D.A. Baghdasaryan

Optical properties of narrow band prolate ellipsoidal quantum layers ensemble

Abstract. Electronic states and direct interband light absorption in the ensemble of prolate spheroidal quantum layers are considered. The problem of finding the one-electron wave function and energy spectrum have been solved exactly. Absorption edge dependence on the thickness of the layer in the strong size quantization regime has been obtained. The effect of nonparabolicity of the dispersion law of energy levels and optical absorption have been taken into account and calculations are carried out for the cases of both parabolic and Kane’s dispersion laws. Selection rules have been revealed. Absorption coefficient dependence on the frequency of incident light has been obtained, taking into account dispersion of nanolayer thicknesses for the cases of both symmetric and asymmetric distribution functions.

Single-electron states in semiconductor nanospherical layer of large radius

In a spherical core/shell/shell nanolayer the single-particle states were considered in the regime of strong quantizations. The relation between the geometrical dimensions of the corresponding components of a sample are chosen in such a way that the differences between the characteristics of materials form a quantum well for the charge carriers in the middle layer. The adequate approximate approaches are suggested to determine analytically the energy spectrum and the wave functions of the single-electron states in the spherical nanolayer. A comparison of the results of the analytical and the numerical calculations is performed. The interval values of the ratio between the layer thickness and its radius at which the results of proposed approximations coincide with the satisfactory accuracy with the results of numerical calculations are determined.

Quantum model of the prolate spheroidal Thomson hydrogen atom

In a uniformly charged prolate spheroidal Thomson hydrogen atom the electron states have been investigated. It has been shown from the mathematical point of view that the problem is equivalent to a spheroidal hydrogen atom in a parabolic potential with the cylindrical symmetry. In the framework of adiabatic approximation, the energy of ground state has been calculated. Comparison with the case of uncharged spheroidal quantum dot has been made, and the analytical form of wave function of electron has been also obtained.

Exciton states and direct interband light absorption in the ensemble of toroidal quantum dots

Abstract. One electron and exciton states in toroidal quantum dot (QD) have been considered. The convenient coordinate system has been defined and the Schrodinger equation has been solved in these coordinates. The electron energy spectrum and wave function dependence on the geometrical parameters of toroidal QD have been obtained. The comparison with the results obtained by numerical methods has been done. Optical absorption has been considered in both cases of “small” toroid when the interaction of an electron and a hole is neglected and cases of relatively “large” toroid when the correlation between the particles has been taken into account. Interband optical transitions have been considered in the ensemble of toroidal QDs. The selection rules for quantum transitions and absorption edge dependence on the geometrical parameters have been obtained.

Conical quantum dot: Electronic states and dipole moment

The electronic states in a conical quantum dot in the framework of the adiabatic approximation as well as the combined approach with the perturbation theory have been considered. The obtained results have been compared with the results of numerical methods–the finite element and the Arnoldi methods. The interpolation formula for the energy correction and its dependence on the geometric parameters of the conical quantum dot have been obtained. The comparing of the wave functions obtained by different methods and the range of applicability of different methods have been defined. The dependence of the z-component of the dipole moment on the geometric parameters of the structure has been considered.

Impurity with two electrons in the spherical quantum dot with Unite confinement potential

Two-electron states in a spherical QD with the hydrogenic impurity located in the center and with a finite height confinement potential barrier are investigated. The effective mass mismatch have been taken into account. The dependence of ground state energy and Coulomb electron-electron interaction energy correction on the QD size is studied. The problem of the state exchange time control in QD is discussed, taking into account the spins of the electrons in the Russell-Saunders approximation. The effect of quantum emission has been shown.