1,721,683 research outputs found
Investigation of deep level defects in CdTe thin films
No full textIn the past few years, a large body of work has been dedicated to CdTe thin film semiconductors, as the electronic and optical properties of CdTe nanostructures make them desirable for photovoltaic applications. The performance of semiconductor devices is greatly influenced by the deep levels. Knowledge of parameters of deep levels present in as-grown materials and the identification of their origin is the key factor in the development of photovoltaic device performance. Photo Induced Current Transient Spectroscopy technique (PICTS) has proven to be a very powerful method for the study of deep levels enabling us to identify the type of traps, their activation energy and apparent capture cross section. In the present work, we report the effect of growth parameters and LASER irradiation intensity on the photo-electric and transport properties of CdTe thin films prepared by Close-Space Sublimation method using SiC electrical heating element. CdTe thin films were grown at three different source temperatures (630, 650 and 700 °C). The grown films were irradiated with Nd:YAG LASER and characterized by Photo-Induced Current Transient Spectroscopy, Photocurrent measurementand Current Voltage measurements. The defect levels are found to be significantly influenced by the growth temperature
Effects of single-layer Shockley stacking faults on the transport properties of high-purity semi-insulating 4H–SiC
No full textThe electrical properties of high-purity 4H–SiC epitaxial layers are investigated. The current density
versus applied voltage curves shows that some specimens have space charge limited transport
behavior. Lampert–Mark model for trap-controlled electron transport in semi-insulating materials
demonstrated the presence of an intragap state at 0.26 eV below the conduction band. Photodeep
level transient spectroscopy has confirmed the presence of a deep level at about 0.3 eV below the
conduction band only in samples with non-Ohmic behavior. Cathodoluminescence imaging has
revealed the presence of high luminescent areas related to stacking faults SFs under the devices
showing non-Ohmic behavior. The presence of single-layer SFs was detected by
cathodoluminescence spectroscopy due to the typical emission at 2.95 eV. Thus, we demonstrated
that the SFs modified the charge transport from Ohmic conduction to space charge limited
conduction of the affected samples. © 2010 American Institute of Physics. doi:10.1063/1.345616
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
Leggere Boezio secondo Boezio: l’assioma II del «De Hebdomadibus»
No full textA new interpretation of the second axiom of the 'De hebdomadibus', the most philosophical of the so-called 'Opuscula theologica', written by the late Antique author Severinus Boethius (480-525 ca.
Remarks on the air recirculation in HVAC systems during the SARS-CoV-2 outbreak: the case of all-air ducted plants
No full textThe SARS-CoV-2 pandemic has aroused great interest in the HVAC community, both as regards to the design of new systems and for the management and operation strategies of the existing ones. The risk management plays a key role in all-air systems based on air recirculation among segregated spaces. Following an analyti- cal approach, this paper assesses the infection risk in several HVAC systems layouts. It takes into account the role of air renewal and recirculation and the gain made possible by means of virus charge removal or deactivation (through filtration or other technologies such as UV-C irradiation, ionisation ...), with special regard to the management of airflows that depends on the chosen plant layout
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