1. Anomalous Formation of Irradiation-Induced Nitrogen-Vacancy Centers in 5 nm-Sized Detonation Nanodiamonds
- Author
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Frederick T.-K. So, Alexander I. Shames, Daiki Terada, Takuya Genjo, Hiroki Morishita, Izuru Ohki, Takeshi Ohshima, Shinobu Onoda, Hideaki Takashima, Shigeki Takeuchi, Norikazu Mizuochi, Ryuji Igarashi, Masahiro Shirakawa, and Takuya F. Segawa
- Subjects
Condensed Matter - Materials Science ,Quantum sensing ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Electron irradiation ,DEFECTS AND IRREGULARITIES (CRYSTALLOGRAPHY) ,Nitrogen-vacancy center ,Nanodiamonds ,Detonation Nanodiamonds (DNDs) ,Annealing ,EPR SPECTROSCOPY ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,General Energy ,Physical and Theoretical Chemistry - Abstract
Nanodiamonds containing negatively charged nitrogen-vacancy (NV−) centers are versatile room-temperature quantum sensors in a growing field of research. Yet, knowledge regarding the NV− formation mechanism in very small particles is still limited. This study focuses on the formation of the smallest NV−-containing diamonds, 5 nm detonation nanodiamonds (DNDs). As a reliable method to quantify NV− centers in nanodiamonds, half-field signals in electron paramagnetic resonance (EPR) spectroscopy are recorded. By comparing the NV− concentration with a series of nanodiamonds from high-pressure high-temperature (HPHT) synthesis (10−100 nm), it is shown that the formation process in 5 nm DNDs is unique in several aspects. NV− centers in DNDs are already formed at the stage of electron irradiation, without the need for high-temperature annealing, an effect related to the very small particle size. Also, the NV− concentration (in atomic ratio) in 5 nm DNDs surpasses that of 20 nm-sized nanodiamonds, which contradicts the observation that the NV− concentration generally increases with particle size. This can be explained by the 10 times higher concentration of substitutional nitrogen atoms in the studied DNDs ([NS ≈ 1000 ppm]) compared to the HPHT nanodiamonds ([NS ≈ 100 ppm]). Upon electron irradiation at a fluence of 1.5 × 10^19 e−/cm2, DNDs show a 12.5-fold increment in the NV− concentration with no sign of saturation reaching 1 out of about 80 DNDs containing an NV− center. These findings can be of interest for the creation of defects in other very small semiconductor nanoparticles beyond NV-nanodiamonds as quantum sensors., The Journal of Physical Chemistry C, 126 (11), ISSN:1932-7455, ISSN:1932-7447
- Published
- 2022