2021/05/11 by Federico Gorrini, C. Dorigoni, Gorrini, Federico +11
Materials Science · Engineering · #Diamond and Carbon-based Materials Research #Electronic and Structural Properties of Oxides #Laser-induced spectroscopy and plasma
paper · pdf · doi:10.48550/arxiv.2105.04939
Shallow, negatively-charged Nitrogen-Vacancy centers (NV-) in diamond have\nbeen proposed for high-sensitivity magnetometry and spin-polarization transfer\napplications. However, surface effects tend to favor and stabilize the less\nuseful neutral form, the NV0 centers. Here, we report the effects of green\nlaser irradiation on ensembles of nanometer-shallow NV centers in flat and\nnanostructured diamond surfaces as a function of laser power in a range not\npreviously explored (up to 150 mW/\μm2). Raman spectroscopy,\noptically-detected-magnetic-resonance (ODMR) and charge-photoconversion\nfluorescence detection are applied to characterize the properties and dynamics\nof NV- and NV0 centers. We demonstrate that high laser power strongly promotes\nphotoconversion of NV0 to NV- centers. Surprisingly, the excess NV- population\nis stable over a time scale of one hundred milliseconds after switching off the\nlaser, resulting in long-lived enrichment of shallow NV-. The beneficial effect\nof photoconversion is less marked in nanostructured samples. Our results are\nimportant to inform the design of samples and experimental procedures for\napplications relying on ensembles of shallow NV- centers in diamond.\n