Ultrahigh nitrogen-vacancy center concentration in diamond

Abstract

High concentration of negatively charged nitrogen-vacancy (${\text{NV}}^{-}$) centers was created in diamond single crystals containing approximately 100 ppm nitrogen using electron and neutron irradiation and subsequent thermal annealing in a stepwise manner. Continuous wave electron paramagnetic resonance (EPR) was used to determine the transformation efficiency from isolated N atoms to ${\text{NV}}^{-}$ centers in each production step and its highest value was as high as 17.5 %. Charged vacancies are formed after electron irradiation as shown by EPR spectra, but the thermal annealing restores the sample quality as the defect signal diminishes. We find that about 25 % of the vacancies form NVs during the annealing process. The large ${\text{NV}}^{-}$ concentration allows to observe orientation dependent spin-relaxation times and also the determination of the hyperfine and quadrupole coupling constants with high precision using electron spin echo (ESE) and electron-nuclear double resonance (ENDOR). We also observed the EPR signal associated with the so-called W16 centers, whose spectroscopic properties might imply a nitrogen dimer-vacancy center for its origin.

References in corpus (7)

• High-sensitivity diamond magnetometer with nanoscale resolution
• Coherence of Nitrogen-Vacancy Electronic Spin Ensembles in Diamond
• Magnetic field imaging with NV ensembles
• Quenching Spin Decoherence in Diamond through Spin Bath Polarization
• Electron spin decoherence of single Nitrogen-Vacancy defects in diamond
• Creating diamond color centers for quantum optical applications
• Efficient Conversion of Nitrogen to Nitrogen-Vacancy Centers in Diamond Particles with High-Temperature Electron Irradiation

Cited by in corpus (3)

• Large Room Temperature Bulk DNP of ${}^{13}$C via P1 Centers in Diamond
• Terahertz Emission From Diamond Nitrogen-Vacancy Centers
• Demonstration of NV-detected ${}^{13}$C NMR at 4.2 T