The interplay between ion beam modification techniques in the MeV range and the controlled generation of negatively charged nitrogen-vacancy (NV-) centers in nitrogen-doped synthetic diamond crystals is explored. An experimental approach employing both light (H+) and heavy (Br+6) ions was followed to assess their respective impacts on the creation of NV- centers, using different ion energies or fluences to generate varying amounts of vacancies. Photoluminescence spectroscopy was applied to characterize NV- and neutral NV0 centers. Initially, no NV centers were detected post-irradiation, despite the presence of substitutional nitrogen and vacancies. However, after annealing at 800C (and in some cases at 900C), most samples exhibited a high density of NV0 and especially NV- centers. This demonstrates that thermal treatment is essential for vacancy-nitrogen recombination and NV- formation, often through electron capture from nearby nitrogen atoms. Notably, we achieved high NV- densities without graphitization, which is essential for preserving the material's properties for quantum applications. This study underscores and quantifies the effectiveness of MeV-range ions in controlling vacancy distributions and highlights their potential for optimizing NV- center formation to enhance the sensitivity of diamond-based quantum magnetic sensors.
@article{arxiv.2412.03386,
title = {Diamond-defect engineering of NV- centers using ion beam irradiation},
author = {J. L. Sánchez Toural and J. García-Pérez and R. Bernardo-Gavito and D. Granados and A. Andrino-Gómez and G. García and J. L. Pau and M. A. Ramos and N. Gordillo},
journal= {arXiv preprint arXiv:2412.03386},
year = {2024}
}