Laser induced heating of Si nanocrystals

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

doi:10.1016/j.jnoncrysol.2010.05.035

Cited by 11 publications

(19 citation statements)

References 20 publications

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“…The observation of two Raman bands of Si for laser powers above certain threshold values was previously reported in the work of Gibilisco et al [15] where Si nanocrystals, purposely grown from a vapor phase on a graphite substrate, were impinged by a laser beam with powers of about 5 mW, similar to our case. This similarity of the findings suggests that Si nanocrystals are present on the surface of our wafer samples, and their connection to the bulk do not allow a good thermal conduction, so that the heat induced by laser irradiation cannot be carried away.…”

Section: Heating Of Nanocrystalssupporting

confidence: 86%

Silicon Nanocrystals on the Surface of Standard Si Wafers: A Micro-Raman Investigation

Mohammed¹,

Cazzanelli²,

Fasanella³

et al. 2018

MSCE

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The presence of silicon nanocrystals on the surface of standard wafer samples of Si, conserved under "usual" laboratory conditions, has been investigated by micro-Raman analysis, performed for increasing intensity of laser irradiation. The poor thermal connection of such small crystals to the Si wafer bulk allows for the appearance of two well distinct Raman bands in the spectra, with a different evolution for increasing irradiance levels: the first, expected, due to bulk silicon response, the other one assignable to the silicon nanocrystals. A careful analysis of peak position and linewidth has been carried out, both for the Raman contribution from the nanocrystals, reaching high temperatures under irradiation (up to 1400 K), and for the one from the "bulk" Si, which remains practically at room temperature. The analysis of the spectra and the comparison with previous studies on nc-Si suggest that such nanocrystals do not have a very small size, so that the observed changes of spectral parameters are mainly due to laser heating, rather than quantum confinement effects. In any case, we performed also an independent size determination by AFM mapping, confirming a size distribution well peaked between 50 and 100 nm. As a corollary from this analysis, we get the indication that apparent linewidths and positions, at low laser irradiation levels, can be slightly changed in the presence of nc-Si on the surface. It is due to the different thermal responses of bulk and nanocrystalline components, inducing unresolved separate components; this hypothesis suggests reanalysing some previous experimental data, in particular for many Raman spectra of Si collected at "room temperature".

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Section: Heating Of Nanocrystalssupporting

confidence: 86%

Silicon Nanocrystals on the Surface of Standard Si Wafers: A Micro-Raman Investigation

Mohammed¹,

Cazzanelli²,

Fasanella³

et al. 2018

MSCE

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“…A similar explanation can be invoked for bulk Si. It is important to remind that the specific layer thickness univocally determines the temperature locally reached under the laser beam with a variation limited to ± 20 K. Moreover, the size of the individual Si grains composing the layer (few hundred nanometers) is by far larger than that allowing any PL due to size confinement effects122233031.…”

Section: Resultsmentioning

confidence: 99%

Giant photoluminescence emission in crystalline faceted Si grains

Faraci

Pennisi

Alberti

et al. 2013

Sci Rep

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Empowering an indirect band-gap material like Si with optical functionalities, firstly light emission, represents a huge advancement constantly pursued in the realization of any integrated photonic device. We report the demonstration of giant photoluminescence (PL) emission by a newly synthesized material consisting of crystalline faceted Si grains (fg-Si), a hundred nanometer in size, assembled in a porous and columnar configuration, without any post processing. A laser beam with wavelength 632.8 nm locally produce such a high temperature, determined on layers of a given thickness by Raman spectra, to induce giant PL radiation emission. The optical gain reaches the highest value ever, 0.14 cm/W, representing an increase of 3 orders of magnitude with respect to comparable data recently obtained in nanocrystals. Giant emission has been obtained from fg-Si deposited either on glass or on flexible, low cost, polymeric substrate opening the possibility to fabricate new devices.

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“…There is am ore or less increasing linear relationship with the increasei nt he thermostatically controlled temperature for both samples. This indicatest hat local heating is produced in small particles, [12] as is the case of the TiO 2 used (25 nm). As will be explained below, this behavior is related to effects of phononic confinement.…”

Section: Computational Frameworkmentioning

confidence: 86%

“…The calculation of the temperature reached by the samples was performed by applying Equations (1)–(3):

\exp [- \frac{h \overline{ν}}{k T}] = \frac{I_{normala} [ν] / {((), μ + \overset{ν}{true})}^{3}}{I_{normals} [ν] / {((), μ - \overset{ν}{true})}^{3}}

\exp [- \frac{h \overline{ν}}{k T}] = \frac{I_{normala} [ν] / {((), μ + \overset{ν}{true})}^{4}}{I_{normals} [ν] / {((), μ - \overset{ν}{true})}^{4}}

\exp [- \frac{h \overline{ν}}{k T}] = \frac{I_{normala} [ν]}{I_{normals} [ν]}

…”

Section: Theorymentioning

confidence: 99%

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A Study of Overheating of Thermostatically Controlled TiO₂ Thin Films by Using Raman Spectroscopy

et al. 2015

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In this study a classic Raman spectroscopy method is applied and the intensity ratio of Stokes and anti-Stokes peaks is used to measure the temperature of thermostatically controlled TiO2 thin films. In addition, three mathematical formulae are used and analyzed to estimate the temperature of the TiO2 thin films. Overheating of the samples above the thermostatically controlled temperature was observed while recording the Raman spectra, with a temperature increase of up to 30 K being detected. DFT-periodic calculations showed that the anatase (101) surface had a smaller band gap than bulk anatase. Thus, it can absorb the laser radiation with a wavelength of 532 nm that is used in the experimental setup. Part of the absorbed photon energy transfers into phonon energy, heating up the anatase phase, thus leading to the heating of the samples. Moreover, overheating of the samples indicates that the experimental method used in this study can lead to deviations in their real absolute temperature values.

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Laser induced heating of Si nanocrystals

Cited by 11 publications

References 20 publications

Silicon Nanocrystals on the Surface of Standard Si Wafers: A Micro-Raman Investigation

Silicon Nanocrystals on the Surface of Standard Si Wafers: A Micro-Raman Investigation

Giant photoluminescence emission in crystalline faceted Si grains

A Study of Overheating of Thermostatically Controlled TiO₂ Thin Films by Using Raman Spectroscopy

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Laser induced heating of Si nanocrystals

Cited by 11 publications

References 20 publications

Silicon Nanocrystals on the Surface of Standard Si Wafers: A Micro-Raman Investigation

Silicon Nanocrystals on the Surface of Standard Si Wafers: A Micro-Raman Investigation

Giant photoluminescence emission in crystalline faceted Si grains

A Study of Overheating of Thermostatically Controlled TiO2 Thin Films by Using Raman Spectroscopy

Contact Info

Product

Resources

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A Study of Overheating of Thermostatically Controlled TiO₂ Thin Films by Using Raman Spectroscopy