Surface-induced charge state conversion of nitrogen-vacancy defects in nanodiamonds

Abstract

We present a study of the charge state conversion of single nitrogen-vacancy (NV) defects hosted in nanodiamonds (NDs). We first show that the proportion of negatively-charged NV − defects, with respect to its neutral counterpart NV 0 , decreases with the size of the ND. We then propose a simple model based on a layer of electron traps located at the ND surface which is in good agreement with the recorded statistics. By using thermal oxidation to remove the shell of amorphous carbon around the NDs, we demonstrate a significant increase of the proportion of NV − defects in 10-nm NDs. These results are invaluable for further understanding, control and use of the unique properties of negatively-charged NV defects in diamond.

Stimulated Emission Depletion Microscopy Resolves Individual Nitrogen Vacancy Centers in Diamond Nanocrystals

“…This resulted in the creation of 0À20 NV centers per nanodiamond. 20 The unwanted graphitic layers, which form on the ND surface during ARTICLE these first steps, are removed by air oxidation at 550°C for 1 h. The resulting oxidized fluorescent NDs were diluted with deionized water to a concentration of about 1 mg/mL. This aqueous suspension was further diluted to a concentration of 1:200 in deionized water and spin coated onto a 210 μm thick quartz coverslip.…”

Diamond Nanophotonics

“…However, more attention should be devoted to behaviour of color centers near interfaces. In particular, stability of emitters in close proximity to surfaces and effect of different surface terminations must be studied in more details [159][160][161] , and for other defects than the NV center. Since many nanophotonic devices require thin (several hundred nanometres thick) membranes, a robust methodology of reliably engineering color centers with close to bulk diamond properties in these thin membranes must be developed.…”

Stray-field imaging of magnetic vortices with a single diamond spin

“…A detailed description of the setup as well as the method to graft a diamond nanocrystal at the apex of the AFM tip can be found in Rondin et al 13 We use commercially available diamond nanocrystals (SYP 0.05; Van Moppes SA, Geneva), in which single NV defects were created through high-energy electron irradiation (13.6 MeV) followed by thermal annealing at 800°C. The irradiated nanocrystals were finally oxidized in air at 550°C during 2 h. This procedure enables to reduce the size of the nanodiamonds and leads to an efficient charge state conversion of the created NV defects into the negatively charged state 33 . For the experiments reported in the main article, the size of the nanodiamonds were in the B20-nm range, as verified using AFM images before grafting the nanodiamond at the apex of the tip.…”