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Focuses on a study which investigated ultraviolet light induced changes in polyimide liquid-cyrstal alignment films. Experimental procedure; Experimental results; Discussion.

Solid boron and antimony doping of silicon and SiGe grown by molecular beam epitaxy using disilane and germane as sources has been studied. Elemental boron is a well behaved p-type dopant. At effusion cell temperatures of 1700-1750°C, hole carrier concentrations in the 10 cm range have been obtained. Elemental antimony doping shows surface segregation problems. For uniformly doped layers, the as-grown materials do not show n-type conductivity. Electron concentrations in the 10 cm range were obtained by post-growth conventional and rapid thermal annealing at 900 and 1000°C, respectively. The electron Hall mobility improves with optimum annealing time. Delta doping of buried layers exhibits slightly better incorporation behavior including significant surface riding effects. [ABSTRACT FROM AUTHOR]

Molecular beam epitaxial growth of pseudomorphic SiGe/Si layers using disilane (SiH) and elemental germanium has been studied for the first time. It is found that at a fixed flow rate of SiH, the germanium content in the SiGe alloys is a function of the germanium cell temperature. Heterostructures and multi-quantum wells with good surface morphology, excellent crystalline quality, and abrupt interfaces are demonstrated, indicating little or no sourcerelated transient effects. [ABSTRACT FROM AUTHOR]

Examines use of supersonically injected pulses of phosphine to achieve uniform and high levels of in situ n-type doping in silicon during molecular beam epitaxy. Application of highly doped semiconductor regions spectroscopy profiles in silicon-doped with phosphine; Results of measured Hall electron concentrations and mobilities.

Far-infrared absorption spectra have been measured for molecular beam epitaxial InAs/Al0.36Ga0.64Sb multiquantum wells by Fourier transform infrared spectroscopy using light incident normal to the layers. The special band lineup for this heterostructure system causes an overlap of the electron and hole states. The measured absorption peak varies in the wavelength range of 5–10 μm in the temperature range of 100–300 K. [ABSTRACT FROM AUTHOR]

We report, for the first time, temperature-dependent intersubband absorption data in doped pseudomorphic InxGa1-xAs/Al0.4Ga0.6As (0≤x≤0.15) multiquantum wells. In this composition range the absorption resonance varies in the range 6–7 μm for 50 Å wells, which agrees extremely well with theoretical calculations. [ABSTRACT FROM AUTHOR]