Growth, microstructure, UV and orange pink emission from ZnO nanocones

Chawla, Santa; Jayanthi, K.; Singh, Sumitra; Chander, Harish

doi:10.1016/j.jcrysgro.2008.04.050

Cited by 11 publications

(4 citation statements)

References 29 publications

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“…The 2.21–2.25 eV peaks are attributed to oxygen interstitials (O i ) [44,46–47]. According to Wang et al [18], emission bands at 1.9–2.0 eV of ZnO ALD ultrathin films are due to doubly ionized oxygen vacancies ( V (O) ++ ) [48].…”

Section: Resultsmentioning

confidence: 99%

Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

Chaaya¹,

Viter²,

Bechelany³

et al. 2013

Beilstein J. Nanotechnol.

134

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SummaryA study of transmittance and photoluminescence spectra on the growth of oxygen-rich ultra-thin ZnO films prepared by atomic layer deposition is reported. The structural transition from an amorphous to a polycrystalline state is observed upon increasing the thickness. The unusual behavior of the energy gap with thickness reflected by optical properties is attributed to the improvement of the crystalline structure resulting from a decreasing concentration of point defects at the growth of grains. The spectra of UV and visible photoluminescence emissions correspond to transitions near the band-edge and defect-related transitions. Additional emissions were observed from band-tail states near the edge. A high oxygen ratio and variable optical properties could be attractive for an application of atomic layer deposition (ALD) deposited ultrathin ZnO films in optical sensors and biosensors.

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Section: Resultsmentioning

confidence: 99%

Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

Chaaya¹,

Viter²,

Bechelany³

et al. 2013

Beilstein J. Nanotechnol.

134

View full text Add to dashboard Cite

show abstract

“…Emissions have, however, been experimentally reported over more or less the entire visible spectra, with for example both blue 19 and orange fluorescence. 20 Some work also indicates that the fluorescence, under certain conditions, can be tuned over a wide spectrum. 14,[21][22][23] Several different hypotheses for the precise mechanisms for these transitions have been suggested.…”

Section: Introductionmentioning

confidence: 99%

A size dependent discontinuous decay rate for the exciton emission in ZnO quantum dots

Jacobsson

Viarbitskaya

Mukhtar

et al. 2014

Phys. Chem. Chem. Phys.

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The time resolved UV-fluorescence in ZnO quantum dots has been investigated using femtosecond laser spectroscopy. The measurements were performed as a function of particle size for particles between 3 and 7 nm in diameter, which are in the quantum confined regime. A red shift in the fluorescence maximum is seen while increasing the particle size, which correlates with the shift in band gap due to quantum confinement. The energy difference between the UV-fluorescence and the band gap does, however, increase for the smaller particles. For 3.7 nm particles the fluorescence energy is 100 meV smaller than the band gap energy, whereas it is only 20 meV smaller for the largest particles. This indicates a stabilization of the excitons in the smallest particles. The lifetime of the UV fluorescence is in the picosecond time scale and interestingly, it is discontinuous with respect to particle size. For the smallest particles, the exciton emission life time reaches 30 ps, which is three times longer than that for the largest particles. This demonstrates a transition between two different mechanisms for the UV-fluorescence. We suggest that this is an effect of surface trapping and stabilization of the excitons occurring in the smallest particles but not in the larger ones. We also discuss the time scale limit for slowed hot carrier dynamics in ensembles of quantum confined ZnO particles.

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“…It can be seen that sharp NBE emission, broad visible emission and NIR emission are observed in the PL spectra. The sharp NBE emission can be attributed to the band edge excitonic recombination [18]. Wang et al considered that the NIR emission may be caused by the donoracceptor transition between V O and V Zn and/or the radiative recombination of shallowly trapped electrons with deeply trapped holes at O i [19].…”

Section: Resultsmentioning

confidence: 99%

Study of near white light emission for ZnO thin films grown on silicon substrates

Liu

Gong

et al. 2012

Semicond. Sci. Technol.

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ZnO thin films at growth time of 6, 8, 10 and 12 h were prepared by hydrothermal approach. The microstructure, surface morphology and photoluminescence properties were investigated by x-ray diffraction, field-emission scanning electron microscope and fluorescence spectrometer. The results reveal that all the thin films have hexagonal wurzite structure and preferential orientation along the c-axis. The density of nanorods increases first and then decreases with the increase of growth time. The photoluminescence spectra consist of sharp near band-edge, broad visible and near-infrared emissions. The chromaticity coordinates and color rendering indices of ZnO thin film at growth time of 10 h are x = 0.3537, y = 0.3744 and 90, respectively. The mechanisms of the green, yellow, orange-red, red and near-infrared emissions were discussed in detail.

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Growth, microstructure, UV and orange pink emission from ZnO nanocones

Cited by 11 publications

References 29 publications

Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

A size dependent discontinuous decay rate for the exciton emission in ZnO quantum dots

Study of near white light emission for ZnO thin films grown on silicon substrates

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