Impact of Helium Ion Implantation Dose and Annealing on Dense Near-Surface Layers of NV Centers

Abstract

The implantation of diamonds with helium ions has become a common method to create hundreds-nanometers-thick near-surface layers of NV centers for high-sensitivity sensing and imaging applications; however, optimal implantation dose and annealing temperature are still a matter of discussion. In this study, we irradiated HPHT diamonds with an initial nitrogen concentration of 100 ppm using different implantation doses of helium ions to create 200-nm thick NV layers. We compare a previously considered optimal implantation dose of ∼1012 He+/cm2 to double and triple doses by measuring fluorescence intensity, contrast, and linewidth of magnetic resonances, as well as longitudinal and transversal relaxation times T1 and T2. From these direct measurements, we also estimate concentrations of P1 and NV centers. In addition, we compare the three diamond samples that underwent three consequent annealing steps to quantify the impact of processing at 1100 ∘C, which follows initial annealing at 800 ∘C. By tripling the implantation dose, we have increased the magnetic sensitivity of our sensors by 28±5%. By projecting our results to higher implantation doses, we demonstrate that it is possible to achieve a further improvement of up to 70%. At the same time, additional annealing steps at 1100 ∘C improve the sensitivity only by 6.6 ± 2.7%.

Nitrogen-Vacancy Magnetometry of Individual Fe-Triazole Spin Crossover Nanorods

“…Hz −1/2 ). With improvements in the experimental setup, for example, by doping the diamond with high density of NVs, 66 and performing pulsed NV measurements 67 could improve the sensitivity to below 50 nT Hz −1/2 and study the magnetic properties of individual nanoparticles below 10 nm.…”

The Study of the Efficiency of Nitrogen to Nitrogen‐Vacancy (NV)‐Center Conversion in High‐Nitrogen Content Samples

“…We should stress that the observed conversion efficiency of 37% AE 4% exceeds many recently published results, including detailed studies and optimizations of the annealing procedure, while the annealing procedure in this work is rather trivial and is only the first step of much more advanced ones. [31,[42][43][44] This suggests that the irradiation dose for the high-concentrated samples has a very large impact on the final conversion efficiency and must be kept as high as possible. We could expect that the application of a more optimal annealing procedure may further enhance the conversion efficiency.…”

“…Similar results were recently achieved with He ion implantation. [ 44 ] Sophisticated annealing procedures have been used in later cases. In the case of lower nitrogen concentration (about 3 ppm) about 15% conversion efficiency to NV − with a similar amount of NV 0 has been reported with electron irradiation by 3 MeV electrons.…”

Recent Progress on Interfaces in Nanomaterials for Nuclear Radiation Resistance

“…Helium ion implantation and high temperature annealing are commonly utilized experimental means to mimic nuclear reactor conditions. [37,38] To evaluate the impacts of the defects including vacancies, self-interstitials and helium, the in situ TEM He + implantation and annealing were conducted at both room temperature and 600 °C on a nanocrystalline iron matrix. [39] At intermediate temperatures, the accumulation of point defects rather than the displacement cascades leads to the formation of a dislocation loop.…”