1,720,978 research outputs found
Photo-Induced Nonlinearities in Fowler-Nordheim Plots for Field Emission of SiC Nanowires
No full textIn this contribution the field emission by tunneling of electrons of 3C-SiC nanowires on Si substrate, grown by CVD method via Ni catalyst, has been investigated. Scanning electron images have quantified the low density of the nanowires over the sample surface. In order to exclude any contribution to the Field Emission phenomenon from the Si substrate, the field emission measurements have been performed before and after removing the SiC nanowires. The Field Emission experiments have been carried out in dark conditions and by shining the sample surface. The extracted Fowler-Nordheim (F-N) plots show that the Field Emission from nanowires is highly sensitive to illumination parameters. When using lighting, a partition in three regions of the F-N plot has been observed. In the low field region, the F-N plot is linear or metallic-like, then it follows a saturation-current region and finally the high field region is characterized by a sharp increase.
Departure from the standard F-N theory, that is the influence of light and temperature on the Field Emission phenomenon, is well assessed for bulk semiconductor cathodes [1], but it has been rarely observed in single SiC nanowires [2]. To the authors’ knowledge, this contribution reports for the first time the strong deviation from F-N linear behavior for multiple SiC nanowires dispersed over planar substrate.
Field Emission data from quantum-confined structures are both useful for the study of their fundamental physics, but also because of promising technological applications, such as electron sources, high-resolution electron beam instruments, and Field Emission displays.
[1] G. N. Fursey, Field Emission in Vacuum Microelectronics (Kluwer Academic, New York, 2005)
[2] M. Choueib , A. Ayari, P. Vincent, M. Bechelany, D. Cornu, and S. T. Purcell, "Strong deviations from Fowler-Nordheim behavior for field emission from individual SiC nanowires due to restricted bulk carrier generation", Physical Review B 79, 075421 (2009
Defect level characterization of silicon nanowire arrays: Towards novel experimental paradigms
No full textThe huge amount of knowledge, and infrastructures, brought by silicon (Si) technology, make Si Nanowires (NWs) an ideal choice for nano-electronic Si-based devices. This, in turn, challenges the scientific research to adapt the technical and theoretical paradigms, at the base of established experimental techniques, in order to probe the properties of these systems. Metal-assisted wet-Chemical Etching (MaCE) [1, 2] is a promising fast, easy and cheap method to grow high aspect-ratio aligned Si NWs. Further, contrary to other fabrication methods, this method avoids the possible detrimental effects related to Au diffusion into NWs. We investigated the bandgap level diagram of MaCE Si NW arrays, phosphorous-doped, by means of Deep Level Transient Spectroscopy. The presence of both shallow and deep levels has been detected. The results have been examined in the light of the specificity of the MaCE growth. The study of the electronic levels in Si NWs is, of course, of capital importance in view of the integration of Si NW arrays as active layers in actual devices
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
On the UV responsivity of neutron irradiated 4H-SiC
No full textWe report on UV responsivity of 4H-SiC photodiodes irradiated by 1 MeV neutrons.Current-voltage characteristics, photoresponse spectra, and responsivity were obtained with lightwavelength from 200 to 450 nm. Photoresponse results slightly affected by irradiation up to thethreshold fluence critical=81014 cm−2. At fluences critical the rejection rate is in the order of103 in the range of 200–320 nm while it is less than 102 at about 320 nm. The abrupt increase inmidgap traps induced by irradiation at critical, observed by photoinduced current transientspectroscopy, proves carrier generation/trapping to be the controlling mechanism for theresponsivity. © 2008 American Institute of Physics
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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