Piezoresistivity of silicon quantum well wire

Abstract

In this paper, the piezoresistive coefficient of silicon quantum well wire has been estimatedusing k.p theory and the deformation potential concept and has been observed to be 5.5times higher compared to that of the bulk for a quantum well width of 2.5 nm. The effect ofthe quantum confinement of holes on the bandstructure of nanocrystalline silicon resultingin the separation of light hole and heavy hole subbands has been considered. On theapplication of stress, there is a further shift in the energy levels of heavy hole andlight hole bands, leading to a change in the carrier concentration and effectivemass of holes in the respective subbands which ultimately is responsible for theenhancement of the piezoresistive coefficient. The change in the energy levelsand effective mass are significant below well width dimensions of 5 and 20 nm,respectively.