BAND-EDGE LUMINESCENCE OF STRAINED SIXGE1-X/SI SINGLE QUANTUM-WELL STRUCTURES GROWN ON SI(111) BY SI MOLECULAR-BEAM EPITAXY

Band-edge luminescence, no-phonon transitions due to symmetry-breaking alloy disordering in SiGe layers and transverse optical phonon replicas, were observed for the first time in Si0.8Ge0.2/Si single quantum well (SQW) structures grown on Si(111) substrates. SQWs were successfully grown by "solid source" Si molecular beam epitaxy at temperatures above 700-degrees-C strictly retaining well-ordered surface reconstruction as disclosed by intense Laue spots in in situ electron diffraction images. Low temperature growth was invariably associated with development of streaky features and was found to be detrimental to luminescence efficiency.