Space Charge Effects Due to Near Contact Non-Uniform Electric Fields in Semi-Insulating GaAs

1992 ◽  
Vol 261 ◽  
Author(s):  
Narbeh Derhacobian ◽  
Nancy M. Haegel
Keyword(s):  
Theoretical Model ◽  
Electric Field ◽  
Electric Fields ◽  
Power Law ◽  
Current Density ◽  
Charge Effects ◽  
Constant Bias ◽  
Contact Field ◽  
Minority Carriers ◽  
Good Agreement

ABSTRACTVariable length semi-insulating GaAs p+-υ-n+ diodes are used to investigate the influence of near contact electric field non-uniformities on the injection of minority carriers. The results show that despite the presence of highly linear IV characteristics, significant nonuniformities in the electric field dominate the device response. The current density through the device is shown to depend on the device length with a power law J ∞ (L)1.0 at a constant bias. The experimental results are compared, with good agreement, to a theoretical model which treats semi-insulating GaAs as a trap-dominated relaxation semiconductor. Electroabsorption measurements are used to observe the slow transients associated with the appearance of near contact field nonuniformities.

The Electric Field Measuring by Phase Selective Photoreflectance

1996 ◽  
Vol 421 ◽  
Author(s):  
J. S. Hwang ◽  
W. Y. Chou ◽  
S. L. Tyan ◽  
Y. C. Wang ◽  
H. Shen
Keyword(s):  
Electric Field ◽  
Theoretical Calculation ◽  
Buffer Layer ◽  
Electric Fields ◽  
Phase Angle ◽  
Substrate Interface ◽  
Field Measuring ◽  
Lock In ◽  
Good Agreement ◽  
Reference Phase

AbstractThe built-in electric fields in a MBE grown δ-doped GaAs homojunction have been investigated by the techniques of photoreflectance and phase suppression. Two Franz-Keldysh oscillation features originating from two different fields in the structure superimpose with each other in the photoreflectance spectrum. By properly selecting the reference phase of the lock-in amplifier, one of the features can be suppressed, thus enabling us to determine the electric fields from two different regions. We have demonstrated that only two PR spectra, in-phase and outphase components, are needed to find the phase angle which suppresses one of the features. The electric field in the top layer is 3.5 ± 0.2 × 105 V/cm, which is in good agreement with theoretical calculation. The electric field in the buffer layer is 1.2 ± 0.1 × 104 V/cm, which suggests the existence of interface states at the buffer/substrate interface.

Electric field assisted hydrogen fluoride etching of silica

2009 ◽  
Vol 465 (2111) ◽  
pp. 3447-3462 ◽  
Author(s):  
Ruy Batista Santiago Neto ◽  
Bernhard Lesche
Keyword(s):  
Theoretical Model ◽  
Electric Field ◽  
Electric Fields ◽  
Chemical Reaction ◽  
Hydrogen Fluoride ◽  
Critical Analysis ◽  
Mean Field ◽  
Nonlinear Effects ◽  
Dipole Orientation ◽  
Field Screening

The influence of electric fields on the velocity of the chemical reaction 4HF+SiO 2 →SiF 4 +2H 2 O in aqueous solution is investigated experimentally. The field strengths used were high enough to measure nonlinear effects. The results permit a critical analysis of a theoretical model known in literature. The basic idea of dipole orientation changing the rate of the primary step of the chemical reaction can explain the experimental data, but several important details of the original model had to be changed. The primary step involves two hydrogen fluoride (HF) molecules rather than one, and field screening by mobile ions has a significant influence causing nonlinear effects. The fact that field screening plays an important role implies that electric field-assisted HF etching of silica may by used as an instrument for measuring ion concentrations in highly concentrated electrolytes. The data measured may be well described by a theoretical model based on mean field approximations. The results give an insight into the structure of highly concentrated hydrofluoric acid and also permit a critical analysis of applications of the effect in measuring electric fields written in glass samples by electrothermal poling. The effect may also be used for shaping glass surfaces.

ELECTRIC FIELD INFLUENCE ON TRAVELING WAVE PROPAGATION AND STATIONARY PATTERN FORMATION

1995 ◽  
Vol 05 (03) ◽  
pp. 797-807 ◽  
Author(s):  
J. MOSQUERA ◽  
M. GÓMEZ-GESTEIRA ◽  
V. PÉREZ-MUÑUZURI ◽  
A.P. MUÑUZURI ◽  
V. PÉREZ-VILLAR
Keyword(s):  
Wave Propagation ◽  
Pattern Formation ◽  
Electric Field ◽  
Electric Fields ◽  
Traveling Wave ◽  
Traveling Fronts ◽  
Spatial Terms ◽  
Oregonator Model ◽  
Field Influence ◽  
Good Agreement

The electric field influence on pattern formation and traveling wave propagation is investigated in the framework of the Oregonator model. When an electric field is applied to a system that can suffer spatial instabilities, Turing and Turing-like patterns (traveling fronts that become stationary patterns when reaching a zero-flux boundary) are observed. On the other hand, when an electric field is applied to a system that cannot become unstable by spatial terms and where wavefronts are propagating in the absence of electric fields, the velocity of these wavefronts is modified and can even be reversed. This is in good agreement with previous experimental results.

scholarly journals Use of Transport Coefficients to Calculate Properties of Electrode Sheaths of Electric Arcs

1997 ◽  
Vol 50 (3) ◽  
pp. 539 ◽  
Author(s):  
J. J. Lowke ◽  
J. C. Quartel
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Cathode Surface ◽  
Transport Coefficients ◽  
Electric Arcs ◽  
Charge Effects ◽  
Positive Ions ◽  
Thermionic Cathodes ◽  
Principal Source ◽  
Electrode Sheath

Particle conservation equations for electrons and positive ions, together with Poisson"s equation to account for space-charge effects on the electric field, have been solved for the electrode sheath regions of electric arcs. For thermionic cathodes and the anode, we find that the ambipolar diffusion approximation is generally valid. At the surface of the anode we find that there is generally a small retarding electric field. For non-thermionic cathodes and no ionisation due to the electric field in the sheath, we calculate unrealistically high sheath voltages and even then, find that the electric fields at the cathode surface are insufficient for field emission. It is suggested that photoionisation in the region close to the cathode may be a principal source of electrons for non-thermionic cathodes.

An Alternative Approach for Modeling the Hot Carrier Degradation of the Si/SiO2 Interface

1998 ◽  
Vol 513 ◽  
Author(s):  
Zhi Chen ◽  
Jinju Lee ◽  
Joseph W. Lyding
Keyword(s):  
Experimental Data ◽  
Theoretical Model ◽  
Power Law ◽  
Interface Trap ◽  
Hot Carrier ◽  
Alternative Approach ◽  
Physical Insight ◽  
Insight Into ◽  
Good Agreement ◽  
Hot Carrier Degradation

ABSTRACTAn alternative approach for modeling the hot carrier degradation of the Si/SiO2 interface based on the dispersive characteristics of the interface trap generation has been proposed. The timedependent interface trap generation has been modeled using the stretched exponential expression. The conventional power law of degradation is just the approximation of this general form. Very good agreement has been found between the theoretical model and the experimental data. This approach gives more physical insight into the understanding of the mechanism for the interface trap generation.

On the compact modelling of Si nanowire and Si nanosheet MOSFETs

2021 ◽  
Author(s):  
Antonio Cerdeira ◽  
Magali Estrada ◽  
Marcelo Antonio Pavanello
Keyword(s):  
Electric Field ◽  
Electron Concentration ◽  
Current Density ◽  
Electric Field Distribution ◽  
Double Gate ◽  
Si Nanowire ◽  
Circuit Simulator ◽  
Aspect Ratios ◽  
Good Agreement ◽  
Tcad Simulations

Abstract In this paper, 3D TCAD simulations are used to show that the electron concentration, current density, and electric field distribution from the interface at the lateral channels and from the top channel to the centre of the silicon wire, in Nanowire and Nanosheet structures, are practically same. This characteristic makes possible to consider that the total channel width for these structures is equal to the perimeter of the transistor sheet, allowing to extend the application of the Symmetric Doped Double-Gate Model (SDDGM) model to Nanowires and Nanosheets MOSFETs, with no need to include new parameters. The Model SDDGM is validated for this application using several measured and simulated structures of Nanowires and Nanosheets transistors, with different aspect ratios of fin width and fin height, showing very good agreement between measured or simulated characteristics and modelled. SDDGM is encoded in Verilog-A language and implemented in SmartSPICE circuit simulator.

How does dissipation work in the electron diffusion region of asymmetric magnetic reconnection

2020 ◽  
Author(s):  
Michael Hesse ◽  
Cecilia Norgren ◽  
Paul Tenfjord ◽  
James Burch ◽  
Yi-Hsin Liu ◽  
...  
Keyword(s):  
Electric Field ◽  
Magnetic Reconnection ◽  
Stagnation Point ◽  
Electric Fields ◽  
Current Density ◽  
Electron Flow ◽  
Diffusion Region ◽  
Density Maximum ◽  
Density Peak ◽  
Electron Diffusion

<p>At some level, magnetic reconnection functions by means of a balance between current dissipation, and current maintenance due to the reconnection electric field. While this dissipation is well understood process in symmetric magnetic reconnection, the way nonideal electric fields interact with the current density in asymmetric reconnection is still unclear. In symmetric reconnection, the current density maximum, the X point location, and the nonideal electric field determined by the divergence of the electron pressure tensor usually coincide. In asymmetric reconnection, however, the electric field at the X point can be partly provided by bulk inertia terms, implying that the X point cannot be the dominant location of dissipation. On the other hand, we know that the nongyrotropic pressure-based electric field must dominate at the stagnation point of the in-plane electron flow, and that electron distributions here feature crescents. The further fact that the current density peak is shifted off the position of the X point indicates that there may be a relation between this current density enhancement, the location of the stagnation point, and the electron nongyrotropies. In this presentation we report on further progress investigating the physics of the electron diffusion region in asymmetric reconnection with a focus on how to explain the dissipation operating under these conditions. </p>

scholarly journals Time-Dependent Electric Field Distribution in Layered Paper-Oil Insulation

2019 ◽  
pp. 58-63 ◽  
Author(s):  
Gunnar Håkonseth ◽  
Erling Ildstad
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Fields ◽  
Current Density ◽  
Test Object ◽  
Dielectric Response ◽  
Electric Field Distribution ◽  
Time Dependent ◽  
Polarization Current ◽  
Dependent Polarization

Layered paper–oil insulation is used in several types of HVDC equipment. In order to better understand breakdown mechanisms and optimize the design, it is important to understand the electric field distribution in the insulation. In the present work, a test object with such insulation has been modeled as a series connection of oil and impregnated paper. The permittivity, conductivity, and the dielectric response function has been measured for impregnated paper and oil separately and used as parameters in a dielectric response model for the layered insulation system. A system of differential equations has been established describing the voltages across each material, i.e. across each layer of the test object. These equations have been solved considering a DC step voltage across the whole test object. Based on this, the time-dependent electric field in each material as well as the time-dependent polarization current density in the test object have been calculated. The calculated polarization current density was found to agree well with the measured polarization current density of the test object. This indicates that application of dielectric response theory gives a good estimate of the time-dependent electric field distribution in layered insulation systems. The results show that 90 % of the change from initial values to steady-state values for the electric fields has occurred within the first 35 minutes after the voltage step. This applies to the electric fields in both of the materials of the examined test object at a temperature of 323 K.

Electric field in media with power-law spatial dispersion

2016 ◽  
Vol 30 (10) ◽  
pp. 1650132 ◽  
Author(s):  
Vasily E. Tarasov
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Power Law ◽  
Wave Vector ◽  
Point Charge ◽  
Spatial Dispersion ◽  
Multipole Expansion ◽  
The Media ◽  
The Absolute

In this paper, we consider electric fields in media with power-law spatial dispersion (PLSD). Spatial dispersion means that the absolute permittivity of the media depends on the wave vector. Power-law type of this dispersion is described by derivatives and integrals of non-integer orders. We consider electric fields of point charge and dipole in media with PLSD, infinite charged wire, uniformly charged disk, capacitance of spherical capacitor and multipole expansion for PLSD-media.

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