Disk-Shaped GaN Quantum Dots Embedded in AlN Nanowires for Room-Temperature Single-Photon Emitters Applicable to Quantum Information Technology

We demonstrate an optically pumped single-photon emitter operating at room temperature based on disk-shaped GaN/AlN quantum dots embedded in the nanowire (dot-in-wire) structure, which can act as an optical source for future quantum information technologies. The disk-like geometry of the quantum dot (QD) leads to well-defined strain distribution and controllable optical properties of the QD structure, which is revealed by theoretical calculations using a continuous elasticity model. Site-controlled GaN/AlN dot-in-wires are grown by selective area growth on prepatterned Ti/N-polar AlN/Si substrates using molecular beam epitaxy. The internal quantum efficiency of GaN QDs is 31.1%, and their photoluminescence (PL) wavelengths are in good agreement with the calculation. Measured by a micro-PL spectroscopy integrated with a Hanbury-Brown and Twiss setup, the second-order correlation at zero time delay (g(2)(0)) reaches 0.19 at room temperature for the site-controlled GaN/AlN dot-in-wires. Our work provides a promising approach to realize high-performance single-photon emission devices on-demand for application in quantum information technology.