Impacts of Single Nitrogen Atoms and Vacancies on the Formation of Nitrogen-Vacancy Defects in Diamond

Abstract

Using the diamond samples with different N concentrations and irradiated by 10 MeV electron beam with the doses varied from 2.5 × 1017 to 1.0 × 1019 cm−2, the formation of negatively- and neutrally-charged nitrogen-vacancy (NV− and NV0) defects is explored by quantitatively characterizing the concentration of NV defects with the absorption coefficient of NV− at the zero phonon line (ZPL). It is found that NV− centers are predominant in the samples with high N concentrations and irradiated by electron beam with low doses. With the increase in the irradiation dose, NV− concentration is almost linearly increased and NV0 starts to appear in the diamond samples. For the samples with low N and sufficient vacancies, NV0 centers will become predominant and the NV− concentration is relatively low. In the formation of NV defects, excessive N and vacancy seem to act as the roles of donor and acceptor, respectively, and thus dominate the formation of NV− and NV0 centers. In addition to NV− and NV0 centers, other irradiation defects are observed to be luminescent and in association with N and vacancy concentrations. The ZPL490 defects are usually brighter than others in the samples with high N concentrations, while the ZPL503 and ZPL467 defects are often observed in the samples with low N and irradiated by electron beam with relatively high doses.

Keywords: diamond, NV defects, formation, absorption and emission