A STUDY OF BROAD-BAND PHOTOLUMINESCENCE FROM SI1-XGEX SI SUPERLATTICES/

Using photoluminescence (PL) obtained with ultraviolet (UV) laser exci tation, we have examined Si1-xGex/Si long-period superlattices (SLs) g rown by molecular beam epitaxy at 500-degrees-C and annealed post-grow th at 550 to 750-degrees-C. Our as-grown samples show broad PL bands, 120 meV below the band gap when the effects of quantum confinement of holes are added in. The broad PL band peak positions shift to higher e nergies as the anneal temperature increases. This coincides with a red uction in the activation energies of the broad PL bands. The broad ban ds from both the as-grown and annealed samples shift to lower energies as the sample temperature increases.