Current-voltage characteristics of a metal-semiconductor contact with a Mott barrier

An analytical solution for the current-voltage characteristics of a metal-semiconductor contact with a Mott barrier is derived with allowance made for the space charge of carriers in the n ⁺-i junction. The main assumption used in solving the Poisson equation is that the bulk doping of the i layer is ignored. The dependences of the electric current on the voltage are calculated for the characteristic cases of the thermionic emission and diffusion mechanisms of charge transfer. In contrast to the classical Mott result, the inclusion of the space charge of carriers in the calculation limits the increase in the electric current at a forward bias and decreases the nonlinearity of the current-voltage characteristics.     

Breakdown of the quantum Hall effect due to electron heating

The breakdown of the Quantum Hall effect observed on GaAs-AlGaAs samples is quantitatively explained in terms of peculiar electron-heating characteristic to the Quantum Hall regime. The current instability originates from an S-shaped current-voltage characteristic. Further, exponential dependence of the dissipative conductivity on the electric field, observed in the lower field range, is interpreted as a consequence of the finite size of the wave function of localized states in the presence of potential gradient.     

Absolute negative conductivity and spontaneous current generation in semiconductor superlattices with hot electrons

We study transport through a semiconductor superlattice with an electric field parallel to and a magnetic field perpendicular to the growth axis. Using a semiclassical balance equation model with elastic and inelastic scattering, we find that (1) the current-voltage characteristic becomes multistable in a large magnetic field and (2) "hot" electrons display novel features in their current-voltage characteristics, including absolute negative conductivity and a spontaneous dc current at zero bias. We discuss experimental situations providing hot electrons to observe these effects.     

Longitudinal DC electric discharge in a supersonic air flow

A longitudinal dc electric discharge in a submerged high-pressure supersonic air jet is described. Photographs of the discharge are provided. The experimental voltage across the discharge gap and the discharge current are given for two resistances of the resistor that limits the discharge current over a certain range of the discharge channel length along the air flow. The current-voltage discharge characteristic is provided at a constant discharge length. The main discharge characteristics are obtained from a comparison of the experimental and theoretical results calculated on the basis of the simplest model.     

On the current-voltage characteristic of the oxide process

The transport equations that simulate the passage of the ionic current through an oxide layer under Steady-state conditions have been investigated. These equations are integrated by the method of matched asymptotic expansions. An analysis of the current-voltage characteristic of the system has revealed a region with negative differential conductivity. On this basis, it has been argued that the system is characterized by an instability of the initially uniform distribution of the electric current, which, in turn, leads to the appearance of “current filaments.” The threshold value of this instability is determined.     

Transport in superlattices in the stark ladder regime

The current-voltage characteristic of a semiconductor superlattice in the Stark ladder regime has been calculated. It is shown that the negative differential conductivity onset electric field is defined by the scattering time, which depends only very slightly on the superlattice miniband width.     

Current-voltage characteristic of a narrow-band semiconductor taking into account ionization of impurities

The current-voltage characteristic of a material with a narrow conduction band in a strong electric field is studied taking into account ionization of deeply lying impurities in the model, in which collisions of charge carriers are described in the Fokker-Planck approximation. The results are compared with analogous results obtained in the v approximation. It is shown that the results obtained earlier in the v approximation coincide with our results to within ∼ 5%. It is noted that the Fokker-Planck model additionally provides the temperature dependence of the current-voltage characteristic.     

Theory of space-charge waves in semiconductors with negative differential conductivity

Phenomena that accompany optical excitation of eigenmodes of electron gas oscillation in semiconductors with an N-shaped current-voltage (I-U) characteristic in a strong electric field are investigated theoretically. The dependence of the current flowing through a sample on the oscillation frequency of the interference pattern of light illuminating the sample is analyzed. Nonsteady-state and nonuniform illumination produces an internal electric field, which interacts resonantly with the eigenmodes when the oscillation frequency of the interference pattern coincides with an eigenfrequency of electronic gas oscillation. As the maximum of the I-U curve is approached, the interaction becomes nonlinear in character.     

Effect of Plug Flow on the Stability of Two-Dimensional Arcs

Steady solutions to the governing equations that describe fully two-dimensional arc plasmas in a plug flow have been obtained. The stability of these steady solutions is investigated by calculating the transient created when infinitesmal changes in the electrode potentials are imposed. Comparisons are made with solutions obtained using a one-dimensional electric field. We find that with increasing blowing (Peclet number) the one-dimensional electric field solutions yield increasingly inaccurate results for higher currents. The stability results conform with those given by the classical Kaufmann criterion. We find that convection tends to reduce and eventually to eliminate the declining branch of the current-voltage characteristic. The presence of convection promotes axial temperature gradients in the arc and hastens the transition from the unstable (declining) branch to a stable (increasing) branch of the current-voltage characteristic.     

Single injection current in solid state cylindrical diodes with deep traps

The expressions for current-voltage characteristics of single injection current flow in solid state cylindrical diode containing significant amount of deep traps have been derived with the help of regional approximation method. It is shown that the complete current-voltage characteristic may be divided into well separated current-voltage regimes and the last regime is the pure space-charge-limited trap free regime. The role of deep traps is specially explained in the complete span of current-voltage characteristic.     

Spin polarization of the current in a correlated one-dimensional conductor with an impurity

The spin transport as the current flows through an impurity in a one-dimensional conductor is analyzed. The interacting electrons are described in terms of the Luttinger liquid theory. Both the Coulomb and short-range interactions are considered; the latter appears when the gate screens the long-range part of the Coulomb potential. The cases of magnetic and nonmagnetic impurities are considered. It has been revealed that, for a magnetic impurity, the electric current flow induces the generation of the spin current, which has direct and alternating components. At low temperatures and voltages, the current can be completely spin-polarized. For a nonmagnetic impurity, the spin current generation is absent. The spin current flowing though the wire affects the current-voltage characteristic for both magnetic and nonmagnetic impurities. The results have been obtained for a rather strong electron-electron interaction.     

Theory of the drift motion of charged particles

A differential equation is derived for the time dependence of the average random-motion energy of a particle drifting in an electric field. There is a discussion of the various versions of this equation, the equation of motion which follows from it, and particular solutions. There is a discussion of topics associated with the time dependence of the coordinate of a drifting particle, the average drift velocity, and the current-voltage characteristic of the drift region for the case of a space-charge limitation on the current.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 8, pp. 119–125, August, 1969.     

Thermoelectric Generator on CeB<Subscript>6</Subscript> Crystal: a Study of its Characteristics

Experimental results that demonstrate the electric power generation by using thermoelectric generator on CeB₆ crystal at temperatures below 10 K are presented. The dependence of output power, electric current and efficiency of the generator at various external heating power, loads and ambient temperature are studied. The features of the obtained current-voltage characteristics of the superconductor, fed by the electric current of thermoelectric generator are discussed.     

Electron tunneling through superconducting A1/monolayer/Pb junctions

The current-voltage characteristic of Al/adsorbed monolayer/Pb junctions was measured at 77, 4.2 and 1.8K at applied voltages from 1 to 3 mV. At 77K the current changes linearly with voltage whereas at 4.2 and 1.8 K the relationship becomes nonlinear. From the results at 1.8 K we obtain an approximate band gap for Pb equal to 2.6 meV. The observation of a nonlinear current-voltage characteristic at temperatures where Pb becomes superconducting is strong evidence that the observed current through the insulator is a tunneling current.     

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在四阳极直流放电装置上,测量并分析了辉光放电的电流-电压和发光特征随气压的变化关系。结果表明,采用稳流放电模式比稳压放电具有更宽的稳定放电气压和电流范围,能在从1～800Pa的较宽气压范围内实现氦气辉光放电,放电电流可达到500mA左右。随着电极表面亮斑的变化,对于同一气压,在低电流区,放电电压几乎成指数增长;随电流增大,电压的增长速度变缓;对于高的气压,碰撞频率的增大使得电压随电流升高的速率变小。分析表明,放电处于异常辉光区。从放电管的CCD图像可以看出,对于同一放电电流,随气压的升高,等离子体往阴极收缩。     

Numerical study of the current-voltage characteristic of a plasma-filled high-current diode

A numerical study is performed of a one-dimensional model of a high current plasma-filled diode, connected in a circuit with a voltage generator. Flow of the plasma from an external source into the diode anode-cathode gap through the plane of the cathode grid proves to have a definite effect on the diode current-voltage characteristic. An estimate is made of the limiting current above which formation of a cathode double layer occurs. Generation of explosive emission at a high value of current or the time derivative of current causes rapid expansion of the cathode layer due to a lack of the majority, electron current component and the presence of a phase intensified by plasma erosion. Dependence of the current-voltage characteristic on density of cathode explosive emission centers is noted.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 48–53, October, 1988.     

Current density distribution over the anode surface at a pulse-periodic negative corona in argon

It is found experimentally that as the corona current grows, its radial distribution over the anode narrows and the spot size at the anode decreases. The current-voltage characteristic of a negative corona in argon is approximated by a parabolic function with regard to the experimentally found narrowing of the current cross section on the anode with increasing corona current.     

Analytical model of a plasma photoconverter

The problem of using a photoplasma to directly convert the energy of light into electric energy is investigated theoretically. It is shown that the photo-emf is generated due to the ambipolar potential difference caused by the nonuniform ionization of alkali metal vapor by optical radiation. The current-voltage characteristic is calculated and the efficiency is estimated of a plasma photoconverter with plane electrodes.     

Current-voltage characteristics of radiating Josephson sandwich

Josephson sandwich is considered, along which the radiating chain of vortices travels. Uniform movement of the chain is supported by bias current. The current-voltage characteristic connecting this current with the voltage at the Josephson junction is found. It is shown that when the current increases, generation of electromagnetic waves with frequency weakly dependent on the current is possible.