Fig. 1

CFM image and ODMR spectra of NV centres fabricated by C₅N₄H_n ion implantation. a Fabrication of triple NV centre with nanometre separation by C₅N₄H_n ion implantation. When a C₅N₄H_n-65 keV ion hits the diamond, it decomposes into individual atoms. The red, black, and blue spheres represent nitrogen atoms, carbon atoms, hydrogen atoms, respectively. The vacancies are created by these ions and presented by grey spheres. During the annealing process, the vacancies mobilize and combined with substitutional nitrogen, interstitial carbon, and other vacancies. If the vacancy meets substitutional nitrogen, the NV centre is created and labelled by NV_A, NV_B, and NV_C with dashed circles in the figure. The C₅N₄H_n ion acts as an ideal point source, and the position of each atom is determined by ion straggling. The average distance and standard deviation of the implanted nitrogen atom were calculated to be 9 and 4 nm, respectively, by using the SRIM code. b Typical CFM image of C₅N₄H_n ion implanted region. Yellow dots correspond to single NV centres, and bright red dots correspond to double and triple NV centres. c Typical ODMR spectra of single, double, and triple NV centres. Top four spectra (Single-i), (Single-ii), (Single-iii), and (Single-iv) show four single NV centres with different orientations. The spectra (Double) and (Triple) show double and triple NV centres, respectively. The spectra for triple NV centre are labelled NV_A, NV_B, and NV_C