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L Artus - One of the best experts on this subject based on the ideXlab platform.
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raman scattering study of lo phonon plasmon Coupled Modes in p type ingaas
Journal of Alloys and Compounds, 2015Co-Authors: R Cusco, Nuria Domenechamador, P Y Hung, R Droopad, L ArtusAbstract:Abstract We present a Raman scattering study of LO phonon-Coupled Modes in Be-doped, p-type In0.53Ga0.47As with hole densities ranging from 2.2 × 10 17 to 2.4 × 10 19 cm−3. Two separate phonon-like Coupled Modes are observed in the optical-phonon spectral region, corresponding to InAs-like and GaAs-like overdamped Modes. With increasing free-hole density, these Modes exhibit a redshift and their frequencies approach the respective TO frequencies. Unlike the case of n-type material, no high-frequency L + Coupled mode could be detected. The Raman spectra are analyzed using a dielectric model based on the Lindhard–Mermin susceptibility that takes into account HH and LH intraband transitions as well as HH–LH interband transitions. The model yields good quality fits to the experimental spectra. It is shown that the inter-valence-band processes introduces an additional damping channel that causes the L + mode to be damped out. The comparison between the Raman spectra and the theoretical line-shape calculations suggests the presence of a residual strain and a reduced sublattice interaction in the most heavily doped samples.
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raman scattering study of background electron density in inn a hydrodynamical approach to the lo phonon plasmon Coupled Modes
Journal of Physics: Condensed Matter, 2009Co-Authors: R Cusco, J Ibanez, Esther Alarconllado, Tomohiro Yamaguchi, Yasushi Nanishi, L ArtusAbstract:We use a hydrodynamical approach to analyse the long-wavelength LO-phonon–plasmon Coupled Modes observed in a set of high-quality MBE-grown InN epilayers with electron densities varying over one order of magnitude, from ~2 × 1018 to ~2 × 1019 cm−3. The samples were characterized by scanning electron microscopy, x-ray diffraction and Hall measurements. The correlation observed between the E2high mode frequency, and hence residual strain, and the electron density measured in the layers indicates that the differences in background electron density may be associated with threading dislocations. Owing to the low Raman signal, only the L− branch of the Coupled Modes can be unambiguously observed. The frequency of the L− Raman peak is, however, sensitive enough to the free electron density to allow its determination from lineshape fits to the spectra. These were carried out using an extended hydrodynamical model. Given the small bandgap energy and large conduction band nonparabolicity of InN, suitable expressions for the optical effective mass and mean square velocity that enter the hydrodynamical model were derived. Electron density values extracted from L− lineshape fits agree reasonably well with Hall determinations.
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raman scattering study of the long wavelength longitudinal optical phonon plasmon Coupled Modes in high mobility inn layers
Physical Review B, 2009Co-Authors: R Cusco, L Artus, J Ibanez, Esther Alarconllado, Tomohiro Yamaguchi, Yasushi NanishiAbstract:This work has been supported by the Spanish Ministry of Science and Innovation under contract MAT2007–63617 and by FPI and Ramon y Cajal Programs.
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anomalous dispersion with excitation wavelength of longitudinal optical phonon plasmon Coupled Modes in n ingaas
Journal of Physics: Condensed Matter, 2004Co-Authors: S Hernandez, R Cusco, J Ibanez, M Hopkinson, L ArtusAbstract:We have studied the wavevector dispersion of the L+ Coupled mode in n-type In0.53Ga0.47As by means of Raman scattering using several excitation wavelengths in the range between 457.9 and 720 nm. The optical properties of In0.53Ga0.47As in the range of excitation energies used are strongly affected by the presence of the E1 and E1+Δ1 critical points, and set an upper limit to the wavevector that can be probed by decreasing the excitation wavelength in Raman scattering experiments. The Raman scattering results are analysed using a Lindhard–Mermin model, and it is found that optical absorption strongly affects the Coupled-mode Raman peaks excited with the more energetic lines.
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raman scattering by lo phonon plasmon Coupled Modes in n type in 0 53 ga 0 47 as
Physical Review B, 2001Co-Authors: R Cusco, L Artus, S Hernandez, J Ibanez, M HopkinsonAbstract:We have studied by means of Raman scattering the LO phonon-plasmon Coupled Modes in $n\ensuremath{-}{\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As},$ for carrier densities between $5\ifmmode\times\else\texttimes\fi{}{10}^{16}$ and $5\ifmmode\times\else\texttimes\fi{}{10}^{19} {\mathrm{cm}}^{\ensuremath{-}3}.$ In addition to the ${L}_{+}$ mode, whose frequency rapidly increases with carrier density, two other Coupled Modes are detected that shift to lower frequencies as the carrier density increases. The observed carrier-density dependence of the latter two Modes markedly differs from the Coupled-mode behavior reported so far for ternary alloys, exemplified by that of the ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ alloys. Such a dependence is correctly described by a line-shape model based on the Lindhard-Mermin dielectric function, suitably generalized to ternary alloys. Landau damping effects are shown to play a major role in the carrier-density dependence of the lower-energy Coupled Modes. These effects are clearly observed in ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ because the small electron effective mass and the low optical phonon frequencies in this compound make the single particle excitation region to extend well beyond the frequency region where the lower energy Coupled Modes occur. Line-shape fits to the ${L}_{+}$ Coupled mode using the Lindhard-Mermin model allow a highly sensitive determination of the free-electron density in the $n\ensuremath{-}{\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ samples.
R Cusco - One of the best experts on this subject based on the ideXlab platform.
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raman scattering study of lo phonon plasmon Coupled Modes in p type ingaas
Journal of Alloys and Compounds, 2015Co-Authors: R Cusco, Nuria Domenechamador, P Y Hung, R Droopad, L ArtusAbstract:Abstract We present a Raman scattering study of LO phonon-Coupled Modes in Be-doped, p-type In0.53Ga0.47As with hole densities ranging from 2.2 × 10 17 to 2.4 × 10 19 cm−3. Two separate phonon-like Coupled Modes are observed in the optical-phonon spectral region, corresponding to InAs-like and GaAs-like overdamped Modes. With increasing free-hole density, these Modes exhibit a redshift and their frequencies approach the respective TO frequencies. Unlike the case of n-type material, no high-frequency L + Coupled mode could be detected. The Raman spectra are analyzed using a dielectric model based on the Lindhard–Mermin susceptibility that takes into account HH and LH intraband transitions as well as HH–LH interband transitions. The model yields good quality fits to the experimental spectra. It is shown that the inter-valence-band processes introduces an additional damping channel that causes the L + mode to be damped out. The comparison between the Raman spectra and the theoretical line-shape calculations suggests the presence of a residual strain and a reduced sublattice interaction in the most heavily doped samples.
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raman scattering study of background electron density in inn a hydrodynamical approach to the lo phonon plasmon Coupled Modes
Journal of Physics: Condensed Matter, 2009Co-Authors: R Cusco, J Ibanez, Esther Alarconllado, Tomohiro Yamaguchi, Yasushi Nanishi, L ArtusAbstract:We use a hydrodynamical approach to analyse the long-wavelength LO-phonon–plasmon Coupled Modes observed in a set of high-quality MBE-grown InN epilayers with electron densities varying over one order of magnitude, from ~2 × 1018 to ~2 × 1019 cm−3. The samples were characterized by scanning electron microscopy, x-ray diffraction and Hall measurements. The correlation observed between the E2high mode frequency, and hence residual strain, and the electron density measured in the layers indicates that the differences in background electron density may be associated with threading dislocations. Owing to the low Raman signal, only the L− branch of the Coupled Modes can be unambiguously observed. The frequency of the L− Raman peak is, however, sensitive enough to the free electron density to allow its determination from lineshape fits to the spectra. These were carried out using an extended hydrodynamical model. Given the small bandgap energy and large conduction band nonparabolicity of InN, suitable expressions for the optical effective mass and mean square velocity that enter the hydrodynamical model were derived. Electron density values extracted from L− lineshape fits agree reasonably well with Hall determinations.
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raman scattering study of the long wavelength longitudinal optical phonon plasmon Coupled Modes in high mobility inn layers
Physical Review B, 2009Co-Authors: R Cusco, L Artus, J Ibanez, Esther Alarconllado, Tomohiro Yamaguchi, Yasushi NanishiAbstract:This work has been supported by the Spanish Ministry of Science and Innovation under contract MAT2007–63617 and by FPI and Ramon y Cajal Programs.
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anomalous dispersion with excitation wavelength of longitudinal optical phonon plasmon Coupled Modes in n ingaas
Journal of Physics: Condensed Matter, 2004Co-Authors: S Hernandez, R Cusco, J Ibanez, M Hopkinson, L ArtusAbstract:We have studied the wavevector dispersion of the L+ Coupled mode in n-type In0.53Ga0.47As by means of Raman scattering using several excitation wavelengths in the range between 457.9 and 720 nm. The optical properties of In0.53Ga0.47As in the range of excitation energies used are strongly affected by the presence of the E1 and E1+Δ1 critical points, and set an upper limit to the wavevector that can be probed by decreasing the excitation wavelength in Raman scattering experiments. The Raman scattering results are analysed using a Lindhard–Mermin model, and it is found that optical absorption strongly affects the Coupled-mode Raman peaks excited with the more energetic lines.
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raman scattering by lo phonon plasmon Coupled Modes in n type in 0 53 ga 0 47 as
Physical Review B, 2001Co-Authors: R Cusco, L Artus, S Hernandez, J Ibanez, M HopkinsonAbstract:We have studied by means of Raman scattering the LO phonon-plasmon Coupled Modes in $n\ensuremath{-}{\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As},$ for carrier densities between $5\ifmmode\times\else\texttimes\fi{}{10}^{16}$ and $5\ifmmode\times\else\texttimes\fi{}{10}^{19} {\mathrm{cm}}^{\ensuremath{-}3}.$ In addition to the ${L}_{+}$ mode, whose frequency rapidly increases with carrier density, two other Coupled Modes are detected that shift to lower frequencies as the carrier density increases. The observed carrier-density dependence of the latter two Modes markedly differs from the Coupled-mode behavior reported so far for ternary alloys, exemplified by that of the ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ alloys. Such a dependence is correctly described by a line-shape model based on the Lindhard-Mermin dielectric function, suitably generalized to ternary alloys. Landau damping effects are shown to play a major role in the carrier-density dependence of the lower-energy Coupled Modes. These effects are clearly observed in ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ because the small electron effective mass and the low optical phonon frequencies in this compound make the single particle excitation region to extend well beyond the frequency region where the lower energy Coupled Modes occur. Line-shape fits to the ${L}_{+}$ Coupled mode using the Lindhard-Mermin model allow a highly sensitive determination of the free-electron density in the $n\ensuremath{-}{\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ samples.
J Ibanez - One of the best experts on this subject based on the ideXlab platform.
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raman scattering study of background electron density in inn a hydrodynamical approach to the lo phonon plasmon Coupled Modes
Journal of Physics: Condensed Matter, 2009Co-Authors: R Cusco, J Ibanez, Esther Alarconllado, Tomohiro Yamaguchi, Yasushi Nanishi, L ArtusAbstract:We use a hydrodynamical approach to analyse the long-wavelength LO-phonon–plasmon Coupled Modes observed in a set of high-quality MBE-grown InN epilayers with electron densities varying over one order of magnitude, from ~2 × 1018 to ~2 × 1019 cm−3. The samples were characterized by scanning electron microscopy, x-ray diffraction and Hall measurements. The correlation observed between the E2high mode frequency, and hence residual strain, and the electron density measured in the layers indicates that the differences in background electron density may be associated with threading dislocations. Owing to the low Raman signal, only the L− branch of the Coupled Modes can be unambiguously observed. The frequency of the L− Raman peak is, however, sensitive enough to the free electron density to allow its determination from lineshape fits to the spectra. These were carried out using an extended hydrodynamical model. Given the small bandgap energy and large conduction band nonparabolicity of InN, suitable expressions for the optical effective mass and mean square velocity that enter the hydrodynamical model were derived. Electron density values extracted from L− lineshape fits agree reasonably well with Hall determinations.
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raman scattering study of the long wavelength longitudinal optical phonon plasmon Coupled Modes in high mobility inn layers
Physical Review B, 2009Co-Authors: R Cusco, L Artus, J Ibanez, Esther Alarconllado, Tomohiro Yamaguchi, Yasushi NanishiAbstract:This work has been supported by the Spanish Ministry of Science and Innovation under contract MAT2007–63617 and by FPI and Ramon y Cajal Programs.
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anomalous dispersion with excitation wavelength of longitudinal optical phonon plasmon Coupled Modes in n ingaas
Journal of Physics: Condensed Matter, 2004Co-Authors: S Hernandez, R Cusco, J Ibanez, M Hopkinson, L ArtusAbstract:We have studied the wavevector dispersion of the L+ Coupled mode in n-type In0.53Ga0.47As by means of Raman scattering using several excitation wavelengths in the range between 457.9 and 720 nm. The optical properties of In0.53Ga0.47As in the range of excitation energies used are strongly affected by the presence of the E1 and E1+Δ1 critical points, and set an upper limit to the wavevector that can be probed by decreasing the excitation wavelength in Raman scattering experiments. The Raman scattering results are analysed using a Lindhard–Mermin model, and it is found that optical absorption strongly affects the Coupled-mode Raman peaks excited with the more energetic lines.
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raman scattering by lo phonon plasmon Coupled Modes in n type in 0 53 ga 0 47 as
Physical Review B, 2001Co-Authors: R Cusco, L Artus, S Hernandez, J Ibanez, M HopkinsonAbstract:We have studied by means of Raman scattering the LO phonon-plasmon Coupled Modes in $n\ensuremath{-}{\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As},$ for carrier densities between $5\ifmmode\times\else\texttimes\fi{}{10}^{16}$ and $5\ifmmode\times\else\texttimes\fi{}{10}^{19} {\mathrm{cm}}^{\ensuremath{-}3}.$ In addition to the ${L}_{+}$ mode, whose frequency rapidly increases with carrier density, two other Coupled Modes are detected that shift to lower frequencies as the carrier density increases. The observed carrier-density dependence of the latter two Modes markedly differs from the Coupled-mode behavior reported so far for ternary alloys, exemplified by that of the ${\mathrm{Al}}_{x}{\mathrm{Ga}}_{1\ensuremath{-}x}\mathrm{As}$ alloys. Such a dependence is correctly described by a line-shape model based on the Lindhard-Mermin dielectric function, suitably generalized to ternary alloys. Landau damping effects are shown to play a major role in the carrier-density dependence of the lower-energy Coupled Modes. These effects are clearly observed in ${\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ because the small electron effective mass and the low optical phonon frequencies in this compound make the single particle excitation region to extend well beyond the frequency region where the lower energy Coupled Modes occur. Line-shape fits to the ${L}_{+}$ Coupled mode using the Lindhard-Mermin model allow a highly sensitive determination of the free-electron density in the $n\ensuremath{-}{\mathrm{In}}_{0.53}{\mathrm{Ga}}_{0.47}\mathrm{As}$ samples.
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raman scattering by lo phonon plasmon Coupled Modes in n type inp
Physical Review B, 1999Co-Authors: L Artus, R Cusco, J Ibanez, N Blanco, G GonzalezdiazAbstract:We have studied LO phonon-plasmon Coupled Modes by means of Raman scattering in n-InP for carrier densities between $6\ifmmode\times\else\texttimes\fi{}{10}^{16}$ and $1\ifmmode\times\else\texttimes\fi{}{10}^{19}$ ${\mathrm{cm}}^{\ensuremath{-}3}.$ A line-shape theory based on the Lindhard-Mermin dielectric function that takes into account the nonparabolicity of the InP conduction band as well as temperature and finite wave-vector effects is used to fit the Raman spectra and extract accurate values of the electron density. The results obtained from the Lindhard-Mermin model are compared with the charge density determinations based on the Drude and the hydrodynamical models, and the approximations involved in these models are discussed.
J A Schaefer - One of the best experts on this subject based on the ideXlab platform.
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strong phonon plasmon Coupled Modes in the graphene silicon carbide heterosystem
Physical Review B, 2010Co-Authors: Roland J Koch, Th Seyller, J A SchaeferAbstract:We report on strong coupling of the charge-carrier plasmon ${\ensuremath{\omega}}_{PL}$ in graphene with the surface-optical phonon ${\ensuremath{\omega}}_{SO}$ of the underlying SiC(0001) substrate with low-electron concentration $(n=1.2\ifmmode\times\else\texttimes\fi{}{10}^{15}\text{ }{\text{cm}}^{\ensuremath{-}3})$ in the long-wavelength limit $({q}_{\ensuremath{\parallel}}\ensuremath{\rightarrow}0)$. Energy-dependent energy-loss spectra give clear evidence of two Coupled phonon-plasmon Modes ${\ensuremath{\omega}}_{\ifmmode\pm\else\textpm\fi{}}$ separated by a gap between ${\ensuremath{\omega}}_{SO}({q}_{\ensuremath{\parallel}}\ensuremath{\rightarrow}0)$ and ${\ensuremath{\omega}}_{\text{TO}}({q}_{\ensuremath{\parallel}}⪢0)$, the transverse-optical-phonon mode, in particular, for higher primary electron energies $({E}_{0}\ensuremath{\ge}20\text{ }\text{eV})$. A simplified model based on dielectric theory is able to simulate our energy-loss spectra as well as the dispersion of the two Coupled phonon-plasmon Modes ${\ensuremath{\omega}}_{\ifmmode\pm\else\textpm\fi{}}$. In contrast, Liu and Willis [Phys. Rev. B 81, 081406(R) (2010)] postulate in their recent publication no gap and a discontinuous dispersion curve with a one-peak structure from their energy-loss data.
W. Urbanczyk - One of the best experts on this subject based on the ideXlab platform.
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Quasi-phase-matched third harmonic generation in optical fibers using refractive-index gratings
IEEE Journal of Quantum Electronics, 2011Co-Authors: Karol Tarnowski, Bertrand Kibler, Christophe Finot, W. UrbanczykAbstract:The purpose of this work is to demonstrate the quasi-phase-matching of third harmonic generation process in optical fibers using refractive-index gratings. We compare conversion efficiency calculated with analytical Coupled Modes theory and numerical approach employing system of Coupled generalized nonlinear Schrödinger equation. Moreover, we show that introducing the phase matching condition that takes into account the nonlinear contribution to propagation constants significantly increases the conversion efficiency by several orders of magnitude. Finally we optimize the grating constant to maximize conversion efficiency.
