Room-temperature light emission from a highly strained Si/Ge superlattice

We discuss the formation of a Si/Ge-superlattice (SL) generated by molecular beam epitaxy. Specific growth parameter were chosen to optimize the periodic structure of vertically stacked Ge islands. Optimized SLs show a strong photoluminescence at a wavelength in the region of 1.55 mum up to room temperature. The luminescence is explained by a recombination of electrons in a miniband and holes localized in the Ge islands. The morphology and the crystal structure of the SL, which are influenced by the growth parameters, were analyzed by transmission electron microscopy techniques. It is demonstrated that doping of the SL structure by antimony improves both structural and optical properties. (C) 2003 American Institute of Physics.