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Title: Acoustic phonon spectrum and thermal transport in nanoporous alumina arrays

We report results of a combined investigation of thermal conductivity and acoustic phonon spectra in nanoporous alumina membranes with the pore diameter decreasing from D=180 nm to 25 nm. The samples with the hexagonally arranged pores were selected to have the same porosity Ø ≈13%. The Brillouin-Mandelstam spectroscopy measurements revealed bulk-like phonon spectrum in the samples with D = 180 nm pores and spectral features, which were attributed to spatial confinement, in the samples with 25 nm and 40 nm pores. The velocity of the longitudinal acoustic phonons was reduced in the samples with smaller pores. As a result, analysis of the experimental data and calculated phonon dispersion suggests that both phonon-boundary scattering and phonon spatial confinement affect heat conduction in membranes with the feature sizes D < 40 nm.
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Univ. of California, Riverside, CA (United States)
Publication Date:
OSTI Identifier:
1223601
Grant/Contract Number:
SC0012670
Type:
Accepted Manuscript
Journal Name:
Applied Physics Letters
Additional Journal Information:
Journal Volume: 107; Journal Issue: 18; Conference: Brillouin-Mandelstam Light Scattering Spectroscopy of the Nanoscale Phononic Superlattice Arrays, Nonlinear Optics 2015, Kauai, HI (United States), 26-31 Jul 2015; Journal ID: ISSN 0003-6951
Publisher:
American Institute of Physics (AIP)
Research Org:
Univ. of California, Riverside, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY thermal conductivity; Brillouin-Mandelstam light scattering; phonon confinement; nanoporous alumina; acoustic scattering; nanoporous materials; heat conduction