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Rösch, M.; Atzmüller, R.; Schaack, G.; Cr, Becker

doi:10.1103/physrevb.49.13460

Cited by 16 publications

(5 citation statements)

References 56 publications

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“…34 The other Raman features were observed in all of the filled tube samples. These features are very similar to the multi-phonon spectra often seen with inorganic semiconductors such as HgTe 35 and ZnO 36 which have been shown to be enhanced in nanowire structures. 37 In particular the two lowest energy peaks; at 47cm -1 (peak A) and 51cm -1 (peak B), are associated with two higher energy peaks at precisely twice the energy to within experimental error (labeled 2A and 2B on fig 4).…”

Section: Resultssupporting

confidence: 70%

Raman Spectroscopy of Optical Transitions and Vibrational Energies of ∼1 nm HgTe Extreme Nanowires within Single Walled Carbon Nanotubes

et al. 2014

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This paper presents a Resonance Raman spectroscopy study of ~1 nm diameter HgTe nanowires formed inside single walled carbon nanotubes by melt infiltration. Raman spectra have been measured for ensembles of bundled filled tubes, produced using tubes from two separate sources, for excitation photon energies in the ranges 3.39 to 2.61eV and 1.82 to 1.26eV for Raman shifts down to ~25 cm -1 . We also present HRTEM characterization of the tubes and the results of DFT calculations of the phonon and electronic dispersion relations, and the optical absorption spectrum based upon the observed structure of the HgTe nanowires. All of the evidence supports

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Section: Resultssupporting

confidence: 70%

Raman Spectroscopy of Optical Transitions and Vibrational Energies of ∼1 nm HgTe Extreme Nanowires within Single Walled Carbon Nanotubes

et al. 2014

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“…Consequently, the DP and F interaction contribution to the LO phonon scattering are distinguishable by their contrasting polarization selection rules. The above Raman tensors show that DP and F scattering can be selected when perpendicular and parallel polarization vectors are employed, [ 26–28 ] respectively. These LO phonons transition from forbidden to allowed give rise to non‐zero matrix elements.…”

Section: Discussionmentioning

confidence: 99%

“…These two cases can be distinguished experimentally based on their selection rules via polarizability tensors, and dispersive behavior with respect to excitation energy. [ 26–28 ] In polarization Raman scattering measurements, the observed band intensity is governed by:

normalI \propto {|{\overset{e}{true}}_{normals} . R . {\overset{e}{true}}_{normali}|}^{2}

where

{\overset{truê}{e}}_{i}

and

{\overset{truê}{e}}_{s}

are Cartesian indices related to the electric field vectors of the incident and scattered light, respectively, and

scriptR

is the derivative of the polarization tensor, or also called the Raman tensor, for conventional and Resonant Raman scattering. [ 26–28 ]…”

Section: Discussionmentioning

confidence: 99%

“…Experimentally, it has been demonstrated for several semiconductors that when the backscattering Raman experiment (180° illumination) is performed on the basal facet {001} of a single‐crystal, the Raman tensor corresponding to an LO phonon propagating in the in the [001] direction has the form [ 26–28 ] :

R_{DP}^{LO} goodbreak= ((), \begin{matrix} 0 & α_{DP} & 0 \\ α_{DP} & 0 & 0 \\ 0 & 0 & 0 \end{matrix}), R_{F}^{LO} goodbreak= ((), \begin{matrix} α_{F} & 0 & 0 \\ 0 & α_{F} & 0 \\ 0 & 0 & α_{F .} \end{matrix}),

where α DP and α F are the Raman polarizabilities for DP and F scattering, respectively.…”

Section: Discussionmentioning

confidence: 99%

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Resonance Raman and polarized Raman scattering of single‐crystal hematite

Marshall

Dufresne

2022

J Raman Spectroscopy

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Researchers have demonstrated that the Raman spectra collected on hematite nanoparticles undergo an intensity enhancement, due to a dependence on excitation energy. Especially, the bands at approximately 660 and approximately 1320 cm−1, which are assigned as the 1LO and 2LO modes, respectively, experience the strongest intensity enhancement, which has been attributed to resonance Raman scattering when excited with excitation energy at or close to the band gap. However, the resonance Raman scattering mechanism is not clear and further has not been experimentally determined. To this end, we have undertaken measurements to examine the excitation energy dependence and polarized Raman scattering on a pure single‐crystal of hematite to gain a better understanding of the resonance enhancement mechanism for the 1LO and 2LO modes. Resonance enhancement mechanisms giving rise to LO phonons in semiconductors can be attributed to either the deformation potential (DP) or Fröhlich interactions (F) scattering, or a combination of the two. The DP and F contributions that give rise to LO phonon scattering in semiconductors are distinguishable due to their contrasting selection rules. Here, employing these selection rules, we conducted the following polarization Raman scattering measurements: Z()XXtrueZ0.25em¯, Z()XYtrueZ¯, Z()YYtrueZ¯, Z()YXtrueZ¯, X()YYtrueX¯, X()ZZtrueX¯, and Y()XXtrueY¯ on single‐crystal hematite to distinguish between DP (dipole‐allowed) and F (dipole‐forbidden) scattering. Our polarization experiments strongly suggest that the Fröhlich LO phonon interaction dominates the Raman scattering over the weaker DP contribution. Furthermore, polarization experiments collected using the following geometries Z()X′X′trueZ¯ and 0.25emZ()Y′Y′trueZ¯ demonstrate that the interference between dipole‐allowed and dipole‐forbidden Raman scattering is constructive for LO phonons. Therefore, we attribute the mechanism of resonance Raman scattering of the 1LO and 2LO modes in the Raman spectrum of hematite due to contributions from F and DP processes.

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“…Спектры оптических постоянных твердого раствора Hg 1−x Cd x Te (КРТ) достаточно хорошо изучены в широком спектральном диапазоне [1][2][3][4][5][6][7], включая крайние точки непрерывного ряда растворов HgTe [8,9] и CdTe [10,11]. Для отдельных областей спектра измерены также температурные зависимости оптических постоянных [12,13].…”

Section: Introductionunclassified

Параметрическая модель спектров оптических постоянных Hg-=SUB=-1-x-=/SUB=-Cd-=SUB=-x-=/SUB=-Te и определение состава соединения

Швец¹,

Marin²,

Remesnik³

et al. 2020

Журнал Технической Физики

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A parametric model describing the spectra of the optical constants Hg1-xCdxTe n( lam) and k(lam) for x values in the range from 0.2 to 0.4 is presented. The Model is based on empirical data measured in situ during epitaxial growth of the compound layers. Variants of using the obtained model for determining the composition of MCT in situ in real time are considered. A method for determining the composition based on spectral ellipsometric measurements is proposed, which provides an accuracy no worse than (del)x=±0.0035.

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Resonant Raman scattering in a zero-gap semiconductor: Interference effects and deformation potentials at theE1andE1

Cited by 16 publications

References 56 publications

Raman Spectroscopy of Optical Transitions and Vibrational Energies of ∼1 nm HgTe Extreme Nanowires within Single Walled Carbon Nanotubes

Raman Spectroscopy of Optical Transitions and Vibrational Energies of ∼1 nm HgTe Extreme Nanowires within Single Walled Carbon Nanotubes

Resonance Raman and polarized Raman scattering of single‐crystal hematite

Параметрическая модель спектров оптических постоянных Hg-=SUB=-1-x-=/SUB=-Cd-=SUB=-x-=/SUB=-Te и определение состава соединения

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