1,720,984 research outputs found
Printed and Low Temperature Processed Oxide Electronics with Superior Electrical Performance and Mechanical Reliability
No full textIn line with the forthcoming industrial revolution, printed and flexible electronics is a rapidly developing research area that involves wearable and consumer electronics to be produced in large quantities and be connected via Internet of Things (IoT). In relation to solution processed/printed electronics, oxide semiconductors have developed into a serious contender alongside the organic alternatives, which lead to the plastic electronics excitements in early days, a couple of decades ago. Oxides are increasingly chosen for printed electronics technologies because they are abundant, inexpensive, nontoxic, demonstrate way superior environmental/thermal reliability, and most importantly, possess excellent electronic transport properties. However, on the downside, there are also major challenges, such as high process temperatures, thereby making them not suitable for low-cost, flexible polymer substrates. In addition, their limited mechanical strain tolerance (typically <1%) lower their selection possibilities in typical flexible electronic applications. On the other hand, printed electronics do suffer from a major roadblock, irrespective of the chosen semiconductor technology, which stems from the limited printing resolution that dictates the minimum channel lengths and therefore the maximum operation frequency that can be achieved.
In the present thesis, efforts have been made to look for solutions of some of the above-stated bottlenecks in the printed oxide electronics domain. First, an inorganic-organic composite semiconductor precursor ink has been developed; the printed and thermally cured semiconductor film of the composite material can maintain the excellent carrier mobility of the oxide semiconductors, even when they are in near-equal amounts. On the other hand, the presence of large quantity of organics ensures its superior strain tolerance and unaltered transistor properties for bending fatigue tests
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performed down to 1.5 mm bending radius. Next, devices made out of oxide nanoparticles have also been investigated, here the curing temperature can be as low as 100 °C, and therefore, such devices may very well be fabricated on paper or polyethylene terephthalate (PET) substrates. Here, our proposed approach offers a general recipe for low temperature curable nanodispersions/nanoinks; in this case, aromatic surfactants have been used to stabilize the nanoparticles that sublimates near room temperature. In this regard, stable nanoinks from In2O3 nanoparticles are developed using an aromatic compound thymol as the stabilizer; a quick heating at 100 °C ensures its complete removal from the semiconductor film/particle surfaces. High performance field-effect transistors (FETs) have been fabricated and characterized. Next, printable conducting inks are also the essential elements to print passive components in every electronic device; they also have a widespread use in various other application domains, such as transparent touch sensors, heaters, antistatic coating, antenna etc. Here, a precisely controlled synthesis of a mixed-phase of Ag-Ag2O nanoparticles and further a nanoink has been carried out that demonstrated low curing temperature of 80 °C to 120 °C, alongside excellent strain tolerance of layers printed on standard photo-paper substrates.
Next, attempts have been made to circumvent the printing resolution limits that at present hover around tens of micrometers range and are three orders of magnitude larger than the dimensions typically used in Si-technology. In this regard, an innovative device architecture that allows easy printing of edge-FETs with near vertical electronic transport through the printed semiconductor layer has been proposed; this can lower the effective channel lengths down to few tens of nanometers, as in this case the thickness of the printed layer becomes the dimension of interest. The FETs fabricated on PET substrate demonstrate high current saturation, On-Off ratio etc.,
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however, more interestingly, the depletion-mode inverters have demonstrated a signal gain >200 and switching frequency >300 kHz. In addition, taking advantage of the vertical device geometry a tensile strain tolerance up to 5% has been demonstrated
Inkjet-Printed Co-continuous Mesoporous Oxides for Surface Dominated Functional Devices
No full textOver the last few decades, printed and flexible electronics have emerged as a major area of research, which may cater multiple domains of application requirements for the forthcoming industrial revolution. The solution processed/printed devices can be ideally suited for cost-effective, volume production of sensors and other electronic components that can be connected through Internet of Things (IoT). In this regard, a large variety of sensors may find their application in essential parameter monitoring at industrial premises, wearables, smart textiles, smart appliances, smart packaging, etc., On the other hand, the ability to print the backplane electronics may truly revolutionize the pharmaceutical, diagnostics, and display industries. Next, among available and printable semiconductor technologies (such as polymer, oxides, carbon nanostructures, and various 2D semiconductors) inexpensive, non-toxic, easy-to-print, environmentally stable, abundant, and high mobility metal oxides are believed to have an overall edge in technology commercialization and therefore have been chosen as the printable semiconductor material in the present study. On the other hand, it may be noted that the electronic devices that come under the purview of printed electronics are predominantly surface-dominated devices. Therefore, in this thesis, a soft templating technique has been developed to provide co-continuous, mesoporous structures; the method has earlier been known for fabrication of films using processes, such as dip coating, here, it has now been modified to suit commercial inkjet printing process. A large variety of n- and p-type, undoped and doped, oxide semiconductors (In2O3, SnO2, CuO, Sn: In2O3 (ITO)) have been fabricated with different polymer templating agents to realize printed, large-area, homogeneous, co-continuous, mesoporous structures with large surface-to-volume ratio and pore size varying between 15-50 nm for different semiconducting oxide systems and curing temperatures. The printed mesoporous oxides are then utilized to fabricate fully-printed and extremely high performance (in terms of sensitivity, selectivity, and stability) volatile organic species (e.g. ethanol) sensors or gas (e.g. chlorine, NO2, etc.) sensors. At the same time, identical material systems have been used to fabricate high power printed transistors and fully printed complementary metal-oxide semiconductor (CMOS) electronics on different substrate
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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