Hydrogen related defect complexes in ZnO nanoparticles

Senthilkumar, K.; Tokunaga, Masayuki; Okamoto, H.; Senthilkumar, O.; Fujita, Yasuhisa

doi:10.1063/1.3485049

Cited by 33 publications

(29 citation statements)

References 18 publications

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“…Hydrogen is one of the most common impurity in hydrothermally grown ZnO, and will be trapped easily by vacancies or impurities because of low migration barrier 27. The V Zn –H complexes have been proposed to be a possible positron trapping center in ZnO 28, but they are not likely since the hydrogen impurities are very unstable at high temperatures, and will be removed easily at 500–700 °C 29–32. Li impurity has been regarded as a cause for the increase of positron lifetime, which exist in high concentration and mostly reside on the Zn‐site in hydrothermally grown ZnO 25.…”

Section: Resultsmentioning

confidence: 99%

Effect of high temperature annealing on defects and optical properties of ZnO single crystals

Jiang

Wang

Zou

et al. 2012

Physica Status Solidi (a)

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Hydrothermal grown ZnO single crystals were annealed in N2 or O2 between 900 and 1300 °C. Positron lifetime measurements reveal a single lifetime in all the ZnO samples before and after annealing. The positron lifetime is about 181 ps after annealing at 900 °C in either N2 or O2 atmosphere. However, increase of the positron lifetime is observed after further annealing the sample at higher temperatures up to 1300 °C, and it has a faster increase in O2 ambient. Temperature dependence measurements show that the positron lifetime has very slight increase with temperature for the 900 °C annealed sample, while it shows notable variation for the sample annealed at 1300 °C. This implied that annealing at high temperature introduces additional defects. These defects are supposed to be Zn vacancy‐related defects. Cathodoluminescence (CL) measurements indicates enhancement of both UV and green emission after annealing, and the enhancement of green emission is much stronger for the samples annealed in O2 ambient. The possible origin of green emission is tentatively discussed.

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Section: Resultsmentioning

confidence: 99%

Effect of high temperature annealing on defects and optical properties of ZnO single crystals

Jiang

Wang

Zou

et al. 2012

Physica Status Solidi (a)

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“…However, the nonlinear optical properties, including second-harmonic generation (SHG) and the two-photon emission (TPE) process in ZnO nanomaterials, such as nanoparticles, nanowires and nanotubes, are not well understood. In most reports, ZnO materials are reported to exhibit either SHG or TPE depending on the surface orientation or nature of defect states within the nanostructures [4,5,[10][11][12][13][14][15][16]. As the linear and nonlinear absorption depends on the impurities and crystal defects at the surface and inside the crystal structure, a systematic control of the synthesis process can provide a means to tailor the optical properties of the system.…”

Section: Introductionmentioning

confidence: 99%

Optimization of nonlinear optical properties of ZnO micro and nanocrystals for biophotonics

Urban

Lin

Kumar

et al. 2011

Opt. Mater. Express

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The defect and impurity states in ZnO nanocrystals synthesized using the plasma arc technique can be modified to optimize the nonlinear optical properties for optoelectronic and biophotonic applications. Highly efficient second harmonic signals over a wide range of near-infrared wavelengths, spanning from 735 nm-980 nm, has been observed and can be used in biological imaging. The use of further high energy excitation ranging from 700 nm-755 nm leads to two-photon absorption and yields broadband two photon emission extending from the 370 nm-450 nm wavelength regime which can be useful for therapeutic applications.

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“…These sharp peaks are related to substitutional hydrogen at oxygen site H O bond to the lattice Zn site (Zn-H O ) [9]. The strong peak at 1374 cm −1 is also visible, indicating that -COO groups are not completely removed in sample 11 [26].…”

Section: Xrd Patterns Of Zno Nanostructures (Samples 2 5 and 11) 31mentioning

confidence: 88%

“…On the other hand, the visible emission is mainly attributed to the surface or structural defects of the crystal, resulting in large variations in the emission peaks [8]. The existence of certain defect complexes such as V Zn -H i , O-H, and Zn-H O has advantages over the pure semiconductor and quantum dots ZnO nanostructures [9] and a wide visible-emission at the deep level defect in the ZnO nanoparticles (NPs) are due to the existence of cationic Zn vacancies (V Zn ), oxygen vacancies (V O ), Zn interstitials (Zn i ), charge defects, surface defects and their complex defects [10].…”

Section: Introductionmentioning

confidence: 98%

Influence of Modified ZnO Quantum Dots and Nanostructures as New Antibacterials

Fakhroueian¹,

Harsini²,

Chalabian³

et al. 2013

ANP

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Antibacterial activities of various spherical zinc oxide nanoparticles and nano special morphological structures including quantum dots, nanorod arrays, nanoporous shapes and needle-like crystals had been investigated as new nanomedicine compounds. Also antibacterial activity based on minimal inhibitory concentration and the growth inhibitory zone (well method) was evaluated. ZnO nanostructures were fabricated by novel hydrolysis sol-gel-hydrothermal process followed with rapid quenching as new technique using glycerine, vegetable fatty esters such as coconut, sunflower and Lauric alcohol ethoxylated as organic templates soluble in eco-friendly nanofluids. The results showed that Bacillus anthracis and Pseudomonas aerogenes were extremely sensitive to treatment with unique ZnO nanostructured. Their growth inhibitory zone presented 30 mm and 25 mm inhibition zone with better inhibitory effect compared to the Gentamicin antibiotic standard. ZnO nanostructures had also been indicated to have a wide range of antibacterial activities against both Gram-positive and Gram-negative bacteria especially more effective on (gr+) species using the growth inhibitory zone. We could design and make significant formulations of fatty acids and esters-capped ZnO quantum dots nanofluids which created high promising agents for controlling Anthrax, Staphylococcus epidermidis and their influences in antimicrobial properties with low cost for future.

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Hydrogen related defect complexes in ZnO nanoparticles

Cited by 33 publications

References 18 publications

Effect of high temperature annealing on defects and optical properties of ZnO single crystals

Effect of high temperature annealing on defects and optical properties of ZnO single crystals

Optimization of nonlinear optical properties of ZnO micro and nanocrystals for biophotonics

Influence of Modified ZnO Quantum Dots and Nanostructures as New Antibacterials

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