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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.

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At least 649 records · Page 36
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Ion implanted epitaxially grown ZnSe

The epitaxial growth of ZnSe on (100) Ge using the close-spaced transport process is described. Substrate temperature of 575 C and source temperatures of 675 C yield 10 micron, single crystal layers in 10 hours. The Ge substrates provides a nonreplenishable chemical transport agent and the epitaxial layer thickness is limited to approximately 10 microns. Grown epitaxial layers show excellent photoluminescence structure at 77 K. Grown layers exhibit high resistivity, and annealing in Zn vapor at 575 C reduces the resistivity to 10-100 ohms-cm. Zinc vapor annealing quenches the visible photoluminescence.

Source record↗
NASA NTRS1977

Skin-implant multiwire connector

Construction of device utilizing high-purity carbon is biocompatible as well as hygienic, Design allows for easy connections and disconnections in dark, cleaning and maintenance and less snagging of clothing and other articles by device. Guides and magnetic coupling preclude need for locks, screwing, or latching.

Owens, L. J.↗
NASA NTRS1979

Implantable digital hearing aid

Hearing aid converts analog output of microphone into digital pulses in about 10 channels of audiofrequencies. Each pulse band could be directly connected to portion of auditory nerve most sensitive to that range.

Kissiah, A. M., Jr.↗
NASA NTRS1977

Effect of surface texture by ion beam sputtering on implant biocompatibility and soft tissue attachment

The objectives in this report were to use the ion beam sputtering technique to produce surface textures on polymers, metals, and ceramics. The morphology of the texture was altered by varying both the width and depth of the square pits which were formed by ion beam erosion. The width of the ribs separating the pits were defined by the mask used to produce the texture. The area of the surface containing pits varies as the width was changed. The biological parameters used to evaluate the biological response to the texture were: (1) fibrous capsule and inflammatory response in subcutaneous soft tissue; (2) strength of the mechanical attachment of the textured surface by the soft tissue; and (3) morphology of the epidermal layer interfacing the textured surface of percutaneous connectors. Because the sputter yield on teflon ribs was approximately an order of magnitude larger than any other material the majority of the measurements presented in the report were obtained with teflon.

Gibbons, D. F.↗
NASA NTRS1980

Evidence for a secular variation in the C-13/C-12 ratio of carbon implanted in lunar soils

A curve of delta(C-13) vs delta(N-15) for lunar soils and breccias shows that the previously recorded 30% change in delta(N-15) is associated with a change in delta(C-13). The correlation represents concurrent changes in the isotope ratios of both elements at their source, and does not result from maturation effects or nonselective sample contamination. A computation of the relative production rates of C-13 and N-15 shows that spallation reactions in the sun could produce the observed ratio of the delta(C-13) to delta (N-15) variations.

Becker, R. H.↗
NASA NTRS1980

Characterization of silicon-gate CMOS/SOS integrated circuits processed with ion implantation

The double layer metallization technology applied on p type silicon gate CMOS/SOS integrated circuits is described. A smooth metal surface was obtained by using the 2% Si-sputtered Al. More than 10% probe yield was achieved on solar cell controller circuit TCS136 (or MSFC-SC101). Reliability tests were performed on 15 arrays at 150 C. Only three arrays failed during the burn in, and 18 arrays out of 22 functioning arrays maintained the leakage current below 100 milli-A. Analysis indicates that this technology will be a viable process if the metal short circuit problem between the two metals can be reduced.

Woo, D. S.↗
NASA NTRS1984

Radiation damage and defect behavior in ion-implanted, lithium counterdoped silicon solar cells

Boron doped silicon n+p solar cells were counterdoped with lithium by ion implanation and the resultant n+p cells irradiated by 1 MeV electrons. The function of fluence and a Deep Level Transient Spectroscopy (DLTS) was studied to correlate defect behavior with cell performance. It was found that the lithium counterdoped cells exhibited significantly increased radiation resistance when compared to boron doped control cells. It is concluded that the annealing behavior is controlled by dissociation and recombination of defects. The DLTS studies show that counterdoping with lithium eliminates at least three deep level defects and results in three new defects. It is speculated that the increased radiation resistance of the counterdoped cells is due primarily to the interaction of lithium with oxygen, single vacancies and divacancies and that the lithium-oxygen interaction is the most effective in contributing to the increased radiation resistance.

Weinberg, I.↗