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High-Efficiency Solar Cells for Large-Scale Electricity Generation (open access)

High-Efficiency Solar Cells for Large-Scale Electricity Generation

One strategy for helping the solar industry to grow faster is to use very high efficiency cells under concentrating optics. By using lenses or mirrors to concentrate the light, very small solar cells can be used, reducing the amount of semiconductor material and allowing use of higher efficiency cells, which are now >40% efficient.
Date: September 26, 2008
Creator: Kurtz, S.; Olson, J.; Geisz, J.; Friedman, D.; McMahon, W.; Ptak, A. et al.
System: The UNT Digital Library
Physics Design Requirements for the National Spherical Torus Experiment Liquid Lithium Divertor (open access)

Physics Design Requirements for the National Spherical Torus Experiment Liquid Lithium Divertor

Recent NSTX high power divertor experiments have shown significant and recurring benefits of solid lithium coatings on PFC's to the performance of divertor plasmas in both L- and H- mode confinement regimes heated by high-power neutral beams. The next step in this work is installation of a liquid lithium divertor (LLD) to achieve density control for inductionless current drive capability (e.g., about a 15-25% ne decrease from present highest non-inductionless fraction discharges which often evolve toward the density limit, ne/nGW~1), to enable ne scan capability (x2) in the H-mode, to test the ability to operate at significantly lower density for future ST-CTF reactor designs (e.g., ne/nGW = 0.25), and eventually to investigate high heat-flux power handling (10 MW/m2) with longpulse discharges (>1.5s). The first step (LLD-1) physics design encompasses the desired plasma requirements, the experimental capabilities and conditions, power handling, radial location, pumping capability, operating temperature, lithium filling, MHD forces, and diagnostics for control and characterization.
Date: September 26, 2008
Creator: Kugel, W.; Bell, M.; Berzak,L.; Brooks, A.; Ellis, R.; Gerhardt, S. et al.
System: The UNT Digital Library
EUV micro-exposure tool at 0.5 NA for sub-16 nm lithography (open access)

EUV micro-exposure tool at 0.5 NA for sub-16 nm lithography

The resolution limit of present 0.3 NA 13.5 nm wavelength micro-exposure tools is compared to next generation lithography research requirements. Findings suggest that a successor design is needed for patterning starting at the 16 nm semiconductor process technology node. A two-mirror 0.5 NA optical design is presented, and performance expectations are established from detailed optical and lithographic simulation. Here, we report on the results from a SEMATECH program to fabricate a projection optic with an ultimate resolution limit of approximately 11 nm.
Date: September 26, 2008
Creator: Goldstein, Michael; Hudyma, Russ; Naulleau, Patrick & Wurm, Stefan
System: The UNT Digital Library