Miniband-related 1.4–1.8 μm luminescence of Ge/Si quantum dot superlattices

The luminescence properties of highly strained, Sb-doped Ge/Si multi-layer heterostructures with incorporated Ge quantum dots (QDs) are studied. Calculations of the electronic band structure and luminescence measurements prove the existence of an electron miniband within the columns of the QDs. Miniband formation results in a conversion of the indirect to a quasi-direct excitons takes place. The optical transitions between electron states within the miniband and hole states within QDs are responsible for an intense luminescence in the 1.4–1.8 µm range, which is maintained up to room temperature. At 300 K, a light emitting diode based on such Ge/Si QD superlattices demonstrates an external quantum efficiency of 0.04% at a wavelength of 1.55 µm

STRUCTURAL, COMPOSITIONAL, AND OPTICAL PROPERTIES OF ULTRATHIN Si/Ge SUPERLATTICES

Strained-layer superlattices (SLS) composed of a sequence of ultrathin Si and Ge layers are grown on Ge(110) buffer layers by MBE. Crystalline quality, relaxation of asymmetrically SLS, and interdiffusion are studied in situ by LEED and AES. New optical transitions in the range of 0.7 to 0.8 eV are observed with photoluminescence experiments

Silicon/Germanium Strained-Layer Superlattices

High quality Si/Ge strained layer superlattices are achieved by low temperature molecular beam epitaxy on Si, SixGe1−x and Ge substrates. Various characterization techniques are used to obtain information on critical thickness, strain distribution, misfit dislocations, interface sharpness and superlattice periodicity. The band structure is strongly influenced by strain and zone folding effects. Two-dimensional electron systems can be realized in the wider gap Si layers due to the strain-induced lowering of the conduction band. New optical transitions in the infrared regime are observed with short period Si/Ge superlattices

Diamant als Elektronikmaterial Abschlussbericht

Diamond thin films were obtained by heteroepitaxial nucleation with substrate bias on (001) silicon substrates in a microwave plasma assisted chemical vapour deposition process. The influence of deposition parameters on the diamond layer growth has been studied with special regard to the dependency of thermal and electric properties on layer parameters, e.g. phase impurities, doping, layer morphology and crystal orientation. For lateral thermal diffusivity measurements a spectrometer has been constructed based on the principle of photothermal deflection spectroscopy at transient thermal gratings. The improvement of thermal and electric properties together with the progress in doping, microstructuration and bonding of the diamond films represent a basic know how for the development of microelectronic elements. (WEN)Available from TIB Hannover: F95B2097+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Entwicklung halbleitender Diamantschichten und deren Qualifikation als Material fuer aktive elektronische Bauelemente Abschlussbericht

Available from TIB Hannover: F98B1229+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman