Positive and negative charge creation in the SiO2 film of a MOS transistor by high electric field stress

The aim of this work was to study the charge creation in the SiO₂ layer of a Si MOSFET induced by the electric field stress in the Fowler-Nordheim (FN) tunneling regime. At lower field, typical positive oxide charge generation has been observed. With an increasing stressing field, which is accompanied by an increasing FN electron injection current, negative charge creation has been found. The possible sources of charges and the mechanisms of their generation are presented.     

Spatial rectification of the electric field of space charge waves

A new phenomenon associated with a nonlinear interaction of optically excited space charge waves has been discovered in photorefractive crystals of the sillenite family. This interaction provides a spatial rectification of the electric field of the space charge waves and leads to a temporally oscillating, but spatially homogeneous electric field of the order of 50-60 V/cm which is detected by a probe beam via the electro-optic effect. Taking into account that the displacement current plays an important role, we demonstrate a very good agreement between the experimental data and the suggested theoretical model.     

Pair creation in the field of a moving charge

We consider the creation of fermion and boson pairs in the field of a charge moving in a circle. We show that the effect is observable for χ=(Ω/m)(E/m_Q)²～ 1.     

Effect of an electric field in the space charge region on surface states

The quantization of the current carriers and the effect of an electric field in the space charge region on Tamm surface states are investigated within the framework of the Kronig-Penney model and in the effective mass approximation.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 70–77, October, 1991.     

Nonstationary motion of electrons in a double plasma layer subjected to the self-consistent electric field of the space charge

Nonstationary 1D equations describing the motion of electrons in a double plasma layer subjected to the self-consistent electric field of the space charge are investigated with allowance for friction force. Analytical solutions to a set of nonlinear hydrodynamic equations for plasma electrons are derived. The variation of the electric field strength, as well as of the electron velocity and concentration, in space and time is found. Electron plasma motions of different types of symmetry are characterized in terms of dynamic parameters.     

Particle creation in a time-dependent electric field revisited

We adopt the general formalism for analyzing evolution of gaussian states of quantized fields in time-dependent backgrounds in the Schrodinger picture (presented in detail in Mahajan and Padmanabhan [G. Mahajan, T. Padmanabhan, Gen. Rel. Grav. 40 (2008) 661]) to study the example of a spatially uniform electric field background (in a time-dependent gauge) which is kept turned on for a finite duration of time. In particular, we study the time-dependent particle content, defined in terms of the concept of instantaneous eigenstates, and describe how it captures the time evolution of the quantized field modes. The actual particle creation process occurs over a relatively short interval in time, and the particle content saturates rather quickly. We also compare the power spectrum of the field modes, computed in the asymptotic limit, with the corresponding situation in a cosmological de Sitter background. Particle creation under the influence of a spiked electric field localized in time, as a particular limiting case of the above general model, is also considered.     

Numerical computation of potential profiles and energy spectrum in the space charge region of semiconductors at high electric field

Numerical computations of the potential profiles are performed for the space charge region of semiconductors with a spherical nonparabolic conduction band at a high electric field externally applied to the surface. For the obtained potential profiles, the energy spectrum in the surface region was calculated for an electron moving perpendicularly to the surface (field emitted electron). To perform this calculation, a special iterative procedure was developed to compute the complex eigenvalues of the Hamiltonian with an arbitrary potential.     

长直带电导体柱的电场及其电荷面密度

通过保角变换法及其变换关系,求解长直带电导体柱的电场分及电荷面密度,利用数学软件MATLAB对其场分布进行数值模拟,并绘制出电荷面密度的分布曲线.     

Dependence of space charge field and gain coefficient on the applied electric field in photorefractive materials

Intensity dependent space charge field and gain coefficient in the photorefractive medium due to the two interfering beams have been calculated by solving the material rate equations in presence of externally applied dc electric field. The gain coefficient has been studied with respect to variations in the input intensity, modulation depth, concentration ratio and normalized diffusion field in the absence and presence of the externally applied dc electric field. Space charge field has also been computed by varying the intensity ratio in the presence and absence of the externally applied dc electric field. It has been found that the rate of change of the space charge field with the normalized dc field decreases with the increasing intensity ratio for different values of the normalized diffusion field. It has also been found that the externally applied dc electric field has appreciable effect only when it is larger than the diffusion field.     

Three-dimensional simulation of electric field and space charge in the advanced hybrid particulate collector

The advanced hybrid particulate collector (AHPC) is an efficient hybrid system that combines the electrostatic precipitator (ESP) and the bag filter in a unique approach. In this study, an unstructured finite volume method (FVM) is used to compute the three-dimensional distributions of the electric field and the space charge density in an AHPC setup for two cases: without the perforated plate and with the perforated plate. The current–voltage characteristics of the AHPC setup are measured. The current on the bag plate has a mean value 7.82 μA without the perforated plate and 0.08 μA with the perforated plate for the measured voltages. The total currents are used to calculate the charge density at the corona wire according to the Peek's formula. For both cases, the numerical predictions of the current–voltage relations of the plates of the model AHPC agree well with the measurements. When the AHPC has the perforated plate, numerical results show that the electric field and space charge density distributions on the perforated plate have the same number of peaks corresponding to the holes. The electric field on the bag plate surface is lower than that of the top plate and the perforated plate. Though the bag plate has low current, its surface still has high space charge density. When the AHPC has no perforated plate, the electric field is higher than six times and the space charge density is higher than three times that of the case with the perforated plate on the bag plate surface.     

Pair creation by a photon in an electric field

The process of pair creation by a photon in a constant and homogeneous electric field is investigated basing on the polarization operator in the field. The total probability of the process is found in a relatively simple form. At high energy the quasiclassical approximation is valid. The corrections to the standard quasiclassical approximation (SQA) are calculated. In the region of relatively low photon energies, where SQA is unapplicable, the new approximation is used. It is shown that in this energy interval the probability of pair creation by a photon in electric field exceeds essentially the corresponding probability in a magnetic field. This approach is valid at the photon energy much larger than the “vacuum” energy in electric field: ω?eE/m. For smaller photon energies the low energy approximation is developed. At ω?eE/m the found probability describes the absorption of soft photon by the particles created by an electric field.     

线电荷与介质圆柱所形成的电场

在线电荷电场的电势调和展开式的基础上,得出线电荷电场内存在介质圆柱时电势的级数解.并以此来分析长直线电荷与介质圆柱所形成的电场的电像,从而给出电势与电像有关的解析表达式,进一步得出等势线(面)与电场线方程,并利用软件MATLAB绘制出电场线和等势线图予以验证.     

Negative space charge and electric field intensity in polymeric insulators at low temperatures

The effect of negative space charge accumulation due to injection of electrons from cathode microprotrusions on the steady-state and transient electric field distributions in polymer dielectrics is discussed. An isolated microprotrusion is modeled by a spherical capacitor in which an electrode of smaller radius is the cathode. The calculations include the fact that the distribution of negative space charge depends on the rate of capture and liberation of electrons by traps, while the activation energy of this process depends on the electric field intensity. An exponential energy distribution is proposed for the traps. It is shown that significant electrical overvoltages can only appear near the cathode microtips immediately after switching on the voltage. In the course of 10⁻⁶–10⁻⁵ s, the coefficient of electrical overvoltage drops to a few units and approaches its steady-state value. The region of significant electrical overvoltage is localized, and is the same order as the dimensions of the microtip. Fiz. Tverd. Tela (St. Petersburg) 40, 1167–1172 (June 1998)     

The equivalence principle and an electric charge in a gravitational field

It is shown that there is no violation of the strong principle of equivalence in the case of an electric charge either falling freely or supported in a static uniform gravitational field. For a freely falling charge, the global electromagnetic field distribution at any instant is found to be the same as that of a charge which is moving uniformly with respect to an inertial frame with a velocity equal to the instantaneous velocity of the freely falling charge. In the case of a charge supported in the gravitational field, the total electromagnetic field energy, as measured by freely falling observers instantaneously at rest with respect to the charge, is shown to be equal to the Coulomb field energy of a charge permanently stationary in an inertial frame. The conclusion here, that in neither of the two cases does the charge emit electromagnetic radiation, is independent of our choice of the observer's frame of reference.     

Erratum to: Peculiarities of pair creation by a peak electric field

Russian Physics Journal -     

The c-axis fluctuation conductivity in layered superconductors in a strong electric field under a magnetic field

The effect of a high electric field on the c-axis fluctuation conductivity in layered superconductors near the superconducting transition is investigated by the time-dependent Ginzburg-Landau equation. The c-axis fluctuation conductivity is calculated in self-consistent Gaussian approximation for an arbitrarily strong electric field and a magnetic field perpendicular to the layers. Our results include all Landau levels and have refined analytical form. The results in linear response are in good agreement with the experimental data in a wide region around T _c in high T _c superconductor. We also show that high electric fields can be effectively used to suppress the c-axis fluctuation conductivity in high-temperature superconductors.     

A percolation approach to study the high electric field effect on electrical conductivity of insulating polymer

The effect of percolation threshold on the behaviour of electrical conductivity at high electric field of insulating polymers has been briefly investigated in literature. Sometimes the dead ends links are not taken into account in the study of the electric field effect on the electrical properties. In this work, we present a theoretical framework and Monte Carlo simulation of the behaviour of the electric conductivity at high electric field based on the percolation theory using the traps energies levels which are distributed according to distribution law (uniform, Gaussian, and power-law). When a solid insulating material is subjected to a high electric field, and during trapping mechanism the dead ends of traps affect with decreasing the electric conductivity according to the traps energies levels, the correlation length of the clusters, the length of the dead ends, and the concentration of the accessible positions for the electrons. A reasonably good agreement is obtained between simulation results and the theoretical framework.     

Electronic contribution to electric field gradient in dilute alloys

A simple relation for calculating the electronic contribution to the electric field gradient in dilute alloys of transition metals is reported and is compared with the conduction electron charge shift model. The dependence of the field gradient on thes andd electrons and the difference in radii between the host and the probe atoms is considered for calculating the field gradient. It is found that thed electrons are the major contributors to the field gradient.