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DESIGN AND ANALYSIS OF AN INTEGRATED PULSE MODULATED S-BAND POWER AMPLIFIER IN GALLIUM NITRIDE PROCESS

Description: The design of power amplifiers in any semi-conductor process is not a trivia exercise and it is often encountered that the simulated solution is qualitatively different than the results obtained. Phenomena such as oscillation occurring either in-band or out of band and sometimes at subharmonic intervals, continuous spectrum noticed in some frequency bands, often referred to as chaos, and jumps and hysteresis effects can all be encountered and render a design useless. All of these problems might… more
Date: April 4, 2012
Creator: SEDLOCK, STEVE
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Inverted Metamorphic Multijunction (IMM) Cell Processing Instructions

Description: This technical report details the processing schedule used to fabricate Inverted Metamorphic Multijunction (IMM) concentrator solar cells at The National Renewable Energy Laboratory (NREL). These devices are used as experimental test structures to support the research at NREL that is focused on increasing the efficiency of photovoltaic power conversion. They are not intended to be devices suitable for deployment in working concentrator systems primarily because of heat sinking issues. The proce… more
Date: February 1, 2012
Creator: Duda, A.; Ward, S. & Young, M.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Wide Bandgap Extrinsic Photoconductive Switches

Description: Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single c… more
Date: January 17, 2012
Creator: Sullivan, J S
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
open access

Comparative Study of Zn(O,S) Buffer Layers and CIGS Solar Cells Fabricated by CBD, ALD, and Sputtering: Preprint

Description: Zn(O,S) thin films were deposited by chemical bath deposition (CBD), atomic layer deposition, and sputtering. Composition of the films and band gap were measured and found to follow the trends described in the literature. CBD Zn(O,S) parameters were optimized and resulted in an 18.5% efficiency cell that did not require post annealing, light soaking, or an undoped ZnO layer. Promising results were obtained with sputtering. A 13% efficiency cell was obtained for a Zn(O,S) emitter layer deposited… more
Date: June 1, 2012
Creator: Ramanathan, K.; Mann, J.; Glynn, S.; Christensen, S.; Pankow, J.; Li, J. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Simple intrinsic defects in GaAs : numerical supplement.

Description: This Report presents numerical tables summarizing properties of intrinsic defects in gallium arsenide, GaAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz and O.A. von Lilienfeld, 'Simple intrinsic defects in GaAs', Modelling Simul. Mater. Sci Eng., Vol. 17, 084007 (2009), and intended for use as reference tables for a defect physics package in device models. The numerical results for density functional theory ca… more
Date: April 1, 2012
Creator: Schultz, Peter Andrew
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Electrical Bias as an Alternate Method for Reproducible Measurement of Copper Indium Gallium Diselenide (CIGS) Photovoltaic Modules: Preprint

Description: Light-to-dark metastable changes in thin-film photovoltaic (PV) modules can introduce uncertainty when measuring module performance on indoor flash testing equipment. This study describes a method to stabilize module performance through forward-bias current injection rather than light exposure. Measurements of five pairs of thin-film copper indium gallium diselenide (CIGS) PV modules indicate that forward-bias exposure maintained the PV modules at a stable condition (within 1%) while the unbias… more
Date: August 1, 2012
Creator: Deline, C.; Stokes, A.; Silverman, T. J.; Rummel, S.; Jordan, D. & Kurtz, S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

NREL Explores Earth-Abundant Materials for Future Solar Cells (Fact Sheet)

Description: Researchers at the National Renewable Energy Laboratory (NREL) are using a theory-driven technique - sequential cation mutation - to understand the nature and limitations of promising solar cell materials that can replace today's technologies. Finding new materials that use Earth-abundant elements and are easily manufactured is important for large-scale solar electricity deployment.
Date: October 1, 2012
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

NREL Scientists Spurred the Success of Multijunction Solar Cells (Fact Sheet)

Description: Before 1984, many scientists believed that high-quality gallium indium phosphide (GaInP) alloys could not be grown for use as semiconductors because the alloys would separate. One researcher at the Solar Energy Research Institute (SERI) thought differently. His name was Jerry Olson, and his innovative thinking changed solar history. Olson identified a material combination that allowed the multijunction cell to flourish. It is now the workhorse that powers satellites and the catalyst for renewed… more
Date: September 1, 2012
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Ammothermal Growth of GaN Substrates For LEDs

Description: Advanced Research Projects Agency-Energy project sheet summarizing general information about a new program to develop less expensive, more efficient LEDs (project title "High-Pressure Ammonothermal Process for Bulk Gallium Nitride Crystal Growth for Energy Efficient Commercially Competitive Lighting") including critical needs, innovation and advantages, impacts, and contact information. This sheet is the first open solicitation, announcing funding opportunities for involvement in the project.
Date: May 11, 2012
Creator: Soraa, Inc.
Item Type: Refine your search to only Text
Partner: UNT Libraries Government Documents Department
open access

NREL Produces Highly Efficient, Wide-Bandgap, Thin-Film Solar Cells (Fact Sheet)

Description: Researchers at the National Renewable Energy Laboratory (NREL) are finding new ways to manufacture thin-film solar cells made from copper, indium, gallium, and selenium - called CIGS cells - that are different than conventional CIGS solar cells. Their use of high-temperature glass, designed by SCHOTT AG, allows higher fabrication temperatures, opening the door to new CIGS solar cells employing light-absorbing materials with wide 'bandgaps.'
Date: September 1, 2012
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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