Effect of neutron irradiation on the hydrogen state in CVD diamond films

Khomich, А.А.; Dzeraviaha, A. N.; Poklonskaya, O. N.; Хомич, А. В.; Khmelnitsky, R. A.; Poklonski, N. A.; Ralchenko, V.G.

doi:10.1088/1742-6596/1135/1/012019

Cited by 4 publications

(7 citation statements)

References 27 publications

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“…The optical and thermophysical properties of the films approached those of the best natural single crystals [ 16 ]. The N concentration in the samples was ~10 17 cm −3 in the substitution position, and the concentration of hydrogen located at intercrystallite boundaries was ≤ 2 × 10 19 cm −3 (determined by optical absorption in UV [ 17 ] and IR [ 18 ], respectively). CVD-diamond plates, 480 μm thick, were polished to optical quality and irradiated in a wet channel of an IVV-2M nuclear reactor, in a fast neutron flux of ~10 14 cm −2 s −1 (with energies > 0.1 MeV) and fluences F = 1 × 10 18 , 3 × 10 18 , 1 × 10 19 , 2 × 10 19 and 2 × 10 20 cm −2 at 325 ± 10 K [ 19 ].…”

Section: Samples and Methodsmentioning

confidence: 99%

Probing the Nanostructure of Neutron-Irradiated Diamond Using Raman Spectroscopy

2020

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Disordering of crystal lattice induced by irradiation with fast neutrons and other high-energy particles is used for the deep modification of electrical and optical properties of diamonds via significant nanoscale restructuring and defects engineering. Raman spectroscopy was employed to investigate the nature of radiation damage below the critical graphitization level created when chemical vapor deposition and natural diamonds are irradiated by fast neutrons with fluencies from 1 × 1018 to 3 × 1020 cm−2 and annealed at the 100–1700 °C range. The significant changes in the diamond Raman spectra versus the neutron-irradiated conditions are associated with the formation of intrinsic irradiation-induced defects that do not completely destroy the crystalline feature but decrease the phonon coherence length as the neutron dose increases. It was shown that the Raman spectrum of radiation-damaged diamonds is determined by the phonon confinement effect and that the boson peak is present in the Raman spectra up to annealing at 800–1000 °C. Three groups of defect-induced bands (first group = 260, 495, and 730 cm−1; second group = 230, 500, 530, 685, and 760 cm–1; and third group = 335, 1390, 1415, and 1740 cm−1) were observed in Raman spectra of fast-neutron-irradiated diamonds.

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Section: Samples and Methodsmentioning

confidence: 99%

Probing the Nanostructure of Neutron-Irradiated Diamond Using Raman Spectroscopy

2020

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“…Concentration of substitutional nitrogen in the samples before neutron irradiation was evaluated from UV-visible absorption spectra according to procedure described elsewhere [46]. The bounded hydrogen (CH x groups) concentration was determined from IR absorption spectra [39]. The properties of four investigated samples are summarized in Table 1.…”

Section: Methodsmentioning

confidence: 99%

“…The irradiation of synthetic and natural diamonds leads to the formation of several hundred different optically active defects, including intrinsic and impurity-related, point and extended ones [5,6,16,34,36,39,40,48,54,59,66]. In this regard, it is not surprising that, along with a group of AC bands near 4100 cm −1 , other ZPLs are observed in the IR absorption spectra in a higher frequency range.…”

Section: Defect Structure Upon Moderate Radiation Damagementioning

confidence: 99%

“…IR spectroscopy is a powerful technique to study radiative defects in neutron-and electron-irradiated diamonds, as the defects are uniformly distributed in the bulk. Radiation damage effects on the one-phonon absorption band [34][35][36][37][38] and hydrogen- [31,35,39] and nitrogen-related [35,37,38,40,41] local vibrational modes are among the most studied.…”

Section: Introductionmentioning

confidence: 99%

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IR Spectroscopy of Vacancy Clusters (Amber Centers) in CVD Diamonds Nanostructured by Fast Neutron Irradiation

Khomich

Хмельницкий

Kozlova

et al. 2023

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We investigated the IR absorption spectra of CVD diamond damaged by fast neutrons (>0.1 MeV) with high fluences ranging from 1 × 1018 to 2 × 1019 cm−2 and annealed at temperatures of 200 °C to 1680 °C. After annealing above 1000 °C, the formation of “amber-centers” (ACs), associated with multivacancy clusters, is detected as deduced from the appearance of a strong absorption line at 4100 cm−1. Moreover, the concentration of the ACs in the irradiated diamond can be an order of magnitude higher than that observed previously in the darkest brown natural diamonds. A number of other absorption lines, including the H1b center at 4936 cm−1 (0.612 eV) and new lines at ~5700 cm−1 (0.706 eV) and 9320 cm−1 (1.155 eV) not reported before in the literature, are observed, and their intensity evolutions at annealing temperatures are documented. At the highest fluences, all the lines show reduced intensities and broadening and spectral shifts due to a very high defect concentration and partial amorphization. The obtained experimental data can be used for the analysis of defect generation, transformations and healing in irradiated synthetic and natural diamonds.

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“…Such films contained rather high concentration (~10 20 cm −3 ) of bounded hydrogen (CH x groups) located at the intercrystalline boundaries. It was shown earlier [91] that neutrons act on grain boundaries in diamond dislodging hydrogen into the grain bulk for distances of the order of a few micrometers. At the same time, numerous defects are formed, including those with uncompensated spin.…”

Section: Magnetic Properties Of Diamonds Irradiated With Fast Neutronsmentioning

confidence: 98%

Magnetic and Optical Properties of Natural Diamonds with Subcritical Radiation Damage Induced by Fast Neutrons

et al. 2023

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Raman spectroscopy and magnetic properties of the natural single crystalline diamonds irradiated with high fluences of fast reactor neutrons have been investigated. Raman spectra transformations were studied in the range from moderate levels up to radiation damage leading to diamond graphitization. The selection of fast neutrons irradiated diamonds for magnetic measurements was carried out according to Raman scattering data on the basis of the intensity criterion and the spectral position of the “1640” band. It was found that in natural diamonds irradiated with neutrons with an extremely high subcritical fluence F = 5 × 1020 cm−2, the transition from a diamagnetic to a ferromagnetic state is observed at the Curie–Weiss temperature of ≈150 K. The energy of the exchange magnetic interaction of uncompensated spins is estimated to be ≈1.7 meV. The differential magnetic susceptibility estimated from the measurements of magnetic moment for temperature 2 K in the limit of B ≈ 0 is χdiff ≈ 1.8 × 10−3 SI units. The nature of magnetism in radiation-disordered single-crystal hydrogen- and metal-free natural diamond grains was discussed.

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Effect of neutron irradiation on the hydrogen state in CVD diamond films

Cited by 4 publications

References 27 publications

Probing the Nanostructure of Neutron-Irradiated Diamond Using Raman Spectroscopy

Probing the Nanostructure of Neutron-Irradiated Diamond Using Raman Spectroscopy

IR Spectroscopy of Vacancy Clusters (Amber Centers) in CVD Diamonds Nanostructured by Fast Neutron Irradiation

Magnetic and Optical Properties of Natural Diamonds with Subcritical Radiation Damage Induced by Fast Neutrons

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