V. D. Krevchik

Impurity absorption of light in structures with quantum dots

The impurity absorption of light in a quantum dot with a parabolic potential profile is considered within the framework of the model of a zero radius potential in the effective mass approximation. The sensitivity of the effect of position disorder to the size factor at the transition from a quantum well to a quantum dot is revealed. The spectral dependence of the coefficient of impurity absorption of light is investigated with account of the spread in size of quantum dots. It is shown that the account of spread in size results in smearing of discrete absorption lines. The impurity absorption edge depends on the parameters of quantum dots and the depth of the impurity level.

Drag effect of one-dimensional electrons upon photoionization of D(−) centers in a longitudinal magnetic field

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.

Features of the electron-photon drag effect in a spiral ribbon in the external magnetic field

The features of the photon drag effect in a spiral two-dimensional ribbon, which are associated with an asymmetric electron energy spectrum in a longitudinal magnetic field, have been studied theoretically. The effect of the anisotropic transfer of the photon momentum to the electron system in a spectral dependence of the photon drag current density has been revealed.

Magnetooptical properties of a molecular D 2 − -ion in a quantum wire

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 D2− 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 D2− center exhibits the quantum-confined Zeeman effect with strongly pronounced oscillations of interference nature.

Energy spectrum of the A+ + e complex in a quantum dot in the adiabatic approximation

The energy states of an A+ + e complex in a quantum dot described within the hard-wall potential model are considered using the zero-range potential method in the adiabatic approximation. These complexes can be formed under nonequilibrium conditions (for example, under photoexcitation). A relationship describing the dependence of the binding energy of a hole located at a neutral acceptor on the parameters of the zero-range potential of the system and the quantum state of the electron is obtained analytically. It is demonstrated that, in quantum dots of small radius, the binding energy of a hole in the A+ + e complex can be considerably higher than the ground-state energy of the A+ stationary center.