Influences of template layer thickness on strain fields and transition energies in self-assembled SiGe/Si quantum dots

This paper investigates the influence of thickness of template layer on strain fields and transition energies in lens-shaped self-assembled SiGe/Si quantum dots. This study analyzes strain fields in and around quantum dots on the basis of the theory of linear elasticity. Strain fields are then incorporated into the steady-state effective-mass Schrödinger equation. Energy levels and wavefunctions of both electrons and holes are calculated. The calculated results of strain-induced phonon frequency are consistent with previous results obtained by Raman spectroscopy. Moreover, the calculated transition energy agrees well with previous experimental photoluminescence data. Numerical results also suggest that transition energy decreases as the template layer thickness increases.