Effects of External Magnetic Fields on Optical Properties of an Oxide Quantum Dot Using the Smorodinsky–Winternitz Potential

Abstract

The effects of a magnetic field and geometrical confinement on the ground-state energy of an exciton and the optical gain in a CdO/ZnO spherical core/shell quantum dot have been investigated using the Smorodinsky–Winternitz potential. The impact of the dielectric constant discontinuity at the nanostructure boundaries is included, as well as the built-in internal fields comprising the spontaneous and piezoelectric polarizations within the heterostructure. Numerical calculations are carried out to obtain the exciton energy using the variational formalism within the single-band effective-mass approximation, whereas the optical properties are found using the compact density matrix method. The magnetic-field-induced oscillator strength and the transition lifetime of the exciton are investigated as functions of the dot radius in the core/shell quantum dot. The normalized optical matrix elements and the optical gain as a function of the carrier density in the presence of a magnetic field strength are studied. The results reveal that the exciton energy is insensitive to the magnetic field in the strong geometrical confinement region. The optical matrix elements increase with the charge carrier screening for all the magnetic field strengths, and this effect can be applied to improve the optical gain.