Shallow Donor Impurity States with Excitonic Contribution in GaAs/AlGaAs and CdTe/CdSe Truncated Conical Quantum Dots under Applied Magnetic Field

Abstract

Using the effective mass approximation in a parabolic two-band model, we studied the effects of the geometrical parameters, on the electron and hole states, in two truncated conical quantum dots: (i) GaAs-(Ga,Al)As in the presence of a shallow donor impurity and under an applied magnetic field and (ii) CdSe–CdTe core–shell type-II quantum dot. For the first system, the impurity position and the applied magnetic field direction were chosen to preserve the system’s azimuthal symmetry. The finite element method obtains the solution of the Schrödinger equations for electron or hole with or without impurity with an adaptive discretization of a triangular mesh. The interaction of the electron and hole states is calculated in a first-order perturbative approximation. This study shows that the magnetic field and donor impurities are relevant factors in the optoelectronic properties of conical quantum dots. Additionally, for the CdSe–CdTe quantum dot, where, again, the axial symmetry is preserved, a switch between direct and indirect exciton is possible to be controlled through geometry.

Light Absorption Enhancement and Laser-Induced Damage Ability Improvement of Aluminum Alloy 6061 with Non-Porous Alumina/CdSe@Al2O3/SiO2 Functional Gradient Films

“…Semiconductor nanocrystals (SNCs) such as cadmium selenide (CdSe) quantum dots offer wide applications in the fields of photovoltaics, solar energy harvesting, nanophotonics, imaging, sensing and other fields [ 20 , 21 , 22 , 23 , 24 , 25 ]. Since incident radiation causes excitation of free electrons, metal nanoparticles (MNPs) can generate intense electric fields in their vicinity [ 26 ].…”

Infrared relative dielectric permittivity and refractive index on the spherical CdSe/ZnS heteronanocrystals with self-consistent field

“…The authors obtained a highest performance in a double-QD layers with the maximum luminous yield of 3.64cd/A. Using the finite element method withing the effective mass approximation, Vinasco et al [33] reported the effects of applied magnetic field of the shallow donor impurity states and excitonic contributions in GaAs/AlGaAs and CdTe/ CdSe truncated conical QDs under applied magnetic field. In order to obtain the Coulomb interaction, the authors used a first order perturbative calculation.…”

Spin–Orbit and Zeeman Effects on the Electronic Properties of Single Quantum Rings: Applied Magnetic Field and Topological Defects

“…Irregularities in materials are found because of impurities' presence; they become zones of attraction or repulsion and create Coulomb-type interactions due to the impurity and carrier charges. The influence of a shallow donor impurity on the excitonic contribution in GaAs/AlGaAs and CdTe/CdSe truncated cone quantum dots can be found in [21]. Ghanbari et al [22] studied the effects of impurity presence on thermodynamic parameters (heat capacity, free energy, entropy, mean energy, and Gibbs free energy).…”