Exciton binding energy and interband absorption in a cylindrical quantum dot GaN/InxGa1-xN

Abstract

Quantum dots represent a particularly intriguing class of materials due to their unique crystalline structure, characterized by the emergence of a substantial internal piezoelectric field, even at low indium concentrations. This distinctive feature renders them versatile for a wide range of applications, including light-emitting diodes spanning from red to ultraviolet wavelengths, solar panels, microcontrollers, and energy generation technologies. This research delves into the exploration of exciton states within cylindrical 1 Gan/In Ga N xx − quantum dots (QDs). To effectively model the confinement potential of such QDs, the modified Pöschl-Teller potential is employed in the axial direction, while for the radial direction parabolic potential is used. The study initially focuses on assessing the dependence of critical parameters. This includes the wave function, ground, and first excited state energies, as well as binding energies. These dependencies are examined regarding with the geometric characteristics of the quantum dot and the concentration of indium within the material. Of particular interest are the observed effects of varying indium concentrations, which have a profound impact on the internal piezoelectric field, influencing the spatial separation of electron-hole pairs and modulating the band gap curvature. Subsequently, our investigation extends to the analysis of absorption processes, specifically the interband absorption and the creation of the electron hole pair. We scrutinize the intricate relationships between these absorption processes, the geometric properties of the quantum dots, and the indium concentration. In addition, the selection rules have been revealed for the corresponding quantum transitions. In summary, this study provides valuable insights into the excitonic properties of cylindrical 1-GaN/In Ga N xx quantum dot considering taking into account piezoelectric effects arising due to the indium concentrations.