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Two express methods are presented in this paper. The first method is a high-resolution gamma-spectroscopic method based on a germanium detector, the second method is an IR-spectroscopic method. The applied complex of methods allows to determine the sources of uranium and thorium, identify the rhythms of uranium accumulation associated with regional events; identify areas with a high content of uranium due to the influence of local sources (faults, hydrothermal, etc.); determine the amount of authigenous uranium in the composition of total uranium; determine thermal maturity of organic matter in shales without their preliminary demineralization. To identify levels of increased uranium intensity in the high-carbon strata, a set of indicators has been proposed, which includes both applied indicators in practice of geological work and new indicators. New indicators have been tested on the collection of shale reference samples. For them, values ​​were established that characterize the processes of uranium accumulation and uranium removal. On the example of Ukhta Region according to the proposed indicators, the sections from the Vendian-Riphean to Domanic inclusive were interpreted. The performed work showed the possibility of comparing the calculated gamma-spectroscopic data with the data of other methods. This opens up a broader perspective for the use of express non-destructive gamma-spectroscopic method for detecting levels with a high content of uranium in the shale rocks, to which ore-bearing concentrations of a number of metals are also confined.

Searching for the optimal parameters of nanoelectronic devices is a primal problem in modeling. We solve this problem through the example of the electron ballistic switch in a quantum network model. For this purpose, we use a computing scheme in which closed channels are taken into account. It allows calculating correctly a scattering matrix of the switch and, consequently, the electric currents flowing through it. Without loss of generality, we consider a model of a two-junction switch at room temperature. This device is characterized by localization of the controlling electric field in the domain before branching. We optimize switch parameters using a genetic algorithm. At the expense of optimization, the switch efficiency for InP, GaAs and GaSb reached 77–78%. It is established that, for the considered materials, the volt–ampere characteristics of the device are close to the linear ones at bias voltages of 0–50 mV. It allowed describing with good accuracy electron transport in the switch by means of a $$3\times 3$$ matrix of approximate conductivity. Finally, based on the parameter optimization of the two-junction switch, we formulate the general scheme of modeling nanoelectronic devices in the framework of a quantum network formalism.

Spin-depending scattering is studied on a two-dimensional quantum network constructed of a quantum well with three semi-infinite quantum wires (an input wire and two terminals ) attached to it. The spin-orbital interaction causing selective scattering in the network is described by the Rashba Hamiltonian. The transmission of electrons across the well from the input quantum wire to terminals is caused by the excitation of a resonance oscillatory spin-mode in the well. For thin quantum networks we suggest also an approximate formula which defines the resonance transmission of electrons across the quantum well, depending on the shape of the standing spin-mode in the quantum well.

This article offers a consistent interpretation of the dynamic behavior of a real interface in measurements. The studied interface consists of a Ge-substrate with a monolayer of dipole molecules and a wet electrode. The gradual removal of protons from the SCR during long-term cyclic polarization of the interface with the blocking potential of the dipole layer shows that hydrogen in germanium exists in the proton form. Hereupon the balance of the electron and proton concentrations in SCR determines the value of the stationary potential, and the excess of the proton concentration over the equilibrium one corresponds to the density of surface states. The inertia of the proton transfer in the SCR with respect to the transfer of electrons and holes determines the screening conditions for the potential in SCR and, therefore, the features of the dynamics of the interface parameters. The enrichment of the surface with electrons facilitates the proton dissolution in the SCR and thereby compensates for the expected increase in interface capacitance due to the increase in accumulated charge. The experimentally confirmed effect of controlled dissolution of protons in the SCR opens the perspective of a new approach to the design of charge storage devices and techniques of electrocoating.

A semiconductor—organic-insulator system with spatially distributed charge is created with a uniquely low density of fast surface states (Nss) at the interface. A system with Nss ≈ 5 × 1010 cm–2 is obtained for the example of n-Ge and the physical characteristics of the interface are measured for this system with liquid and metal field electrodes. For a system with an organic insulator, the range of variation of the surface potential from enrichment of the space-charge region of the semiconductor to the inversion state is first obtained without changing the mechanism of interaction between the adsorbed layer and the semiconductor surface. The effect of enhanced polarization of the space-charge region of the semiconductor occurs due to a change in the spatial structure of mobile charge in the organic dielectric layer. The system developed in the study opens up technological opportunities for the formation of a new generation of electronic devices based on organic film structures and for experimental modeling of the electronic properties of biological membranes.

It is demonstrated that the field emission from graphene-like structures (GLSs) has a very low excitation threshold (about two orders of magnitude lower than that of metals and semiconductors). It is shown that the total energy distribution (TED) of field emission electrons from GLSs differs considerably from the spectra obtained for metals. The existence of two maxima of this distribution (spaced 0.7–1.7 eV apart), significant broadening of the energy distribution, and a shift of these maxima depending on the electric field intensity are reported. The resonance nature of low-threshold field emission from GLSs is confirmed.

We present a brief critical review of modern theoretical interpretations of the low-threshold field emission phenomenon for metallic electrodes covered with carbon structures, taking the latest experiments into consideration, and confirming the continuity of spectrum of resonance states localized on the interface of the metallic body of the cathode and the carbon cover. Our proposal allowed us to interpret the double maxima of the emitted electron’s distribution on full energy. The theoretical interpretation is presented in a previous paper which describes the (1 + 1) model of a periodic 1D continuous interface. The overlapping of the double maxima may be interpreted taking into account a 2D superlattice periodic structure of the metal-vacuum interface, while the energy of emitted electrons lies on the overlapping spectral gaps of the interface 2D periodic lattice.

The electrolyte-semiconductor interface is widely spread in physical, chemical, and biological systems, which makes the task of refining the physical interface model relevant for the development of studies of living and nonliving systems. When studying the properties of the solid-liquid interface, traditionally the main attention is paid to the most structurally mobile part of the system, namely the liquid, under the assumption that the ion structure of the near surface region of the solid remains unchanged. This article presents the results of numerical simulation of the electronic properties of the interface depending on the course of the potential in the subsurface layer of a semiconductor in the presence of mobile ions inside it. In this case, the properties of the classical and dimensionally quantized space charge region of the semiconductor are also compared. It is shown that the transport time of hydrogen ions in the subsurface region of Ge and the polarization time of the interface in the practical application of the field effect are of the same scale. This does not allow one to neglect the transport of ions in the space charge region of the semiconductor when interpreting the experimental data. The numerical data are given for the room temperature.

This paper proposes the semispectral method for the calculation of the scattering matrices for the charge carriers in quasi-one-dimensional quantum systems described by the Schrodinger equation. An efficient and accurate calculation method is achieved by adding of reference solutions at selected energy points to the eigenfunction expansion of the Green's function. A numerical simulation of the quantum wire with the square cross-section in transverse electric field was performed by different methods. The example problem of a quantum wire in a transverse electric field is used to compare the semispectral method with alternative approaches. We find that the semispectral method reliably converges and is significantly faster than the direct solution while the eigenfunction expansion approach has convergence issues. These results allow us to propose the semispectral method as a universal and efficient approach to calculation of the transmission coefficients for the Landauer formula as well as other scattering-based entities.

The charge properties of a multilayer structure, composed of silicon-carbide polytypes on a silicon substrate, are investigated. Knowledge of the properties of the space-charge region of silicon and the possibility of affecting the surface of a structure by the field effect [1] provides data on the charge processes at the interfaces between the polytypes. These data are urgent for improving the methods of synthesizing electronic structures based on SiC polytypes.

A method for calculating the parameters of the space-charge region in a thin film of a semiconductor with Kane’s charge-carrier dispersion relation at room temperature is proposed. A self-consistent calculation scheme for solving the system of coupled Poisson, Klein-Gordon-Fock, and Schrodinger equations for mercury cadmium telluride is implemented. Exact solutions for the subband dispersion relations are obtained. Linearization of the coordinate dependence of the potential in thin films is demonstrated and limits on the applicability of the triangular-well approximation are established. The coordinate dependence of the potential and charge density and the capacitance-voltage characteristics calculated within the context of the effective-mass approximation and of phenomenological theory are compared and the limits of applicability of the phenomenological description of the space-charge region are determined. The influence of the heavyhole subsystem on the main characteristics of the space-charge region is revealed.

A fast scheme for calculating the surface differential capacitance of a semiconductor film with an ohmic contact on the rear side is proposed within the self-consistent solution of the Schrodinger and Poisson equations. The method is considered using germanium as an example. Comparison with the results of the phenomenological calculation revealed the specifics of size-quantization effects on the capacitance-voltage characteristic of the film.

It was shown earlier that the excitation threshold of electron emission from carbon nanoclusters is extremely low (two to three orders of magnitude lower than for metals and semiconductors). In this work, this effect is confirmed by direct experiments with graphene and graphene-like structures. A new model explaining this effect by resonance tunneling due to size quantization is suggested. A low-threshold explosive emission is discovered.

In this work we investigated the possibility of applying the method of Atomic Layer Deposition to obtain thin films of zinc oxide deposited in narrow channels of micro channel plate. Calculations were carried out to find the optimum conditions for the synthesis. The resulting films have good continuity and uniformity. The electrical conductivity was studied on zinc oxide in the initial stages of growth on structures which we prepared.

It is shown that adsorption of nucleic acid molecules and their monomeric components, i.e., nitrogenous bases, from aqueous solutions results in the formation of an insulating layer on the germanium surface. Comparatively small values of the insulator charge and the surface-state density point to promising applications of nucleotides for both the formation of germanium-based insulator-semiconductor structures with nanoscale insulating layers and low surface-state densities at the phase interface, and for germanium surface passivation. Changes in the electronic properties of the space-charge region of germanium during nucleotide adsorption on its surface can be used as a method for determining the nucleotide molecule concentration in aqueous solutions.

A theoretical model of logical element NOT based on a two-dimensional electron waveguide is proposed. The results of optimization of the parameters of geometry and the external electric field to accomplish the maximal efficiency of operation of the device are considered.

A fast scheme for calculating the surface differential capacitance of a semiconductor film with an ohmic contact on the back side is proposed within the phenomenological theory of the space-charge region. The calculation method is considered by the example of a semiconductor with a parabolic dispersion relation (n-Ge). A phenomenon of capacitance-voltage characteristic drop with a decrease in the film thickness is revealed, which is not related to the quantum-confinement effects.

A new approach to the investigation of hydrogen transport via a germanium membrane separating two compartments of an electrochemical cell filled with an aqueous electrolyte is proposed. According to this, one side of the membrane is cathode-polarized until the evolution of hydrogen, then the transport of hydrogen to the opposite side is studied by monitoring a change in the surface charge by measuring the electrode potential and the differential capacitance of the germanium-electrolyte interface. This approach has good prospects for studying the behavior of hydrogen in semiconductors (in particular, for determining the mechanisms of hydrogen transport and charged state of hydrogen species in semiconductors), admits simple experimental realization, has a nondestructive character, and can be used at room temperature.

Carbon nano-cluster cathodes exhibit a low threshold electron emission, which is 2-3 orders lower than on metals and semiconductors. We confirm the effect by direct experiments with graphene structures. We are suggesting a model based on the interference electrons wave function in 3D-space charge region of carbon structure interface with vacuum. The low-threshold emission is explained, in frames of the model, by the resonance properties of the barrier formed on the interface. Also in the following topics: interpretation of recent experimental findings for saturation of the field emission; local spectral analysis of multidimensional periodic lattices: dispersion via DN-map; examples of iso-energetic surfaces associated with solvable models of periodic lattice; Lagrangian version of the operator extension algorithm; solvable models of selected one-body spectral problems; quantum dot attached to the node of a quantum graph; a solvable model of a discrete lattice and spectral structure of a 1D superlattice via analytic perturbation procedure.

One-electron spin-dependent scattering problem is considered on the star-shaped 2-d quantum network consisting of a quantum well and few relatively thin leads attached to it. The resonance nature of transmission coefficients is revealed based on accurate analysis of interaction between the running spin-waves in the leads and the standing spin-waves in the quantum well. Modeling of the transport problem on the two-dimensional junction by the 1-d scattering problem on the corresponding quantum graph is discussed.

It is shown experimentally and theoretically that structures that exhibit properties of two-and one-dimensional electron gas at room temperature can be formed on the basis of CdHgTe compounds in a semiconductor-electrolyte system. The methods for fabricating the quantum-confinement structures and in situ monitoring of the physical properties of such structures are described.

We present the results of the year work in the frame of the EU ESPRIT Project 28890 NTCONGS “New technology for the control of narrow-gap semiconductors”. This work has involved both theoretical and experimental study, as well as the development of new specific equipment, towards the creation of a new generation of nanoelectronic devices able to operate at 77 K and even at room temperature.

Self-consistent calculations of the Rashba splitting both in inversion and accumulation InAs layers were carried out using a method based on reducing 6×6 and 8×8 Kane matrix equations to a Schrodinger-type equation. Disregarding the Γ7-band contribution yielded a splitting magnitude overestimated by 50%. The essentially nonlinear dependence of splitting on the two-dimensional (2D) wavevector k restricts the applicability of the Rashba parameter α (coefficient at the k-linear term in the spectrum), including its value at the Fermi level, because of a strong dependence of the latter on the approximations applied to the two-dimensional spectrum. The relative differences Δn/n of the spin-split subband populations, calculated for the inversion layer, were found to be 2–3 times lower than those measured by Matsuyama et al. (see text). The experimental study of accumulation InAs layers showed that the corresponding value Δn/n does not exceed the calculated one, ∼0.02. The approach employed to describe the 2D spectrum (including spin-orbit splitting) was also shown to be adequate when applied to the case of quasi-classical quantization in a classically self-consistent surface potential.

The measured parameters of spin-orbit spectral splitting in HgCdTe-based MIS structures with positive and negative Kane gap E g are compared with the parameters calculated using the three-and four-band Kane model. The disregard of the finite spin-orbit splitting Δ of the valence band in calculations leads to exaggerated values of Rashba splitting (especially for E g < 0) even for small ratios |E g|/Δ, although the subband parameters averaged over two spin branches of the spectrum in the two-, three-, and four-band Kane approximations for the same concentrations are practically identical. In the zero-gap HgCdTe, the measured as well as calculated values are noticeably higher, but the four-band approximation leads to values of splitting for both materials which are 20–40% lower than the experimental value. The inclusion of the interband interaction reduces these discrepancies, but does not eliminate them completely. It is shown that the approximations of the 2D spectrum with spin-orbit splitting linear in quasimomentum, which are conventionally used in the analysis, may lower the effective Rashba parameter by a factor of 2–4.

The field effect method in electrolytes is used for finding the electrophysical characteristics of the surface and the band parameters in the surface layers of the semiconductor TlBiSe 2 . In this paper the dispersion law and the effective mass of electrons of a conduction band, the concentration of ionized donor impurities, and the energy position of the Fermi level are defined. The experimental and theoretically calculated C(V) characteristics are compared.

The method of field effect in electrolytes was used to determine the surface electrical properties and band parameters in surface layers of semiconductor solid solutions (TlBiSe2)1−x-(TlBiS2)x at room temperature. The dispersion law, the effective mass of electrons in the conduction band, the ionized donor impurity density, and the Fermi level are determined. The experimental and theoretically calculated capacitance-voltage characteristics are compared.

The field-effect method in electrolyte was used to study the zero-gap semiconductor HgSe-electrolyte (saturated solution of KCl) system by measuring the capacitance-voltage and current-voltage characteristics. A technique for the estimation of the matrix element P of the quasi-momentum operator from capacitance-voltage characteristics was proposed, and the value of P for HgSe was determined at T=295 K.

A Scattering problem is studied for Neumann Laplacian with a continuous potential on a domain with a smooth boundary and few semi-infinite wires attached to it at the points of contact on the boundary. In resonance case when the frequency of the incoming waves in the wires coincides with some resonance frequency of the domain the approximate formula for the transmission coefficient from one wire to another is derived: in the case of weak interaction between the domain and the wires the transmission coefficient is proportional to the product of values of the corresponding resonance eigenfunction of inner problem at the corresponding points of contact.

Two-dimensional (2D) electron gas at interface anodic oxide – HgTe (1 1 0) is studied experimentally (by magneto-capacitance spectroscopy method) and theoretically at carriers surface density up to 6×10 12 cm −2 . The measurements show the population up to four subbands with well-resolved Rashba spin splitting in Fourier transforms. The carriers distribution among electric subbands agrees with the theory. However, the experimental relative differences of occupancies of spin sub-subband (0.17–0.3) exceed the calculated ones (0.14). This discrepancy testifies to the interface contribution to spin–orbit splitting. The partial capacitance oscillations for different spin branches in ground subband differ not only by the period but by the amplitudes also. Because of this the measured effective cyclotron masses in this subband correspond to the theoretical values for high-energy spin branch whereas in excited subbands to an average over two branches.

The quantum interference properties of simple model systems of arrays of barriers are considered. We discuss the capabilities for realizing new nanodevices based on the constructive interference for coding and decoding signals.

A procedure is proposed for determining the stoichiometric composition of an intrinsic semiconductor Hg1−xCdxTe, relying upon the field effect in an electrolyte. An original comparative analysis of experimental capacitance-voltage characteristics and those calculated in terms of a quantum description of the space charge region provides the x value in the surface layer of the semiconductor at a depth comparable with the Debye screening radius. The determined stoichiometric compositions are presented for four Hg1−xCdxTe samples (x=0.205, 0.245, 0.290, and 0.330).

The first study of the two-dimensional electron gas in the surface layers on zero-gap HgMnTe is carried out experimentally (by the magnetocapacitance spectroscopy method) and theoretically. The exchange interaction is manifested only in the temperature shift of beat nodes of magneto-oscillations. Information about exchange effects is obtained only by our modelling of oscillations, because any pronounced changes in the position of oscillations are not observed and the separate spin components are not resolved. The theory for the description of a spectrum in a magnetic field and magneto-oscillations with allowance for exchange and spin-orbit (SO) interaction for Kane semiconductors with direct and inverted bands is advanced. The modelling shows that the SO splitting far exceeds the contribution due to exchange interaction. The comparison between experiment and theory for different temperatures and parameters of exchange interaction is reported. The calculated amplitudes of `partial' oscillations for different spin branches of the spectrum are essentially different in accordance with the observed difference in the intensity of corresponding lines in Fourier spectra. The dominant mechanisms of the scattering responsible for the broadening of Landau levels are discussed.

Two-dimensional electron gas at the anodic oxide-HgTe(110) interface is studied experimentally (by the magnetocapacitance spectroscopy method) and theoretically for carrier surface density up to 6×1012 cm-2. The measurements show the population of up to four subbands with well-resolved Rashba spin splitting in the Fourier transforms. The carrier distribution among the electric subbands agrees with the theory. However, the experimental relative differences of occupancies of spin sub-subbands (0.17-0.3) exceed the calculated ones (0.14). This discrepancy indicates an interface contribution to the spin-orbit splitting. The partial capacitance oscillations for different spin branches in the ground subband differ not only in period but also in amplitude. Because of this, the measured effective cyclotron masses in this subband correspond to the theoretical values for the high-energy spin branch whereas in the excited subbands each corresponds to an average over two branches.

The processes taking place on the surface of semiconductors in electrolytes are discussed in terms of spatial and temporal self-organization. The capacitance and conductance of the semiconductor surface are shown to change abruptly at a critical electrode potential. Concurrently, the density of surface states at the interface decreases, which is characteristic of the formation of ordered crystalline structures. Experimental data are presented for Ge, CdHgTe, and HgTe in electrolyte solutions with glucose, ammonia, EDTA, and thiourea additions.

A new method of self-consistent quantum calculation of the density of the space charge near the surface of a crystal is carried out for a semiconductor with parabolic dispersion law of bands. The remarkable feature is the solution of the Schrodinger equation for electrons and holes in the energy range, including both bound energy states and the states in the continuum. Voltage-capacitance dependences of MIS structures are calculated.

Carbon nano-cluster cathodes exhibit a low threshold electron emission, which is 2–3 orders lower than on metals and semiconductors. We confirm the effect by direct experiments with graphene structures. We are suggesting the model based on interference electrons wave function in 2D-space charge region of carbon and Tamm's surface states of dangling bonds. This barrier is transparent for electrons at Fermi level due to the resonance.

First of all: disregard all of so called "preliminary physical expectations", because all these expectations are just a pseudonym for prejudices elaborated by the older generation. These words belong to Dirac, not to me. The right way of creating new physics is different: one should begin with a beautiful mathematical idea. But it should be really beautiful! No special relations to physics is compulsory. But if it is really beautiful, it will certainly match useful physical applications, though it is not predefined, what sort of applications and where: it depends on physical consequenceswhich may be extracted from the mathematical scheme.

The field-effect method in electrolytes is used for finding the band structure parameters in surface layers of zero-gap semiconductors (ZGS) (CdHg)Te. It is found that the conduction band both in surface layers and in the volume of ZGS (CdHg)Te obeys the ultrarelativistic dispersion relation. The electron effective mass in surface layers of ZGS (CdHg)Te is close to the electron effective mass in the volume of ZGS (CdHg)Te. It is stated that the heavy-hole valence band both in surface layers and in the volume of ZGS (CdHg)Te has a non-parabolic dispersion relation, and that the heavy-hole effective mass is less than 0.5m0 and depends on the composition of (CdHg)Te. It is found that the position of the Fermi level in ZGS (CdHg)Te is described in the model of zero-gap semiconductors with fluctuating potential. The “step” structure in the dependences of the differential capacitance of the space-charge layer in ZGS (CdHg)Te on temperature at fixed values of the surface potential is observed experimentally for the first time. [Russian Text Ignored].

Detonation carbon materials (DCM) composed of non-equilibrium nano-structures show the low-threshold field emission (LTFE). These materials have forward-looking application especially due to high reproducibility of the LTFE-phenomenon on a surface of emitter, where the emitting centers are homogeneously distributed. In this paper we link the effect of LTFE to the nature of the corresponding wave functions based on the experiment results obtained for DCM by the field effect on electrolytes. As we had shown before DCM had been described by an ultra-relativistic dispersion function with extremely small effective mass of electrons and the size-quantization effect had been observed in DCM at even room temperature. Our results based on emission and electrolyte technics of the field-effect measurements in DCM along with modern observations of the field emission in strong electric fields allowed to propose a new resonance transmission model for LTFE-phenomenon, which is alternative to most widely discussed models based on the field-enhancing factors or barrier-lowering mechanisms.

A new approach to the investigation of hydrogen transport via a germanium membrane separating two compartments of an electrochemical cell filled with an aqueous electrolyte is proposed. According to this, one side of the membrane is cathode-polarized until the evolution of hydrogen, then the transport of hydrogen to the opposite side is studied by monitoring a change in the surface charge by measuring the electrode potential and the differential capacitance of the germanium-electrolyte interface. This approach has good prospects for studying the behavior of hydrogen in semiconductors (in particular, for determining the mechanisms of hydrogen transport and charged state of hydrogen species in semiconductors), admits simple experimental realization, has a nondestructive character, and can be used at room temperature.

The single-electron transport through a junction of quantum network is modeled as a specific scattering problem for the Schrodinger operator on the system of semi-infinite cylindrical domains (quantum wires) short-circuited by a compact domain (quantum well or dot). For calculation of the one-body scattering parameters of any junction having form of a compact domain with piece-wise smooth boundary and attached thin wires a semi-analytic perturbation procedure based on a specially selected intrinsic large parameter is suggested. The approximate scattering matrix of a thin junction obtained in this way is the scattering matrix of the corresponding solvable model.