Superlattice of spherical quantum dots with a trapezoidal potential profile with weak coupling of quasiparticles between layers of quantum dots

Abstract

A theoretical study of the spectrum of quasiparticles in a superlattice of spherical quantum dots (QDs) with a trapezoidal potential profile with a weak coupling of quasiparticles between QD layers is carried out. The calculations were performed using the example of spherical QDs InGaAs embedded in GaAs in the form of a superlattice. The model of the trapezoidal QD profile with three variable parameters is especially suitable for considering such zero-dimensional structures when, due to the different lattice constants of the QD material and the matrix medium, the boundary between them is fuzzy and is modeled by a certain transition region. The dependences of the energies of the underlying bands on the geometric parameters of the superlattice are investigated, which can be used to determine the metric of zero-dimensional structures by comparing it with the experimental intraband absorption spectra. The sensitivity of the position of the bands to changes in the parameters of the potential profile is revealed, which makes it possible to efficiently analyze the tunneling passage of carriers between QDs, to study the processes of controlled relaxation of carriers in QDs, which is important for the operation of lasers based on zero-dimensional structures with mismatched lattice constants of the QD material and the matrix medium.