The g-factor tensors of electron and hole in self-assembled (In,Ga)As/GaAs quantum dots are studied by time-resolved ellipticity measurements in a three dimensional vector magnet system. Both g-factor tensors show considerable deviations from isotropy. These deviations are much more pronounced for the hole than for the electron and are described by different anisotropy factors, which can even have opposite signs.

The electron spin precession about an external magnetic field was studied by Faraday rotation on an inhomogeneous ensemble of singly charged, self-assembled (In,Ga)As/GaAs quantum dots. From the data the dependence of electron g-factor on optical transition energy was derived. A comparison with literature reports shows that the electron g-factors are quite similar for quantum dots with very different geometrical parameters, and their change with transition energy is almost identical.

Koenraad, P. M. (2012). Atomically resolved study of the morphology change of InAs/GaAs quantum dot layers induced by rapid thermal annealing. Applied

We present effective-mass calculations of the bound-state energy levels of electrons confined inside lens-shaped In x Ga1−x As quantum dots (QDs) embedded in a GaAs matrix, taking into account the strain as well as the In gradient inside the QDs due to the strong In segregation and In-Ga intermixing present in the In x Ga1−x As/GaAs system. In order to perform the calculations, we used a continuum model for the strain, and the QDs and wetting layer were divided into their constituting monolayers, each one with a different In concentration, to be able to produce a specific composition profile. Our results clearly show that the introduction of such effects is very important if one desires to correctly reproduce or predict the optoelectronic properties of these nanostructures.

We present anisotropic nonparabolic position-dependent effective-mass calculations of the bound energy levels of electrons confined in lens-shaped InxGa1−xAs quantum dots embedded in a GaAs matrix. The strain and In gradient inside the quantum dots and their wetting layer (due to the strong In segregation effect present in the InxGa1−xAs/GaAs system) were taken into account. The bound eigenstates and eigenenergies of electrons in a finite 3D confinement potential were determined by the full numerical diagonalization of the Hamiltonian. The quantum dots and their wetting layer were sliced into a finite number of monolayers parallel to the substrate surface, each one with a specific In concentration, in order to be able to reproduce any composition profile along the growth direction. A comparison between the eigenenergies of the “pure” InAs quantum dots and the quantum dots with an inhomogeneous In content indicates that In segregation dramatically affects their electronic structure and must be taken into account if one wishes to accurately simulate the real optoelectronic properties of such nanostructures.