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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 613 records · Page 34
All sourcesNASA NTRSDOE OSTI
NASA NTRS1975

Reciprocity testing of Kodak film type SO-289 multispectral infrared aerial film

Kodak multispectral infrared aerial film type SO-289 was tested for reciprocity characteristics because of the variance between the I-B sensitometer exposure times (8 seconds and 4 seconds) and the camera exposure time (1/500 second) used on the ASTP stratospheric aerosol measurement project. Test exposures were made on the flight emulsion using a Mead star system sensitometer, the films were processed to ASTP control standards, and the resulting densities read and reciprocity data calculated. It was found that less exposure was required to produce a typical density (1.3) at 1/500 second exposure time than at an 8 second exposure time. This exposure factor was 2.8.

Lockwood, H. E.↗
NASA NTRS1978

Effects of accumulated film layers on the accuracy of quartz film thickness monitors

The effect of accumulation layers on the accuracy of quartz thin-film thickness monitors is evaluated. Use of an expanded plane wave ultrasonic propagation theory correctly accounts for observed experimental data. The magnitude of the maximum errors calculated for simply reversing the order of a series of aluminum gold deposits is on the order of 5%. If one totally neglects intervening layers, multiple film propagation and nonlinearity can produce errors greater than 50%.

Heyman, J. S.↗
NASA NTRS1980

Tribological properties of sputtered MoS2 films in relation to film morphology

Thin sputter-deposited MoS2 films with thicknesses ranging from 2000 to 6000 A have shown excellent lubricating properties when sputtering parameters and substrate conditions are properly selected and controlled. The lubricating properties are strongly influenced by the crystalline-amorphous structure, morphology, and composition of the films. The coefficient of friction can range from 0.04 (which is effective lubrication) to 0.4 (no lubricating action).

Spalvins, T.↗
NASA NTRS1987

The calibration of photographic and spectroscopic films. A densitometric analysis of IIaO film flown aboard the space shuttle transportation system STS3, STS8, and STS7

The results of these studies have implications for the utilization of the IIaO spectroscopic film on the future shuttle and space lab missions. These responses to standard photonic energy sources will have immediate application for the uneven responses of the film photographing a star field in a terrestrial or extraterrestrial environment with associated digital imaging equipment.

Hammond, Ernest C., Jr.↗
NASA NTRS1996

Method of forming multi-element thin hot film sensors on polyimide film

The invention comprises a method of forming a multi-element, thin hot film sensor on a polyimide film. The sensor is formed by first cleaning one surface of the polyimide. Then, under a continuous vacuum, the surface is simultaneously cleaned by ion bombardment while nickel is deposited by evaporation. The ion beam cleaning is discontinued and copper is then deposited to an initial thickness by evaporation without a break in the vacuum. The vacuum is then removed and a final thickness of copper is deposited by plating. Sensor patterns are then defined in the nickel and copper layers using conventional photolithography and etching techniques.

Hopson, Jr., Purnell↗
DOE OSTI2015

Structural evolution of epitaxial SrCoO{sub x} films near topotactic phase transition

Control of oxygen stoichiometry in complex oxides via topotactic phase transition is an interesting avenue to not only modifying the physical properties, but utilizing in many energy technologies, such as energy storage and catalysts. However, detailed structural evolution in the close proximity of the topotactic phase transition in multivalent oxides has not been much studied. In this work, we used strontium cobaltites (SrCoO{sub x}) epitaxially grown by pulsed laser epitaxy (PLE) as a model system to study the oxidation-driven evolution of the structure, electronic, and magnetic properties. We grew coherently strained SrCoO{sub 2.5} thin films and performed post-annealing at various temperatures for topotactic conversion into the perovskite phase (SrCoO{sub 3-δ}). We clearly observed significant changes in electronic transport, magnetism, and microstructure near the critical temperature for the topotactic transformation from the brownmillerite to the perovskite phase. Nevertheless, the overall crystallinity was well maintained without much structural degradation, indicating that topotactic phase control can be a useful tool to control the physical properties repeatedly via redox reactions.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Characterization of Epitaxial Film Silicon Solar Cells Grown on Seeded Display Glass: Preprint

We report characterizations of epitaxial film crystal silicon (c-Si) solar cells with open-circuit voltages (Voc) above 560 mV. The 2-um absorber cells are grown by low-temperature (<750 degrees C) hot-wire CVD (HWCVD) on Corning EAGLE XG display glass coated with a layer-transferred (LT) Si seed. The high Voc is a result of low-defect epitaxial Si (epi-Si) growth and effective hydrogenpassivation of defects. The quality of HWCVD epitaxial growth on seeded glass substrates depends on the crystallographic quality of the seed and the morphology of the epitaxial growth surface. Heterojunction devices consist of glass/c-Si LT seed/ epi n+ Si:P/epi n- Si:P/intrinsic a-Si:H/p+ a-Si:H/ITO. Similar devices grown on electronically 'dead' n+ wafers have given Voc630 mV and8%efficiency with no light trapping features. Here we study the effects of the seed surface polish on epi-Si quality, how hydrogenation influences the device character, and the dominant junction transport physics.

14 SOLAR ENERGY↗
DOE OSTI2012

Characterization of Field Exposed Thin Film Modules: Preprint

Test arrays of thin film modules have been deployed at the Solar Energy Centre near New Delhi, India since 2002-2003. Performances of these arrays were reported by O.S. Sastry [1]. This paper reports on NREL efforts to support SEC by performing detailed characterization of selected modules from the array. Modules were selected to demonstrate both average and worst case power loss over the 8 yearsof outdoor exposure. The modules characterized included CdTe, CIS and three different types of a-Si. All but one of the a-Si types were glass-glass construction. None of the modules had edge seals. Detailed results of these tests are presented along with our conclusions about the causes of the power loss for each technology.

14 SOLAR ENERGY↗
DOE OSTI2011

Ethylene Glycol Adsorption and Reaction over CeOX(111) Thin Films

This study reports the interaction of ethylene glycol with well-ordered CeO{sub x}(111) thin film surfaces. Ethylene glycol initially adsorbs on fully oxidized CeO{sub 2}(111) and reduced CeO{sub 2-x}(111) through the formation of one C-O-Ce bond and then forms a second alkoxy bond after annealing. On fully oxidized CeO{sub 2}(111) both recombination of ethylene glycol and water desorption occur at low temperature leaving stable -OCH{sub 2}CH{sub 2}O- (ethylenedioxy) intermediates and oxygen vacancies on the surface. This ethylenedioxy intermediate goes through C-C bond scission to produce formate species which then react to produce CO and CO{sub 2}. The formation of water results in the reduction of the ceria. On a reduced CeO{sub 2-x}(111) surface the reaction selectivity shifts toward a dehydration process. The ethylenedioxy intermediate decomposes by breaking a C-O bond and converts into an enolate species. Similar to the reaction of acetaldehyde on reduced CeO{sub 2-x}(111), the enolate reacts to produce acetaldehyde, acetylene, and ethylene. The loss of O from ethylene glycol leads to a small amount of oxidation of the reduced ceria.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2012

Real time x-ray studies during nanostructure formation on silicon via low energy ion beam irradiation using ultrathin iron films

Real time grazing incidence small angle x-ray scattering and x-ray fluorescence (XRF) are used to elucidate nanodot formation on silicon surfaces during low energy ion beam irradiation of ultrathin iron-coated silicon substrates. Four surface modification stages were identified: (1) surface roughening due to film erosion, (2) surface smoothing and silicon-iron mixing, (3) structure formation, and (4) structure smoothing. The results conclude that 2.5 Multiplication-Sign 10{sup 15} iron atoms in a 50 nm depth triggers surface nanopatterning with a correlated nanodots distance of 25 nm. Moreover, there is a wide window in time where the surface can have correlated nanostructures even after the removal of all the iron atoms from the sample as confirmed by XRF and ex-situ x-ray photoelectron spectroscopy (XPS). In addition, in-situ XPS results indicated silicide formation, which plays a role in the structure formation mechanism.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2014

Non-equilibrium deposition of phase pure Cu{sub 2}O thin films at reduced growth temperature

Cuprous oxide (Cu{sub 2}O) is actively studied as a prototypical material for energy conversion and electronic applications. Here we reduce the growth temperature of phase pure Cu{sub 2}O thin films to 300 °C by intentionally controlling solely the kinetic parameter (total chamber pressure, P{sub tot}) at fixed thermodynamic condition (0.25 mTorr pO{sub 2}). A strong non-monotonic effect of P{sub tot} on Cu-O phase formation is found using high-throughput combinatorial-pulsed laser deposition. This discovery creates new opportunities for the growth of Cu{sub 2}O devices with low thermal budget and illustrates the importance of kinetic effects for the synthesis of metastable materials with useful properties.

36 MATERIALS SCIENCE↗