Influence of precursor age on defect states in ZnO nanorods

Buryi, M.; Babin, V.; Chang, Yu-Ying; Remeš, Z.; Míčová, Júlia; Šimek, Daniel

doi:10.1016/j.apsusc.2020.146448

Cited by 28 publications

(29 citation statements)

References 47 publications

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“…This band can be assigned to excitonic luminescence [8,33]. A similar conclusion can be made about the weak broadband peaking at 650-800 nm, which may be correlated with defect-related emission [5,34]. For a more considerable amount of ZnO layers heated at 800 • C (800_50), those characteristic peaks start to dominate the RL spectrum, which is an expected effect.…”

Section: Luminescence Studysupporting

confidence: 56%

The Influence of Recrystallization on Zinc Oxide Microstructures Synthesized with Sol–Gel Method on Scintillating Properties

et al. 2021

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Zinc oxide (ZnO) is one of the wide-bandgap semiconductors, which may be useful in a plethora of electronic, optical, piezoelectric, and scintillating applications. The following article consists in a structural and luminescence analysis of ZnO microfilms grown on a sapphire substrate with a sol–gel method. The films were annealed at different temperatures. The structures were investigated with the XRD and Raman methods, by which the influence of the substrate on the structure of the film was determined. The luminescence of films was investigated with room-temperature fluorescence, radioluminescence, and thermoluminescence.

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Section: Luminescence Studysupporting

confidence: 56%

The Influence of Recrystallization on Zinc Oxide Microstructures Synthesized with Sol–Gel Method on Scintillating Properties

et al. 2021

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“…Its origin has been attributed to singly ionized oxygen vacancies [ 22 ], due to the wide consensus of the electron paramagnetic resonance (EPR) signal g=1.96 assignment to these defects [ 23 ]. Nevertheless this association is still under debate [ 24 , 25 , 26 ]. Several others hypotheses have been proposed, among which a recombination mechanism that involves electrons trapped in shallow levels with holes trapped in deep levels [ 27 ], and surface defects [ 28 ].…”

Section: Introductionmentioning

confidence: 99%

Morphology Related Defectiveness in ZnO Luminescence: From Bulk to Nano-Size

et al. 2020

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This study addresses the relationship between material morphology (size, growth parameters and interfaces) and optical emissions in ZnO through an experimental approach, including the effect of different material dimensions from bulk to nano-size, and different excitations, from optical sources to ionizing radiation. Silica supported ZnO nanoparticles and ligand capped ZnO nanoparticles are synthesized through a sol–gel process and hot injection method, respectively. Their optical properties are investigated by radioluminescence, steady-state and time-resolved photoluminescence, and compared to those of commercial micrometric powders and of a bulk single crystal. The Gaussian spectral reconstruction of all emission spectra highlights the occurrence of the same emission bands for all samples, comprising one ultraviolet excitonic peak and four visible defect-related components, whose relative intensities and time dynamics vary with the material parameters and the measurement conditions. The results demonstrate that a wide range of color outputs can be obtained by tuning synthesis conditions and size of pure ZnO nanoparticles, with favorable consequences for the engineering of optical devices based on this material.

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“…Another important application of the ZnO nanostructures is radiation detectors (scintillators) [ 8 , 9 ]. Moreover, they have the strong potential for ultrafast detection in time-of-flight positron emission tomography [ 10 ] due to ultraviolet (UV) exciton emission with the maximum at about 380 nm (3.26 eV) [ 11 , 12 , 13 , 14 , 15 ]. However, a serious drawback of ZnO is the presence of large amount of intrinsic and extrinsic luminescent defects such as differently charged zinc or oxygen vacancies (V Zn,O ), zinc interstitials or impurities [ 11 , 12 , 16 , 17 ].…”

Section: Introductionmentioning

confidence: 99%

“…Improvement of the exciton emission requires certain material engineering steps, including suppression of the crystal defects [ 25 , 26 ] by modifying conditions of growth [ 13 , 14 ] or choosing proper dopants. The latter could be, for instance, of the donor property serving as effective suppliers of free electrons.…”

Section: Introductionmentioning

confidence: 99%

“…Molybdenum with the 3+–6+ row of charge states is an eligible candidate in this case since its improvement of the conductivity of ZnO:Mo nanorods and thin films has previously been observed [ 20 , 27 , 28 ]. In the past decade post-growth treatment, for example, annealing in air or exposure to hydrogen or oxygen plasma, has appeared the most efficient tool for the moderation of ZnO properties [ 13 , 14 , 19 , 20 , 21 , 29 , 30 , 31 , 32 ].…”

Section: Introductionmentioning

confidence: 99%

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Free-Standing ZnO:Mo Nanorods Exposed to Hydrogen or Oxygen Plasma: Influence on the Intrinsic and Extrinsic Defect States

et al. 2022

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Cationic doping of ZnO nanorods has gained increased interest as it can lead to the production of materials with improved luminescent properties, electrical conductivity and stability. We report on various Mo-doped ZnO powders of nanorods synthesized by the hydrothermal growth method. Further annealing or/and cold hydrogen or oxygen plasma modification was applied. The atomic structure of the as-grown and plasma-modified rods was characterized by X-ray diffraction. To identify any possible changes in morphology, scanning electron microscopy was used. Paramagnetic point defects were investigated by electron paramagnetic resonance. In particular, two new types of defects were initiated by the plasma treatment. Their appearance was explained, and corresponding mechanisms were proposed. The changes in the luminescence and scintillation properties were characterized by photo- and radioluminescence, respectively. Charge trapping phenomena were studied by thermally stimulated luminescence. Cold plasma treatment influenced the luminescence properties of ZnO:Mo structures. The contact with hydrogen lead to an approximately threefold increase in intensity of the ultraviolet exciton-related band peaking at ~3.24 eV, whereas the red band attributed to zinc vacancies (~1.97 eV) was suppressed compared to the as-grown samples. The exciton- and defect-related emission subsided after the treatment in oxygen plasma.

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Influence of precursor age on defect states in ZnO nanorods

Cited by 28 publications

References 47 publications

The Influence of Recrystallization on Zinc Oxide Microstructures Synthesized with Sol–Gel Method on Scintillating Properties

The Influence of Recrystallization on Zinc Oxide Microstructures Synthesized with Sol–Gel Method on Scintillating Properties

Morphology Related Defectiveness in ZnO Luminescence: From Bulk to Nano-Size

Free-Standing ZnO:Mo Nanorods Exposed to Hydrogen or Oxygen Plasma: Influence on the Intrinsic and Extrinsic Defect States

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