SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Efforts concentrated on reducing the electrical sheet resistance of sputtered cadmium stannate films, installing and testing equipment for spray coating experiments, and sputter deposition of thin cadmium sulfide layers onto cadmium stannate electrodes. In addition, single crystal silicon wafers were coated with cadmium stannate. Work also continued on the development of the backwall CdS solar cell.
Nanoscale semiconductors, known as quantum dots (QDs), possess unique size-tunable optical and electrical properties. With continued research into quantum information storage and quantum communication, the need for near-infrared single photon emitters and absorbers has gained prominence. Lead sulfide QDs have only recently been explored as a reliable near-infrared single photon emitters with the addition of a protective cadmium sulfide shell. Despite the increased air and room temperature stability of these QDs, long photon emission times have limited widespread application. This work examines the enhanced photon emission due to the Purcell effect provided by the layering of copper sulfide. In particle, this work synthesized lead sulfide cores in the 10 nm range, successfully layered cadmium sulfide through cation exchange, and attempted the cation exchange of copper sulfide, as identified with near-infrared absorbance spectra, transmission electron microscopy, and photoluminescence spectra.
Nucleation and growth of crystalline films of silicon, germanium, and cadmium sulfide on substrates of plastic and glass were investigated. Amorphous films of germanium, silicon, and cadmium sulfide on amorphous substrates of glass and plastic were converted to the crystalline condition by electron bombardment.
The sun sensor flight performance data were analyzed along with the results of a newly developed cruise sensor life in order to better understand cadmium sulfide sun sensor performance. A set of mathematical models was constructed which closely approximated the observed sun sensor flight and laboratory test results. These models revealed, among other things, that (1) the aging phenomena in the sintered cadmium sulfide light detector varies across the detector width in proportion to the illumination history, (2) the current cruise sun sensor design is extremely sensitive to changes in the reflected illumination within the sensor housing, (3) the reflected illumination within the detector housing is proportional to the area and intensity of the solar disk observed at the spacecraft, and (4) the acquisition sun sensor becomes a low impedance path across the sensor bridge when in the vicinity of a large-angular-diameter, low-intensity light source.
DNA nanotechnology offers a wide toolkit of molecular functionalities and scales, including intricate motifs less than 10 nm and periodic structures exceeding 100 µm. At larger scales, however, there are often significant tradeoffs for DNA structures, namely stability and mechanical strength. This work describes the design, synthesis, and characterization of a functionalized DNA crystal. Using a ligated DNA crystal grants significant freedom for various functional materials to be applied, in this case, semiconducting cadmium sulfide and palladium metal. Properties investigated in this study include stability, mechanical strength, and optoelectronic properties such as photoluminescence (PL) and electric conductivity. Significant changes are observed based on the functional material applied to DNA crystals. The Young's modulus of the crystal varies by about five orders of magnitude when functionalized with palladium. PL and semiconductive behaviors were observed when cadmium sulfide was attached. These crystals represent an expansion of the capabilities of DNA structures at these length scales, and additionally a platform for future studies exchanging the materials or altering the ligation scheme.
Solar cells and optical configurations for the SSPS were examined. In this task, three specific solar cell materials were examined: single crystal silicon, single crystal gallium arsenide, and polycrystalline cadmium sulfide. The comparison of the three different cells on the basis of a subsystem parametric cost per kW of SSPS-generated power at the terrestrial utility interface showed that gallium arsenide was the most promising solar cell material at high concentration ratios. The most promising solar cell material with no concentration, was dependent upon the particular combination of parameters representing cost, mass and performance that were chosen to represent each cell in this deterministic comparative analysis. The potential for mass production, based on the projections of the present state-of-the-art would tend to favor cadmium sulfide in lieu of single crystal silicon or gallium arsenide solar cells.
Photoconductor concepts, and properties of recrystallized evaporated cadmium sulfide layers
Not provided.
Interaction of electronic current with hypersonic waves in solids - current saturation effects and build-up of acoustic flux in cadmium sulfide
Relationship of direct polarization transitions to valence bond of cadmium sulfide
Gold thin film structure on cadmium sulfide surfaces
Electron microscopy of cadmium sulfide thin film surfaces
Electronic current interaction with hypersonic waves in cadmium sulfide crystal
Characteristics of vacuum deposited thin film cadmium sulfide photodetectors for space navigation
Evaporation and recrystallization of cadmium sulfide layers - vapor deposition
Optical and electrical properties of cadmium sulfide solar cells
Volume effect cadmium sulfide position sensitive photodetectors for space star tracking applications
Optical coatings for cadmium sulfide thin film solar cells