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.

• Autores: Pulgar Velásquez, Lorenz; Gil Corrales, John Alexander; Duque Echeverri, Carlos Alberto; Morales Aramburo, Álvaro Luis; Sierra Ortega, José; Vinasco Suárez, Juan Alejandro; Laroze, David; Radu, Adrian; Kasapoglu, Esin; Restrepo Arango, Ricardo León
• Tipo de recurso: Article of investigation
• Fecha de publicación: 2021
• Institución: Universidad de Antioquia
• Repositorio: Repositorio UdeA
• Idioma: eng
• OAI Identifier: oai:bibliotecadigital.udea.edu.co:10495/26172
• Acceso en línea: http://hdl.handle.net/10495/26172
• Palabra clave: Truncated conical quantum dots; Puntos cuánticos cónicos truncados; Exciton states; Estados de excitón; Donor-impurity states; Applied magnetic field; Type II quantum dots
• Rights: openAccess
• License: http://creativecommons.org/licenses/by/2.5/co/