Phys. Lett. 103, 211910 (2013)]