Negatively Charged Nitrogen-Vacancy Centers in a 5 nm Thin ¹²C Diamond Film

Abstract

We report successful introduction of negatively charged nitrogen-vacancy (NV(-)) centers in a 5 nm thin, isotopically enriched ([(12)C] = 99.99%) diamond layer by CVD. The present method allows for the formation of NV(-) in such a thin layer even when the surface is terminated by hydrogen atoms. NV(-) centers are found to have spin coherence times of between T2 ~ 10-100 μs at room temperature. Changing the surface termination to oxygen or fluorine leads to a slight increase in the NV(-) density, but not to any significant change in T2. The minimum detectable magnetic field estimated by this T2 is 3 nT after 100 s of averaging, which would be sufficient for the detection of nuclear magnetic fields exerted by a single proton. We demonstrate the suitability for nanoscale NMR by measuring the fluctuating field from ~10(4) proton nuclei placed on top of the 5 nm diamond film.

Broadband, large-area microwave antenna for optically detected magnetic resonance of nitrogen-vacancy centers in diamond

“…A portion of doped N forms NV centers. [29][30][31] The NV density is estimated to be of the order of 10 15 cm −3 .…”

Isotope engineering of silicon and diamond for quantum computing and sensing applications

“…8(c) displays a 5-nm-thick isotopically enriched 12 C film. [158] For the 100-nm-thick film, T 2~1 .7 ms [ Fig. 8(b)].…”

“…In this regard, the T 24 5 µs in the 5-nm-thick film was long enough (at least theoretically) to detect a magnetic field from a single-proton nuclear spin. [158] There have been two types of isotopically enriched, 12 C diamond CVD films containing shallow NV − centers that have succeeded in detecting the magnetic field from a small ensemble of proton nuclear spins; one was produced by UC Santa Barbara (UCSB) [159] and the other was fabricated by the Keio University-AIST collaboration in Japan. [158] While the UCSB sample was employed successfully by the IBM Almaden Research Center to detect the NMR of the proton spins confined in 24 nm 3 of polymethyl methacrylate (PMMA), placed directly on the diamond surface, [163] the Keio-AIST sample succeeded in (along with the Keio-AIST-ETH collaboration) Figure 8.…”

Synthesis of luminescent europium defects in diamond

“…Diamond possesses a very large band gap (5.5 eV) that can accommodate a variety of optically active defects. Furthermore, the progress in growing isotopically pure diamond, (by minimising 13 C isotopes) has recently enabled very long spin coherence times of the NV 16,17 . The chemical stability of diamond means that nanodiamonds exhibit excellent photostability and cytotoxicitymaking them promising as bio-labels and biosensors.…”