Raman spectra of oxide zinc powders and single crystals

Никитенко, В. А.; Plekhanov, V. G.; Mukhin, S. V.; Tkachev, Maria

doi:10.1007/bf02606743

Cited by 31 publications

(10 citation statements)

References 2 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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“…Figure 1 displays the Raman spectra of the ultrafine ZnO:NaCl powder (sample 1), purified powder (sample 2), and a bulk ZnO crystal. The Raman spectrum of the ZnO crystal shows six peaks corresponding to optical phonons at the center of the Brillouin zone, at 99, 380, 405, 430, 574, and 592 cm -1 , and several twophonon bands [5,6]. The Raman frequencies of the crystal agree well with data in the literature.…”

Section: Methodssupporting

confidence: 84%

Secondary emission of nanocrystalline zinc oxide

et al. 2006

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The Raman and photoluminescence (PL) spectra of nanocrystalline zinc oxide produced by mechanochemical synthesis were measured using a pulsed nitrogen laser (337.1 nm) and xenon lamp (360 nm) as excitation sources in PL measurements and a cw Nd:YAG laser in Raman measurements. PL was observed in the range 400-800 nm. The Raman spectrum of nanocrystalline (90 nm) ZnO was compared to that of coarsegrained ZnO. The Raman bands of nanocrystalline zinc oxide were found to be shifted to lower frequencies and broadened. Laser radiation was shown to cause local heating of zinc oxide up to 1000 K, resulting in photoinduced formation of zinc nanoclusters. Mixtures of zinc oxide and sodium chloride powders are heated to substantially lower temperatures. Under nitrogen laser excitation, the green PL band (535 nm), characteristic of bulk ZnO, is shifted to longer wavelengths by 85 nm. The results are interpreted in terms of light confinement in zinc oxide microclusters consisting of large number of nanocrystallites. The photoinduced processes in question may be a viable approach to producing metal-insulator structures in globular photonic crystals, opals, filled with zinc oxide.

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“…A sharp strong peak located at 436 cm -1 due to E 2H mode, this is the intrinsic characteristic of the Raman-active mode of wurtzite hexagonal ZnO. A broad peak around 1150 cm -1 was also observed in large wavenumber region which corresponds to the optical overtone [38,39]. The well defined acoustic overtones E 2H modes in zinc oxide prepare from different zinc salt (chloride, nitrate and sulphate) are shown in figure 11.…”

Section: Resultsmentioning

confidence: 91%

Synthesis from zinc oxalate, growth mechanism and optical properties of ZnO nano/micro structures

Raj

Joshi

Varma

2011

Cryst. Res. Technol.

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We report the synthesis of various morphological micro to nano structured zinc oxide crystals via simple precipitation technique. The growth mechanisms of the zinc oxide nanostructures such as snowflake, rose, platelets, porous pyramid and rectangular shapes were studied in detail under various growth conditions. The precursor powders were prepared using several zinc counter ions such as chloride, nitrate and sulphate along with oxalic acid as a precipitating agent. The precursors were decomposed by heating in air resulting in the formation of different shapes of zinc oxide crystals. Variations in ZnO nanostructural shapes were possibly due to the counter ion effect. Sulphate counter ion led to unusual rose-shape morphology. Strong ultrasonic treatment on ZnO rose shows that it was formed by irregular arrangement of micro to nano size hexagonal zinc oxide platelets. The X-ray diffraction studies confirmed the wurzite structure of all zinc oxide samples synthesized using different zinc counter ions. Functional groups of the zinc oxalate precursor and zinc oxide were identified using micro Raman studies. The blue light emission spectra of the various morphologies were recorded using luminescence spectrometer.

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Raman spectra of oxide zinc powders and single crystals

Cited by 31 publications

References 2 publications

Anharmonic Optical Phonon Effects in ZnO Nanocrystals

Anharmonic Optical Phonon Effects in ZnO Nanocrystals

Secondary emission of nanocrystalline zinc oxide

Synthesis from zinc oxalate, growth mechanism and optical properties of ZnO nano/micro structures

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