Conductivity of a semiconductor quantum wire with a parabolic confinement potential was studied within the framework of the zero-range potential model, containing donor impurities, in the longitudinal with respect to its axis electric field at low temperatures. A dispersion equation determining the dependence of the binding energy of the impurity on the electric field strength was obtained. It has been shown that the bound state of an electron on an impurity is destroyed by a strong electric field, i.e. the thermoelectric phenomenon of ionization occurs. It was found that under conditions of low temperatures the dependence of the current density in a quantum wire in the longitudinal electric field has a superlinear character.

The dependence of the average binding energy of the resonance g -state of a D 2 − center on the induction of an external magnetic field in a quantum well with a parabolic confining potential is studied using the zero-range potential method. It has been shown that with an increasing exchange interaction, the character of the dependence of the average binding energy of the resonance g -state of the D 2 − center on the induction of the external magnetic field changes. It has been assumed that in GaAs / AlGaAs quantum wells alloyed with small Si donors, resonance D 2 − states can exist under conditions of exchange interaction. It has been found that in spectra of impurity magneto-optical absorption in multiwall quantum structures, exchange interaction manifests itself as oscillations of interference origin.

In the model of a zero-radius potential, the article studies the influence of an external electric field on the photoluminescence of a quantum molecule, which is connected with the electron radiative transition from U-state to g-term of D -center under conditions of dissipative tunnelling.The photoluminescence probability is shown to increase approximately by two orders when the external electric field strength causes the initially asymmetric double-well oscillatory potential (simulating the quantum molecule) to become a symmetric one. The photoluminescence probability has been shown to be highly sensitive to such parameters of dissipative tunneling as temperature, frequency of phonon mode, and the heat-bath interaction constant.

The average binding energy and the level width for the resonant D(-)-state in a quantum molecule have been calculated in the presence of an external electric field. The calculations were performed in the zeroradius potential model with allowance for the tunneling decay of the resonant state. The external electric field is shown to stimulate the decay of resonant D(-)-states under conditions of dissipative tunneling. It was found that the curve of the probability of photoionization of the D(-)-center as a function of the external electric field strength has two peaks that are connected with a change in the symmetry of the double-well oscillator potential of the quantum molecule and with the transformation (caused by the electric field) of envelope wave functions, respectively.

The D (−) states in a quantum well under the magnetic field longitudinal with respect to the axis of growth of the structure are considered. In the context of the model of the zero-radius potential, an equation that defines the dependence of the binding energy of the D (−) state on the parameters of the potential of the structure, the coordinates of the D (−) center, and the strength of the magnetic field is derived. The results are compared with the experimental data on the dependence of the binding energy of the D (−) state on the magnetic field. There is satisfactory agreement between the theoretical calculations and experimental data in the range of magnetic fields B < 10 T. The role of dimensionality in the modification of the coordinate dependence of the binding energy on the 2 D → 1 D → 0 D transition is clarified. The impurity magnetooptical absorption coefficient in a multiple quantum well structure is calculated, and the spectral dependence of the coefficient is studied. It is shown that a substantial contribution to the broadening of the absorption lines is made by the dispersion of quantum well widths in the structure.

The states of the electron localized at a donor in the quantum constriction with parabolic electron potential in the presence of a magnetic field that is longitudinal with respect to the axis of the constriction are considered. The dispersion relation for electrons was derived analytically in the context of the model of the zero-radius potential taking into account the effect of a magnetic field on the D(−) state in the quantum constriction. It is found that the singularity in the electron spectrum in the quantum constriction manifests itself in the dependences of the binding energy of the D(−) state and the edge of the extrinsic-absorption band on the effective length of the constriction. The evolution of both the binding energy of the D(−) state and the spectrum of intrinsic magnetooptical absorption in the quantum constriction as the strength of a longitudinal magnetic is varied is studied. The results are compared with those in the case of the D(−) state in a quantum wire.

The dispersion equation for an electron localized at the D 0 -center in the quantum narrowing in the presence of a magnetic field longitudinal with respect to the axis of constriction is analytically derived within the model of zero-radius potential. It is found that a special feature of the electron spectrum in the quantum narrowing manifests itself in the dependence of the D(−)-state binding energy on the effective constriction length. The evolution of the D(−)-state binding energy with changes in the longitudinal magnetic-field strength is investigated and compared with the case of D(−)-states in quantum wires.

The problem of electron binding states in field of two D0 centres in semiconductive quantum well (QW) in the presence of an external longitudinal magnetic field (along the QW growth axis) is studied within the framework of zero-range potential model. It is found that the magnetic field leads to a considerable change in positions of g- and u-terms, and to a stabilization of the D2- states in QW. It is shown that a form of impurity magneto-optical absorption spectrum essentially depends on the light polarization direction and on the spatial configuration of the D2- molecular ion in QW.

The quantum-well D(−)-states in the presence of magnetic field longitudinal with respect to the growth axis are considered. Within a model of zero-radius potential, an equation is derived that determines the dependence of the D(−)-state binding energy on the parameters of the potential of the structure, coordinates of the D(−) center, and the magnetic field. The results are compared with the experimental dependence of the D(−)-state binding energy on the magnetic field and the data are shown to be in good agreement with calculations for magnetic fields B < 10 T. A dimension factor is defined in the dependence of the binding energy on coordinates for the 2D → 1D → 0D transition.

The magnetoabsorption of light by quantum dot — D(−)-center complexes synthesized in a transparent dielectric matrix — is theoretically studied with allowance for dispersed quantum dot (QD) sizes. In the effective mass approximation, an analytical expression for the impurity magnetoabsorption coefficient of light polarized in the quantizing magnetic polarization field direction is derived.

In the framework of a model of zero-range potential, the problem of bound states of an electron in the field of two D0 centers (a two-center problem) in a semiconductor quantum wire is considered in the presence of a longitudinal magnetic field. It is shown that the magnetic field produces a significant shift of g and u terms and stabilizes the D 2 − states in quantum wires. It is found that, in the case of transverse polarization of light, the spectral dependence of the photoionization cross section of a D 2 − center exhibits the quantum-confined Zeeman effect with strongly pronounced oscillations of interference nature.

A theory is elaborated for the impurity photon drag effect in a semiconductor quantum wire exposed to a longitudinal magnetic field B directed along the axis of the quantum wire. The phonon drag effect is associated with the transfer of the longitudinal photon momentum to localized electrons in optical transitions from D (−) states to hybrid-quantized states of the quantum wire, which is described by a confinement parabolic potential. An analytical expression for the drag current density is derived within the model of a zero-range potential in the effective mass approximation, and the spectral dependence of the drag current density is examined at different magnitudes of B and parameters of the quantum wire upon electron scattering by a system of impurities with short-range potentials. It is established that the spectral dependence of the drag current density exhibits a Zeeman doublet with a clear beak-shaped peak due to optical transitions of electrons from D (−) states to states with the magnetic quantum number m =1. The possibility of using the photon drag effect in a longitudinal magnetic field for the development of laser radiation detectors is analyzed.

The impurity magneto-optical absorption for the cases of longitudinal and transversal light polarization with respect to the quantum wire axis has been theoretically studied. Analytical expressions for the corresponding D(-)-centers photo-ionization cross sections under the action of longitudinal magnetic field have been obtained, and their spectral dependences for InSb quantum wires have been investigated.

Magneto-optical absorption by the quantum dot (QD) with impurity center (IC or D(-)-center) complexes synthesized in a transparent dielectric matrix, with consideration of the QD size dispersion, is theoretically studied. Within the framework of effective mass approach, the analytical expression for the light impurity magneto-optical absorption coefficient for both the longitudinal and transversal polarizations with respect to the direction of external quantizing magnetic field is calculated.

The magnetooptical properties of 〈quantum dot〉-〈impurity center〉 complexes formed in a transparent insulator host were studied. In order to describe one-electron states of a quantum dot, a parabolic model of the confinement potential was used. In terms of the zero-range potential model in the effective-mass approximation, the coefficient of extrinsic absorption of light polarized parallel and perpendicular to the direction of an external magnetic field (longitudinal and transverse polarizations, respectively) was calculated taking into account variance in the quantum-dot size. It was shown that, in the case of longitudinal polarization, the edge of the extrinsic-absorption band shifts in a magnetic field to shorter wavelengths and the absorption coefficient increases several times. In the case of transverse polarization, the quantum-dimensional Zeeman effect is observed in the extrinsic-absorption spectrum. It was also shown that the anisotropy of the magnetooptical absorption is a nonmonotonic function of the frequency of light and does not depend critically on the impurity-level position.

Within the framework of zero-range potential model in the ap-proach of effective mass, the impurity absorption by the complex Quantum Dot-Impurity Center in an external constant uniform magnetic field is considered. Under condition that the influence of a magnetic field on the ground state of quantum dot is negligible, we have derived the light absorption coefficient of impurity for the case of longitudinal polarization. It is shown that with an increase of the intensity of magnetic field the threshold of an impurity absorption band is shifted to the short-wave spectrum region. Also, the absorption coefficient increases by several times that can be explained as a result of the "magnetic freezing" effect for the ground state of quantum dot.

The light absorption by the quantum point - impurity center complex in an external quantizing magnetic field is studied in the effective mass approximation for the model of zero-radius potential. An expression for the absorption coefficient of light having longitudinal polarization by an impurity is derived when the influence of the magnetic field on the ground state of the impurity at the quantum point can be neglected. It is demonstrated that the edge of the absorption band of the impurity is shifted toward shorter wavelengths with increasing magnetic field strength. In this case, the absorption coefficient increases several times, which is interpreted as the effect of magnetic freezing-in of the ground state of the quantum point.