311 research outputs found
Selective-area high-quality germanium growth for monolithic integrated optoelectronics
Cataloged from PDF version of article.Selective-area germanium (Ge) layer on silicon (Si)
is desired to realize the advanced Ge devices integrated with
Si very-large-scale-integration (VLSI) components. We demonstrate
the area-dependent high-quality Ge growth on Si substrate
through SiO2 windows. The combination of area-dependent
growth and multistep deposition/hydrogen annealing cycles has
effectively reduced the surface roughness and the threading dislocation
density. Low root-mean-square surface roughness of 0.6 nm
is confirmed by atomic-force-microscope analysis. Low defect density
in the area-dependent grown Ge layer is measured to be as low
as 1 × 107 cm−2 by plan-view transmission-electron-miscroscope
analysis. In addition, the excellent metal–semiconductor–metal
photodiode characteristics are shown on the grown Ge layer to
open up a possibility to merge Ge optoelectronics with Si VLSI
Experimental and theoretical investigation of phosphorus in-situ doping of germanium epitaxial layers
Cataloged from PDF version of article.We investigate phosphorus in-situ doping characteristics in germanium (Ge) during epitaxial growth by spreading resistance profiling analysis. In addition, we present an accurate model for the kinetics of the diffusion in the in-situ process, modeling combined growth and diffusion events. The activation energy and pre-exponential factor for phosphorus (P) diffusion are determined to be 1.91 eV and 3.75 x 10(-5) cm(2)/s. These results show that P in-situ doping diffusivity is low enough to form shallow junctions for high performance Ge devices. (C) 2013 Elsevier B.V. All rights reserve
High-Efficiency p-i-n Photodetectors on Selective-Area-Grown Ge for Monolithic Integration
Cataloged from PDF version of article.We demonstrate normal incidence p-i-n photodiodes
on selective-area-grown Ge using multiple hydrogen annealing
for heteroepitaxy for the purpose of monolithic integration. An
enhanced efficiency in the near-infrared regime and the absorption
edge shifting to longer wavelength is achieved due to 0.14% residual
tensile strain in the selective-area-grown Ge. The responsivities
at 1.48, 1.525, and 1.55 μm are 0.8, 0.7, and 0.64 A/W, respectively,
without an optimal antireflection coating. These results are
promising toward monolithically integrated on-chip optical links
and in telecommunications
Scientific cruise report of the arctic expedition ARK-XX/3 of RV Polarstern in 2004: Fram Strait, Yermak Plateau and East Greenland Continental Margin
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Polymer electrolytes for a rechargeable li-Ion battery
Lithium-ion polymer electrolyte battery technology is attractive for many consumer and military applications. A Li{sub x}C/Li{sub y}Mn{sub 2}O{sub 4} battery system incorporating a polymer electrolyte separator base on novel Li-imide salts is being developed under sponsorship of US Army Research Laboratory (Fort Monmouth NJ). This paper reports on work currently in progress on synthesis of Li-imide salts, polymer electrolyte films incorporating these salts, and development of electrodes and cells. A number of Li salts have been synthesized and characterized. These salts appear to have good voltaic stability. PVDF polymer gel electrolytes based on these salts have exhibited conductivities in the range 10{sup -4} to 10{sub -3} S/cm
Physics at a 100 TeV pp collider: beyond the Standard Model phenomena
This report summarises the physics opportunities in the search and study of
physics beyond the Standard Model at a 100 TeV pp collider.Comment: 196 pages, 114 figures. Chapter 3 of the "Physics at the FCC-hh"
Repor
Excess Higgs Production in Neutralino Decays
The ATLAS and CMS experiments have recently claimed discovery of a Higgs
boson-like particle at ~5 sigma confidence and are beginning to test the
Standard Model predictions for its production and decay. In a variety of
supersymmetric models, a neutralino NLSP can decay dominantly to the Higgs and
the LSP. In natural SUSY models, a light third generation squark decaying
through this chain can lead to large excess Higgs production while evading
existing BSM searches. Such models can be observed at the 8 TeV LHC in channels
exploiting the rare diphoton decays of the Higgs produced in the cascade decay.
Identifying a diphoton resonance in association with missing energy, a lepton,
or b-tagged jets is a promising search strategy for discovery of these models,
and would immediately signal new physics involving production of a Higgs boson.
We also discuss the possibility that excess Higgs production in these SUSY
decays can be responsible for enhancements of up to 50% over the SM prediction
for the observed rate in the existing inclusive diphoton searches, a scenario
which would likely by the end of the 8 TeV run be accompanied by excesses in
the diphoton + lepton/MET and SUSY multi-lepton/b searches and a potential
discovery in a diphoton + 2b search.Comment: 42 pages, 19 figure
Constraints on Sub-GeV Dark Matter--Electron Scattering from the CDEX-10 Experiment
We present improved germanium-based constraints on sub-GeV dark matter via
dark matter--electron (-) scattering using the 205.4 kgday
dataset from the CDEX-10 experiment. Using a novel calculation technique, we
attain predicted - scattering spectra observable in high-purity
germanium detectors. In the heavy mediator scenario, our results achieve 3
orders of magnitude of improvement for larger than 80 MeV/c
compared to previous germanium-based - results. We also present the
most stringent - cross-section limit to date among experiments using
solid-state detectors for larger than 90 MeV/c with heavy
mediators and larger than 100 MeV/c with electric dipole
coupling. The result proves the feasibility and demonstrates the vast potential
of a new - detection method with high-purity germanium detectors in
ultralow radioactive background.Comment: 6 pages, 3 figures. Version updated to match PRL versio
Movement of the human foot in 100 pain free individuals aged 18–45 : implications for understanding normal foot function
Background:
Understanding motion in the normal healthy foot is a prerequisite for understanding the effects of pathology and thereafter setting targets for interventions. Quality foot kinematic data from healthy feet will also assist the development of high quality and research based clinical models of foot biomechanics. To address gaps in the current literature we aimed to describe 3D foot kinematics using a 5 segment foot model in a population of 100 pain free individuals.
Methods:
Kinematics of the leg, calcaneus, midfoot, medial and lateral forefoot and hallux were measured in 100 self reported healthy and pain free individuals during walking. Descriptive statistics were used to characterise foot movements. Contributions from different foot segments to the total motion in each plane were also derived to explore functional roles of different parts of the foot.
Results:
Foot segments demonstrated greatest motion in the sagittal plane, but large ranges of movement in all planes. All foot segments demonstrated movement throughout gait, though least motion was observed between the midfoot and calcaneus. There was inconsistent evidence of movement coupling between joints. There were clear differences in motion data compared to foot segment models reported in the literature.
Conclusions:
The data reveal the foot is a multiarticular structure, movements are complex, show incomplete evidence of coupling, and vary person to person. The data provide a useful reference data set against which future experimental data can be compared and may provide the basis for conceptual models of foot function based on data rather than anecdotal observations
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