Optoelectronic properties of GaN and GaAs cylindrical nanostructures: Tuning excitonic Q-LED across the UV, visible, and IR domains

Bound and unbound excitonic and optoelectronic properties of cylindrical nanostructures (GaAs and GaN) have been investigated. Based on the effective mass approximation, we have calculated the correlated and uncorrelated ground-state electron–hole energies and interband emission properties, within a variational approach. Additionally, we investigate how geometric parameters, including the height and radius of the core, impact these properties. Our results reveal that the quantum dot size significantly affects both the bound and unbound excitonic properties, as well as the interband emission energy and its corresponding wavelength. As the quantum dot size decreases, the emission spectrum shifts from visible to infrared (telecommunication wavelengths), specifically for unbound excitons in the visible range ([684 nm–780 nm]) and infrared range ([780 nm–841 nm]), and for bound excitons in the visible range ([769 nm–780 nm]) and infrared range ([780 nm–866 nm]) in GaAs nanostructures. In contrast, for GaN nanostructures, the emission transitions into the ultraviolet region, with unbound excitons in the range [327 nm–351 nm] and bound excitons in the range [293 nm–350 nm]. These results underscore the crucial role of quantum confinement in tailoring the optical properties of semiconductor nanostructures for potential applications in the telecommunications, Q-LED, and photonics domains.