Atomistic modeling of the phonon dispersion and lattice properties of free-standing (100) Si nanowires

Author

Paul, Abhijeet ; Luisier, Mathieu ; Klimeck, Gerhard

Author_Institution

Sch. of Electr. & Comput. Eng. & Network for Comput. Nanotechnol., Purdue Univ., West Lafayette, IN, USA

fYear

2010

fDate

26-29 Oct. 2010

Firstpage

1

Lastpage

4

Abstract

Phonon dispersions in (100) silicon nanowires (SiNW) are modeled using a Modified Valence Force Field (MVFF) method based on atomistic force constants. The model replicates the bulk Si phonon dispersion very well. In SiNWs, apart from four acoustic like branches, a lot of flat branches appear indicating strong phonon confinement in these nanowires and strongly affecting their lattice properties. The sound velocity (V_snd) and the lattice thermal conductance K_l decrease as the wire cross-section size is reduced whereas the specific heat (C_ν) increases due to increased phonon confinement and surface-to-volume ratio (SVR).

Keywords

acoustic wave velocity; elemental semiconductors; nanowires; phonon dispersion relations; semiconductor quantum wires; silicon; specific heat; thermal conductivity; Si; acoustic like branches; atomistic force constants; atomistic modeling; bulk Si phonon dispersion; flat branches; free-standing (100) silicon nanowires; lattice properties; lattice thermal conductance; modified valence force field method; sound velocity; specific heat; strong phonon confinement; surface-to-volume ratio; wire cross-section size; Dispersion; Heating; Lattices; Nanowires; Phonons; Silicon; Wire;

fLanguage

English

Publisher

ieee

Conference_Titel

Computational Electronics (IWCE), 2010 14th International Workshop on

Conference_Location

Pisa

Print_ISBN

978-1-4244-9383-8

Type

conf

DOI

10.1109/IWCE.2010.5677959

Filename

5677959