Phonons in highly-crystalline mesoporous silicon: The absence of phonon-softening upon structuring silicon on sub-10 nanometer length scales

This article presents inelastic thermal neutron scattering experiments probing the phonon dispersion in mesoporous silicon with pores 8 nm across. Scattering studies reveal energy–momentum relation for transverse and longitudinal phonons along high symmetry directions ΓL¯, ΓK¯ ΓX¯ Brillouin zone. The up to energies of 35 meV unambiguously proves that group velocities highly-crystalline are not modified by nanostructuring down sub-10 nanometer length scales. On these scales, there is apparently no effect structuring on elastic moduli silicon. No evidence can be found phonon-softening topologically complex, geometrically disordered putting it contrast nanotubes nanoribbons.