Current-injection quantum-entangled-pair emitter using droplet epitaxial quantum dots on GaAs(111)A

A source of single photons and quantum entangled photon pairs is a key element in quantum information networks. Here, we demonstrate the electrically driven generation of quantum entangled pairs using a naturally symmetric GaAs quantum dot grown by droplet epitaxy. Coincidence histograms obtained at a temperature of 10 K reveal the generation of quantum entangled pairs that have a fidelity to the Bell pairs of 0.71 ± 0.015, much beyond the classical limit. We study the temperature dependent device characteristics and estimate the maximum operation temperature to be ∼ 65 K, which is essentially limited by the weak charge carrier confinement in the present dot system. Our study offers a guideline for the fabrication of quantum entangled pair sources suitable for practical use.