11 research outputs found

    Micro-spectroscopy on silicon wafers and solar cells

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    Micro-Raman (μRS) and micro-photoluminescence spectroscopy (μPLS) are demonstrated as valuable characterization techniques for fundamental research on silicon as well as for technological issues in the photovoltaic production. We measure the quantitative carrier recombination lifetime and the doping density with submicron resolution by μPLS and μRS. μPLS utilizes the carrier diffusion from a point excitation source and μRS the hole density-dependent Fano resonances of the first order Raman peak. This is demonstrated on micro defects in multicrystalline silicon. In comparison with the stress measurement by μRS, these measurements reveal the influence of stress on the recombination activity of metal precipitates. This can be attributed to the strong stress dependence of the carrier mobility (piezoresistance) of silicon. With the aim of evaluating technological process steps, Fano resonances in μRS measurements are analyzed for the determination of the doping density and the carrier lifetime in selective emitters, laser fired doping structures, and back surface fields, while μPLS can show the micron-sized damage induced by the respective processes

    Sociétés locales, appropriation de l’espace et toponymie dans la vallée de Munster et son débouché rhénan

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    Woehl Bernard, Schalck Louis, Froehlicher Robert, Ritz-Bruppacher Josiane, Vogler Pierre. Sociétés locales, appropriation de l’espace et toponymie dans la vallée de Munster et son débouché rhénan. In: Revue des sciences sociales de la France de l'Est, N°10, 1981. pp. 100-122

    Micro-spectroscopy on silicon wafers and solar cells

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    <p>Abstract</p> <p>Micro-Raman (&#956;RS) and micro-photoluminescence spectroscopy (&#956;PLS) are demonstrated as valuable characterization techniques for fundamental research on silicon as well as for technological issues in the photovoltaic production. We measure the quantitative carrier recombination lifetime and the doping density with submicron resolution by &#956;PLS and &#956;RS. &#956;PLS utilizes the carrier diffusion from a point excitation source and &#956;RS the hole density-dependent Fano resonances of the first order Raman peak. This is demonstrated on micro defects in multicrystalline silicon. In comparison with the stress measurement by &#956;RS, these measurements reveal the influence of stress on the recombination activity of metal precipitates. This can be attributed to the strong stress dependence of the carrier mobility (piezoresistance) of silicon. With the aim of evaluating technological process steps, Fano resonances in &#956;RS measurements are analyzed for the determination of the doping density and the carrier lifetime in selective emitters, laser fired doping structures, and back surface fields, while &#956;PLS can show the micron-sized damage induced by the respective processes.</p

    Preliminary Analysis of Loss Rates of Honey Bee Colonies During Winter 2015/16 from the Coloss Survey

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    In this short note we present comparable loss rates of honey bee colonies during winter 2015/16 from 29 countries, obtained with the COLOSS questionnaire. Altogether, we received valid answers from 19,952 beekeepers. These beekeepers collectively wintered 421,238 colonies, and reported 18,587 colonies with unsolvable queen problems and 32,048 dead colonies after winter. This gives an overall loss rate of 12.0% (95% confidence interval 11.8-12.2%) during winter 2015/16, with marked differences among countries. Beekeepers in the present study assessed 7.6% (95% CI 7.4-7.8%) of their colonies as dead or empty, and 4.4% (95% CI 4.3-4.5%) as having unsolvable queen problems after winter. The overall analysis showed that small operations suffered higher losses than larger ones. A table with detailed results and a map showing response and relative risks at regional level are presented.WoSScopu
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