Quantum confinement and thermal effects on the Raman spectra of Si nanocrystals

Faraci, G.; Gibilisco, S.; Pennisi, A.

doi:10.1103/physrevb.80.193410

Cited by 59 publications

(52 citation statements)

References 23 publications

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“…The laser power during measurements is fixed at 0.3 W/mm 2 . This laser power is sufficiently lower than the threshold power (1 mW/lm 2 ) for the Fano effect, 32,33 which is an artificial broadening and red-shift as a result of laser induced heating. It is also experimentally verified that the selected laser power does not induce any artificial shift and broadening in the Raman spectrum of Si-NCs.…”

Section: Methodsmentioning

confidence: 99%

Direct characterization of nanocrystal size distribution using Raman spectroscopy

Doğan

Sanden

2013

Journal of Applied Physics

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We report a rigorous analytical approach based on one-particle phonon confinement model to realize direct detection of nanocrystal size distribution and volume fraction by using Raman spectroscopy. For the analysis, we first project the analytical confinement model onto a generic distribution function, and then use this as a fitting function to extract the required parameters from the Raman spectra, i.e., mean size and skewness, to plot the nanocrystal size distribution. Size distributions for silicon nanocrystals are determined by using the analytical confinement model agree well with the one-particle phonon confinement model, and with the results obtained from electron microscopy and photoluminescence spectroscopy. The approach we propose is generally applicable to all nanocrystal systems, which exhibit size-dependent shifts in the Raman spectrum as a result of phonon confinement.

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Section: Methodsmentioning

confidence: 99%

Direct characterization of nanocrystal size distribution using Raman spectroscopy

Doğan

Sanden

2013

Journal of Applied Physics

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“…Temperature dependent Raman scattering studies for Si NSs for temperatures above 300 K have been reported previously [17][18][19][20][21][22] by combining heating and confinement effects. Many authors [18][19][20][21][22] explain the Raman line-shape at elevated temperature by simply considering the temperature dependence of Raman peak position and FWHM as formulated by Balkanski et al [4]. He used the higher order anharmonicity in light scattering by optical phonons to incorporate the effect of temperature on zone center optic phonons only.…”

Section: Introductionmentioning

confidence: 96%

Thermal Effects on Electron-Phonon Interactions in Silicon Nanostructures

Kumar

Shukla

2010

Silicon

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Raman spectroscopy of silicon nanostructures, recorded using an excitation laser power density of 1.0 kW/cm 2 , was employed here to reveal the dominance of thermal effects at temperatures higher than room temperature. The room temperature Raman spectrum showed only phonon confinement and Fano effects. Raman spectra recorded at higher temperatures showed an increase in FWHM and a decrease in asymmetry ratio with respect to its room temperature counterpart. Experimental Raman scattering data were analyzed successfully using theoretical Raman line-shapes generated by incorporating the temperature dependence of a phonon dispersion relation. The experimental and theoretical temperature dependent Raman spectra are in good agreement. Although quantum confinement and Fano effects persist, heating effects start dominating at temperatures higher than room temperature.

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“…Instead, the strength of the RCF model is its ability to give a fast estimation of the nanostructure size, when it is applied properly, as well as to provide a means to determine the temperature that develops due to the Raman laser heating. 2,14 In addition to resolving the problem of the phononweighting function, we show in this paper how the isotropic RCF model can be generalized for nanostructures fabricated from materials with anisotropic phonon-dispersion properties. This issue is of special importance for highly anisotropic materials such as titanium oxide, which possesses strongly anisotropic dispersion relations.…”

Section: Introductionmentioning

confidence: 99%

Modified phonon confinement model for Raman spectroscopy of nanostructured materials

et al. 2010

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This work describes further development of the confinement theory used for fitting of the Ramanspectroscopy signal obtained from nanostructured materials. We present a simple algebraic method for the incorporation of an anisotropic phonon-dispersion function into the phonon confinement model. The anisotropy is shown to have particular effects on low-dimensional systems, of sizes below ϳ15 nm, even for systems with low anisotropy such as Ge. Experimental verification of the model is provided by fitting the Raman signal from Ge nanowires grown on quartz substrates. The interplay between the temperature change due to Raman laser heating and the size of the nanostructures is discussed.

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Quantum confinement and thermal effects on the Raman spectra of Si nanocrystals

Cited by 59 publications

References 23 publications

Direct characterization of nanocrystal size distribution using Raman spectroscopy

Direct characterization of nanocrystal size distribution using Raman spectroscopy

Thermal Effects on Electron-Phonon Interactions in Silicon Nanostructures

Modified phonon confinement model for Raman spectroscopy of nanostructured materials

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