Photoelectric-Yield Studies of c-Si/a-Si:H Interfaces

1995 ◽  
Vol 377 ◽  
Author(s):  
M. Sebastiani ◽  
L. Di Gaspare ◽  
C. Bittencourt ◽  
F. Evangelisti
Keyword(s):  
Valence Band ◽  
Precise Determination ◽  
Spectroscopy Study ◽  
Final State ◽  
A Value ◽  
Valence Band Discontinuity

ABSTRACTWe report the first yield spectroscopy study on well characterized c-Si/a-Si:H heterojunctions grown in situ under UHV conditions. We find that this spectroscopy, when operated in the constant final state mode, allows a direct and precise determination of the valence-band discontinuity at the interface. A value of δEv = 0.44 ± 0.02 eV was found for the discontinuity.

Growth and Characterization of the Binary Defect Alloy Cu2-xSe and the Relation to II–VI/I–III–VI Heterojunction Formation

1995 ◽  
Vol 378 ◽  
Author(s):  
Art J. Nelson ◽  
K. Sinha ◽  
John Moreland
Keyword(s):  
Electronic Structure ◽  
Valence Band ◽  
Photoemission Spectroscopy ◽  
Interfacial Chemistry ◽  
Valence Band Offset ◽  
Force Microscopy ◽  
Atomic Force ◽  
Valence Band Discontinuity

AbstractSynchrotron radiation soft x-ray photoemission spectroscopy was used to investigate the development of the electronic structure at the CdS/Cu2Se heterojunction interface. Cu2−xSe layers were deposited on GaAs (100) by molecular beam epitaxy from Cu2Se sources. Raman spectra reveal a strong peak at 270 cm−1, indicative of the Cu2−xSe phase. Atomic force microscopy reveals uniaxial growth in a preferred (100) orientation. CdS overlayers were then deposited in-situ, at room temperature, in steps on these epilayers. Photoemission measurements were acquired after each growth in order to observe changes in the valence band electronic structure as well as changes in the Se3d and Cd4d core lines. The results were used to correlate the interfacial chemistry with the electronic structure and to directly determine the CdS/Cu2−xSe and heterojunction valence band discontinuity and the consequent heterojunction band diagram. These results are compared to the valence band offset (ΔEv) for the CdS/CuInSe2 heterojunction interface.

Modified ferron assay for speciation characterization of hydrolyzed Al(III): a precise k value based judgment

2009 ◽  
Vol 59 (4) ◽  
pp. 823-832 ◽  
Author(s):  
Ye Changqing ◽  
Wang Dongsheng ◽  
Wu Xiaohong ◽  
Qu Jiuhui ◽  
John Gregory
Keyword(s):  
Kinetic Constant ◽  
Nonlinear Least Squares ◽  
Precise Determination ◽  
K Value ◽  
First Order ◽  
First Order Kinetics ◽  
Parallel Reactions

The speciation of Al-OH complexes in terms of Ala, Alb and Alc could be achieved by traditional ferron assay and Alb is generally considered as Al13, however, the inherent correlation between them remains an enigma. This paper presents a modified ferron assay to get precise determination of Al13 using nonlinear least squares analysis, and to clarify the correlation between Alb and Al13. Two parallel reactions conforming to pseudo-first-order kinetics can simulate the complicate reactions between polynuclear complexes and ferron successfully. Four types of experimental kinetic constant (k value) of Al-OH complexes can be observed by this method when investigating three typical aluminium solutions. Comparing with the results of 27Al NMR, the species with moderate kinetics around 0.001 s−1 can be confirmed to resemble to Al13 polycation. The other types of kinetics are also well-regulated in partially neutralized aluminium solutions with various OH/Al ratios (b values) in the range 0 ∼ 2.5. It would provide potential means to trace the in-situ formation of Al13 in dilute solutions such as coagulation with Al-based coagulants

scholarly journals The PADME Detector

2018 ◽  
Vol 170 ◽  
pp. 01007 ◽  
Author(s):  
Paola Gianotti
Keyword(s):  
Beam Energy ◽  
Positron Beam ◽  
Precise Determination ◽  
Final State ◽  
Missing Mass ◽  
Dark Photon ◽  
Key Points ◽  
Background Events

The PADME experiment, by using the positron beam of the Frascati laboratory, aims at searching for signals of a dark photon, A′ . It will evaluate the final state missing mass of the process e+ e- → A′ γ by knowing the beam energy and measuring the four-momentum of the ordinary recoil photon. The precise determination of this quantity, and the capability to reject background events, are the key points for the success of the experiment. In this paper a description of each component of the PADME detector is given.

Precise Determination of Percent Cure of Epoxide Polymers and Composites via Fiber-Optic Raman Spectroscopy and Multivariate Analysis

1997 ◽  
Vol 51 (2) ◽  
pp. 247-252 ◽  
Author(s):  
Jeffrey F. Aust ◽  
Karl S. Booksh ◽  
Christopher M. Stellman ◽  
Richard S. Parnas ◽  
Michael L. Myrick
Keyword(s):  
Raman Spectroscopy ◽  
Multivariate Analysis ◽  
Real Time ◽  
Fiber Optic ◽  
Precise Determination ◽  
Probe Design ◽  
Epoxide Polymers ◽  
Time Determination

A method for real-time determination of the percent cure of epoxies via in situ fiber-optic Raman spectroscopy has been developed. This method utilizes a probe design developed for real-time monitoring of polymer curing and multivariate analysis to interpret the data and determine percent cure. This method was demonstrated to be reliable to ±0.54% of cure in laboratory samples over a 50–99% cure range. A preliminary study measuring cure percentage in an industrial, glass-reinforced composite has been shown to be reliable to ±0.82% in the 40–90% cure range.

Oceanwide Precise Determination of Sea Surface Height from In-Situ Measurements on Cargo Ships

2014 ◽  
Vol 37 (1) ◽  
pp. 77-96 ◽  
Author(s):  
Ole Roggenbuck ◽  
Jörg Reinking ◽  
Alexander Härting
Keyword(s):  
Sea Surface Height ◽  
Precise Determination ◽  
In Situ Measurements ◽  
Sea Surface

scholarly journals Technique for Measuring Spatial Distribution of the Surface Acoustic Wave Velocity in Metals

2016 ◽  
Vol 41 (4) ◽  
pp. 741-746 ◽  
Author(s):  
Oleh Mokryy ◽  
Oleksandr Tsyrulnyk
Keyword(s):  
Spatial Distribution ◽  
Spatial Resolution ◽  
Rayleigh Waves ◽  
High Spatial Resolution ◽  
Steel Specimen ◽  
Precise Determination ◽  
Local Velocity ◽  
A Value ◽  
Spatially Inhomogeneous

Abstract In this paper a possibility of determining a local velocity of the surface acoustic Rayleigh waves using a transducer, with the rigidly connected emitting and receiving parts, is considered. A problem on spatial resolution of such a transducer for investigation of inhomogeneous specimens is also examined. A high spatial resolution can be obtained due to the transducer displacement by a value less than the distance between the emitting and receiving parts. It is shown that in this case it is not necessary to measure the transducer displacement with a high accuracy for precise determination of the velocity. Such an effect is obtained through measuring the velocity of surface waves in one local region of the specimen with respect to the other. The criterion for optimal spatial resolution selection during spatially inhomogeneous specimens study is also proposed. The proposed criterion use is illustrated on the example of the determination of spatial distribution of the surface acoustic velocity in a steel specimen subjected to inhomogeneous plastic deformation.

X‐ray photoemission core level determination of the GaSb/AlSb heterojunction valence‐band discontinuity

1986 ◽  
Vol 49 (16) ◽  
pp. 1037-1039 ◽  
Author(s):  
G. J. Gualtieri ◽  
G. P. Schwartz ◽  
R. G. Nuzzo ◽  
W. A. Sunder
Keyword(s):  
Valence Band ◽  
Core Level ◽  
X Ray ◽  
Valence Band Discontinuity
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