Lifetimes of Confined Acoustic Phonons in Ultra-Thin Silicon Membranes

Abstract

We study the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultra-thin 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 \sim 4.7 ns to 5 ps with decreasing membrane thickness from \sim 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.

References in corpus (5)

• Energy Dissipation and Transport in Nanoscale Devices
• A Mechanical Mass Sensor with Yoctogram Resolution
• Strong coupling between single-electron tunneling and nano-mechanical motion
• High-Q Nanomechanics via Destructive Interference of Elastic Waves
• Phonons in Slow Motion: Dispersion Relations in Ultra-Thin Si Membranes

Cited by in corpus (21)

• Tutorial: Time-domain thermoreflectance (TDTR) for thermal property characterization of bulk and thin film materials
• Heat conduction tuning using the wave nature of phonons
• A 1D Optomechanical crystal with a complete phononic band gap
• Two-Dimensional Phononic Crystals: Disorder Matters
• Phonon Heat Conduction in Corrugated Silicon Nanowires Below the Casimir Limit
• Boundary scattering of phonons: specularity of a randomly rough surface in the small perturbation limit
• Dimensional crossover of acoustic phonon lifetime in $2H$-MoSe${}_2$
• A generalized decay law for particle- and wave-like thermal phonons
• A Self-Assembled Metamaterial for Lamb Waves
• Picosecond ultrasonics with a free-running dual-comb laser
• Mechanically Generating Entangled Photons from the Vacuum: A Microwave Circuit-Acoustic Resonator Analogue of the Unruh Effect
• Analogue Gravity on a Superconducting Chip
• Assessing Phonon Coherence Using Spectroscopy
• Nanocrystalline silicon optomechanical cavities
• Influence of ferroelastic domain walls on thermal conductivity
• Three-dimensional phonon population anisotropy in silicon nanomembranes
• Sensing Coherent Phonons with Two-photon Interference
• Long-Lived Coherent Acoustic Phonons in Epitaxially Grown III-V Adiabatic Cavities
• A perspective on inelastic light scattering spectroscopy for probing transport of collective acoustic excitations
• Anomalous frequency scaling of acoustic phonon damping in nickel cavities fabricated by ps-laser delamination
• Determining Phonon Coherence Using Photon Sideband Detection