Excitation wavelength dependence of the visible photoluminescence from amorphous ZnO granular films

Zhang, W. C.; Wu, Xiaohong; Chen, H. T.; Zhu, Jianxi; Huang, G.S.

doi:10.1063/1.2924421

Cited by 76 publications

(32 citation statements)

References 30 publications

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“…Recently, Djurišić et al reported the monotonic quenching and blue‐shift of green emissions of ZnO nanostructures with increasing excitation wavelength, and suggested that the green emissions involve transitions from shallow donor and deep acceptor levels 58. Zhang et al reported the monotonic quenching and red‐shift of green emissions of amorphous ZnO granular films, and attributed the green emission to recombination of electrons trapped in the conduction band and deeply trapped holes in oxygen vacancies 59. Here, the first feature of blue emissions demonstrates that the initial state of the corresponding transitions should be below the conduction band‐edge.…”

Section: Resultsmentioning

confidence: 99%

Blue Luminescence of ZnO Nanoparticles Based on Non‐Equilibrium Processes: Defect Origins and Emission Controls

Zeng

Duan

et al. 2010

Adv Funct Materials

1,606

899

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High concentrations of defects are introduced into nanoscale ZnO through non‐equilibrium processes and resultant blue emissions are comprehensively analyzed, focusing on defect origins and broad controls. Some ZnO nanoparticles exhibit very strong blue emissions, the intensity of which first increase and then decrease with annealing. These visible emissions exhibit strong and interesting excitation dependences: 1) the optimal excitation energy for blue emissions is near the bandgap energy, but the effective excitation can obviously be lower, even 420 nm (2.95 eV < Eg = 3.26 eV); in contrast, green emissions can be excited only by energies larger than the bandgap energy; and, 2) there are several fixed emitting wavelengths at 415, 440, 455 and 488 nm in the blue wave band, which exhibit considerable stability in different excitation and annealing conditions. Mechanisms for blue emissions from ZnO are proposed with interstitial‐zinc‐related defect levels as initial states. EPR spectra reveal the predominance of interstitial zinc in as‐prepared samples, and the evolutions of coexisting interstitial zinc and oxygen vacancies with annealing. Furthermore, good controllability of visible emissions is achieved, including the co‐emission of blue and green emissions and peak adjustment from blue to yellow.

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Section: Resultsmentioning

confidence: 99%

Blue Luminescence of ZnO Nanoparticles Based on Non‐Equilibrium Processes: Defect Origins and Emission Controls

Zeng

Duan

et al. 2010

Adv Funct Materials

1,606

899

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“…Hence, due to the size induced quantum confinement effect, the band gap for smaller particles will be wider. [27][28][29][30] This quantum confinement effect may be qualitatively understood using Eq. (2) developed for particle-in-a-box model.…”

Section: B Optical Propertiesmentioning

confidence: 99%

Nanosecond and ultrafast optical power limiting in luminescent Fe2O3 hexagonal nanomorphotype

Thomas¹,

Sreekanth

Abraham³

2015

Journal of Applied Physics

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Efficient ultrafast optical limiting using single walled carbon nanotubes functionalized noncovalently with free base and metalloporphyrins Nonlinear optical absorption and optical power limiting properties of Fe 2 O 3 hexagonal nanomorphotype are investigated using open aperture Z-scan technique with the 5 ns and 100 fs laser pulses, at 532 nm and 800 nm excitation domains. At relatively low pulse energies (below 5 lJ), sample shows saturable absorption (SA), but on going to the higher energies an interesting switchover from saturable absorption to effective two photon absorption is observed in both excitation domains. The magnitude of effective two photon absorption coefficients is calculated to be in the range of 10 À10 m/W for nanosecond and 10 À15 m/W for femtosecond laser pulse energies, respectively. XRD and TEM study reveals the polycrystalline nature, hexagonal morphology, and size of the nanostructure. The luminescence emission property is examined by photoluminescence spectroscopy (PL). It is found that some strange features exist in the luminescence spectra that are consistent with the nanoparticles size distribution. The PL emission lines are explained as originated from various optical band edges due to the size induced quantum confinement and band gap resonant PL absorption/emission behavior of semiconductor nanostructures. V C 2015 AIP Publishing LLC.

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“…5 revealed the presence of oxygen related defects in the ZnO crystal lattice. The wide band with two maximums at 580 and 650 nm at the photoluminescence spectra corresponds to irradiative recombination via energy levels in the ZnO band gap associated with oxygen vacancies in ZnO crystal lattice and interstitial oxygen atoms [5,13]. Narrow band with the maximum at 380 nm is also presented on the spectra.…”

Section: Resultsmentioning

confidence: 85%

Seed Layer Assisted Hydrothermal Deposition of Low-resistivity ZnO Thin Films

et al. 2017

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In this work, we describe the combination of hydrothermal and atomic layer deposition (ALD) for growing low-resistivity ZnO polycrystalline continuous films. The effect of the thickness of ALD seed layers on the morphology of the hydrothermal ZnO films was studied. It was shown that ZnO films hydrothermally deposited on very thin seed layer consist of separate nanorods but in the case of 20 nm seed layer ZnO films transform to uniform continuous layers comprising of closely packed vertically aligned crystallites. Photoluminescence spectra were shown to exhibit broad band behavior in the visible range, corresponding to radiative recombination processes via oxygen defects of ZnO crystalline lattice, and narrow band in the UV region, associated with band-to-band recombination processes. It was shown that the resistivity of the obtained ZnO films is decreased gradually with the increase of ZnO films thickness and determined by the presence of crystal lattice defects in the seed layer.

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Excitation wavelength dependence of the visible photoluminescence from amorphous ZnO granular films

Cited by 76 publications

References 30 publications

Blue Luminescence of ZnO Nanoparticles Based on Non‐Equilibrium Processes: Defect Origins and Emission Controls

Blue Luminescence of ZnO Nanoparticles Based on Non‐Equilibrium Processes: Defect Origins and Emission Controls

Nanosecond and ultrafast optical power limiting in luminescent Fe2O3 hexagonal nanomorphotype

Seed Layer Assisted Hydrothermal Deposition of Low-resistivity ZnO Thin Films

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