GaN Quantum Dots in Resonant Cavity Nanopillars as Deep‐UV Single‐Photon Sources

Herein, integrating GaN quantum dots (QDs) within a resonant cavity is focused on. Utilizing metal‐organic vapor phase epitaxy, controlled growth of GaN QDs on AlN is achieved. A deep‐UV distributed Bragg reflector (DBR) with high reflectivity in the 250–300 nm range, using AlN and Al 0.7 Ga 0.3 N layers to maximize refractive index contrast, is developed. A 50‐period DBR achieves 98% reflectivity at a wavelength of 272 nm. Scanning transmission electron microscopy and electron energy loss spectroscopy analyses reveal a trisection of DBR periods, attributed to a Ga composition pulling effect during growth. The real structure's reflectivity is simulated and matched well with measured data, though actual reflectivity is lower than the ideal. Cathodoluminescence studies at T = 17 K show emission peaks from both the DBR and the GaN QDs. Further, single‐photon emission is demonstrated with a g (2) ( t = 0) value of 0.41 at 272.7 nm, confirming the potential for deep‐UV single‐photon sources. Additionally, the creation of a planar resonant cavity with enhanced emission intensity and vertical nanopillar structures with an aspect ratio of 11 and a diameter of 400 nm confirm the successful integration of GaN QDs in advanced UV photonic structures.