Single photon source based on an InGaN quantum dot in a site-controlled optical horn structure

We report the realization of single photon emission from an InGaN quantum dot in a GaN inverted truncated-pyramid structure: a single photon horn. The structural parameters of the quantum dots, especially the quantum confinement in the (0001) direction, are well controlled by optimizing the planar single InGaN quantum well to be of ∼2 monolayers. Based on conventional nanoimprint pillars combining with a simple regrowth process, the single photon horn structure is realized with an efficient photon emission of 8 × 10⁵ photons/s while still maintaining a g⁽²⁾(0) < 0.5 even at an extremely low excitation power of 35 nW (4.5 W cm⁻²).