Electrical excitation of color centers in diamond: Toward practical single-photon sources

Optical sources that deliver single photons on demand play a key role in quantum cryptography and optical quantum computations. At present, color centers in wide-bandgap semiconductors, such as the nitrogen-vacancy (NV) and silicon-vacancy (SiV) centers in diamond, are considered to be the most promising candidates for practical quantum information applications owing to their unique emission properties at room temperature. However, for practical reasons, single-photon sources should be pumped electrically, which is required for integrability, scalability, and energy efficiency. However, diamond and related wide-bandgap semiconductor materials are at the interface between insulators and semiconductors, which makes electrical excitation of color centers very challenging. Here, we report on our progress in the understanding of single-photon electroluminescence of color centers in diamond, discuss different factors affecting the brightness of these emitter under electrical excitation, and study how to improve the performance of electrically- pumped single-photon sources based on color centers in diamond.