Optical Transitions in the Pseudomorphic 4x4 Monolayer Si/Ge Strained Layer Superlattice on Si(001)

Estimates are presented for the lower lying optical transition energies associated with the psuedomorphic 4x4 monolayer Si/Ge strained layer superlattice on Si(001). Band lineups are obtained by combining a phenomenological treatment of the strained bandgaps with a full self-consistent treatment of the ground state properties of the 4x4 monolayer Si/Ge supercell. These self-consistent interface calculations have demonstrated that charge densities and potentials within the 4x4 supercell retain their bulk characteristics outside a region confined to one monolayer on either side of the heterointerface; thus justifying our use of bulk parameters to character the cubic Si and strained Ge.