Ultrabright electrically driven single-photon source on diamond operating above room temperature

Operation at the single-photon level is beneficial for energy efficiency in optical and optoelectronic devices and opens new prospects for novel applications, ranging from quantum cryptography to quantum computations. In this regard, efficient single-photon sources operating upon electrical injection at room temperature are crucially important. Color centers in diamond are currently considered to be the best candidates capable of room temperature operation. These defects in the lattice structure have been studied intensively during the last two decades, and optically driven single-photon sources have been demonstrated. However, the possibility of operation upon electrical injection was not clear until recently mainly because diamond is a unique material at the interface between solid-state and semiconductor physics. The demonstrated photon emission rate under electrical pumping did not exceed a few tens of kcounts per second [1], which is several orders of magnitude lower than the emission rate of optically pumped centers [2] and is well below the level required for practical applications. Since the mechanism of electroluminescence of the color center in diamond was not known, it was not clear to what extent the single-photon emission rate upon electrical injection could be increased.