(a) CL image of the top (100) Sumitomo HPHT diamond surface. Different colors identify different sectors in the diamond crystal, e.g., the black is the (111) growth sector. “a” indicates a high nitrogen sector while “b” indicates low nitrogen sectors. (b) A representative PL spectrum from a pristine HPHT diamond prior to the implantations recorded at 10 K from sector a. (c) A representative PL from a pristine CVD sample recorded at 10 K. The ZPL of centered at 637 nm is clearly seen. The hump centered at 660 nm is the phonon sideband of the center and the line at 572 nm is the first order Raman line. Note that the width of the ZPL is much narrower for the CVD sample than for the HPHT sample due to lower nitrogen concentration.
PL confocal maps of various implantation routes. (a) 30 keV implanted into HPHT diamond in a high nitrogen region, (b) low nitrogen region. 2 MeV implantation into (c) a high nitrogen region of the HPHT sample, (d) low nitrogen region, and (e) a CVD sample. The PL intensity is clearly higher at the high nitrogen concentration regions of the HPHT diamond. It is also notable that there is a PL enhancement at the edges of the mask in (d) and (e).
(a) PL spectrum from 2 MeV implanted region of HPHT sample. (b) PL spectrum from 2 MeV implanted region of a CVD sample. The data recorded at . The ZPL of the CVD sample is much narrower and a strain splitting of the peak can be resolved.
A PL from a nitrogen implanted CVD diamond compared with a PL recorded from a not implanted area. An emission enhancement and a major peak broadening are observed due to the implantation. The intensity scale is the same for both spectra.
Summary of increase in a emission due to various irradiation routes. Note that represents the lower bound assuming no vertical diffusion of vacancies. The 2 MeV and the 30 keV Ni/Er irradiation into HPHT diamond resulted in the maximum concentration of and 6.3 ppm, respectively.
Summary of increase in a emission due to various nitrogen implantations into CVD diamond. Here represents the lower bound assuming no vertical diffusion of nitrogen, as well as negligible contribution from N-V centers formed by vacancies diffusing into the substrate and combining with native nitrogen. A nitrogen implantation into CVD diamond resulted in a maximum concentration of -although the high energy/low dose strategy of 50 keV and yielded the highest conversion efficiency of 8.7% of
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