Study program to improve the open-circuit voltage of low resistivity single crystal silicon solar cells

The results of a 14 month program to improve the open circuit voltage of low resistivity silicon solar cells are described. The approach was based on ion implantation in 0.1- to 10.0-ohm-cm float-zone silicon. As a result of the contract effort, open circuit voltages as high as 645 mV (AMO 25 C) were attained by high dose phosphorus implantation followed by furnace annealing and simultaneous SiO2 growth. One key element was to investigate the effects of bandgap narrowing caused by high doping concentrations in the junction layer. Considerable effort was applied to optimization of implant parameters, selection of furnace annealing techniques, and utilization of pulsed electron beam annealing to minimize thermal process-induced defects in the completed solar cells

Russia\u27s Struggle For Maritime Prestige During the Era of Navalism

The Soviet Union\u27s efforts to build a powerful fleet, its interest in a naval station to serve its Mediterranean squadron, its feelers through Persia to a warm water port, and its special development programs to meet operational requirements have antecedents in tsarist times. The goals of that earlier flexing of muscle were confounded by technology and politics

Applications of ion implantation to high performance, radiation tolerant silicon solar cells

Progress in the development of ion implanted silicon solar cells is reported. Effective back surface preparation by implantation, junction processing to achieve high open circuit voltages in low-resistivity cells, and radiation tolerance cells are among the topics studied

Processing of silicon solar cells by ion implantation and laser annealing

Methods to improve the radiation tolerance of silicon cells for spacecraft use are described. The major emphasis of the program was to reduce the process-induced carbon and oxygen impurities in the junction and base regions of the solar cell, and to measure the effect of reduced impurity levels on the radiation tolerance of cells. Substrates of 0.1, 1.0 and 10.0 ohm-cm float-zone material were used as starting material in the process sequence. High-dose, low-energy ion implantation was used to form the junction in n+p structures. Implant annealing was performed by conventional furnace techniques and by pulsed laser and pulsed electron beam annealing. Cells were tested for radiation tolerance at Spire and NASA-LeRC. After irradiation by 1 MeV electrons to a fluence of 10 to the 16th power per sq cm, the cells tested at Spire showed no significant process induced variations in radiation tolerance. However, for cells tested at Lewis to a fluence of 10 to the 15th power per sq cm, ion-implanted cells annealed in vacuum by pulsed electron beam consistently showed the best radiation tolerance for all cell resistivities

Genealogía Espiritual y Descendencia de Hildegardis de Bingen

-(1098-1179): La mujer en la perspectiva BenedictinaLo que queremos significar con el término de «genealogía espiritual» de Hildegardis de Bingen es el hecho de que no podemos considerar a esta mujer extraordinaria como un fenómeno aislado, como la irrupción de un prodigio femenino en el mundo y el tiempo tan masculino de las cruzadas. Aunque ella y su hermana de orden Gertrudis de Helfta (1256_1302), posterior a ella en un siglo, fueron sin duda las máximas exponentes del monacato femenino medieval derivado de Benito de Nursia y su Regla, ellas forman parte de una familia espiritual muy marcada, que a través de sus antecesoras anglosajonas en Germanía - una Walburga, una Lioba, una Thecla, una Hugueburga -, a través de las grandes abadesas de Inglaterra misma (pensemos en Hilda de Whitby) se remonta hasta la misma Sta. Escolástica, hermana de San Benito

Meier, Johannes; Amado Aymoré, Fernando; Jesuiten aus Zentraleuropa in Portugiesischund Spanisch-Amerika. Band I: Brasilien (1618-1760). Aschendorff Verlag, Münster 2005, 356 pp.

Meier, Johannes; Amado Aymoré, Fernando; Jesuiten aus Zentraleuropa in Portugiesischund Spanisch-Amerika. Band I: Brasilien (1618-1760). Aschendorff Verlag, Münster 2005, 356 pp

CONSIDERACIONES SOBRE LA REFORMA GREGORIANA DE LA IGLESIA

El presente artículo aborda una revisión del proceso de la reforma de la Iglesia medieval llevada a cabo por Gregorio VII en el siglo XI desde una perspectiva que pone en relación dicha reforma con algunos de los problemas que actualmente se debaten y critican desde el mundo secular al eclesiástico católico. Los antecedentes de la reforma gregoriana, su preparación por la labor de los pontífices anteriores, los principales alcances de sus repercusiones en el Occidente medieval, así como en la Historia de la Iglesia, son puestos en relieve por el autor

Celebrities as an aspect of the brand´s identity : the influence of testimonials regarding a brand´s image

In dieser Arbeit geht es um die Rolle prominenter Testiominials in der Werbung und deren Wirkung auf das Image einer Marke. Gesättigte Märkte, Informationsüberlastung und das veränderte Anspruchsverhalten der Konsumenten, stellt die Markenkommunikation vor neue Herausforderungen. Um aus der Masse heraus zu stechen setzen die Unternehemen Schlüsselreize ein. Ob ein Prominenter einen Schlüsselreiz darstellen kann und welche Chancen und Risiken diese Werbeform beinhaltet wird in der folgenden Arbeit untersucht

Record High Efficiency Screen-Printed Belt Co-Fired Cells on Cast Multi-Crystalline Silicon

Presented at the 19th European Photovoltaic Solar Energy Conference and Exhibition, Paris, France; June 7-11, 2004.Record-high efficiency screen-printed 4 cm(2) solar cells were achieved on HEM and Baysix cast multi-crystalline silicon. These cells were fabricated using a simple, manufacturable process involving POCl3 diffusion for a 45 Ω/ ٱ emitter, PECVD SiN(x):H deposition for a single-layer antireflection coating and rapid co-firing of an Ag grid, an Al back contact, and Al-BSF formation in a belt furnace. This process scheme resulted in effective impurity gettering and defect passivation. It also contributed to good ohmic contacts with series resistance of < 1Ω-cm(2), back surface recombination velocity of < 500 cm(2)/s, high average bulk lifetimes in the range of 100-250 μs after cell processing and fill factors of ~0.78. These parameters resulted in record high, 16.9% and 16.8% efficient screen-printed cells on HEM (Heat Exchanger Method) and Baysix mc-Si (confirmed by NREL). The identical process applied to the un-textured Float zone (FZ) wafers gave an efficiency of 17.2%. The optimized co-firing cycle, when applied to HEM mc-Si wafers with starting lifetimes varying over a wide range from 4 - 70 μs, resulted in a very tight efficiency range of 16.6% to 16.8% as a result of efficient defect gettering and passivation. Model calculations performed using the simple cell design and measured cell parameters agreed well with the experimental cell efficiency