Modification of the phonon spectrum of bulk Si through surface nanostructuring

Abdo Iskandar (1, 2) , Agnieszka Gwiazda (2) , Yi Huang (2) , Michel Kazan (1) , Aurélien Bruyant (2) , Malek Tabbal (1) , Gilles Lerondel (2)

1 AUB - American University of Beirut [Beyrouth]
2 LNIO - Laboratoire de Nanotechnologie et d'Instrumentation Optique

n this paper, we present experimental evidence on the change of the phonon spectrum and vibrational properties of a bulk material through phonon hybridization mechanisms. The phonon spectrum in a finite material is strongly affected by the presence of free surfaces, which is the addition of a contribution from an essentially two-dimensional crystal. The phonon spectrum of a bulk material can hence be altered by a hybridization mechanism between confined phonon modes in nanostructures introduced on the surface of a bulk material and the underlying bulk phonon modes. We measured the heat capacities of bare and surface-structured silicon substrates originating from the same silicon wafer. Then, we deduced important features of the phonon spectra of the samples investigated through a rigorous analysis of the measured heat capacity curves. The results show that the shape and size of the nanostructures made on the surface of the bulk substrate have a strong effect on the phonon spectrum of the bulk material.

Keywords: Electron gas; Dispersion function; Debye temperature; Semiconductor device fabrication; Lattice dynamics; Vibrational properties; First-principle calculations; Phonons; Semiconductor materials; Thermodynamic properties

Domains: Micro and nanotechnologies/Microelectronics; Materials Science [cond-mat.mtrl-sci]

Abdo Iskandar, Agnieszka Gwiazda, Yi Huang, Michel Kazan, Aurélien Bruyant, et al.. Modification of the phonon spectrum of bulk Si through surface nanostructuring. Journal of Applied Physics, 2016, 120 (9), pp.095106. ⟨10.1063/1.4962208⟩. ⟨hal-02404443⟩