Vacancy-impurity centers in diamond: perspectives of synthesis and applications
Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk, Moscow, Russian Federation
The bright luminescence of impurity-vacancy complexes in diamond, combined with its high chemical and radiation resistance, makes diamond an attractive platform for production of single-photon emitters and luminescence biomarkers for application in nanoelectronics and medicine. Two representatives of this kind of defects in diamond, silicon-vacancy (SiV) and germanium-vacancy (GeV) centers are discussed in this review with paying attention to their similarities and differences from the more thorough studied nitrogen-vacancy (NV) complexes. The recent discovery of GeV luminescence center opens a unique opportunity for the controlled synthesis of single photon emitters in nanodiamonds. In this review, we demonstrate prospects of high-pressure high-temperature (HPHT) technique for creation of single-photon emitters not only as an auxiliary to chemical vapor deposition (CVD) and ion-implantation methods, but also as a primary synthesis tool for producing color centers in nanodiamonds. Beside practical applications, comparative studies of these two complexes, which belong to the same structural class of defects, have fundamental meaning for deeper understanding of shelving levels, electronic structure and optical properties of these centers. In conclusion, we discuss few open problems regarding structure, charge state and practical application of these centers, which still require their solution.