CHARACTERIZATION OF SI SI1-XGEX/SI QUANTUM-WELLS BY CATHODOLUMINESCENCE IMAGING AND SPECTROSCOPY/

Cathodoluminescence (CL) imaging and spectroscopy have been used to ch aracterize fully strained SiGe quantum wells grown on Si. At T approxi mate to 5 K, the CL spectra contain only band edge luminescence featur es. Monochromatic imaging with the no-phonon line attributed to the bo und excitons in the quantum well, has shown that the distribution of t he luminescence from the wells is not uniform. The thinnest well (33 A ngstrom) contained a low density of nonradiative (luminescence reducti on up to 100%) spots 40-100 mu m in size. The thickest well (500 Angst rom) contained similar nonradiative spots and also dark line features oriented along the [110] directions. These dark line features are area s of nonradiative recombination (up to 70%) and have been identified b y transmission electron microscopy as misfit dislocations.