Strong exciton confinement in site-controlled GaN quantum dots embedded in nanowires

Abstract

The optical properties of site-controlled single GaN quantum dots (QDs) embedded in nanowires are presented. These properties are largely determined by a strong carrier confinement due to the small size of the dots (0.5 ∼ 1 nm in height). The QDs emit in the deep-ultraviolet region of the electromagnetic spectrum and exhibit the biexciton binding energy of 52 meV, which is the largest value ever reported in III-V semiconductor QDs. Furthermore, the dots luminesce at room-temperature and have short exciton decay times of ∼300 ps due to an increased oscillator strength. These findings indicate that these site-controlled QDs are promising for various applications in quantum information devices.