QUROPE Quantum Information Processing and Communication in Europe

Single-photon sources that provide non-classical light states on demand have a broad range of applications in quantum communication, quantum computing and metrology. Single-photon emission has been demonstrated using single atoms, ions, molecules, diamond colour centres and semiconductor quantum dots. Significant progress in highly efficient and entangled photons sources has recently been shown in semiconductor quantum dots; however, the requirement of cryogenic temperatures due to the necessity to confine carriers is a major obstacle. Here, we show the realization of a stable, room-temperature, electrically driven single-photon source based on a single neutral nitrogen-vacancy centre in a novel diamond diode structure. Remarkably, the generation of electroluminescence follows kinetics fundamentally different from that of photoluminescence with intra-bandgap excitation. This suggests electroluminescence is generated by electron–hole recombination at the defect. Our results prove that functional single defects can be integrated into electronic control structures, which is a crucial step towards elaborate quantum information devices.