Temporally resolved laser induced plasma diagnostics of single crystal silicon — Effects of ambient pressure

Cowpe, J.S.; Astin, J.S.; Pilkington, R.D.; Hill, Arthur E.

doi:10.1016/j.sab.2008.09.007

Cited by 41 publications

(18 citation statements)

References 26 publications

(34 reference statements)

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“…The Doppler effect induces a broadening in line width for Si (I) 288.16 nm of less than 3.2 × 10 -6 nm, assuming that the plasma temperature is the maximum determined in this study [38]. The electron density of the plasma relates to the Stark pressure broadening of the emission line profiles according to Equation 2…”

Section: Plasma Electron Density and Lte Considerationsmentioning

confidence: 81%

Hardness determination of bio-ceramics using Laser-Induced Breakdown Spectroscopy

Cowpe

Moorehead

Moser

et al. 2011

Spectrochimica Acta Part B: Atomic Spectroscopy

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Abstract:Laser-Induced Breakdown Spectroscopy (LIBS) was applied to the analysis of bioceramic samples. The relationship between sample hardness and LIBS plasma properties was investigated, with comparison to conventional Vickers hardness measurements. The plasma excitation temperature T e was determined using the lineto-continuum ratio for the Si (I) 288.16 nm emission line; we have demonstrated a linear relationship between sample surface hardness and plasma temperature. Results indicate that hardness determination based on measurements of T e offers greater reproducibility than Vickers hardness measurements, under the conditions considered here. The validity of spectroscopic diagnostics based on LTE was confirmed.

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Section: Plasma Electron Density and Lte Considerationsmentioning

confidence: 81%

Hardness determination of bio-ceramics using Laser-Induced Breakdown Spectroscopy

Cowpe

Moorehead

Moser

et al. 2011

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…(8)] to obtain the lifetimes reported in Fig. 4 was deemed suitable for the 80/20 superlattices since the coefficient of determination value 41 for the most affected modes was 0.9. For completeness, the power spectra and lifetimes of 60/40 superlattices are also included in Fig.…”

Section: B Power Spectramentioning

confidence: 99%

Disruption of superlattice phonons by interfacial mixing

et al. 2013

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Molecular dynamics simulations and lattice dynamics calculations are used to study the vibrational modes and thermal transport in Lennard-Jones superlattices with perfect and mixed interfaces. The secondary periodicity of the superlattices leads to a vibrational spectrum (i.e., dispersion relation) that is distinct from the bulk spectra of the constituent materials. The mode eigenvectors of the perfect superlattices are found to be good representations of the majority of the modes in the mixed superlattices for up to 20% interfacial mixing, allowing for extraction of phonon frequencies and lifetimes. Using the frequencies and lifetimes, the in-plane and cross-plane thermal conductivities are predicted using a solution of the Boltzmann transport equation (BTE), with agreement found with predictions from the Green-Kubo method for the perfect superlattices. For the mixed superlattices, the Green-Kubo and BTE predictions agree for the cross-plane direction, where thermal conductivity is dominated by low-frequency modes whose eigenvectors are not affected by the mixing. For the in-plane direction, mid-frequency modes that contribute to thermal transport are disrupted by the mixing, leading to an underprediction of thermal conductivity by the BTE. The results highlight the importance of using a dispersion relation that includes the secondary periodicity when predicting phonon properties in perfect superlattices and emphasize the challenges of estimating the effects of disorder on phonon properties.

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“…Considering a plasma temperature of ~10 5 K for Al [14,15], ~⋅ 5 10 4 K for Si [30], and ~10 4 K for LiNbO 3 [31] obtained when irradiating the targets with nanosecond pulses, eq. (6) gives a plasma hydrodynamic length of ~50 µm.…”

Section: Resultsmentioning

confidence: 99%

Influence of the pulse number and fluence of a nanosecond laser on the ablation rate of metals, semiconductors and dielectrics

Vladoiu

Stafe

Negutu

et al. 2009

Eur. Phys. J. Appl. Phys.

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HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L'archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. AbstractWe investigated the pulsed laser ablation of metallic (Al), semiconductor (Si), and wide bandgap dielectric (LiNbO 3 ) targets in air at normal atmospheric conditions by using 4.5 ns pulses at 532 nm wavelength. We determined the dependence of the ablation rate on the pulse number and laser fluence. The number of consecutive laser pulses hitting the target on the same area was between 5 and 40, and the laser fluence was varied in the range of 10-250 J/cm 2 by changing the irradiated area at the target surface. We find that the ablation rate of the three targets is approximately constant when the pulse number is smaller than 15. Further increase of the pulse number leads to a decrease of the ablation rate, the fastest decrease of the ablation rate with pulse number being observed for the dielectric target. The dependence of the ablation rate on the laser fluence indicates two different regimes. In the first regime, which is for values of the fluence smaller than the threshold value (~70 J/cm 2 for Al, ~90 J/cm 2 for Si, and ~180 J/cm 2 for LiNbO 3 ), the ablation rate increases approximately logarithmically with the fluence. In the second regime, characterized by values of the fluence greater than the threshold value, there is a steep increase of the ablation rate. This sudden jump of the ablation rate at the threshold fluence is due to the transition from normal vaporisation to phase explosion, and to the changes in the dimensionality of the plasma-plume hydrodynamics from one-dimensional to three-dimensional.

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Temporally resolved laser induced plasma diagnostics of single crystal silicon — Effects of ambient pressure

Abstract: Laser-Induced Breakdown Spectroscopy of silicon was performed using a nanosecond pulsed frequency doubled Nd:YAG (532 nm) laser. The temporal evolution of the laser ablation plumes in air at atmospheric pressure and at an ambient pressure of

Cited by 41 publications

References 26 publications

Hardness determination of bio-ceramics using Laser-Induced Breakdown Spectroscopy

Hardness determination of bio-ceramics using Laser-Induced Breakdown Spectroscopy

Disruption of superlattice phonons by interfacial mixing

Influence of the pulse number and fluence of a nanosecond laser on the ablation rate of metals, semiconductors and dielectrics

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