Open AccessEffect of size-dependent elastic constants on electrical properties of strain silicon nanowires
Author(s) -
Jiahong Zhang,
Fang Gu,
Qingquan Liu,
Bing-Lin Gu,
Min Li
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.4226
Subject(s) - materials science , condensed matter physics , nanowire , lattice constant , ballistic conduction , elastic modulus , silicon , electronic band structure , nanotechnology , composite material , physics , optics , electron , quantum mechanics , diffraction , metallurgy
Starting from the Keating model, a semi-continuum atomistic lattice model, with directly taking into account the discrete nature in width and thickness direction, is proposed to calculate the elastic constants and Youngs modulus of single crystal silicon nanowires (SiNWs). Based on the six-band k·p theory and the deformation potential concept, and taking into account the quantum-size effect and spin-orbit coupling, a numerical model for the valence band structures of SiNWs in various transport orientations is established by using the finite difference method. Then we use a top-of-the-barrier ballistic field-effect transistor (FET) model to investigate the effects of the uniaxial stress and the elastic constants on ballistic transport properties of the p-type SiNW FETs in combination with the calculation results from the two models mentioned above. It is found that the elastic constants and Youngs modulus of the SiNW are highly size-dependent, which is in good agreement with the available molecular dynamics result. Furthermore, our calculations indicate that the effect of size-dependent elastic constants on ballistic transport current of the SiNW FET strongly depends on the effect of the uniaxial stress on ballistic transport current, because when the uniaxial stress induces a significant change in valence band structures of SiNWs, the size-dependent elastic constants can obviously modify the valence band structure.