Shallow-impurity-related binding energy and linear optical absorption in ring-shaped quantum dots and quantum-well wires under applied electric field

The electronic states of two-dimensional (2D) semiconductor quantum wells and quantum wires of disk-and ring-like geometries, under the application of lateral static electric fields, are investigated. The effects of a shallow hydrogenic impurity on the energy levels of both the electron and hole states are reported and the respective binding energies are calculated. The eigenfunctions and eigenvalues of the Hamiltonian are retrieved under the effective mass approximation applying a direct matrix diagonalization scheme in conjunction with a 2D finite element method. A finite confinement potential is chosen for the structures, which are embedded in a 2D-box bounded by a hard-wall potential. It is shown that the first order optical absorption coefficient strongly depends on the geometrical parameters and external perturbations of the systems allowing for an optimization of the opto-electronic properties through control of the latter. (C) 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim