Strain-induced modulation of band structure of silicon

摘要

This work presents ab initio study of strain-induced modulation of band structure of Si. It is shown that at straining pressures > 12 GPa, band structure of Si can be turned from indirect to direct. Both the bottommost conduction band and topmost valence band are located at the Γ point. The conduction band minimum at the Γ point of the strained Si is found to be much more dispersive than that at the X point of the unstressed Si. Consequently, electrical conductivity through the Γ valley is suggested to be more superior than the X point of the unstressed Si. Barrier height, which is needed to transfer electrons in the Γ point to X/L points or from Γ point to X/L to Γ point have been calculated. The results have been applied to explain peculiarities of electronic structure and light emission of Si based materials containing dislocations and voids.