Characterization of Fast Diffusing Charged Defects in Semiconductors

1995 ◽  
Vol 378 ◽  
Author(s):  
T. Heiser ◽  
A. Zamouche ◽  
A. Mesli
Keyword(s):  
Room Temperature ◽  
Charge Movement ◽  
Capacitance Change ◽  
Ion Drift ◽  
Defect Reactions ◽  
Defects In Semiconductors ◽  
Charged Defects ◽  
Kinetics Of ◽  
Good Agreement

AbstractA novel technique is introduced to study fast diffusing charged defects in semiconductors. It is based on the capacitance change induced by ion drift in a reverse biased Schottky barrier. It is shown that such charge movement yields exponential capacitance transients, which contain information about the defect concentration and mobility. The method is checked on Li-diffused samples, where the extracted diffusion coefficient are in good agreement with literature data. It is next applied to interstitial copper (Cui) in silicon. In the proposed experiment Cui gives rise to a well defined signal which enables us to investigate near room temperature defect reactions involving Cui. The diffusion data extracted from copper diffused and quenched silicon samples establishes the origin of the signal. Near room temperature precipitation kinetics of Cui are studied and energy barriers are extracted.

Pyrolysis of Sugarcane Bagasse: A Consecutive Reactions Kinetic Model from TGA Experiments

2010 ◽  
Vol 660-661 ◽  
pp. 593-598 ◽  
Author(s):  
Kássia Graciele dos Santos ◽  
Taisa S. Lira ◽  
Valéria V. Murata ◽  
Marco Gianesella ◽  
Marcos A.S. Barrozo
Keyword(s):  
Kinetic Model ◽  
Sugarcane Bagasse ◽  
Room Temperature ◽  
Linear Method ◽  
Pyrolysis Kinetics ◽  
Heating Rates ◽  
Exponential Factor ◽  
Consecutive Reactions ◽  
Kinetics Of ◽  
Good Agreement

The pyrolysis kinetics of sugarcane bagasse in nitrogen flow was studied by thermogravimetric analysis from room temperature to 1173 K at different heating rates (1.5, 3, 5, 10, 15, 20, 30 and 50 K/min). As there are three distinct devolatilization peaks in the DTG curve, each peak was associated to thermal decomposition of an individual biomass subcomponent (hemicellulose, cellulose and lignin). The kinetic model adopted was a consecutive reactions model. The kinetic parameters of the pyrolysis process, such as activation energy and pre-exponential factor, were calculated by least squares non-linear method and Scilab are used as the simulation tool. The simulated results showed a good agreement with the experimental data and the parameters found are similar to reported by the literature.

Synthesis and Characterization of Nano Crystalline Hydroxyapatite Spheroids Using Anionic Template for Bio Applications

2011 ◽  
Vol 493-494 ◽  
pp. 723-727
Author(s):  
P.Michael SL Shanthi ◽  
M. Ashok ◽  
R.V. Mangalaraja ◽  
T. Balasubramanian
Keyword(s):  
Size Distribution ◽  
Room Temperature ◽  
Precipitation Method ◽  
Uniform Size ◽  
Nano Crystalline ◽  
Co Precipitation ◽  
Anionic Template ◽  
Template Material ◽  
Good Agreement

Nano crystalline Hydroxyapatite (HAp) spheroids of uniform size distribution of diameter ~200 nm have been prepared by co-precipitation method at room temperature. The anionic surfactant SDS has been used as the template material. The calcinated samples were subjected to FTIR and XRD characterizations to confirm the phase of HAp. The Ca/P ratio that has been measured from the EDS spectrum 1.69 has good agreement with the theoretical value. The SEM and TEM images reveal the nano spherical nature and narrow size distribution of the HAp particles, which were good candidates for drug delivery applications.

NMR Study of the Crystallization Kinetics of Cis-Poly(Isoprene)s

1973 ◽  
Vol 46 (1) ◽  
pp. 22-29 ◽  
Author(s):  
R. C. Hirst ◽  
H. Y. Chen
Keyword(s):  
Room Temperature ◽  
Curve Shape ◽  
X Ray Diffraction ◽  
Rigid Lattice ◽  
X Ray ◽  
Nmr Study ◽  
Accurate Comparison ◽  
Dilatometric Studies ◽  
Kinetics Of ◽  
Good Agreement

Abstract The satisfactory agreement between our NMR results and X-ray diffraction results for the crystallinity in stark rubber at room temperature lead us to conclude that the NMR rigid lattice fraction, PRL, may be taken as equal to the fractional crystallinity obtained by other methods. Similarly, the good agreement between the time dependence of PRL at low temperature and the theoretical curve shape strongly suggest that the NMR crystallinity method works well down to at least −25° C for natural rubber and synthetic cis-poly (isoprene). It would be desirable to compare carefully the NMR crystallinity found for rubber crystallized at −25° C with X-ray diffraction results, but we have been unable to find any such X-ray diffraction studies at −25° C. Maximum values of ΔV/V≅0.025 from dilatometric studies appear to imply somewhat smaller crystallinities than those found by NMR, but an accurate comparison is not possible without having X-ray diffraction densities at −25° C. While the present experiments were carried out on unfilled, unstretched, unvulcanized samples, the NMR crystallinity method is equally applicable to samples which are filled, stretched, and vulcanized. Naturally any additive or impurity containing hydrogen is a possible source of interference, but there should be no difficulty in correcting for such interferences.

Computational analyses of cryptic intermediates in the native unfolding pathways of barnase and thioredoxin

Biologia ◽  
2015 ◽  
Vol 70 (4) ◽  
Author(s):  
Tambi Richa ◽  
Thirunavukkarasu Sivaraman
Keyword(s):  
Computational Tool ◽  
Exchange Method ◽  
Proline Isomerization ◽  
Hydrogen Deuterium ◽  
Equilibrium Unfolding ◽  
Computational Analyses ◽  
Unfolding Kinetics ◽  
Kinetics Of ◽  
Good Agreement

AbstractOwing to various experimental constraints, detection and characterization of cryptic intermediates (CIs) presumably existing in the unfolding kinetics of barnase and thioredoxin were not successful by native-state hydrogen-deuterium exchange method at pH 6.4, 306 K and pH 7.0, 298 K, respectively. We have herein demonstrated possible existence of CIs under the solution conditions in native unfolding of the proteins by means of OneG-Vali. Structure and stability of each CI detected for the two proteins by the computational tool have also been delineated and the results were in good agreement with folding intermediates detected in the energetic landscapes of the proteins by variety of methods as reported in the literature. Moreover, we have also discussed unique merits of the computational tool to addressing extent of contributions of cis/trans proline isomerization and CIs on estimating overall thermodynamic stabilities (by various types of equilibrium unfolding experiments) of the proteins.

scholarly journals Kinetic Analysis of the Transformation from 14M Martensite to L21 Austenite in Ni-Fe-Ga Melt Spun Ribbons

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 849
Author(s):  
Alejandro F. Manchón-Gordón ◽  
Raúl López-Martín ◽  
Jhon J. Ipus ◽  
Javier S. Blázquez ◽  
Peter Svec ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Room Temperature ◽  
Solidification Process ◽  
Austenite Phase ◽  
Isothermal Kinetics ◽  
Martensitic Transition ◽  
Characteristic Parameters ◽  
First Order ◽  
Kinetics Of ◽  
Good Agreement

In this study, the non-isothermal kinetics of the martensitic transition from 14M modulated martensite to austenite phase in Ni55Fe19Ga26 ribbons obtained by melt-spinning has been analyzed. The proximity of the martensitic transition to room temperature makes it very sensitive to pressure and subtle differences for different pieces of the ribbon (ascribed to stresses stored in the ribbon during its rapid solidification process). Despite the dispersion in the characteristic parameters of the transition, a general behavior is observed with a decreasing activation energy as the heating rate increases due to the nucleation driven character of the transition. It has been shown that a first-order autocatalysis can describe the temperature evolution of the austenite fraction using only two experimental temperatures. Predicted curves are in good agreement with experimental data.

Room Temperature Contactless Electromodulation Characterization of a Wafer-Sized InGaAs/GaAs/GaAlAs Grinsch Laser Structure

1995 ◽  
Vol 406 ◽  
Author(s):  
Wojciech Krystek ◽  
M. Leibovitch ◽  
Fred H. Pollak ◽  
Godfrey Gumbs ◽  
T. Konopelski
Keyword(s):  
Room Temperature ◽  
Heavy Hole ◽  
Index Of Refraction ◽  
Single Quantum Well ◽  
Graded Index ◽  
Hole Level ◽  
Function Calculation ◽  
Lasing Frequency ◽  
Good Agreement

AbstractUsing contactless electroreflectance at 300K we have characterized the complete potential profile of a pseudomorphic 0.98 μm InGaAs/GaAs/GaAlAs graded index of refraction separate confinement heterostructure laser fabricated by molecular beam epitaxy. Signals were detected from all three relevant portions of the sample. Comparison of the observed transitions from the InGaAs single quantum well (SQW) section with an envelope function calculation (including the effects of strain) made it possible to evaluate the In composition and width of SQW. These values were in good agreement with the intended parameters. The energy of 11H, the fundamental conduction to heavy-hole level (which is closely related to the lasing frequency) can easily be determined to less than ± 1 nm at 300K. From the period of the observed Franz-Keldysh oscillations from the graded GaAlAs region it was possible to directly evaluate the built-in electric field in the structure.

Preparation and Characterization of Sr, Ba Filled Type-I Ge Clathrate Single Crystals

2007 ◽  
Vol 336-338 ◽  
pp. 896-899 ◽  
Author(s):  
Ke Feng Cai ◽  
L.C. Zhang ◽  
Q. Lei
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Nominal Composition ◽  
Type I ◽  
Vibrational Modes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Optimum Synthesis ◽  
Good Agreement

Sr or Ba filled type-I Ge clathrate single crystals were prepared using high pure elemental Ga, Ge, and Sr or Ba as the starting materials, and Ga as a flux. Powder X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC) were used to characterize the crystals, respectively. The results show that large and well-crystallized single crystals can be prepared under optimum synthesis condition. The composition of the crystals is in good agreement with the nominal composition (M8Ga16Ge30, M=Sr, Ba). Raman spectra of the single crystals were studied at room temperature and several of the Raman active vibrational modes in the crystals have been identified.

Avalanche Ruggedness Characterization of 10 kV 4H-SiC MOSFETs

2019 ◽  
Vol 963 ◽  
pp. 773-776 ◽  
Author(s):  
Ashish Kumar ◽  
Sanket Parashar ◽  
Edward van Brunt ◽  
Shadi Sabri ◽  
Satyaki Ganguly ◽  
...  
Keyword(s):  
Failure Analysis ◽  
Room Temperature ◽  
Single Pulse ◽  
Operating Conditions ◽  
Device Failure ◽  
Measured Range ◽  
Good Agreement

In this paper, single pulse unclamped inductive switching (UIS) test of Wolfspeed Gen-3 10 kV, 15 A 4H-SiC MOSFETs is performed for four operating conditions at room temperature. The avalanche energy is observed to be around 7.0 J. The measured values are in good agreement with expected behavior, which may be extrapolated beyond the experimentally measured range. Failure analysis was conducted after each device failure to observe the failure locations. Avalanche parameters of SiC MOSFETs with various voltage ratings are compared. The avalanche energy of the Gen-3 10 kV, 15 A 4H-SiC MOSFETs is obtained to be superior to earlier generations of 10 kV SiC MOSFETs.

X-ray powder diffraction structural characterization of Pb1 − x Ba x Zr0.65Ti0.35O3 ceramic

2007 ◽  
Vol 63 (5) ◽  
pp. 713-718 ◽  
Author(s):  
M. Mir ◽  
V. R. Mastelaro ◽  
P. P. Neves ◽  
A. C. Doriguetto ◽  
D. Garcia ◽  
...  
Keyword(s):  
Phase Transition ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Ceramic Materials ◽  
Powder Diffraction Data ◽  
Rietveld Refinements ◽  
X Ray ◽  
Cubic Structure ◽  
Good Agreement

The structure of Pb1 − x Ba x Zr0.65Ti0.35O3 (PBZT) ceramic materials with 0.00 ≤ x ≤ 0.40 was studied using synchrotron X-ray powder diffraction data. According to the Rietveld refinements, the structure of PBZT ceramics with x = 0.00, 0.10 and 0.20 at room temperature was rhombohedral R3c. A phase transition from rhombohedral to cubic was observed at 543 and 463 K for x = 0.10 and 0.20, respectively. The refinement for the compositions x = 0.30 and x = 0.40 showed a cubic structure from 10 to 450 K, in good agreement with the dielectric properties of these samples.

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