cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Enhanced Light Extraction in Tunnel Junction Enabled Top Emitting UV LEDs
Creators: name: Zhang, Yuewei
name: Allerman, Andrew
name: Krishnamoorthy, Sriram
name: Akyol, Fatih
name: Moseley, Michael W.
name: Armstrong, Andrew
name: Rajan, Siddharth
Publisher: name: arXiv
Year: 2015
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: The efficiency of ultra violet LEDs is critically limited by the absorption losses in p-type and metal layers. In this work, surface roughening based light extraction structures are combined with tunneling-based top-contacts to realize highly efficient top-side light extraction efficiency in UV LEDs. Surface roughening of the top n-type AlGaN contact layer is demonstrated using self-assembled Ni nano-clusters as etch mask. The top surface roughened LEDs were found to enhance external quantum efficiency by over 40% for UV LEDs with a peak emission wavelength of 326 nm. The method described here can enable highly efficient UV LEDs without the need for complex manufacturing methods such as flip chip bonding.
description: 10 pages, 4 figures, submitted
Regulation of black-hole accretion by a disk wind during a violent outburst of V404 Cygni
Creators: name: Muñoz-Darias, T.
name: Casares, J.
name: Sánchez, D. Mata
name: Fender, R. P.
name: Padilla, M. Armas
name: Linares, M.
name: Ponti, G.
name: Charles, P. A.
name: Mooley, K. P.
name: Rodriguez, J.
Publisher: name: arXiv
Year: 2016
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Accretion of matter onto black holes is universally associated with strong radiative feedback and powerful outflows. In particular, black hole transients show outflows whose properties are strongly coupled to those of the accretion flow. This includes X-ray winds of ionized material, expelled from the accretion disc encircling the black hole, and collimated radio jets. Very recently, a distinct optical variability pattern has been reported in the transient black hole transient V404 Cyg, and interpreted as disrupted mass flow into the inner regions of its large accretion disc. Here, we report on the discovery of a sustained outer accretion disc wind in V404 Cyg, which is unlike any seen previously. We find that the outflowing wind is neutral, has a large covering factor, expands at 1% of the speed of light and triggers a nebular phase once accretion sharply drops and the ejecta become optically thin. The large expelled mass (> 10^-8 Msun) indicates that the outburst was prematurely ended when a sizeable fraction of the outer disc was depleted by the wind, detaching the inner regions from the rest of the disc. The luminous, but brief, accretion phases shown by transients with large accretion discs imply that this outflow is most likely a new fundamental ingredient regulating mass accretion onto black holes.
description: Published in Nature on 9 May 2016
The Launching of Cold Clouds by Galaxy Outflows II: The Role of Thermal Conduction
Creators: name: Brüggen, Marcus
name: Scannapieco, Evan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We explore the impact of electron thermal conduction on the evolution of radiatively-cooled cold clouds embedded in flows of hot and fast material, as occur in outflowing galaxies. Performing a parameter study of three-dimensional adaptive mesh refinement hydrodynamical simulations, we show that electron thermal conduction causes cold clouds to evaporate, but it can also extend their lifetimes by compressing them into dense filaments. We distinguish between low column-density clouds, which are disrupted on very short times, and high-column density clouds with much-longer disruption times that are set by a balance between impinging thermal energy and evaporation. We provide fits to the cloud lifetimes and velocities that can be used in galaxy-scale simulations of outflows, in which the evolution of individual clouds cannot be modeled with the required resolution. Moreover, we show that the clouds are only accelerated to a small fraction of the ambient velocity because compression by evaporation causes the clouds to present a small cross-section to the ambient flow. This means that either magnetic fields must suppress thermal conduction, or that the cold clouds observed in galaxy outflows are not formed of cold material carried out from the galaxy.
description: accepted by ApJ
A Short Counterexample to the Inverse Generator Problem on non-Hilbertian Reflexive $L^p$-spaces
Creators: name: Fackler, Stephan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Functional Analysis (math.FA)
subject: FOS: Mathematics
subject: 47D05 (Primary)

description: We show that the bilateral shift group on $L^p(\mathbb{R})$ for $p \in (1, \infty) \setminus \{2\}$ provides a counterexample to the inverse generator problem.
description: 6 pages; final version
An algorithm for computing the 2D structure of fast rotating stars
Creators: name: Rieutord, M.
name: Lara, F. Espinosa
name: Putigny, B.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Stars may be understood as self-gravitating masses of a compressible fluid whose radiative cooling is compensated by nuclear reactions or gravitational contraction. The understanding of their time evolution requires the use of detailed models that account for a complex microphysics including that of opacities, equation of state and nuclear reactions. The present stellar models are essentially one-dimensional, namely spherically symmetric. However, the interpretation of recent data like the surface abundances of elements or the distribution of internal rotation have reached the limits of validity of one-dimensional models because of their very simplified representation of large-scale fluid flows. In this article, we describe the ESTER code, which is the first code able to compute in a consistent way a two-dimensional model of a fast rotating star including its large-scale flows. Compared to classical 1D stellar evolution codes, many numerical innovations have been introduced to deal with this complex problem. First, the spectral discretization based on spherical harmonics and Chebyshev polynomials is used to represent the 2D axisymmetric fields. A nonlinear mapping maps the spheroidal star and allows a smooth spectral representation of the fields. The properties of Picard and Newton iterations for solving the nonlinear partial differential equations of the problem are discussed. It turns out that the Picard scheme is efficient on the computation of the simple polytropic stars, but Newton algorithm is unsurpassed when stellar models include complex microphysics. Finally, we discuss the numerical efficiency of our solver of Newton iterations. This linear solver combines the iterative Conjugate Gradient Squared algorithm together with an LU-factorization serving as a preconditionner of the Jacobian matrix.
description: 40 pages, 12 figures, accepted in J. Comput. Physics
FACCE ERA-GAS: Monitoring and Mitigation of greenhouse gases from agri and silvi-culture. Overview of the ERA-NET, highlights of the research calls and abstracts of funded projects
Creators: name: Muscat, Abigail
name: Bunthof, Christine
name: Ní Choncubhair, Órlaith
name: Kelly, Raymond
Publisher: name: Zenodo
Year: 2023
Subjects: agriculture
silviculture
forestry
livestock
greenhouse gases
climate mitigation

description: The agriculture and forestry sectors in Europe face significant challenges in achieving climate neutrality by
 2035 while maintaining food and biomass security in a changing climate. As a result, the incorporation of abatement
 strategies into tailored sustainable production systems and the implementation of these strategies on the ground are of the utmost importance In addition, the inclusion of C sinks as an offsetting option, particularly in forestry and agricultural soils means that verification of sinks and the impact of management on those sinks is vital

 FACCE ERA GAS is the ERA NET Cofund for Monitor ing Mitigation of Greenhouse Gases ( from Agri and Silvi culture The consortium of FACCE ERA GAS consists of 19 partner organisations from 13 countries Denmark, Finland, France, Germany, Ireland, Latvia, the Netherlands, Norway, Poland, Romania, Sweden, Turkey and the United Kingdom Additional partners, including other ERA NETs, have jointly contributed to research calls Teagasc the Irish Agriculture and Food Development Authority, coordinates the ERA-NET. The aim of FACCE ERA GAS is to strengthen the transnational coordination of research programmes and provide added value to research and innovation on GHG mitigation and monitoring in the European Research Area and New Zealand By coordinating and aligning research efforts, FACCE ERA GAS aims to develop enabling technologies and innovative solutions to improve inventories, increase the GHG efficiency of food, feed and fuel production and enhance carbon sinks FACCE ERA GAS works closely with other ERA-NETs and reinforce s existing collaborations between actors in the research area (e g via FACCE JPI and the Global Research Alliance.
The very wide-field $gzK$ galaxy survey -- I. Details of the clustering properties of star-forming galaxies at $z \sim 2$
Creators: name: Ishikawa, Shogo
name: Kashikawa, Nobunari
name: Toshikawa, Jun
name: Onoue, Masafusa
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the results of clustering analysis on the $z \sim 2$ star-forming galaxies. By combining our data with data from publicly available archives, we collect $g$-, $\zb / z$-, and $K$-band imaging data over 5.2 deg$^{2}$, which represents the largest area BzK/gzK survey. We apply colour corrections to translate our filter-set to those used in the original BzK selection for the gzK selection. Because of the wide survey area, we obtain a sample of 41,112 star-forming gzK galaxies at $z \sim 2$ (sgzKs) down to $\KAB < 23.0$, and determine high-quality two-point angular correlation functions (ACFs). Our ACFs show an apparent excess from power-law behaviour at small angular scale $(θ\la 0.01^{\circ})$, which corresponds the virial radius of a dark halo at $z \sim 2$ with a mass of $\sim 10^{13} \Msun$. We find that the correlation lengths are consistent with the previous estimates over all magnitude range; however, our results are evaluated with a smaller margin of error than that in previous studies. The large amount of data enables us to determine ACFs differentially depending on the luminosity of the subset of the data. The mean halo mass of faint sgzKs $(22.0 < K \leq 23.0)$ was found to be $\Mh = (1.32^{+0.09}_{-0.12}) \times 10^{12} h^{-1} \Msun$, whereas bright sgzKs ($18.0 \leq K \leq 21.0)$ were found to reside in dark haloes with a mass of $\Mh = (3.26^{+1.23}_{-1.02}) \times 10^{13} h^{-1} \Msun$.
description: 15 pages, 12 figures, published in MNRAS
Maxwell perturbations on Kerr-anti-de Sitter: quasinormal modes, superradiant instabilities and vector clouds
Creators: name: Wang, Mengjie
name: Herdeiro, Carlos
Publisher: name: arXiv
Year: 2015
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: Scalar and gravitational perturbations on Kerr-anti-de Sitter (Kerr-AdS) black holes have been addressed in the literature and have been shown to exhibit a rich phenomenology. In this paper we complete the analysis of bosonic fields on this background by studying Maxwell perturbations, focusing on superradiant instabilities and vector clouds. For this purpose, we solve the Teukolsky equations numerically, imposing the boundary conditions we have proposed in\cite{Wang:2015goa} for the radial Teukolsky equation. As found therein, two Robin boundary conditions can be imposed for Maxwell fields on Kerr-AdS black holes, one of which produces a new set of quasinormal modes even for Schwarzschild-AdS black holes. Here, we show these different boundary conditions produce two different sets of superradiant modes. Interestingly the "new modes" may be unstable in a larger parameter space. We then study stationary Maxwell clouds, that exist at the threshold of the superradiant instability, with the two Robin boundary conditions. These clouds, obtained at the linear level, indicate the existence of a new family of black hole solutions at the nonlinear level, within the Einstein-Maxwell-AdS system, branching off from the Kerr-Newman-AdS family. As a comparison with the Maxwell clouds, scalar clouds on Kerr-AdS black holes are also studied, and it is shown there are Kerr-AdS black holes that are stable against scalar, but not vector modes, with the same "quantum numbers".
description: 15 pages, 3 tables, 10 figures
The $^{63}$Ni(n,$γ$) cross section measured with DANCE
Creators: name: Weigand, M.
name: Bredeweg, T. A.
name: Couture, A.
name: Göbel, K.
name: Heftrich, T.
name: Jandel, M.
name: Käppeler, F.
name: Lederer, C.
name: Kivel, N.
name: Korschinek, G.
name: Krticka, M.
name: O'Donnell, J. M.
name: Ostermöller, J.
name: Plag, R.
name: Reifarth, R.
name: Schumann, D.
name: Ullmann, J. L.
name: Wallner, A.
Publisher: name: arXiv
Year: 2015
Subjects: subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: The neutron capture cross section of the s-process branch nucleus $^{63}$Ni affects the abundances of other nuclei in its region, especially $^{63}$Cu and $^{64}$Zn. In order to determine the energy dependent neutron capture cross section in the astrophysical energy region, an experiment at the Los Alamos National Laboratory has been performed using the calorimetric 4$π$ BaF$_2$ array DANCE. The (n,$γ$) cross section of $^{63}$Ni has been determined relative to the well known $^{197}$Au standard with uncertainties below 15%. Various $^{63}$Ni resonances have been identified based on the Q-value. Furthermore, the s-process sensitivity of the new values was analyzed with the new network calculation tool NETZ.
description: 11 pages, 13 pages
The very wide-field $gzK$ galaxy survey -- II. The relationship between star-forming galaxies at $z \sim 2$ and their host haloes based upon HOD modelling
Creators: name: Ishikawa, Shogo
name: Kashikawa, Nobunari
name: Hamana, Takashi
name: Toshikawa, Jun
name: Onoue, Masafusa
Publisher: name: arXiv
Year: 2016
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: We present the results of an halo occupation distribution (HOD) analysis of star-forming galaxies at $z \sim 2$. We obtained high-quality angular correlation functions based on a large sgzK sample, which enabled us to carry out the HOD analysis. The mean halo mass and the HOD mass parameters are found to increase monotonically with increasing $K$-band magnitude, suggesting that more luminous galaxies reside in more massive dark haloes. The luminosity dependence of the HOD mass parameters was found to be the same as in the local Universe; however, the masses were larger than in the local Universe over all ranges of magnitude. This implies that galaxies at $z \sim 2$ tend to form in more massive dark haloes than in the local Universe, a process known as downsizing. By analysing the dark halo mass evolution using the extended Press--Schechter formalism and the number evolution of satellite galaxies in a dark halo, we find that faint Lyman break galaxies at $z \sim 4$ could evolve into the faintest sgzKs $(22.0 < K \leq 23.0)$ at $z \sim 2$ and into the Milky-Way-like galaxies or elliptical galaxies in the local Universe, whereas the most luminous sgzKs $(18.0 \leq K \leq 21.0)$ could evolve into the most massive systems in the local Universe. The stellar-to-halo mass ratio (SHMR) of the sgzKs was found to be consistent with the prediction of the model, except that the SHMR of the faintest sgzKs was smaller than the prediction at $z \sim 2$. This discrepancy may be attributed that our samples are confined to star-forming galaxies.
description: 14 pages, 9 figures, accepted for publication in MNRAS
Geometric Correction in Diffusive Limit of Neutron Transport Equation in 2D Convex Domains
Creators: name: Guo, Yan
name: Wu, Lei
Publisher: name: arXiv
Year: 2016
Subjects: subject: Analysis of PDEs (math.AP)
subject: FOS: Mathematics

description: Consider the steady neutron transport equation with diffusive boundary condition. In [Wu and Guo(2015) Comm. Math. Phys.] and [Wu and Yang and Guo(2016) Preprint], it was discovered that geometric correction is necessary for the Milne problem of Knudsen-layer construction in a disk or annulus. In this paper, we establish diffusive limit for a 2D convex domain. Our contribution relies on novel $W^{1,\infty}$ estimates for the Milne problem with geometric correction in the presence of a convex domain, as well as an $L^{2m}-L^{\infty}$ framework which yields stronger remainder estimates.
description: 60 pages
Discrete Breathers and Multi-Breathers in Finite Vibro-Impact Chain
Creators: name: Grinberg, Itay
name: Gendelman, Oleg V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Exactly Solvable and Integrable Systems (nlin.SI)
subject: FOS: Physical sciences

description: We explore dynamics of discrete breathers and multi-breathers in finite one-dimensional chain. The model involves parabolic on-site potential with rigid constraints and linear nearest-neighbor coupling. The rigid non-ideal impact constraints are the only source of nonlinearity and damping in the model. The model allows derivation of exact analytic solutions for the breathers and multi-breathers with arbitrary set of localization sites, both in conservative and forced-damped settings. We choose periodic boundary conditions; exact solutions for other types of the boundary conditions are also possible. Local character of the nonlinearity allows explicit derivation of a monodromy matrix for the breather solutions. Consequently, a stability of the derived breather and multi-breather solutions can be efficiently studied in the framework of simple methods of linear algebra, and with rather moderate computational efforts. We demonstrate that finitness of the chain fragment and proximity of the localization sites strongly effect existence and stability patterns of these localized solutions.
Energy spectra of massive two-body decay products and mass measurement
Creators: name: Agashe, Kaustubh
name: Franceschini, Roberto
name: Hong, Sungwoo
name: Kim, Doojin
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: We have recently established a new method for measuring the mass of unstable particles produced at hadron colliders based on the analysis of the energy distribution of a massless product from their two-body decays. The central ingredient of our proposal is the remarkable result that, for an unpolarized decaying particle, the location of the peak in the energy distribution of the observed decay product is identical to the (fixed) value of the energy that this particle would have in the rest-frame of the decaying particle, which, in turn, is a simple function of the involved masses. In addition, we utilized the property that this energy distribution is symmetric around the location of peak when energy is plotted on a logarithmic scale. The general strategy was demonstrated in several specific cases, including both beyond the SM particles, as well as for the top quark. In the present work, we generalize this method to the case of a massive decay product from a two-body decay; this procedure is far from trivial because (in general) both the above- mentioned properties are no longer valid. Nonetheless, we propose a suitably modified parametrization of the energy distribution that was used successfully for the massless case, which can deal with the massive case as well. We establish the accuracy of this parametrization using concrete examples of energy spectra of Z bosons from the decay of a heavier stop into a Z boson and a lighter stop. We then study a realistic application for the same process, but now including dominant backgrounds and using foreseeable statistics at LHC14, in order to determine the performance of this method for an actual mass measurement. The upshot of our present and previous work is that, in spite of energy being a Lorentz-variant quantity, its distribution emerges as a powerful tool for mass measurement at hadron colliders.
description: 37 pages, 8 figures
Jüdische Riten und Bräuche beim Begräbnis
Creators: name: Werblowsky, R. J. Z.
Publisher: name: Concilium
Year: 1970

description: Concilium, Bd. 4 Nr. 2 (1968): Concilium: Internationale Zeitschrift für Theologie, Band 4, Heft 2
3D Optical Simulation of Scattering in Thin Film Silicon Solar Cells
Creators: name: Peters, M.
name: Battaglia, C.
name: Aberle, A.G.
name: Bläsi, B.
name: Luther, J.
name: Glunz, S.W.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Thin Film Crystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2764-2767
description: Efficient light trapping is of great importance for thin-film silicon solar cells. Randomly textured TCO or glass substrates provide excellent light trapping and are frequently applied. Optical simulation of such textures is
challenging due to a large variety of occurring geometrical features. In this paper we suggest an approach for the 3D optical simulation of scattering structures. This approach is based on a simulation and investigation of the constituting single structure features and subsequent implementation of the solar cell structure into the rigorous coupled wave analysis (RCWA). In this paper we present first results of this method for a microcrystalline silicon solar cell deposited on a sputtered and etched ZnO surface. The simulated absorption for the single structures is compared to quantum efficiency measurements on large areas. Good agreement between simulation and measurement is found. Comparing periodic and random structures, we find that small periodic structures can increase the absorbed
photocurrent density by up to 3 mA/cm2. The best result was obtained for a structure with a diameter of D = 800 nm.
Role of Hydrogen in Promoting the Splitting of Silicon Film during High Temperature Annealing of Porous Silicon
Creators: name: Ghannam, M.Y.
name: Alomar, A.
name: Poortmans, J.
name: Mertens, R.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Thin Film Crystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2821-2824
description: An attempt is made to explain the specific role of hydrogen in promoting thin film splitting from crystalline
silicon wafers with buried voids transformed from pores or trenches during annealing at high temperature.
It is suggested that the main effect of hydrogen is to speed up the breaking of lateral silicon straps
separating the voids, causing their coalescence. Such an effect is related, through several mechanisms, to
the chemistry of high temperature hydrogen diffusion in silicon. Straps between voids collapse by the
pressure exerted by hydrogen molecules formed inside the voids, a process similar to exfoliation of
hydrogen induced defects (HID) in single crystalline silicon supersaturated with hydrogen and annealed at
high temperature. Also annealing in hydrogen reduces the cohesive strength of the void surface by forming
low energy SiH complexes. Finally, chemical etching of the straps is envisaged with the presence of
fluorine radicals and all species required for chemical etching of silicon.
Improvement of Short-Circuit Current in Silicon-Based Thin Film Solar Cells Using ZnO Films with Very High Haze Value
Creators: name: Hongsingthong, A.
name: Krajangsang, T.
name: Fujioka, H.
name: Sichanugrist, P.
name: Konagai, M.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2633-2636
description: Zinc oxide (ZnO) thin films with high haze value were successfully developed using soda-lime glasssubstrate
etching before ZnO film deposition. Effects of soda-lime glass treatment conditions on the properties of
ZnO films were systematically investigated. It was found that the larger crater surface and high rms roughness of
soda-lime glass could be obtained when the glass treatment gas pressure was 13 Pa. It was also found that the surface
morphology of ZnO films can be modified by controlling the surface morphology of soda-lime glass substrate
without deterioration of their good electrical properties. By employing developed high-haze ZnO film deposited on
etched soda-lime glass substrate as front TCO films in μc-Si:H single-junction solar cells, we obtained an efficiency
of 8.15% with improved quantum efficiency and largely enhanced Jsc. Thus, the obtained ZnO films deposited on
etched soda-lime glass have a lot of potentials to be used as the front TCO layers in silicon-based thin film solar cells
as well as a new promising low-cost substrate.
On the eclipsing binary ELHC 10 with occulting dark disc in the Large Magellanic Cloud
Creators: name: Garrido, H. E.
name: Mennickent, R. E.
name: Djurasevic, G.
name: Schmitdtobreick, L.
name: Graczyk, D.
name: Villanova, S.
name: Barría, D.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences
subject: F.2.2

description: We investigate the luminous star ELHC 10 located in the bar of the Large Magellanic Cloud, concluding that it is a SB1 long-period eclipsing binary where the main eclipse is produced by an opaque structure hiding the secondary star. For the more luminous component we determine an effective temperature of 6500 $\pm$ 250 $K$, log\,g = 1.0 $\pm$ 0.5 and luminosity 5970 L$_{\sun}$. From the radial velocities of their photospheric lines we calculate a mass function of 7.37 $\pm$ 0.55 M$_{\sun}$. Besides Balmer and forbidden N II emission, we find splitting of metallic lines, characterized by strong discrete absorption components (DACs), alternatively seen at the blue and red side of the photospheric spectrum. These observations hardly can be interpreted in terms of an structured atmosphere but might reflect mass streams in an interacting binary. The primary shows signatures of s-process nucleosynthesis and might be a low-mass post-AGB star with a rare evolutionary past if the binary is semi-detached. The peak separation and constancy of radial velocity in H$α$ suggest that most of the Balmer emission comes from a circumbinary disc.
description: 16 pages, 17 figures, accepted for publication in MNRAS
Prescriptions for measuring and transporting local angular momenta in general relativity
Creators: name: Flanagan, Éanna É.
name: Nichols, David A.
name: Stein, Leo C.
name: Vines, Justin
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: For observers in curved spacetimes, elements of the dual space of the set of linearized Poincaré transformations from an observer's tangent space to itself can be naturally interpreted as local linear and angular momenta. We present an operational procedure by which observers can measure such quantities using only information about the spacetime curvature at their location. When applied by observers near spacelike or null infinity in stationary, vacuum, asymptotically flat spacetimes, there is a sense in which the procedure yields the well-defined linear and angular momenta of the spacetime. We also describe a general method by which observers can transport local linear and angular momenta from one point to another, which improves previous prescriptions. This transport is not path independent in general, but becomes path independent for the measured momenta in the same limiting regime. The transport prescription is defined in terms of differential equations, but it can also be interpreted as parallel transport in a particular direct-sum vector bundle. Using the curvature of the connection on this bundle, we compute and discuss the holonomy of the transport law. We anticipate that these measurement and transport definitions may ultimately prove useful for clarifying the physical interpretation of the Bondi-Metzner-Sachs charges of asymptotically flat spacetimes.
description: 10 pages, 1 figure, refines aspects of arXiv:1411.4599
Microscopic Measurements of Polycrystalline Silicon Thin Films on Glass
Creators: name: Fejfar, A.
name: Vetushka, A.
name: Ledinsky, M.
name: Kocka, J.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Thin Film Crystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2788-2790
description: Microscopic study of charge transport collection in silicon thin films can be studied with resolution
down to ~10 nm, which allows study of individual crystalline grains in microcrystalline silicon or individual
crystallites separated by grain boundaries within the polycrystalline silicon grains on glass. We have developed two
complementary approaches: conductive atomic force microscopy (C-AFM) and measurements with two probes
navigated by a scanning electron microscope. We have also proposed and tested a novel procedure for
measurements of the same spot after repeated mounting. The procedure uses simple nanoindentation marks which
can be easily localized with high precision in various microscopes used (optical, scanning electron microscope, CAFM).
This enables measurements of the same spot on a sample before and after technological steps (e.g.
hydrogenation or deposition) and thus an investigation of microscopic effects of these treatments.
High Precision Laser Scribing for Thin Film Solar Cells
Creators: name: Witte, R.
name: Frei, B.
name: Schneeberger, S.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2718-2723
description: In a continuously growing solar photo voltaic market with both, crystalline silicon (c-Si) as well as
thin-film technology, the continuous growth is directly dependent on the manufacturing costs for solar cells. The
key factors for cost reduction are innovative ideas to optimize precision and throughput. Lasers are excellent
tools to provide highly efficient processes with impressive accuracy. They can excel best in combination with
fast and precise motion systems for a maximum gain in the manufacturing process, yielding best cost of
ownership.
With this work an industrial tool is presented that combines a series of unique and innovative solutions for thinfilm
scribing. The combination of a new substrate holding technique on a machine with a fast and precise motion
system is the base for a cost effective scribing machine. With the vacuum glass holding technique it is possible
to gain a tighter tolerance range, making the process more stable to fluctuations in the substrate thickness and
therefore increasing the process window significantly. This is further supported by the fact that the substrate is
fixed throughout the whole scribing process to reduce vibration induced issues. Utilizing new laser sources with
fiber guided beam delivery can reduce the weight on the accelerated parts and is permitting high-speed processing
up to 2000 mm/sec while keeping the beam quality at a M2 below 1.5. A further improvement that comes with
fiber guided lasers is the short beam path in the working head, reducing the alignment and set-up time to a
fraction that is currently the case for laser scribing systems.
All the above mentioned improvements are influencing the production time and reliability. To improve the
module efficiency directly through the laser scribing process one way to go is to reduce the dead zone. Utilizing
the high precision of the system a module with a dead zone of sub 100m is demonstrated bringing all the
advantages to bear. Also an outlook is given on the possible impact on cell efficiency, manufacturing costs, and
cost of ownership implementing such a concept into production.
Shear induced solidification of athermal systems with weak attraction
Creators: name: Zheng, Wen
name: Liu, Hao
name: Xu, Ning
Publisher: name: arXiv
Year: 2016
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: FOS: Physical sciences

description: We find that unjammed packings of frictionless particles with rather weak attraction can always be driven into solid-like states by shear. The structure of shear-driven solids evolves continuously with packing fraction from gel-like to jamming-like, but is almost independent of the shear stress. In contrast, both the density of vibrational states (DOVS) and force network evolve progressively with the shear stress. There exists a packing fraction independent shear stress $σ_c$, at which the shear-driven solids are isostatic and have a flattened DOVS. Solid-like states induced by a shear stress greater than $σ_c$ possess properties of marginally jammed solids and are thus strictly-defined shear jammed states. Below $σ_c$, states at all packing fractions are under isostaticity and share common features in the DOVS and force network, although their structures can be rather different. Our study reveals the significance of the shear stress in determining properties of shear-driven solids and leads to an enriched jamming phase diagram for weakly attractive particles.
description: 5 pages, 3 figures
Effect of AZO–Coating Thickness on a-Si:H p-i-n Solar-Cell Performance
Creators: name: Santos, JD.
name: Fernández, S.
name: Cárabe, J.
name: Gandía, JJ.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2727-2730
description: There is some controversy about the origin of the low fill factor obtained in a-Si:H p-i-n solar cells
deposited onto ZnO:Al (AZO). While some authors found a blocking AZO/p contact, others related this
performance worsening to a P-I interface deterioration. This work attempts to shed light on this phenomenon by
means of a detailed analysis of p-i-n devices deposited onto Asahi-U-type glass coated with AZO. The results
obtained suggest that both hypotheses are valid. The blocking AZO/p contact has a greater impact on FF, but its
effect does not depend on thickness. On the contrary, p-i deterioration increases for coating thickness ranging
between 0 to 70 nm. This process seems to affect negatively the VOC.
Silane Plasma Characteristics Of The DC Saddle Field PECVD System in a Tetrode Configuration
Creators: name: Leong, K.
name: Kosteski, T.
name: Yeghikyan, D.
name: Zukotynski, S.
name: Kherani, N.P.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2736-2739
description: A new DC Saddle Field plasma enhanced chemical vapor deposition system was built for the tetrode
configuration. This electrode configuration consisted of four electrodes one semitranparent anode, one
semitransparent cathode, one solid showerhead cathode, and one substrate holder. The spacing between these four
electrodes is varied. Below the substrate holder an ion mass spectrometer was installed to sample the ion species
travelling towards the substrate. The 100% pure silane plasma was ignited and studied to shed light on the impinging
ion species, ion energy distributions, and film properties with varying electrode spacing. The results indicate that
decreasing the distance between the substrate and cathode leads to a reduction in the high energy ion bombardment.
The semitransparent cathode current appears to be determined by the anode-cathode distance only.
Traceable Flasher-Based Power Measurement of Micromorph Tandem Modules
Creators: name: Meier, J.
name: Adelhelm, R.
name: Apolloni, M.
name: Keller, K.
name: Seghrouchni, Z.
name: Romang, D.
name: Benagli, S.
name: Kroll, U.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2744-2749
description: The mass-produced Micromorph modules attain their performance qualification with the help of
large area solar simulators under standardised conditions. The particular specialty of the tandem structure for the
efficient absorption of the near infrared causes the demand for sophisticated set-ups for a precise technical solar
simulator. For many years, Oerlikon Solar has been working on the accuracy of the performance measurements
and today this paper reports on the approach for a correct measurement based on the scientific metrology of
multi-junctions solar cells. The modified commercial solar simulator with tuneable spectrum, together with the
two reference component cells, is the fundamental instrumentation for the generation of the simulator spectrum
for Micromorph tandem modules. The method for optimising the test conditions will be explained. Furthermore,
the traceability is in the focus to show the way from the certified references to the Micromorph module.
Tandem Junction Thin Film Solar Cells with Hydrogenated Microcrystalline Silicon Germanium as Bottom Cell Absorber Layer by RF PECVD
Creators: name: Zhao, L.
name: Chae, Y.K.
name: Song, D.
name: Wang, D.
name: Frei, M.
name: Agrawal, M.
name: Yuan, Z.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2629-2632
description: Hydrogenated microcrystalline silicon germanium (μc-SiGe:H) alloy can absorb long-wavelength solar
spectrum with lower optical bandgap and higher absorption coefficient in full wavelength range and has been explored with
many techniques both in industry and in academia. In this paper, the process of intrinsic μc-SiGe:H is developed with
Applied Materials’ AKT 4300 radio-frequency (13.56MHz) PECVD system to replace the commonly used hydrogenated
microcrystalline silicon (μc-Si:H) as the bottom cell absorber layer. 11.72mA/cm2 short circuit current density (Jsc) is
measured with 1.2μm thick μc-SiGe:H layer without doing any optimization at the device level. It provides 4.4% higher
current compared to its silicon counterpart with 1.95μm thickness. The quantum efficiency measurement shows gain in the
wavelength range from 600nm to 1100nm. Thickness variation over the 30cmx30cm module area is controlled small than
3.1%. The uniformity is also confirmed with the segment measurement at different locations of the module.
Benefits of Innovative Encapsulants for Micromorph® Technology
Creators: name: Sarigiannidis, C.
name: Asimakopoulou, E.
name: Lekkakos, T.
name: Katsia, E.
name: Moeyersons, L.
name: Fehlings, M.
name: Farmakis, F.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2691-2694
description: HelioSphera SA produces 1.42 m2 Micromorph® tandem solar cells manufactured on equipment
provided by Oerlikon Solar. These cells combine the advantages of amorphous silicon, such us high absorption at
the visible range, with the stability and spectral sensitivity at long wavelengths of microcrystalline silicon.
Photovoltaic modules are expected to maintain power output within acceptable limits over a period of 25 years and
beyond. To meet these challenging lifetime requirements, Heliosphera SA is continuously looking for new cost
effective approaches in collaboration with material suppliers. Encapsulant materials must provide protection and
electrical isolation of the PV module components from the environment. DuPont Photovoltaic Encapsulant
Solutions introduced new innovative encapsulants for PV applications such as DuPont PV5300 sheets based on
Ionomer technology. This paper discusses the use of high performance, cost-effective materials like Ionomer
encapsulants which will improve cell life and maintain cell efficiency.
Simulation of Plasma Enhanced Chemical Vapor Deposition of Microcrystalline Silicon Thin Films in an Industrially Relevant Bench Chamber
Creators: name: Amanatides, E.
name: Mataras, D.
name: Salabas, A.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2695-2698
description: A 2D model of gas phase chemistry of SiH4/H2 discharges was combined to a detailed surface model of μc Si:H thin film growth. The model was used for the investigation of edge effects on the deposition uniformity in a bench chamber similar to those used for micromorph solar panel manufacturing. RF electrode and substrate holder edges were found to affect all plasma properties as electric potential, electron density distribution and species production leading finally to a non-uniform flux of species to the surface and non-uniform deposition rate. Negative ions are produced and accumulated preferentially on the edges probably initiating particle formation in these areas. In addition, material grows rougher and less crystalline on the edges due to the change in the composition of the species reaching the surface and also due to the change in their angle of incidence and the consequent shadowing effects.
Towards Better Understanding of Long-Term Stability in Thin Film Microcrystalline Silicon Solar Cells
Creators: name: Hänni, S.
name: Battaglia, C.
name: Boccard, M.
name: Bugnon, G.
name: Cuony, P.
name: Despeisse, M.
name: Ding, L.
name: Nicolay, S.
name: Sculati-Meillaud, F.
name: Ballif, C.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2699-2703
description: High-efficiency p-i-n microcrystalline silicon single-junction solar cells are fabricated and their longterm
stability is investigated. We focus in particular on the stability of the absorber layer after atmospheric storage in
absence of light and compare non-encapsulated devices with different cell design and crystalline volume fractions.
Furthermore, an innovative stack of transparent conductive oxide is used as front electrode in order to investigate the
effect of small surface roughness on the electrical properties and the stability of solar cells. Finally, an outstanding
single-junction microcrystalline cell showing 10.4% conversion efficiency without anti-reflection coating is presented.
The Effect of Nitrogen Contamination in Hydrogen on Silicon Thin Films Deposited by PECVD and Its Impact on Solar Cell Performance
Creators: name: Madec, A.
name: Chevrel, H.
name: Chen, H.-M.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2709-2713
description: Hydrogen is used in the production of both amorphous (a-Si) and microcrystalline (μc-Si ) thin film solar cells.
In this study, we examined the influence of the hydrogen quality, specifically, the nitrogen contamination levels, on the
performance of the solar cells. The films were deposited using a 40 MHz VHF plasma-enhanced chemical vapor deposition
(PECVD) system. During the deposition of Si thin films, the 99.999% (5N ; nitrogen specification is 1 to 3 ppm) purity
hydrogen, normally used to produce both the a-Si and μc-Si films, was replaced with four different purities of hydrogen,
which contain 100, 500, 1000 and 5000 ppm of nitrogen. The properties of the deposited a-Si and μc-Si films are evaluated
with different measurement techniques such as photoconductivity, dark conductivity, SIMS, transmission spectroscopy and
Raman spectroscopy. It was determined that higher levels of nitrogen increased the dark conductivity and also decreased the
photoconductivity. For the μc-Si films deposited under the normal operating conditions, the Raman spectroscopy results
indicated a change in the morphology and a reduction in the film crystallinity at higher nitrogen levels. Solar cell modules
were also manufactured using the same parameters as the single Si film discussed earlier, and films and cell performances
were evaluated by measuring the cell efficiency, filling factor (FF), short circuit current density (Jsc), open circuit voltage
(Voc), and quantum efficiency (QE) measurements. It was observed that the increase of nitrogen contaminant level in the
hydrogen influences the defect density and results in the decrease of the cell performance as measured by the quality
parameters mentioned above.
Microcrystalline Silicon Single Junction Solar Cells on Rough Zinc Oxide
Creators: name: Rohde, M.
name: Severin, D.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2688-2690
description: It is common consensus that thin film silicon solar cell efficiencies need to improve. One approach is to
enhance the light trapping for an increased optical path length inside the absorber layer. This mitigates the relatively
low absorption of the indirect semiconductor silicon and enables higher short circuit currents. Typically, the light
trapping is performed by using a transparent front contact with a rough surface morphology. Despite the higher short
circuit current, strongly textured substrate morphology leads very often to electronically inferior material with
decreased fill factor and lower open circuit voltage. This effect is more pronounced on μc-Si single junctions than on
a-Si/μc-Si tandem junctions. In this work, we study the interplay between the surface morphology and the electronic
properties of μc-Si single junctions. It is found that the morphology can have a significant impact on the silicon
crystallinity which affects the electronic properties of the single junction solar cell. Therefore, single junctions are an
excellent vehicle to further study the trade-off between light trapping and silicon material quality.
Spectral Influences on Measurement Uncertainty of a-Si/μc-Si Multi-Junction Solar Devices
Creators: name: Seifert, H.
name: Hohl-Ebinger, J.
name: Warta, W.
Publisher: name: WIP
Year: 2011
Subjects: Thin Film Solar Cells
Amorphous and Microcrystalline Silicon Solar Cells

description: 26th European Photovoltaic Solar Energy Conference and Exhibition; 2714-2717
description: If multi-junction solar devices are measured at artificial sunlight, the results are strongly affected by the
spectral irradiance of the sun simulator. Therefore a spectral adjustment of a multi-source solar simulator is crucial to
ensure standard test conditions (STC). The calculation of the settings, in terms of spectral correction, is done with respect
to the spectral response (SR) of the reference cell and all sub cells of the test device, as well as the spectral distributions
of each source of the solar simulator. In this study we examine the measurement uncertainties of the SR of both sub cells
of an a-Si/μc-Si tandem solar cell. The relative input data of the spectral correction procedure are varied with random
walks within their uncertainty.