55 research outputs found
Dynamics of nonequilibrium quasiparticles in a double superconducting tunnel junction detector
We study a class of superconductive radiation detectors in which the
absorption of energy occurs in a long superconductive strip while the redout
stage is provided by superconductive tunnel junctions positioned at the two
ends of the strip. Such a device is capable both of imaging and energy
resolution. In the established current scheme, well studied from the
theoretical and experimental point of view, a fundamental ingredient is
considered the presence of traps, or regions adjacent to the junctions made of
a superconducting material of lower gap. We reconsider the problem by
investigating the dynamics of the radiation induced excess quasiparticles in a
simpler device, i.e. one without traps. The nonequilibrium excess
quasiparticles can be seen to obey a diffusion equation whose coefficients are
discontinuous functions of the position. Based on the analytical solution to
this equation, we follow the dynamics of the quasiparticles in the device,
predict the signal formation of the detector and discuss the potentiality
offered by this configuration.Comment: 16 pages, 5 figures Submitted to Superconducting Science and
Technolog
Atomic layer deposition of high-k dielectric layers on Ge and III-V MOS channels
Ge and III-V semiconductors are potential high performance channel materials for future CMOS devices. In this work, we have studied At. Layer Deposition (ALD) of high-k dielec. layers on Ge and GaAs substrates. We focus at the effect of the oxidant (H2O, O3, O2, O2 plasma) during gate stack formation. GeO2, obtained by Ge oxidn. in O2 or O3, is a promising passivation layer. The germanium oxide thickness can be scaled down below 1 nm, but such thin layers contain Ge in oxidn. states lower than 4+. Still, elec. results indicate that small amts. of Ge in oxidn. states lower than 4+ are not detrimental for device performance. Partial intermixing was obsd. for high-k dielec. and GeO2 or GaAsOx, suggesting possible correlations in the ALD growth mechanisms on Ge and GaAs substrates. [on SciFinder (R)
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An overview on the inconsistencies of approach in regulating the capital position of banks: Will the United Kingdom step out of line with Europe?
After the collapse of a number of banking institutions and bailouts of banks by governments, regulators have taken a different attitude and now appear keen to take regulation seriously when it comes to ensuring that banks have adequate capital and sufficient liquidity. Not only that, but in the United Kingdom, the Independent Commission on Banking Reform has made proposals with regard to the capital position of banks. This article, which is an overview, will look at matters from a UK perspective and at the proposals for reform. This article, after its introduction and summary, will look at a number of areas: first, the reforms made by Basel III; second, the regulation of Systemically Important Financial Institutions (Sifis) and the proposals for dealing with these; third, some matters in relation to lending that relate to capital and liquidity generally; fourth, increased stress testing of banks; fifth, derivatives and risk taking and the new proposed structure of regulation in the United Kingdom; sixth, the war of spin between regulators and banks; seventh, Shadow Banking; and eighth, The Independent Commission on Banking Reform and its proposals for reform. It will also be a theme that the various proposals lack consistency and that this could lead to regulatory arbitrage. It is already clear that there are inconsistencies between the various regulatory organisations, with proposals in the United Kingdom indicating that banks will be required to keep much higher levels of capital than those proposed by Basel and the European Community. The views of those who have pointed out inconsistencies between the United Kingdom and Basel/Europe have been highlighted
Systemic Risk: Fire-Walling Financial Systems Using Network-Based Approaches
The latest financial crisis has painfully revealed the dangers arising from a
globally interconnected financial system. Conventional approaches based on the
notion of the existence of equilibrium and those which rely on statistical
forecasting have seen to be inadequate to describe financial systems in any
reasonable way. A more natural approach is to treat financial systems as
complex networks of claims and obligations between various financial
institutions present in an economy. The generic framework of complex networks
has been successfully applied across several disciplines, e.g., explaining
cascading failures in power transmission systems and epidemic spreading. Here
we review various network models addressing financial contagion via direct
inter-bank contracts and indirectly via overlapping portfolios of financial
institutions. In particular, we discuss the implications of the
"robust-yet-fragile" nature of financial networks for cost-effective regulation
of systemic risk.Comment: 19 pages, 7 figure
Insider perspectives on European banking challenges in the post-crisis regulation environment
Operational Risk Management in Practice: Implementation, Success Factors and Pitfalls: Efficient Implementation for Midsize and Small Asset Managers, Hedge Funds, Private Equity Funds, Family Offices
Verteilung des Staubes in der Instillation drei- und zweiphasiger Suspensionen von grubenechtem Feinstaub
High efficiency perovskite solar cells using a PCBM/ZnO double electron transport layer and a short air-aging step
© 2015 Elsevier B.V. All rights reserved. Solution processed CH3NH3PbIxCl3-x based planar heterojunction perovskite solar cells with power conversion efficiency (PCE) above 14% are reported. The devices benefit from a phenyl-C61-butyric acid methyl ester (PCBM)/ZnO double electron transport layer (ETL) as well as a short air-aging step. The role of the additional ZnO ETL is studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and secondary ions mass spectroscopy (SIMS). Apart from improving the energy level alignment, the ZnO layer blocks the reactions between the metal electrode and perovskite components, increasing the air stability of the device. A crucial step in our processing is a short air-aging step for the device, which significantly increases the device performance by reducing the recombination process. Since the ZnO nanoparticle layer requires no thermal annealing, the maximum temperature to fabricate the device can be kept below 100 °C, making this structure compatible with roll-to-roll processing on plastic films.status: publishe
High efficiency perovskite solar cells using a PCBM/ZnO double electron transport layer and a short air-aging step
Solution processed CH3NH3PbIxCl3–x based planar heterojunction perovskite solar cells with power conversion efficiency (PCE) above 14% are reported. The devices benefit from a phenyl-C61-butyric acid methyl ester (PCBM)/ZnO double electron transport layer (ETL) as well as a short air-aging step. The role of the additional ZnO ETL is studied by scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and secondary ions mass spectroscopy (SIMS). Apart from improving the energy level alignment, the ZnO layer blocks the reactions between the metal electrode and perovskite components, increasing the air stability of the device. A crucial step in our processing is a short air-aging step for the device, which significantly increases the device performance by reducing the recombination process. Since the ZnO nanoparticle layer requires no thermal annealing, the maximum temperature to fabricate the device can be kept below 100 °C, making this structure compatible with roll-to-roll processing on plastic films
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