Spin density in hydrogenated amorphous carbon films—different originations

Thin polycrystalline diamond films were synthesized on silicon substrate by Hot Filament Chemical Vapor Deposition (HF CVD) technique from a mixture of hydrogen and different content of methyl alcohol. A comparative study on the Electron Paramagnetic Resonance (EPR), Raman spectroscopy and Scanning Electron Microscopy (SEM) were performed. It was shown that EPR signal, Raman spectra and morphology, studied by SEM, strongly depend on the ratio of CH 3 OH/H 2 in the HF CVD reactor. The peak-to-peak linewidth in EPR signal varies from 0.09 to 0.8 mT depending on diamond quality. The Raman spectra of our diamond film showed, except well defined diamond Raman lines positioned at 1332 cm -1 with different Full Width at Half Maximum (FWHM), a broad band having maximum at around 1530 cm -1 which is characteristic for amorphous carbon phase. The obtained results show that EPR, SEM and Raman spectroscopy yield complementary results about the defects present in CVD diamond films.

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“…Similar values of ΔH pp and spin concentrations were observed for amorphous carbons [38] and also in CVD diamonds [27].…”

supporting

confidence: 80%

“…Such a conclusion is confirmed by EPR spectroscopy. As it is known that amorphous phase of carbon in general is paramagnetic in nature then it can be detected by EPR spectroscopy [37,38]. In figure 3 are shown ESR spectra of diamond films from figure 1.…”

Section: Resultsmentioning

confidence: 99%

Electron paramagnetic resonance and raman spectroscopy characterization of diamond films fabricated by HF CVD method

Fabisiak¹,

Szreiber

Uniszkiewicz

et al. 2010

Cryst. Res. Technol.

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“…The presence of the ν(C−H) modes indicates H bonded to sp 3 -hybridized carbon, and those of the ν(CO) and ν( O C−O) modes are in line with oxidation at CC bonds upon contact to atmosphere. The broad (almost flat) band at 2970−2840 cm −1 reveals similar absorbance of symmetric and asymmetric stretches of C(sp 3 )−H n ( n = 1−3) , contributions. This fact and the lack of absorption above 3000 and 3300 cm −1 (regions of ν(C(sp x )−H), x = 1,2) are in accordance with H preferentially occupying saturated carbon centers.…”

Section: Resultsmentioning

confidence: 88%

Megawatt Ultraviolet Laser Photolysis of Dichloroethenes for Gas-Phase Deposition of Nanosized Chlorinated Soot

et al. 2010

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Highly intense ArF and KrF laser radiation-induced photolysis of gaseous dichloroethenes allows chemical vapor deposition of ultrafine amorphous Cl-substituted hydrogenated carbon soot, which was characterized by FTIR, Raman, X-ray photoelectron and Auger spectroscopy, and electron microscopy, and diagnosed for magnetic and thermal properties. The deposited submicroscopic material was shown to contain C(sp3)−H, C−Cl, C−O, and CO bonds and upon heating to 700 °C to evolve H2, HCl, Cl2, and C/H fragments and transform to graphite-like carbon. The deposited soot is diamagnetic, has a large surface area, and has a potential for synthesis of soot modified at the C−Cl bonds by other substituents.

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