Photoluminescence in short-period Si/Ge strained-layer superlattices

Photoluminescence has been observed in the energy range 0.7 to 0.9 eV in short-period Si/Ge strained-layer superlattices grown on Si(100) and Ge(100) substrates. The luminescence is strongly influenced by period, layer-thickness ratio, and strain distribution. The experimental results are in good agreement with the expected fundamental energy gaps of the superlattices as calculated with a Kronig-Penney type model.