Raman study of the phonon halfwidths and the phonon—plasmon coupling in ZnO

Bairamov, B. H.; Heinrich, A.; Irmer, G.; Toporov, V. V.; Ziegler, E.

doi:10.1002/pssb.2221190126

Cited by 121 publications

(77 citation statements)

References 15 publications

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“…The E 1 (TO), A 1 (TO) and E 1 (LO) peaks were visible at 381 cm −1 , 410 cm −1 , and 585 cm −1 , respectively. The peak positions were in agreement with previously published data [6][7][8]. The Raman spectra measured at different temperatures are plotted in Fig.…”

Section: Measurements and Discussionsupporting

confidence: 91%

Anharmonic Optical Phonon Effects in ZnO Nanocrystals

et al. 2011

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Zinc oxide (ZnO) is a very promising material for optoelectrical devices operating at the short-wavelength end of the visible spectral range and at the near UV. The Raman scattering studies of ZnO heterolayers formed by isothermal annealing show sharp phonon lines. In addition to the A1(TO), E1(TO), E H 2 , and E1(LO) one-phonon lines, we observed two-phonon lines identified as:, and 2LO at 332, 541, and 1160 cm −1 , respectively (at room temperature). The identification of the E H 2 − E L 2 peak was confirmed by its thermal dependence. Temperature dependent measurements in the range 6-300 K show that the phonon frequencies decrease with temperature. The E H 2 peak is at energy 54.44 meV (439.1 cm −1 ), at 4 K and due to phonon-phonon anharmonic interaction, its energy decreases to 54.33 meV (438.2 cm −1 ) at room temperature. The Grüneisen parameter found for this oscillation mode was γ E2H = 1.1 at about 300 K. The intensity of the E H 2 − E L 2 peak increases strongly with temperature and this dependence can be described by the Bose-Einstein statistics with activation energy of 13.8 meV (nearly equal to the energy of the E L 2 phonon).

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Section: Measurements and Discussionsupporting

confidence: 91%

Anharmonic Optical Phonon Effects in ZnO Nanocrystals

et al. 2011

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“…On the other hand, the other modes, such as A 1 (TO), A 1 (LO), E 1 (TO), and E 1 (LO) (at 380, 579, 409.5, and 588 cm À1 , respectively) are overlapped with the lines of the sapphire substrate at 380, 431, 450, and 577 cm À1 as indicated by the asterisks. 1, [45][46][47] The two nonpolar E 2 (low) and E 2 (high) are Raman active, since E 2 (high) is related to the vibration of oxygen atoms, while the E 2 (low) is related to the heavy Zn in the sublattice in the wurtzite structure. Gd-doped ZnO films decreases, the phonon mode E 2 (high) peak shifts toward higher frequencies.…”

Section: Resultsmentioning

confidence: 99%

Identifying the influence of the intrinsic defects in Gd-doped ZnO thin-films

Flemban

Sequeira

Zhang

et al. 2016

Journal of Applied Physics

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Gd-doped ZnO thin films were prepared using pulsed laser deposition at different oxygen pressures and varied Gd concentrations. The effects of oxygen deficiency-related defects on the Gd incorporation, optical and structural properties, were explored by studying the impact of oxygen pressure during deposition and post-growth thermal annealing in vacuum. Rutherford Backscattering Spectrometry revealed that the Gd concentration increases with increasing oxygen pressure for samples grown with the same Gd-doped ZnO target. Unexpectedly, the c-lattice parameter of the samples tends to decrease with increasing Gd concentration, suggesting that Gd-defect complexes play an important role in the structural properties. Using low-temperature photoluminescence (PL), Raman measurements and density functional theory calculations, we identified oxygen vacancies as the dominant intrinsic point defects. PL spectra show a defect band related to oxygen vacancies for samples grown at oxygen deficiency. V C 2016 AIP Publishing LLC.

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“…The peak at 322.4 cm −1 corresponded to a multiple phonon scattering process [32]. The A1-LO phonon peak (561.2 cm −1 ) was blue-shifted from 574, 576 cm −1 [29], and 579 cm −1 [33], owing to the strong interaction between ZnO and the carbon atoms of the CNT fiber. The observation of a peak at 561.2 cm −1 corresponding to the A1-LO mode was close to the theoretically predicted value (548 cm −1 ) [34].…”

Section: Resultsmentioning

confidence: 98%

“…The D band in the Raman spectrum of the CNT fiber (Fig. 6a) [29], E 2 (high) [30], and A1-LO (longitudinal optical) [29] phonons in the ZnO nanoparticles of the ZnO-CNT fiber composite. These were also observed in curve a for the pure ZnO nanoparticles.…”

Section: Resultsmentioning

confidence: 99%

In Situ Solution Process for Fabricating Thermally and Mechanically Stable Highly Conductive ZnO-CNT Fiber Composites

Hossain

Hahn

2017

Acta Phys. Pol. A

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A simple in situ solution process was developed to produce a mechanically and thermally stable ZnO-carbon nanotube fiber composite. ZnO nanoparticles were homogeneously deposited onto the surfaces of and interstices within CNT fibers (between individual CNTs). X-ray photoelectron spectroscopy and Raman analysis revealed that ZnO nanoparticles contained oxygen vacancy defects and CNT fibers included oxygen containing functional group that strongly interacted with Zn. The strong interaction enhanced the mechanical properties of the composite fibers. The Young modulus (20 GPa) and tensile strength (118 MPa) were enhanced compared to the corresponding values of the pristine CNT fibers. The thermal stability was high up to 880• C and light absorption was enhanced across the UV to near IR region in a ZnO-CNT fiber composite. The electrical conductivity of the composite was high up to 954 S/cm despite semiconductor deposition.

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Raman study of the phonon halfwidths and the phonon—plasmon coupling in ZnO

Abstract: O B H a p y m e I -I a q p e 3~b 1~a f i~o M a J I a a nonyruupmra JIHHHM, paman 0,3 cm-l. r I p~ 77 K

Cited by 121 publications

References 15 publications

Anharmonic Optical Phonon Effects in ZnO Nanocrystals

Anharmonic Optical Phonon Effects in ZnO Nanocrystals

Identifying the influence of the intrinsic defects in Gd-doped ZnO thin-films

In Situ Solution Process for Fabricating Thermally and Mechanically Stable Highly Conductive ZnO-CNT Fiber Composites

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