Piezoresistance effect in n-type silicon: from bulk to nanowires

The first order piezoresistance coefficients are examined in the n-type silicon structures with different dimensionality of electron gas: bulk crystal, quantum film (well) and quantum wire. The detail research involves quantum kinetic approach to calculation of the kinetic coefficients (conductivity, mobility, concentration) of electrons in the strained and unstrained states. As scattering system were adopted ionized impurities, longitudinal acoustic phonons and surface roughness. Detailed studies have been carried out for dependences of electron mobility and piezoresistance coefficients on confining dimensions. An alternative explanation is proposed for origin of the giant piezoresistance effect in n-type silicon nanostructures. Comparison of the obtained results shows not only qualitative but even sufficient quantitative agreement with experimental data.