Electrical and Structural Characterization of Web Dendrite Crystals

Minority carrier lifetime distributions in silicon web dendrites are measured. Emphasis is placed on measuring areal homogeneity of lifetime, show its dependency on structural defects, and its unique change during hot processing. The internal gettering action of defect layers present in web crystals and their relation to minority carrier lifetime distributions is discussed. Minority carrier lifetime maps of web dendrites obtained before and after high temperature heat treatment are compared to similar maps obtained from 100 mm diameter Czochralski silicon wafers. Such maps indicate similar or superior areal homogeneity of minority carrier lifetime in webs

Electricity from photovoltaic solar cells: Flat-Plate Solar Array Project final Report. Volume III: Silicon sheet: wafers and ribbons

The Flat-Plate Solar Array (FSA) Project, funded by the U.S. Government and managed by the Jet Propulsion Laboratory, was formed in 1975 to develop the module/array technology needed to attain widespread terrestrial use of photovoltaics by 1985. To accomplish this, the FSA Project established and managed an Industry, University, and Federal Government Team to perform the needed research and development. The primary objective of the Silicon Sheet Task of the FSA Project was the development of one or more low-cost technologies for producing silicon sheet suitable for processing into cost-eompetitive solar cells. Silicon sheet refers to high-purity crystalline silicon of size and thickness for fabrication into solar cells. The Task effort began with state-of-the-art sheet technologies and then solicited and supported any new silicon sheet alternatives that had the potential to achieve the Project goals. A total of 48 contracts were awarded that covered work in the areas of ingot growth and casting, wafering, ribbon growth, other sheet technologies, and programs of supportive research. Periodic reviews of each sheet technology were held, assessing the technical progress and the long-range potential. Technologies that failed to achieve their promise, or seemed to have lower probabilities for success in comparison with others, were dropped. A series of workshops was initiated to assess the state of the art, to provide insights into problems remaining to be addressed, and to support technology transfer. The Task made and fostered significant improvements in silicon sheet including processing of both ingot and ribbon technologies. An additional important outcome was the vastly improved understanding of the characteristics associated with high-quality sheet, and the control of the parameters required for higher efficiency solar cells. Although significant sheet cost reductions were made, the technology advancements required to meet the Task cost goals were not achieved. This FSA Final Report (JPL Publication 86-31, 5101-289, DOE/JPL 1012-125, October 1986) is composed of eight volumes, consisting of an Executive Summary and seven technology reports: Volume I: Executive Summary. Volume II: Silicon Material. Volume III: Silicon Sheet: Wafers and Ribbons Volume IV: High-Efficiency Solar Celis. Volume V: Process Development. Volume VI: Engineering Sciences and Reliability. Volume VII: Module Encapsulation. Volume VIII: Project Analysis and Integration. Two supplemental reports included in the final report package are: FSA Project: 10 Years of Progress, JPL Document 400-279. 5101-279, October 1985. Summary of FSA Project Documentation: Abstracts of Published Documents, 1975 to 1986, JPL Publication 82-79 (Revision 1),5101-221, DOE/JPL-1 012-76, September 1986

Deconvoluting Reversal Modes in Exchange Biased Nanodots

Ensemble-averaged exchange bias in arrays of Fe/FeF2 nanodots has been deconvoluted into local, microscopic, bias separately experienced by nanodots going through different reversal modes. The relative fraction of dots in each mode can be modified by exchange bias. Single domain dots exhibit a simple loop shift, while vortex state dots have asymmetric shifts in the vortex nucleation and annihilation fields, manifesting local incomplete domain walls in these nanodots as magnetic vortices with tilted cores.Comment: 17 pages, 3 figures. Phys. Rev. B in pres

Reverse Engineering of Jury Instructions

Reverse engineering of jury instructions requires (1) creating a decision structure or decision tree for a case, based on a theory of the case, (2) identifying crucial points in the decision structure or decision tree, and (3) incorporating crucial points into the jury instructions. This paper suggests that reverse engineering of jury instructions can be used to instruct jurors about legal concepts and technical terms before they hear jury instructions or closing arguments. The goal is to improve the clarity of instructions to achieve litigation goals

Crystal growth for high-efficiency silicon solar cells workshop: Summary

The state of the art in the growth of silicon crystals for high-efficiency solar cells are reviewed, sheet requirements are defined, and furture areas of research are identified. Silicon sheet material characteristics that limit cell efficiencies and yields were described as well as the criteria for the ideal sheet-growth method. The device engineers wish list to the material engineer included: silicon sheet with long minority carrier lifetime that is uniform throughout the sheet, and which doesn't change during processing; and sheet material that stays flat throughout device processing, has uniform good mechanical strength, and is low cost. Impurities in silicon solar cells depreciate cell performance by reducing diffusion length and degrading junctions. The impurity behavior, degradation mechanisms, and variations in degradation threshold with diffusion length for silicon solar cells were described

Proceedings of the Flat-plate Solar Array Project Research Forum on the High-speed Growth and Characterization of Crystals for Solar Cells

Theoretical and experimental phenomena, applications, and characterization including stress/strain and other problem areas that limit the rate of growth of crystals suitable for processing into efficient, cost-effective solar cells are discussed. Melt spinning, ribbon growth, rapid solidification, laser recrystallization, and ignot growth of silicon and metals are also discussed

Proceedings of the Flat-Plate Solar Array Project Workshop on Crystal Gowth for High-Efficiency Silicon Solar Cells

A Workshop on Crystal Growth for High-Efficiency Silicon Solar Cells was held December 3 and 4, 1984, in San Diego, California. The Workshop offered a day and a half of technical presentations and discussions and an afternoon session that involved a panel discussion and general discussion of areas of research that are necessary to the development of materials for high-efficiency solar cells. Topics included the theoretical and experimental aspects of growing high-quality silicon crystals, the effects of growth-process-related defects on photovoltaic devices, and the suitability of various growth technologies as cost-effective processes. Fifteen invited papers were presented, with a discussion period following each presentation. The meeting was organized by the Flat-Plate Solar Array Project of the Jet Propulsion Laboratory. These Proceedings are a record of the presentations and discussions, edited for clarity and continuity

Carotenoid and SSR marker-based diversity assessment among short duration maize (Zea mays L) genotypes

Based on analysis of variance using a CRD model, significant variation for kernel carotenoid content was found to be present in 25 maize (Zea mays) genotypes. Total carotenoid content was found to be at a minimum (0.94 μg/g) in the white kernel line Sikkim primitive-1, whereas as much as 38.25 μg/g was observed in a dark yellow colored kernel line (1490). TLC profiling of total carotenoids showed that out of 25, 11 lines also had high provitamin-A content, in addition to high kernel carotenoids. Kernel color did not resolve any strong correlation with either total carotenoid content or provitamin-A. Thereby, selection of genotypes for high carotenoid and provitamin-A based on kernel color may not be successful. Jaccard’s similarity coefficients, based on SSR data, were found to vary from 0.17 to 0.97. The highest value of genetic similarity (0.97) was found between Pop31B and Pop31C and therefore they seem to be most similar, whereas inbred lines Pop31D and POB-3, and 1586 and Tarun-1 were most divergent (0.17). The UPGMA den¬drogram constructed using Jaccard similarity coefficients of SSR marker data divided the 25 lines into four groups (A, B, C, and D). Each broad group (Group A and B) was further divided into clusters, thus a total of seven clusters were formed. Cluster strength varied from a minimum of 1 member in cluster III of Group B to a maximum of 5 members in cluster II of Group B. Clustering patterns, in general, revealed that lines with high carotenoid content did not occupy the same cluster. A similar distribution was also observed for lines with a high provitamin-A con¬tent. The marker based clustering pattern therefore did not show strong correlation with quantitative data. Based on total carotenoids and relative provitamin-A content, 11 lines were identified to be a potential source for biofor¬tification of carotene in maize

Differences of Opinion and International Equity Markets

We develop an international financial market model in which domestic and foreign residents differ in their beliefs about the information content in public signals. We determine how informational advantages of domestic investors in the interpretation of home public signals affect equity markets. We evaluate the ability of our model to generate four international-finance anomalies: (i) the co-movement of returns and capital flows, (ii) home-equity preference, (iii) the dependence of firm returns on home and foreign factors, and (iv) abnormal returns around foreign firm cross-listing in the home market. Their relationships with empirical differences-of-opinion proxies are consistent with the model