The Kinetics of Capture and Emission of Discrete DX Related Centers in Silicon Doped AlGaAs Using Time Analyzed Transient Spectroscopy

1995 ◽  
Vol 378 ◽  
Author(s):  
Sandeep Agarwal ◽  
Y. N. Mohapatra
Keyword(s):  
Accurate Identification ◽  
Spectral Lineshape ◽  
Filling Time ◽  
Capacitance Voltage ◽  
Dx Center ◽  
Voltage Transients ◽  
Transient Spectroscopy ◽  
Silicon Doped ◽  
Kinetics Of

AbstractThe kinetics of multiple DX related emission centers are studied using the isothermal Time Analyzed Transient Spectroscopy (TATS) of constant capacitance voltage transients. Four distinct emitting centers have been obtained using higher order TATS in the same silicon doped Al0.33As0.67As sample without use of hydrostatic pressure. Accurate identification of the multiple DX states has allowed a better understanding of the charge redistribution process during capture. Improved resolution due to increase in order of spectroscopy has enabled quantitative fitting of spectral lineshape and thus accounting for degree of nonexponentiality associated with each of the four discrete centers. The capture kinetics of these centers are studied over six orders in magnitude of filling time. The resulting quality of kinetic data makes possible detailed quantitative comparison with kinetics predicted by positive U and negative U models of DX centers. We show that our data is in agreement with positive U model of DX center.

Evidence for Metastabile State of DX Center in AxGa1-xAs

1992 ◽  
Vol 262 ◽  
Author(s):  
Subhasis Ghosh ◽  
Vikram Kumar
Keyword(s):  
Activation Energy ◽  
Deep Level Transient Spectroscopy ◽  
Thermal Activation ◽  
Deep Level ◽  
Thermal Activation Energy ◽  
Dx Centers ◽  
Dx Center ◽  
Transient Spectroscopy ◽  
Silicon Doped ◽  
First Time

ABSTRACTPhoto-Deep Level Transient Spectroscopy with 1.38 eV light reveals a new level with thermal activation energy 0.2 eV of DX centers in silicon doped Alx Ga1-xAs (x = 0.26) for the first time. The observation of this level directly proves the negative-U properties of DX centers and the existence of thermodynamically metastable state DX.

Formation of Intrinsic Defects at MBE-Grown GaAs/AlAs Interfaces

1993 ◽  
Vol 312 ◽  
Author(s):  
P. Krispin ◽  
R. Hey ◽  
H. Kostial ◽  
M. Höricke
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Depth Profiling ◽  
Intrinsic Defects ◽  
Capacitance Voltage ◽  
Charge States ◽  
Transient Spectroscopy ◽  
Silicon Doped ◽  
Arsenic Vacancy

AbstractWe report on a detailed investigation of MBE-grown isotype silicon-doped heterostructures by capacitance/voltage (C/V) technique and deep-level transient spectroscopy (DLTS). A sequence of electrically active defects is found. By depth profiling of the density of the dominant levels it is demonstrated that the corresponding defects are concentrated at the GaAs-on-AlAs (inverted) interface. By comparison with studies on irradiation-induced levels in LPE- or VPE-grown AlGaAs we conclude that the defects at the GaAs/AlAs interface are most probably linked to different charge states of the arsenic vacancy VAs and VAs−ASi pairs.

Hydrogen and Lithium Passivation of Gold in Silicon: A Comparative Study

1995 ◽  
Vol 378 ◽  
Author(s):  
E. ö. Sveinbjörnsson ◽  
S. Kristjansson ◽  
O. Engström ◽  
H. P. Gislason
Keyword(s):  
Complex Formation ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Opposite Charge ◽  
Active Complex ◽  
Capacitance Voltage ◽  
Transient Spectroscopy ◽  
Kinetics Of ◽  
Secondary Ion ◽  
Coulomb Attraction

AbstractWe report studies of passivation of the gold center in silicon by hydrogen and lithium using deep level transient spectroscopy (DLTS), capacitance voltage (CV) profiling and secondary ion mass spectroscopy (SIMS). Both lithium and hydrogen are able to remove the electrical activity of the gold center from the silicon band gap but the passivation mechanisms are different. In the case of lithium the passivation is most likely due to a Coulomb attraction between lithium donors Li+ and gold acceptors Au−. No complex formation is observed between Li+ and Au0. In contrast, hydrogen is able to passivate the gold center without the need of opposite charge states of the species involved. Two Au-H complexes are observed, one (G) electrically active, and another (PA) passive. Based on the annealing kinetics of these complexes we propose that the active complex is a Au-H pair and that the passive complex contains two H atoms (Au-H2).

scholarly journals Емкостная спектроскопия гетероэпитакиальных AlGaAs/GaAs p-i-n-структур

2020 ◽  
Vol 54 (10) ◽  
pp. 1072
Author(s):  
М.М. Соболев ◽  
Ф.Ю. Солдатенков
Keyword(s):  
Thermal Activation ◽  
Correlation Energy ◽  
Deep Level ◽  
Electron Capture Cross Section ◽  
Type Layer ◽  
Capacitance Voltage ◽  
Temperature Dependences ◽  
Carrier Trap ◽  
Dx Center ◽  
Transient Spectroscopy

Temperature dependences of capacitance-voltage (C−V) characteristics and deep-level spectra of the graded highvoltage AlxGa1−xAs p0 −i−n0 junction grown by liquid-phase epitaxy via autodoping with background impurities were investigated. The changes of the C−V characteristics at varied measurement temperature and optical illumination demonstrated that the p0-, i-,n0-type layers in the AlxGa1−xAs under study contain bistable DX centers. In spectra of deep-level transient spectroscopy (DLTS), measured at various bias voltages Vr and filling pulses Vf , a positive DLTS peak is observed for the n 0 -type layer with thermal activation energy Et = 280 meV and electron-capture cross-section σn = 3.17 · 10−14 cm2, which is unusual for a majority-carrier trap. This peak is related to the negatively charged state of the Se/Te donor impurity, which is a bistable DX center with negative correlation energy U.

Persistent Photoconductivity And Thermal Recovery Kinetics Of Low Energy Ar + Bombarded GaAs

1991 ◽  
Vol 223 ◽  
Author(s):  
A. Vaseashta ◽  
L. C. Burton
Keyword(s):  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Thermal Recovery ◽  
Low Energy ◽  
Persistent Photoconductivity ◽  
Transport Parameters ◽  
Excellent Correlation ◽  
Proposed Model ◽  
Transient Spectroscopy ◽  
Kinetics Of

ABSTRACTKinetics of persistent photoconductivity, photoquenching, and thermal and optical recovery observed in low energy Ar+ bombarded on (100) GaAs surfaces have been investigated. Rate and transport equations for these processes were derived and simulated employing transport parameters, trap locations and densities determined by deep level transient spectroscopy. Excellent correlation was obtained between the results of preliminary simulation and the experimentally observed values. The exponential decay of persistent photoconductivity response curve was determined to be due to metastable electron traps with longer lifetime and is consistent with an earlier proposed model.

STUDYING THE KINETIC CHARACTERISTICS OF THE EXTRACTION OF ANTHOCYANINS FROM THE SQUEEZE OF KRASNOSTOP ZOLOTOVSKY

2020 ◽  
Author(s):  
M.A. Egyan ◽  
Keyword(s):  
Reaction Rate ◽  
Sugar Content ◽  
Extraction Process ◽  
Efficiency Coefficient ◽  
Kinetic Characteristics ◽  
Reaction Rate Constants ◽  
Solids Content ◽  
Kinetics Of ◽  
Process Speed

The article shows studies characterizing the quality of the squeeze: the mechanical composition of the squeeze is determined, the structural moisture of each component is determined, the sugar content in the formed process of sedimentation of the juice and its acidity are determined refractometrically. The kinetics of anthocyanins extraction was determined in two ways, the solids content in the extract was calculated, and the reaction rate constants of the extraction process and the efficiency coefficient of ultrasonic amplification of the extraction process speed were calculated.

A model to predict the kinetics of mass loss in wood during thermo-vacuum modification

Holzforschung ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ottaviano Allegretti ◽  
Ignazia Cuccui ◽  
Nasko Terziev ◽  
Laerte Sorini
Keyword(s):  
Mass Loss ◽  
Treatment Process ◽  
Linear Trend ◽  
Thermal Modification ◽  
Thermal Treatments ◽  
Temperature Profiles ◽  
Relative Area ◽  
Heat Power ◽  
Kinetics Of

AbstractMass loss (ML) of wood caused by thermal degradation is one of the most important features of the thermal treatments and referred to as an indicator of intensity and quality of the process. The ML is proportional to the quantity of the effective heat power exchanged during the treatment process, represented by the area of the temperature profile versus time during the process. In this paper a model for the ML prediction based on the relative area was discussed. The model proposed an analytical solution to take into account the non-linear trend of ML when plotted versus temperature and time as observed in isothermal experiments. The model was validated comparing calculated and measured final ML of samples treated during thermal modification tests with different temperature profiles. The results showed that the relative area calculated in a transformed time-temperature space improves the correlation with the measured ML.

Fluorenone oxide: transient spectroscopy and kinetics of its formation and reactions

1985 ◽  
Vol 107 (16) ◽  
pp. 4616-4620 ◽  
Author(s):  
H. L. Casal ◽  
M. Tanner ◽  
N. H. Werstiuk ◽  
J. C. Scaiano
Keyword(s):  
Transient Spectroscopy ◽  
Kinetics Of

scholarly journals Combining experimental and simulation data of molecular processes via augmented Markov models

2017 ◽  
Vol 114 (31) ◽  
pp. 8265-8270 ◽  
Author(s):  
Simon Olsson ◽  
Hao Wu ◽  
Fabian Paul ◽  
Cecilia Clementi ◽  
Frank Noé
Keyword(s):  
Force Field ◽  
Structural Changes ◽  
Markov Models ◽  
Force Fields ◽  
Divide And Conquer ◽  
Simulation Data ◽  
Wide Range ◽  
Simulation And Experiment ◽  
Kinetics Of

Accurate mechanistic description of structural changes in biomolecules is an increasingly important topic in structural and chemical biology. Markov models have emerged as a powerful way to approximate the molecular kinetics of large biomolecules while keeping full structural resolution in a divide-and-conquer fashion. However, the accuracy of these models is limited by that of the force fields used to generate the underlying molecular dynamics (MD) simulation data. Whereas the quality of classical MD force fields has improved significantly in recent years, remaining errors in the Boltzmann weights are still on the order of a few kT, which may lead to significant discrepancies when comparing to experimentally measured rates or state populations. Here we take the view that simulations using a sufficiently good force-field sample conformations that are valid but have inaccurate weights, yet these weights may be made accurate by incorporating experimental data a posteriori. To do so, we propose augmented Markov models (AMMs), an approach that combines concepts from probability theory and information theory to consistently treat systematic force-field error and statistical errors in simulation and experiment. Our results demonstrate that AMMs can reconcile conflicting results for protein mechanisms obtained by different force fields and correct for a wide range of stationary and dynamical observables even when only equilibrium measurements are incorporated into the estimation process. This approach constitutes a unique avenue to combine experiment and computation into integrative models of biomolecular structure and dynamics.

Runner Balance Design of Soap Box Compounding Cavity Based on Moldflow

2014 ◽  
Vol 941-944 ◽  
pp. 1678-1681
Author(s):  
Hong Bing Wang ◽  
Zhi Rong Li ◽  
Chun Hua Sun ◽  
Yi Ping Zhang
Keyword(s):  
Three Dimensional ◽  
Simulation Software ◽  
Injection Mold ◽  
Balance Design ◽  
Filling Time ◽  
Critical Defect ◽  
Filling Analysis ◽  
Different Dimensions ◽  
Moldflow Simulation

Filling unbalance is a critical defect for injection mould. When the upper and lower covers of soap plastic box are produced by injection mold at the same time, filling unbalance in injection would appear because of the different dimensions of the two parts. For advancing the quality of the soap plastic box, the runner system is optimized with the filling analysis module and flow runner balance module of moldflow simulation software. The three-dimensional geometrical models of the two covers are constructed using Pro/e software. In moldflow the runner balance optimization of the soap box compounding cavity is analysis. The results indicate the optimized cross section of the runners can reduce the flow unbalance ratio from 3.38% to 0.73%, and the filling time and pressure can satisfy the demands. According to the analysis results moldflow is appropriate for runner balance design of the plastic products.

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