Optical investigation of as-grown NV centers in heavily nitrogen doped delta layers in CVD diamond

[Display omitted] •3 nm thick delta layer with 1.4 × 1019 cm−3 nitrogen concentration and is achieved.•Optical and spin properties of NV centers, observed in the delta layer are studied.•Methods of concentration measurement of NV centers in delta layers are developed.•NV center surface concentration of 2.7–3.9 μ m−2 is obtained. In this paper, we realize growth of the delta doped layer (3 nm thick) with high concentration of nitrogen atoms (about 1.4 × 1019 cm−3) during CVD diamond growth process. We experimentally investigate the distribution of the nitrogen inside the grown layer and formation of the NV centers during such growth. Using confocal microscopy, we analyze the spatial distribution of the NV centers and investigate the formation efficiency of the NV centers in delta doped layers. The spatial distribution is measured by two methods, using second-order correlation function and emission volume analysis, and NV center concentration is found to be 3.9 ± 0.6 and 2.7 ± 0.2 μm-2 consequently. The divergence between the methods is discussed. As-grown NV centers formation efficiency was found to be 30 times lower than in the case of uniform doped diamond growth. Nevertheless, coherence time of an electron spin for a single NV center inside the delta layer was found to be around 1 μs which is quite reasonable given the concentration of the nitrogen in the sample.