229 research outputs found
Elastic and structural properties of sputtered refractory metal thin films
To fabricate optimal hard and wear-resistant coatings it is necessary to tailor their
mechanical and structural properties for an optimal industrial application. We are exploring elastic and
structural properties of refractory metal (Ta, Nb, Mo and W) thin films of different thicknesses fabricated
by DC magnetron spattering technique on single crystalline Si substrates
Enhanced photoresponse of conformal TiO2/Ag nanorod array-based Schottky photodiodes fabricated via successive glancing angle and atomic layer deposition
Cataloged from PDF version of article.In this study, the authors demonstrate a proof of concept nanostructured photodiode fabrication method via successive glancing angle deposition (GLAD) and atomic layer deposition (ALD). The fabricated metal-semiconductor nanorod (NR) arrays offer enhanced photoresponse compared to conventional planar thin-film counterparts. Silver (Ag) metallic NR arrays were deposited on Ag-film/Si templates by utilizing GLAD. Subsequently, titanium dioxide (TiO2) was deposited conformally on Ag NRs via ALD. Scanning electron microscopy studies confirmed the successful formation of vertically aligned Ag NRs deposited via GLAD and conformal deposition of TiO2 on Ag NRs via ALD. Following the growth of TiO2 on Ag NRs, aluminum metallic top contacts were formed to complete the fabrication of NR-based Schottky photodiodes. Nanostructured devices exhibited a photo response enhancement factor of 1.49 × 102 under a reverse bias of 3 V.
© 2014 American Vacuum Societ
Network Behavior in Thin Film Growth Dynamics
We present a new network modeling approach for various thin film growth
techniques that incorporates re-emitted particles due to the non-unity sticking
coefficients. We model re-emission of a particle from one surface site to
another one as a network link, and generate a network model corresponding to
the thin film growth. Monte Carlo simulations are used to grow films and
dynamically track the trajectories of re-emitted particles. We performed
simulations for normal incidence, oblique angle, and chemical vapor deposition
(CVD) techniques. Each deposition method leads to a different dynamic evolution
of surface morphology due to different sticking coefficients involved and
different strength of shadowing effect originating from the obliquely incident
particles. Traditional dynamic scaling analysis on surface morphology cannot
point to any universal behavior. On the other hand, our detailed network
analysis reveals that there exist universal behaviors in degree distributions,
weighted average degree versus degree, and distance distributions independent
of the sticking coefficient used and sometimes even independent of the growth
technique. We also observe that network traffic during high sticking
coefficient CVD and oblique angle deposition occurs mainly among edges of the
columnar structures formed, while it is more uniform and short-range among
hills and valleys of small sticking coefficient CVD and normal angle
depositions that produce smoother surfaces.Comment: 11 pages, 9 figures, revtex
Constraining Bosonic Supersymmetry from Higgs results and 8 TeV ATLAS multi-jets plus missing energy data
The collider phenomenology of models with Universal Extra Dimensions (UED) is
surprisingly similar to that of supersymmetric (SUSY) scenarios. For each
level-1 bosonic (fermionic) Kaluza-Klein (KK) state, there is a fermionic
(bosonic) analog in SUSY and thus UED scenarios are often known as bosonic
supersymmetry. The minimal version of UED (mUED) gives rise to a
quasi-degenerate particle spectrum at each KK-level and thus, can not explain
the enhanced Higgs to diphoton decay rate hinted by the ATLAS collaboration of
the Large Hadron Collider (LHC) experiment. However, in the non-minimal version
of the UED (nmUED) model, the enhanced Higgs to diphoton decay rate can be
easily explained via the suitable choice of boundary localized kinetic (BLK)
terms for higher dimensional fermions and gauge bosons. BLK terms remove the
degeneracy in the KK mass spectrum and thus, pair production of level-1 quarks
and gluons at the LHC gives rise to hard jets, leptons and large missing energy
in the final state. These final states are studied in details by the ATLAS and
CMS collaborations in the context of SUSY scenarios. We find that the absence
of any significant deviation of the data from the Standard Model (SM)
prediction puts a lower bound of about 2.1 TeV on equal mass excited quarks and
gluons.Comment: 19 page
Minimization of phonon-tunneling dissipation in mechanical resonators
Micro- and nanoscale mechanical resonators have recently emerged as
ubiquitous devices for use in advanced technological applications, for example
in mobile communications and inertial sensors, and as novel tools for
fundamental scientific endeavors. Their performance is in many cases limited by
the deleterious effects of mechanical damping. Here, we report a significant
advancement towards understanding and controlling support-induced losses in
generic mechanical resonators. We begin by introducing an efficient numerical
solver, based on the "phonon-tunneling" approach, capable of predicting the
design-limited damping of high-quality mechanical resonators. Further, through
careful device engineering, we isolate support-induced losses and perform the
first rigorous experimental test of the strong geometric dependence of this
loss mechanism. Our results are in excellent agreement with theory,
demonstrating the predictive power of our approach. In combination with recent
progress on complementary dissipation mechanisms, our phonon-tunneling solver
represents a major step towards accurate prediction of the mechanical quality
factor.Comment: 12 pages, 4 figure
Post abortion family planning counseling as a tool to increase contraception use
<p>Abstract</p> <p>Background</p> <p>To describe the impact of the post-abortion family planning counseling in bringing about the contraceptive usage in women who had induced abortion in a family planning clinic.</p> <p>Method</p> <p>The Diyarbakir Office of Turkish Family Planning Association (DTFPA) is a nonprofit and nongovernmental organization which runs a family planning clinic to serve the lower socio-economic populations, in Diyarbakir-Turkey. Post abortion counseling is introduced by using proper communication skills and with using appropriate methods to women. In this study we introduced contraceptive usage of women who had induced abortion one year ago and followed by DTFPA's clinic.</p> <p>Results</p> <p>55.3% of our clients were not using contraceptive methods before abortion. At the end of the one year, 75.9% of our followed-up clients revealed that they were using one of the modern contraceptive methods. There was no woman with IUD before induced abortion. At the end of one year 124 (52.3%) women had IUD. "A modern method was introduced immediately after abortion" was the most important factor increasing modern method usage.</p> <p>Conclusion</p> <p>Our results advocate that post-abortion counseling may be an effective tool to increase the usage of contraceptives. Improved and more qualified post-abortion family planning counseling should be an integral part of abortion services.</p
Paleoseismic History of the Dead Sea Fault Zone
International audienceThe aim of this entry is to describe the DSF as a transform plate boundary pointing out the rate of activedeformation, fault segmentation, and geometrical complexities as a control of earthquake ruptures. Thedistribution of large historical earthquakes from a revisited seismicity catalogue using detailedmacroseismic maps allows the correlation between the location of past earthquakes and fault segments.The recent results of paleoearthquake investigations (paleoseismic and archeoseismic) with a recurrenceinterval of large events and long-term slip rate are presented and discussed along with the identification ofseismic gaps along the fault. Finally, the implications for the seismic hazard assessment are also discussed
Developing 1D nanostructure arrays for future nanophotonics
There is intense and growing interest in one-dimensional (1-D) nanostructures from the perspective of their synthesis and unique properties, especially with respect to their excellent optical response and an ability to form heterostructures. This review discusses alternative approaches to preparation and organization of such structures, and their potential properties. In particular, molecular-scale printing is highlighted as a method for creating organized pre-cursor structure for locating nanowires, as well as vapor–liquid–solid (VLS) templated growth using nano-channel alumina (NCA), and deposition of 1-D structures with glancing angle deposition (GLAD). As regards novel optical properties, we discuss as an example, finite size photonic crystal cavity structures formed from such nanostructure arrays possessing highQand small mode volume, and being ideal for developing future nanolasers
Dynamics of coupled cell networks: synchrony, heteroclinic cycles and inflation
Copyright © 2011 Springer. The final publication is available at www.springerlink.comWe consider the dynamics of small networks of coupled cells. We usually assume asymmetric inputs and no global or local symmetries in the network and consider equivalence of networks in this setting; that is, when two networks with different architectures give rise to the same set of possible dynamics. Focussing on transitive (strongly connected) networks that have only one type of cell (identical cell networks) we address three questions relating the network structure to dynamics. The first question is how the structure of the network may force the existence of invariant subspaces (synchrony subspaces). The second question is how these invariant subspaces can support robust heteroclinic attractors. Finally, we investigate how the dynamics of coupled cell networks with different structures and numbers of cells can be related; in particular we consider the sets of possible “inflations” of a coupled cell network that are obtained by replacing one cell by many of the same type, in such a way that the original network dynamics is still present within a synchrony subspace. We illustrate the results with a number of examples of networks of up to six cells
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