V.N. Mughnetsyan

Tunability of absorption threshold frequencies and Stark shift in the InSb narrow gap spherical quantum layer

In this work the interband optical absorption and Stark shift in the ensemble of InSb spherical quantum layers are investigated. Calculations are carried out both for the cases of parabolic and Kanes dispersion laws. The distribution of layers by their inner radii is taken into account. The effect of weak electric field on the energy levels coupling is investigated as well. It is found out that the energy spectrum 1s1p1d2s1f2p… for spherical quantum dot turns to the spectrum 1s1p1d1f2s2p… for spherical quantum layer with enough large value of inner radius. It is also shown that in the spherical quantum layer, where the coupling between neighboring states is not negligible, there is no square low dependence of Stark shift on electric field strength in contrast to the rotator model.

Effect of interdiffusion of In and Al atoms on excitonic states in InxGa1−xAs/AlyGa1−yAs quantum dots

The effect of interdiffusion of aluminum and indium atoms on the exciton emission energy and binding energy in InxGa1−xAs/AlyGa1−yAs quantum dots is studied. It is shown that the emission energy increases monotonically with increasing diffusion length, while the binding energy has a maximum.

Binding energy of a hydrogen-like donor impurity in a quantum well-wire in magnetic and electric fields

The effect of a longitudinal magnetic and a transverse electric fields on the binding energy of a hydrogen-like donor impurity is studied for a semiconductor quantum well-wire approximated by a cylindrical well of finite depth. It is shown that the magnetic and electric fields as well as the impurity distance from the wire axis are the effective tools for the influence on the binding energy.

Effect of interdiffusion and magnetic field on impurity states in multiple quantum wells

The effect of interdiffusion on hydrogen-like donor impurity binding energy in a multiple quantum well structure composed of 9 wells and 8 barriers is investigated. The effect of external magnetic field along the growth direction is taken into account as well. The obtained results show that the simultaneous effect of interdiffusion and the external magnetic field give a great opportunity of purposeful manipulation of binding energy and the character of the diffusion effect on binding energy strongly depends on the position of impurity center.

Tunability of absorption threshold frequencies and Stark shift in spherical quantum layer

In the present work the interband optical absorption in the ensemble of spherical quantum layers with weak quantum interaction is investigated. The distribution of layers by their inner radii is taken into account. The effect of weak electric field on the energy levels coupling and absorption character is investigated as well. It is shown that the energy spectrum 1s1p1d2s1f2p... for spherical quantum dot turns to the spectrum 1s1p1d1f2s2p... for spherical quantum layer with enough large value of inner radius. It is also shown that in spherical quantum layer, where the coupling between neighboring states is not negligible, there is no square low dependence of Stark shift on electric field strength in contrast to the rotator model.

Electron capture processes in quantum dots due to one-and two-phonon assisted transitions: The role of optical phonon confinement

Electron capture induced by carrier heating in spherical quantum dot-quantum well (QD-QW) structure is studied theoretically. The capture rate (CR) in one- and two-polar- optical-phonon-mediated capture processes has been studied by taking into account the phonon confinement. We have derived the analytic expressions for carrier CRs which can be conveniently applied to practical calculations for the spherical quantum dot systems. The numerical results of the CR as function of dot radius, lattice temperature and electron density in GaAs/AlAs/vacuum and CdSe/ZnS/H2O QD systems are obtained and discussed.

Effect of Al and Ga Interdiffusion on the Electronic States in GaAs/Ga1−xAlxAs Semiconductor Superlattice

The effect of interdiffusion of Al and Ga atoms on the confining potential and band structure of a three-dimensional superlattice, composed of initially spherical GaAs/Ga1−xAlxAs quantum dots, is investigated in the framework of the modified Wood-Saxon potential model. It is shown that the interdiffusion leads to the disappearance of the quantum dots’ spherical symmetry and to the broadening of the superlattice energy minibands.