Production and characterization of color centers in diamond material
In diamond material strong covalent bonds form an inflexible three-dimensional lattice with the highest atomic density known for any material, resulting in superlative physical qualities like highest thermal conductivity, lowest coefficient of thermal expansion and highest hardness. This outstanding matrix could host equally distinguished atomic color centers. The most prominent one is the negatively charged nitrogen-vacancy (NV) center. Owing to its inherent optical addressability and long spin coherence times, it is an outstanding spin system for quantum information and sensing applications under ambient conditions.
This color center could be generated from diamond material with single substitutional nitrogen atoms by electron irradiation followed by thermal annealing. The standard diamond material made by HPHT synthesis with single substitutional nitrogen atoms (diamond material type Ib) is colored yellow, the green diamonds are irradiated material with high concentration of vacancies and the purple diamonds are irradiated and annealed material with high concentration of negatively charged NV-centers.