1,721,089 research outputs found
NANOcrystalline silicon films for PHOTOvoltaic and optoelectronic applications
No full textNanocrystalline silicon (nc-Si) is not only a truly multifunctional material, due to its potential utilization as a active substrate for a variety of optoelectronic applications (photovoltaic cells, flat plate displays, light emitting diodes), but it presents also the advantage of being a silicon-based, low cost, environmentally clean material.
Therefore, although the optoelectronic properties of nc-Si could not be compared, on the base of the today knowledge, with those of III-V compounds, the possibility of a direct integration of nc-Si devices on silicon substrates used in silicon microelectronics and its better environmental stability with respect to amorphous silicon (a-Si) make of nc-Si a promising opportunity, at least for consumer electronics and low cost photovoltaics.
The work is divided in four main packages, of which the first covers the modelling activities, and the other three the material growth, its characterization and some prototyping activities
Analisi di uno strumento psicometrico per le prove di ammissione universitaria. Applicazione e confronto di un modello classico e del modello dicotomico di Rasch
No full textNon-legacy contamination by 3,3'-dichlorobiphenyl in marine species: comparison between mediterranean area and antarctic region
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Electrical characterization of as-grown and thermally treated 8 inches silicon wafers
No full textMinority and majority carrier properties of as grown and rapid thermally annealed 8′′ Si wafers were investigated. Surface and bulk recombination mechanisms were monitored by measuring surface recombination velocity and minority carrier diffusion length, while the defective state of the material was analyzed by measuring extended defect electrical activity, trap concentration and activation energy. A significant deactivation of the shallow acceptors in the sub-surface region was observed in as-grown wafers and attributed to hydrogen introduced in Si during the chemo-mechanical polishing, while an increase in the defective content of the starting material and, correspondingly, an evident reduction of the diffusion length and an increase in the surface recombination rate were detected in thermally treated wafers
Erbium-doped silicon epilayers grown by liquid-phase epitaxy
No full textA careful analysis of the features of the spectroscopic properties of Er-doped and undoped epitaxial silicon films grown by liquid-phase epitaxy at 950 °C in silicon-saturated indium melts shows that threading dislocations work as effective gettering sites for erbium and oxygen. The last impurity is incorporated in the epitaxial film by back diffusion from the Czochralski substrate during the growth. The photoluminescence emitted by these films appears to be related to the dislocation and is enforced by the presence of erbium-oxygen complexes. © 1999 American Institute of Physics
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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