Negative-donor centers and absorption spectra of quantum dots

Abstract

Negative-donor centers in quantum dots with parabolic confinement potential have been studied for the case with the presence of a perpendicular magnetic field. Calculations are carried out by using the method of numerical diagonalization of the Hamiltonian matrix within the effective-mass approximation. The ground-state electron structures and angular momentum transitions are investigated. The binding energies of the ground and some bound excited states are obtained as a function of the applied magnetic field strength. As the magnetic field strength B is increased, there may appear more bound states. On the basis of the computed energies and wavefunctions, the linear optical absorption coefficients have been examined, for between the 1P and 1S states. The results are presented as a function of the incident photon energy for the different values of the confinement strength and the magnetic field strength. It is found that the optical properties of the negative-donor centers in quantum dots are strongly affected by the confinement strength and the magnetic field strength.

The nonlinear optical rectification coefficient in a hydrogenic quantum ring

“…Shallow impurity increases the conductivity of a semiconductor by several orders of magnitude. In particular, the last two decades have witnessed increasing interest in theoretical and experimental investigations of the behavior of shallow hydrogenic donor and acceptor impurities in semiconductor quantum heterostructures [8][9][10][11][12][13][14][15]. The study of impurity states is one of the main problems in semiconductor low-dimensional systems because the presence of impurities in nanostructures influences significantly the electronic mobility and their optical properties [16].…”

A study of two confined electrons using the Woods–Saxon potential

“…The experimental study of semiconductor QDs is expanding rapidly [3][4][5][6] and electronelectron interaction and correlation effects are shown to be of great importance [7][8][9] in such systems. In the meantime, a large number of theoretical investigations [10][11][12][13] of electronic structures and related magnetic and optical properties in QDs have been performed to explain the experimental observations. Based on a numerical solution of the Coulomb interaction between electrons, a complex groundstate behavior (singlet → triplet state transitions) as a function of a magnetic field has been predicted [8,14].…”