Strain induced change of bandgap and effective mass in silicon nanowires

This work computationally investigates the electromechanical properties of hydrogen passivated silicon nanowires under uniaxial tensile strain. It has been observed that bandgap changes can be as large as 60 and 100 meV per 1% axial strain for [100] and [110] nanowires, respectively. This rate of change in the bandgap is independent of nanowire size and depends only on the growth direction. More importantly, the nature of the bandgap can reversibly change from indirect to direct as a function of strain. It is also observed that for larger diameter nanowires, the indirect-to-direct transition occurs at smaller compressive strain.