Raman scattering from diamond particles

Yoshikawa, Masanobu; Mori, Yuzo; Maegawa, M.; Katagiri, Gen; Ishida, Hideyuki; Ishitani, A.

doi:10.1063/1.109154

Cited by 161 publications

(85 citation statements)

References 12 publications

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“…We optimized the size dependent Γ0 values by fitting the theoretical band shape with the experimental spectra. In agreement with previous studies [24,25] , Γ0 has been found to increase with decreasing the size (fig.4, dotted line). This tendency is well expected from stronger perturbations that a phonon experiences in smaller particles.…”

Section: Figsupporting

confidence: 81%

“…In the present work, we do not discuss the physical mechanisms involved in the homogeneous broadening as well as the analytical equation for it. We refrained from using the inverse size dependence of the dephasing constant Γ0 as suggested in the work [25] , because it gives unreasonably high Γ0 values as the size approaches the amorphous solid. We optimized the size dependent Γ0 values by fitting the theoretical band shape with the experimental spectra.…”

Section: Figmentioning

confidence: 99%

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Quantum‐chemical perspective of nanoscale Raman spectroscopy with the three‐dimensional phonon confinement model

Korepanov

Hamaguchi

2017

J Raman Spectroscopy

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Raman spectroscopy of crystalline/molecular systems is well backed with quantum chemical calculations and group theory, making it a unique characterization tool. For the "intermediate" case of nanoscale systems, however, the use of Raman spectroscopy is limited by the lack of such theoretical bases. Here, we suggest to couple a scaled quantum-mechanical (SQM) calculation with the phonon confinement model (PCM) to construct a universal and physically consistent basis for nanoscale Raman spectroscopy. Unlike the commonly used one-dimensional dispersion PCM, we take into account the confinement along all the three dimensions of the k-space. We apply it to diamond nanoparticles of sub-50nm size, a system with pronounced anisotropy of dispersion for which the use of three-dimensional dispersion is a requisite. The model excellently reproduces sizesensitive spectral features, including the peak position, bandwidth and asymmetry of the sp 3 C-C Raman band. This fundamental approach can be easily generalized to other nanocrystalline solids to hopefully contribute the future development of quantitative nanoscale Raman spectroscopy. Keywords: phonon confinement, nanoparticlesThe continuously growing interest to nanoscale matter drives a strong demand for fast, noninvasive and statistically reliable characterization methods. This makes Raman spectroscopy an indispensable tool for nanoscience. The difficult challenge of Raman spectroscopy of nanoscale materials is to establish a consistent way to link the Raman pattern to the characteristic size of the crystallites. The straightforward approach is to directly calculate the normal modes of nanoparticles as big molecules [1,2] . This requires assumptions of the shape, size and symmetry. The calculated spectra are the set of narrow lines. Since the number of normal modes for nanoparticles is in the order of thousands, such calculations do not seem to be routinely availbale for real systems. The other common approach is the elastic sphere model (ESM), in which the nanoparticle is approximated by a homogeneous isotropic freestanding elastic sphere. The vibrations of such system can be easily derived from first principles calculations [3] . For the nanoparticles of other shapes, as well as systems with the size smaller than ~5nm, the applicability of ESM is limited. For more details on ESM the reader is referred to the review [4] . The third general approach starts from the Raman spectrum of a bulk crystal, for which the selection rules allow only the phonons close to the Brillouin zone (BZ) center. Nano-size crystallites lack the translational symmetry and the quasimomentum preservation does not hold. As a result, BZ points away from the center can also contribute to the Raman spectra. To what extent the selection rule breaks depends on the size of the crystallite. This effect is named the "phonon confinement" after the work of Richter [5] , who first suggested the physical model for describing it. The approach by Richter's is to multiply the phonon wavefunction of the crystal φ...

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Section: Figsupporting

confidence: 81%

Section: Figmentioning

confidence: 99%

Quantum‐chemical perspective of nanoscale Raman spectroscopy with the three‐dimensional phonon confinement model

Korepanov

Hamaguchi

2017

J Raman Spectroscopy

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“…9 Another problem is to detect the "true" PSD averaged spectrum, rather than a local one (i.e., taken at one point). In previous works on ND, [10][11][12] the Raman measurements were mostly done for solid (powder) samples under a microscope. That makes the laser heating inevitable, and the PSD is detected at a particular point of the sample.…”

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confidence: 99%

Communication: Three-dimensional model for phonon confinement in small particles: Quantitative bandshape analysis of size-dependent Raman spectra of nanodiamonds

Korepanov

Witek

Okajima

et al. 2014

The Journal of Chemical Physics

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Raman spectroscopy of nano-scale materials is facing a challenge of developing a physically sound quantitative approach for the phonon confinement effect, which profoundly affects the phonon Raman band shapes of small particles. We have developed a new approach based on 3-dimensional phonon dispersion functions. It analyzes the Raman band shapes quantitatively in terms of the particle size distributions. To test the model, we have successfully obtained good fits of the observed phonon Raman spectra of diamond nanoparticles in the size range from 1 to 100 nm.

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“…However, for a material which contains both, amorphous and nanodiamond regions, or a hybrid combination of both, the two bands usually cannot be distinguished since the difference in location is only a few cm −1 . In addition, upon shrinking of the crystal to the nanoscale, major changes are observed in the Raman response of nanodiamonds: compared to bulk diamond, the nanodiamond peak is shifted to lower frequencies and appears broadened, sometimes with an asymmetry [89][90][91]. The phonon confinement effect is mainly considered as the physical origin for these changes [92].…”

Section: Discussionmentioning

confidence: 99%

Diamond-Like Carbon Nanofoam from Low-Temperature Hydrothermal Carbonization of a Sucrose/Naphthalene Precursor Solution

Frese

Mitchell

Bowers

et al. 2017

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Unusual structure of low-density carbon nanofoam, different from the commonly observed micropearl morphology, was obtained by hydrothermal carbonization (HTC) of a sucrose solution where a specific small amount of naphthalene had been added. Helium-ion microscopy (HIM) was used to obtain images of the foam yielding micron-sized, but non-spherical particles as structural units with a smooth foam surface. Raman spectroscopy shows a predominant sp 2 peak, which results from the graphitic internal structure. A strong sp 3 peak is seen in X-ray photoelectron spectroscopy (XPS). Electrons in XPS are emitted from the near surface region which implies that the graphitic microparticles have a diamond-like foam surface layer. The occurrence of separated sp 2 and sp 3 regions is uncommon for carbon nanofoams and reveals an interesting bulk-surface structure of the compositional units.

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Raman scattering from diamond particles

Cited by 161 publications

References 12 publications

Quantum‐chemical perspective of nanoscale Raman spectroscopy with the three‐dimensional phonon confinement model

Quantum‐chemical perspective of nanoscale Raman spectroscopy with the three‐dimensional phonon confinement model

Communication: Three-dimensional model for phonon confinement in small particles: Quantitative bandshape analysis of size-dependent Raman spectra of nanodiamonds

Diamond-Like Carbon Nanofoam from Low-Temperature Hydrothermal Carbonization of a Sucrose/Naphthalene Precursor Solution

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