Details

Autor(en) / Beteiligte

• Cuffe, J
• Ristow, O
• Chávez, E
• Shchepetov, A
• Chapuis, P-O
• Alzina, F
• Hettich, M
• Prunnila, M
• Ahopelto, J
• Dekorsy, T
• Sotomayor Torres, C M

Titel

Lifetimes of confined acoustic phonons in ultrathin silicon membranes

Ist Teil von

• Physical review letters, 2013-02, Vol.110 (9), p.095503-095503, Article 095503

Ort / Verlag

United States

Erscheinungsjahr

2013

Link zum Volltext

Quelle

American Physical Society Journals

Beschreibungen/Notizen

• We study the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultrathin free-standing silicon membranes. Using an ultrafast pump-probe technique of asynchronous optical sampling, we observe that the decay time of the first-order dilatational mode decreases significantly from ~4.7 ns to 5 ps with decreasing membrane thickness from ~194 to 8 nm. The experimental results are compared with theories considering both intrinsic phonon-phonon interactions and extrinsic surface roughness scattering including a wavelength-dependent specularity. Our results provide insight to understand some of the limits of nanomechanical resonators and thermal transport in nanostructures.