Many next-generation quantum devices rely on single-photon emitters based on optically active defects in solids, known as color centers. Understanding their properties is fundamental to developing novel quantum technologies.

Now, in a study published in APL Materials, a multi-institutional research team led by Osaka University has sought to clarify the origin of the extremely bright color centers at the interface between silicon dioxide (SiO₂) and silicon carbide (SiC).

Previous research has demonstrated a range of factors that can play a role in the formation of these interface color centers, including the effect of annealing after oxidation. However, the energy level structure (i.e., the electronic transitions taking place) responsible for luminescence, a crucial factor for understanding the origin of color centers, was completely unknown.