Raman Effect in Wurtzite- and Zinc-Blende-Type ZnS Single Crystals

Brafman, O.; Mitra, S. S.

doi:10.1103/physrev.171.931

Cited by 230 publications

(128 citation statements)

References 9 publications

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“…However, in the present study, we cannot assign this peak to the TO mode of cubic ZnS because the zone center and zone boundary TO phonon for bulk cubic ZnS are reported to appear at 276 and 303 cm -1 , respectively [42,43]. Brafman and Mitra [44] reported the TO and LO zone center phonons of cubic ZnS crystals to be at 276 and 351 cm -1 respectively, for the Raman spectra of bulk cubic phases of ZnS. According to Smith [45], the coupling between longitudinal phonons and charge density fluctuations (plasmons) in polar semi-conducting systems results in two different LO phonon-plasmon coupled modes (LOPC modes), namely the L + and L -modes.…”

Section: Raman Spectroscopymentioning

confidence: 91%

Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

Onwudiwe

Krüger

Jordaan

et al. 2014

Applied Surface Science

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Research Highlights-Zinc sulphide (ZnS) nanoparticles were synthesised by laser irradiation -The structural and morphological properties of the prepared samples were analysed -Larger particles were obtained by using Na 2 S instead of TAA as the sulphur source.-Phonon softening and line broadening of the peaks were observed -Size reduction occurred in the samples obtained from both sources Graphical Abstract AbstractZinc sulphide (ZnS) nanoparticles have been synthesised by a green approach involving laser irradiation of an aqueous solution of zinc acetate (Znac 2 ) and sodium sulphide (Na 2 S·9H 2 O) or thioacetamide (TAA) in polyvinylpyrrolidone (PVP). The structural and morphological properties of the prepared samples were analysed using a transmission electron microscope, TEM, a high resolution transmission electron microscope, HRTEM, X-ray diffraction, and Raman spectroscopy.The thermal properties were studied using a simultaneous thermal analyser (SDTA). Better dispersed and larger particles were obtained by using sodium sulphide (Na 2 S) instead of TAA as the sulphur source. X-ray diffraction (XRD) analyses and Raman measurement show that the particles have a cubic structure, which is usually a low temperature phase of ZnS. There were phonon softening and line broadening of the peaks which are attributed to the phonon confinement effect. The average crystallite size of the ZnS nanoparticles estimated from the XRD showed a reduction in size from 13.62 to 10.42 nm for samples obtained from Na 2 S, and 9.13 to The absorption spectra showed that the nanoparticles exhibit quantum confinement effects.

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Section: Raman Spectroscopymentioning

confidence: 91%

Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

Onwudiwe

Krüger

Jordaan

et al. 2014

Applied Surface Science

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“…B 1 modes are inactive in both the spectra. 31,32 The A 1 and E 1 symmetry can split into two components: transverse optic (TO) and longitudinal optic (LO), and both of them are highly isotropic, A 1 (TO) = E 1 (TO) and A 1 (LO) = E 1 (LO), which is a characteristic feature of the wurtzite ZnS. 31,33 Fig.…”

Section: B Micro Raman Spectral Analysismentioning

confidence: 99%

Surface plasmon resonance in nanostructured Ag incorporated ZnS films

2015

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Silver incorporated zinc sulfide thin films are prepared by RF magnetron sputtering technique and the influence of silver incorporation on the structural, optical and luminescence properties is analyzed using techniques like grazing incidence X-Ray diffraction (GIXRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), micro-Raman spectroscopy, UV-Vis spectroscopy and laser photoluminescence spectroscopy. XRD analysis presents hexagonal wurtzite structure for the films. A reduction of crystallinity of the films is observed due to Ag incorporation. The Raman spectral analysis confirms the reduction of crystallinity and increase of strain due to the Ag incorporation. AFM analysis reveals a rough surface morphology for the undoped film and Ag incorporation makes the films uniform, dense and smooth. A blue shift of band gap energy with increase in Ag incorporation is observed due to quantum confinement effect. An absorption band (450-650 nm region) due to surface plasmon resonance of the Ag clusters present in the ZnS matrix is observed for the samples with higher Ag incorporation. The complex dielectric constant, loss factor and distribution of volume and surface energy loss of the ZnS thin films are calculated. Laser photoluminescence measurements gives an intense bluish green emission from the ZnS films and a quenching of the PL emission is observed which can be due to the metal plasmonic absorption and non-radiative energy transfer due to Ag incorporation. C 2015 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License. [http://dx

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“…The value of /~cds calculated using equations (3.1) of Hewat (1972) is 1.01 A 2. The elastic constants used were those of Berlincourt, Jaffe & Shiozawa (1963) and the average value of Wo 2 (where too is the zone-centre frequency determined by Raman scattering) was calculated using the data of Tell, Damen & Porto (1966) and Brafman & Mitra (1968). Table 4 show that the parameter values for S are more difficult to determine than those for Cd.…”

Section: Observedmentioning

confidence: 99%

Anharmonic thermal vibrations and the position parameter in wurtzite structures. I. Cadmium sulphide

Stevenson¹,

Milanko²,

Barnea³

1984

Acta Crystallogr Sect B

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Intensity measurements have been carried out with an extended-face single crystal of hexagonal CdS using Mo Ka X-radiation at room temperature. The Bragg intensities were analysed by using the oneparticle potential (OPP) within the framework of Dawson's [Proc. R. Soc. London Set. A (1967), 298, [255][256][257][258][259][260][261][262][263] generalized structure-factor formulation with allowance for cubic anharmonic effects. The position parameter in the wurtzite structure which is not determined by symmetry is evaluated, and its dependence on the temperature-factor model used is demonstrated. The most reliable determination of this position parameter, with allowance for cubic anharmonicity, is 0.37715(8). The observation of significant differences between the intensities of nonsymmetry-related reflections occurring at the same Bragg angle demonstrates the possibility of measuring the anharmonicity of thermal vibrations.

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Raman Effect in Wurtzite- and Zinc-Blende-Type ZnS Single Crystals

Cited by 230 publications

References 9 publications

Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

Laser-assisted synthesis, and structural and thermal properties of ZnS nanoparticles stabilised in polyvinylpyrrolidone

Surface plasmon resonance in nanostructured Ag incorporated ZnS films

Anharmonic thermal vibrations and the position parameter in wurtzite structures. I. Cadmium sulphide

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