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1

Preparation of aluminum-doped zinc oxide (AZO) nano particles by hydrothermal synthesis  

Microsoft Academic Search

Aluminum doped zinc oxide (AZO) nanometric particles were synthesized by hydrothermal method. Aluminum nitrate hydrate, aluminum\\u000a sec-butoxide and zinc nitrate hydrate were used as the starting materials, and n-propanol and 2-butanol were used as solvents.\\u000a Ratio of Al2O3 in ZnO was kept at 10 wt%. Reaction was conducted in a Teflon autoclave at 175–225 °C for 5 h. Ratios of alcohol, H2O

Esin Burunkaya; Nadir Kiraz; Ömer Kesmez; H. Erdem Çamurlu; Meltem Asiltürk; Ertu?rul Arpaç

2010-01-01

2

Electrical properties of aluminum-doped zinc oxide (AZO) nanoparticles synthesized by chemical vapor synthesis.  

PubMed

Aluminum-doped zinc oxide nanoparticles have been prepared by chemical vapor synthesis, which facilitates the incorporation of a higher percentage of dopant atoms, far above the thermodynamic solubility limit of aluminum. The electrical properties of aluminum-doped and undoped zinc oxide nanoparticles were investigated by impedance spectroscopy. The impedance is measured under hydrogen and synthetic air between 323 and 673 K. The measurements under hydrogen as well as under synthetic air show transport properties depending on temperature and doping level. Under hydrogen atmosphere, a decreasing conductivity with increasing dopant content is observed, which can be explained by enhanced scattering processes due to an increasing disorder in the nanocrystalline material. The temperature coefficient for the doped samples switches from positive temperature coefficient behavior to negative temperature coefficient behavior with increasing dopant concentration. In the presence of synthetic air, the conductivity firstly increases with increasing dopant content by six orders of magnitude. The origin of the increasing conductivity is the generation of free charge carriers upon dopant incorporation. It reaches its maximum at a concentration of 7.7% of aluminum, and drops for higher doping levels. In all cases, the conductivity under hydrogen is higher than under synthetic air and can be changed reversibly by changing the atmosphere. PMID:19801771

Hartner, Sonja; Ali, Moazzam; Schulz, Christof; Winterer, Markus; Wiggers, Hartmut

2009-11-01

3

Aluminum doped zinc oxide films grown by atomic layer deposition for organic photovoltaic devices  

Microsoft Academic Search

Aluminum doped zinc oxide (AZO) films were studied as an alternative transparent electrode material to indium tin oxide (ITO) in organic photovoltaic devices. The AZO films were prepared by atomic layer deposition from diethylzinc, water and trimethylaluminum precursors. The same number of deposition cycles resulted in 170 and 90nm thick films at deposition temperatures of 150 and 250°C, respectively. Uniform

Hanna Saarenpää; Tapio Niemi; Antti Tukiainen; Helge Lemmetyinen; Nikolai Tkachenko

2010-01-01

4

Development of Novel Aluminum-Doped Zinc Oxide Film and Its Application to Solar Cells  

NASA Astrophysics Data System (ADS)

We have developed novel aluminum-doped zinc oxide films (AZO-X and AZO-HX films) with a high haze value using wet-chemical etching for various times after dc magnetron sputtering, and have investigated their electrical and optical properties, durability under high-humidity condition, and surface morphology. The AZO-X and AZO-HX films showed good balance between transmittance in the near-infrared area and durability under 85 °C-85%RH condition. These novel films also had a higher haze value after wet chemical etching than normal AZO films. The crater size and haze value of the AZO-HX film increased with increasing etching time in comparison with those of the AZO-X film. The haze value of the AZO-HX film was higher than that of the AZO-X film; their values are 90% at 550 nm and 60% at 800 nm. Furthermore, the AZO-HX film was applied in amorphous silicon (a-Si) single-type solar cells as the front electrode. The short-circuit current of the solar cell using the AZO-HX film was higher than that of the solar cell using the AZO-X film. As an optimization-based result, an efficiency as high as 10.2% was obtained, showing that the new AZO-HX film is a promising material for the front electrode of a-Si solar cells.

Kuramochi, Hideto; Akiike, Ryo; Iigusa, Hitoshi; Tamano, Kimiaki; Utsumi, Kentaro; Shibutami, Tetsuo; Sichanugrist, Porponth; Konagai, Makoto

2012-10-01

5

Holographic grating formation in laser-deposited aluminium-doped zinc oxide and indium tin oxide films  

Microsoft Academic Search

Holographic grating formation is demonstrated in films of the transparent and semiconducting materials aluminium-doped zinc oxide (AZO) and indium tin oxide (ITO) produced by pulsed laser deposition. The holographic gratings are induced by UV laser light at 356 nm. The physics and characteristics of grating formation in laser-deposited AZO and ITO films are compared with those of sputter-deposited indium oxide

Birgitte Thestrup; Carsten Dam-Hansen; Jørgen Schou; Per Michael Johansen

2000-01-01

6

Advanced oxidation processes in azo dye wastewater treatment.  

PubMed

The chemical degradation of synthetic azo dyes color index (C.I.) Acid Orange 7, C.I. Direct Orange 39, and C.I. Mordant Yellow 10 has been studied by the following advanced oxidation processes: Fenton, Fenton-like, ozonation, peroxone without or with addition of solid particles, zeolites HY, and NH4ZSM5. Spectrophotometric (UV/visible light spectrum) and total organic carbon measurements were used for determination of process efficiency and reaction kinetics. The degradation rates are evaluated by determining their rate constants. The different hydroxyl radical generation processes were comparatively studied, and the most efficient experimental conditions for the degradation of organic azo dyes solutions were determined. PMID:16894983

Papi?, Sanja; Koprivanac, Natalija; Bozi?, Ana Loncari?; Vujevi?, Dinko; Dragicevi?, Savka Kusar; Kusi?, Hrvoje; Peternel, Igor

2006-06-01

7

Doped zinc oxide microspheres  

DOEpatents

A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

Arnold, Jr., Wesley D. (Oak Ridge, TN); Bond, Walter D. (Knoxville, TN); Lauf, Robert J. (Oak Ridge, TN)

1993-01-01

8

Doped zinc oxide microspheres  

DOEpatents

A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel. 4 figures.

Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

1993-12-14

9

Water electrolysis-induced optical degradation of aluminum-doped zinc oxide films  

Microsoft Academic Search

A type of optical degradation of aluminium-doped zinc oxide (AZO) films due to water electrolysis-induced reduction reaction was reported. An experiment was designed in which AZO films were immersed in a 0.01M NaOH aqueous solution as cathode to electrolyze water. Significant decreases in the optical transmission of the treated samples were observed. Studies by X-ray diffraction and scanning electron microscope

Linggang Fang; Guojia Fang; Wanping Chen; Chun Li; Su Sheng; Shuang Ma; Xingzhong Zhao

2006-01-01

10

Effect of Substrate Temperature on Optical Properties of Aluminum Zinc Oxide Thin Films Deposited by DC Magnetron Sputtering  

Microsoft Academic Search

In the present work Aluminum doped Zinc Oxide (AZO) thin films have been deposited on glass substrates from room temperature to 300°C by direct current (d.c) magnetron sputtering. The effects of substrate temperature on the crystallization behavior and optical properties of the films have been studied. The optical transmittance of aluminum zinc oxide films are obviously influenced by the substrate

B. Rajesh Kumar; T. Subba Rao

2011-01-01

11

Flexible aluminum-doped zinc-oxide thin-film transistor fabricated on plastic substrates  

NASA Astrophysics Data System (ADS)

We have studied processing and characteristics of flexible Aluminum-doped Zinc Oxide thin-film transistors (AZO TFTs) fabricated on plastic substrates using radio frequency (rf) magnetron sputtering. To improve the performance of flexible AZO TFT, we studied effects of device structures on characteristics of the aluminum-doped zinc oxide thin film transistors. The electrical properties of top-gate type and bottom-gate type AZO TFTs were investigated, respectively. The top-gate type AZO TFTs shows a threshold voltage of 1.4 V, a Ion/Ioff current ratio of 1.0×107, a field effect mobility of 28.2 cm2/ V•s, a subthreshold swing of 0.19 V/decade. And the bottom-gate type AZO TFTs shows a threshold voltage of 1.7 V, a Ion/Ioff ratio of 1.0×107, a field effect mobility of 209 cm2/ V•s, a subthreshold swing of 0.16 V/decade, and the off current of less than 10-11A at room temperature. Both TFTs show low threshold voltage, high Ion/Ioff ratio and high field effect mobility. By comparison, the bottom-gate type AZO TFTs shows better characteristics. The flexible AZO-TFT is a very promising low-cost optoelectronic device for the next generation of invisible and flexible electronics due to flexible, transparency, high mobility, and low-temperature processing.

Han, Dedong; Chen, Zhuofa; Zhao, Nannan; Wang, Wei; Huang, Fuqing; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2014-03-01

12

Fabrication of protective over layer for enhanced thermal stability of zinc oxide based TCO films  

NASA Astrophysics Data System (ADS)

To prevent the loss of oxygen vacancies in aluminium doped zinc oxide (AZO) thin films at high temperature process, and to enhance the thermal stability a protective tin oxide (TO) over layer has been realized. To investigate the protective nature of doped tin oxide layer, fluorine doped tin oxide (FTO) and antimony doped tin oxide (ATO) layers have also been coated on AZO layer. Then, to confirm its stability of opto-electrical properties under high temperature process, structural, optical and electrical studies of AZO single layer, TO/AZO, FTO/AZO and ATO/AZO double layered films were carried out before and after annealing and the results are reported. The XRD results showed that the crystalline nature of double layered films remains unchanged, even after the heat treatment. The UV results depicted that, in all the double layer films the transmission spectra remain unchanged or changed negligibly after annealing, indicating the thermal stability of double layered films. The photoluminescence results also strongly supported the improvement in the thermal stability of double layered films. The electrical studies suggested that the double layered films exhibited better electrical resistivity with bare AZO films.

Ravichandran, K.; Ravikumar, P.; Sakthivel, B.

2013-12-01

13

The oxidation of acid azo dye AY 36 by a manganese oxide containing mine waste.  

PubMed

The oxidative breakdown of acid azo dye acid yellow 36 (AY 36) by a Mn oxide containing mine tailings is demonstrated. The oxidation reaction is pH dependent with the rate of decolorization increasing with decreasing pH. The oxidation reaction mechanism is initiated at the amino moiety and proceeds via successive, one electron transfers from the dye to the Mn oxide minerals. The reaction pathway involves the formation of a number of colorless intermediate products, some of which hydrolyze in a Mn oxide-independent step. Decolorization of the dye is rapid and is observed before the cleavage of the azo-bond, which is a slower process. The terminal oxidation products were observed to be p-benzoquinone and 3-hydroxybenzenesulfonate. The reaction order of the initial decolorization was determined to be pseudo fractional order with respect to pH and pseudo first order with respect to dye concentration and Mn tailings' surface area. PMID:23333488

Clarke, Catherine E; Kielar, Filip; Johnson, Karen L

2013-02-15

14

Characterization of monolayer formation on aluminum-doped zinc oxide thin films.  

PubMed

The optical and electronic properties of aluminum-doped zinc oxide (AZO) thin films on a glass substrate are investigated experimentally and theoretically. Optical studies with coupling in the Kretschmann configuration reveal an angle-dependent plasma frequency in the mid-IR for p-polarized radiation, suggestive of the detection of a Drude plasma frequency. These studies are complemented by oxygen depletion density functional theory studies for the calculation of the charge carrier concentration and plasma frequency for bulk AZO. In addition, we report on the optical and physical properties of thin film adlayers of n-hexadecanethiol (HDT) and n-octadecanethiol (ODT) self-assembled monolayers (SAMs) on AZO surfaces using reflectance FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), contact angle, and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Our characterization of the SAM deposition onto the AZO thin film reveals a range of possible applications for this conducting metal oxide. PMID:18069859

Rhodes, Crissy L; Lappi, Simon; Fischer, Daniel; Sambasivan, Sharadha; Genzer, Jan; Franzen, Stefan

2008-01-15

15

Structural and electrical properties of aluminum-doped zinc oxide films prepared by sol–gel process  

Microsoft Academic Search

Aluminium-doped zinc oxide films were prepared through a non-alkoxide dip-coating technique from zinc acetate and aluminium nitrate in alcoholic solution. The doping concentration in the films varied between 0 and 8at.%. The structural and electrical properties of the Al-doped zinc oxide (AZO) films are investigated in terms of the preparation conditions, such as the Al content, precursor solution, firing and

Radhouane Bel Hadj Tahar

2005-01-01

16

Preparation of transparent conductive AZO thin films for solar cells  

Microsoft Academic Search

A study of the effect of technology parameters (sputtering power, substrate temperature and post-deposition annealing) on structural, electrical and optical properties of aluminium-doped zinc oxide (AZO) thin films was carried out. The optimal technology parameters of preparation were found to get necessary properties of AZO thin films for application in solar cells - the high figure of merit (F ges

V. Tvarozek; P. Sutta; I. Novotny; P. Ballo; L. Harmatha; S. Flickyngerova; L. Prusakova; M. Netrvalova; V. Vavrunkova; A. Pullmannova; E. Vavrinsky; P. Gaspierik; M. Mikolasek

2008-01-01

17

Microstructure evolution of Al-doped zinc oxide films prepared by in-line reactive mid-frequency magnetron sputtering  

Microsoft Academic Search

Aluminium-doped zinc oxide (ZnO:Al or AZO) thin films were deposited on glass substrates by reactive mid-frequency (MF) magnetron sputtering from Zn\\/Al metallic targets. Strong (002) preferred orientation was detected by X-ray diffraction (XRD). It was observed by plan-view transmission electron microscopy (TEM) that an AZO film deposited at low substrate temperature was composed of irregular large grains; but the film

R. J. Hong; X. Jiang

2006-01-01

18

ENZ waveguide of Al-doped zinc oxide for telecommunication applications  

NASA Astrophysics Data System (ADS)

We investigate the incorporation of an epsilon-near-zero (ENZ) material into a waveguide structure in order to suppress dispersion associated with the interaction of light with material in the core, guiding layer. ENZ metamaterials can provide a mechanism for air-core waveguides by introduction of a cladding medium exhibiting a refractive index less than unity. We study the application of aluminum zinc oxide (AZO), a transparent conducting oxide, as the candidate for ENZ waveguides. For this purpose, we design a metamaterial cladding layer with ENZ properties derived from nanoparticles of AZO, and investigate the resulting loss and dispersion of guided optical signals.

Alisafaee, Hossein; Fullager, Daniel B.; Fiddy, Michael A.

2014-02-01

19

Zinc oxide varistors and/or resistors  

DOEpatents

Varistors and/or resistors are described that include doped zinc oxide gel microspheres. The doped zinc oxide gel microspheres preferably have from about 60 to about 95% by weight zinc oxide and from about 5 to about 40% by weight dopants based on the weight of the zinc oxide. The dopants are a plurality of dopants selected from silver salts, boron oxide, silicon oxide and hydrons oxides of aluminum, bismuth, cobalt, chromium, manganese, nickel, and antimony.

Arnold, W.D. Jr.; Bond, W.D.; Lauf, R.J.

1993-07-27

20

Zinc oxide varistors and/or resistors  

DOEpatents

Varistors and/or resistors that includes doped zinc oxide gel microspheres. The doped zinc oxide gel microspheres preferably have from about 60 to about 95% by weight zinc oxide and from about 5 to about 40% by weight dopants based on the weight of the zinc oxide. The dopants are a plurality of dopants selected from silver salts, boron oxide, silicon oxide and hydrons oxides of aluminum, bismuth, cobalt, chromium, manganese, nickel, and antimony.

Arnold, Jr., Wesley D. (Oak Ridge, TN); Bond, Walter D. (Knoxville, TN); Lauf, Robert J. (Oak Ridge, TN)

1993-01-01

21

Highly conductive and transparent reduced graphene oxide/aluminium doped zinc oxide nanocomposite for the next generation solar cell applications  

NASA Astrophysics Data System (ADS)

In this paper, aluminum-doped zinc oxide(AZO)/reduced graphene oxide nano-composite thin films are synthesized by a one-pot, solution-processed method. The nanocomposite film has been extensively characterized using scanning electron microscopy (SEM), X-ray-diffraction (XRD), energy dispersive spectroscopy (EDS), Hall effect measurement and UV-Vis spectroscopy. It is found that the controlled addition of reduced graphene oxide into AZO can lower the film's resistivity without causing significant degradation of optical transparency. In addition, nanocomposite films post-annealed at process temperature at 500 °C possesses the lowest resistivity and the highest optical transmittance and that further increases in the annealing temperature degrades the film's property due to nucleation of other phases of the AZO.

Bu, Ian Y. Y.

2013-12-01

22

Comparative study of sol–gel derived tin-doped indium- and aluminum-doped zinc-oxide coatings for electrical conducting and low-emitting surfaces  

Microsoft Academic Search

Cost-efficient transparent conductive oxide (TCO) compounds based on doped zinc oxide (e.g. aluminum zinc oxideAZO) have been investigated in addition to the well-established functional coatings of doped indium oxide (e.g. indium tin oxide – ITO). The electrical, morphological and optical properties of both types of coatings are compared. For the deposition of transparent conductive oxides, such as tin-doped

M. Rydzek; M. Reidinger; M. Arduini-Schuster; J. Manara

2011-01-01

23

Effect of Al Nanoparticles on the Microstructure, Electrical, and Optical Properties of AZO/Al/AZO Trilayer Thin Film  

NASA Astrophysics Data System (ADS)

In this work, designed growth of aluminum (Al)/aluminum-doped zinc oxide (AZO), AZO/Al/AZO, and AZO/Al multilayer electrodes by radiofrequency (RF) magnetron sputtering on glass substrates was studied. The microstructures, optical properties, and electrical characteristics of the multilayer electrode thin films were analyzed, their structural denseness and thickness were observed by field-emission scanning electron microscopy (FE-SEM), and their crystal orientation was identified by x-ray diffraction (XRD). The resistivity and transmittance of the films were measured by four-point probe and UV-Vis-NIR spectrophotometer, respectively. The resistivity of the AZO/Al/AZO multilayer electrode thin film was 1.55 ? cm. The average transmittance of the AZO/Al/AZO thin film over wavelengths from 400 nm to 800 nm was much better than that of other thin films, since Al nanoparticles distribute in the AZO thin film during the sputtering process, as observed by high-resolution transmission electron microscopy (HRTEM). In addition, the figure of merit of the AZO/Al/AZO trilayer film was much larger than those of the other structures.

Lin, Yen-Sheng; Tseng, Wei-Chih

2012-03-01

24

21 CFR 73.1991 - Zinc oxide.  

Code of Federal Regulations, 2012 CFR

...and suitable in color additive mixtures for coloring...be avoided by good manufacturing practice: Zinc oxide...restrictions. The color additive zinc oxide may be...consistent with good manufacturing practice. (d) Labeling. The color additive and any mixtues...

2012-04-01

25

21 CFR 73.1991 - Zinc oxide.  

...and suitable in color additive mixtures for coloring...be avoided by good manufacturing practice: Zinc oxide...restrictions. The color additive zinc oxide may be...consistent with good manufacturing practice. (d) Labeling. The color additive and any mixtues...

2014-04-01

26

21 CFR 73.1991 - Zinc oxide.  

Code of Federal Regulations, 2013 CFR

...and suitable in color additive mixtures for coloring...be avoided by good manufacturing practice: Zinc oxide...restrictions. The color additive zinc oxide may be...consistent with good manufacturing practice. (d) Labeling. The color additive and any mixtues...

2013-04-01

27

Multi-wavelength Raman scattering of nanostructured Al-doped zinc oxide  

NASA Astrophysics Data System (ADS)

In this work we present a detailed Raman scattering investigation of zinc oxide and aluminum-doped zinc oxide (AZO) films characterized by a variety of nanoscale structures and morphologies and synthesized by pulsed laser deposition under different oxygen pressure conditions. The comparison of Raman spectra for pure ZnO and AZO films with similar morphology at the nano/mesoscale allows to investigate the relation between Raman features (peak or band positions, width, relative intensity) and material properties such as local structural order, stoichiometry, and doping. Moreover Raman measurements with three different excitation lines (532, 457, and 325 nm) point out a strong correlation between vibrational and electronic properties. This observation confirms the relevance of a multi-wavelength Raman investigation to obtain a complete structural characterization of advanced doped oxide materials.

Russo, V.; Ghidelli, M.; Gondoni, P.; Casari, C. S.; Li Bassi, A.

2014-02-01

28

Extended wide band gap amorphous aluminium-doped zinc oxide thin films grown at liquid nitrogen temperature  

Microsoft Academic Search

Amorphous aluminium-doped zinc oxide (AZO) thin films are grown by standard RF sputtering at low temperatures on glass substrates. Due to poor thermal conductivity and thermal energy generated by the sputter gun, controlling the substrate surface temperature is the key to controlling the growth of amorphous and nanocrystalline films. The ratio of grains and amorphous part of the films can

H. Chou; M. S. Yang; C. P. Wu; Y. C. Tsao; B. J. Chen; T. F. Liao; S. J. Sun; J. W. Chiou

2011-01-01

29

Co-sputtered Aluminum Doped Zinc Oxide Thin Film as Transparent Anode for Organic Light-emitting Diodes  

E-print Network

]. As for the target materials, usually the composite target sintered ceramic ZnO:Al2O3 (98:2) target is used for RFCo-sputtered Aluminum Doped Zinc Oxide Thin Film as Transparent Anode for Organic Light, but also because of its optical characteristics. AZO thin film exhibits a sharp UV cut-off and a high

30

Different properties of aluminum doped zinc oxide nanostructured thin films prepared by radio frequency magnetron sputtering  

SciTech Connect

Aluminium doped zinc oxide (AZO) nanostructured thin films are prepared by radio frequency magnetron sputtering on glass substrate using specifically designed ZnO target containing different amount of Al{sub 2}O{sub 3} powder as the Al doping source. The optical properties of the aluminium doped zinc oxide films are investigated. The topography of the deposited films were investigated by Atomic Force Microscopy. Variation of the refractive index by annealing temperature are considered and it is seen that the refractive index increases by increasing the annealing temperature.

Bidmeshkipour, Samina, E-mail: samina204@gmail.com; Shahtahmasebi, Nasser [Ferdowsi University of Mashhad, Department of Physics (Iran, Islamic Republic of)

2013-06-15

31

Electronic structure of spinel oxides: zinc aluminate and zinc gallate  

Microsoft Academic Search

The electronic structure of zinc aluminate (ZnAl2O4) and that of zinc gallate (ZnGa2O4) were studied by the self-consistent tight-binding linearized muffin-tin orbital method with the atomic sphere approximation. The calculated results predict these zinc-based spinel oxides to be direct-gap materials. The direct gap at icons\\/Journals\\/Common\\/Gamma\\

Suresh K. Sampath; D. G. Kanhere; Ravindra Pandey

1999-01-01

32

Comparative toxicity of a zinc salt, zinc powder and zinc oxide to Eisenia fetida, Enchytraeus albidus and Folsomia candida  

Microsoft Academic Search

The pore water zinc concentration and the calcium chloride extracted zinc fraction are higher in the soils spiked with a zinc salt (ZnCl2) compared to soils spiked with zinc oxide or zinc powder. Based on total zinc concentrations in the soil, the acute toxicity of zinc salt to the compost worm Eisenia fetida, the potworm Enchytraeus albidus and the springtail

Koen Lock; Colin R. Janssen

2003-01-01

33

Infrared surface plasmon resonance of AZO-Ag-AZO sandwich thin films.  

PubMed

Near-infrared surface plasmon resonance (SPR) spectra were collected of thin multilayer films of aluminum-doped zinc oxide (AZO) / silver (Ag) / AZO on BK-7 glass in the Kretschmann configuration in air, with the silver layer thickness varying from 5 nm to 50 nm. The SPR results were interpreted by modeling the reflectance with a five-layer transfer-matrix method, with the aid of a simplex algorithm. The model indicated that the Ag plasma frequency was significantly higher than the bulk value, possibly due to Schottky effect charge transfer from the AZO to the Ag layer. Continuous silver films were made as thin as 10 nm, indicating an inhibition of metal island formation for Ag deposited on AZO. PMID:23188286

Guske, Joshua T; Brown, Jeff; Welsh, Alex; Franzen, Stefan

2012-10-01

34

Fabrication and characteristics of high-performance and high-stability aluminum-doped zinc oxide thin-film transistors  

NASA Astrophysics Data System (ADS)

Fully transparent aluminum-doped zinc oxide (AZO) thin-film transistors (TFTs) were successfully fabricated on glass substrates at room temperature. Superior properties, such as a high saturation mobility of 59.3 cm2 V-1 s-1, a positive threshold voltage of 1.3 V, a steep subthreshold swing of 122.9 mV/dec, an off-state current on the order of 10-12 A, and an on/off ratio of 2.7 × 108, were obtained. The electrical properties of the AZO TFTs were successively studied within a period of six months. Small property degenerations could be observed from the test results obtained within the study period, which proved the high-performance and high-stability characteristics of AZO TFTs. Furthermore, hysteresis loop scanning of AZO TFTs was performed, and a small hysteresis could be detected in the scanning curves, which suggested the superior properties of a dielectric and a channel-insulator interface. Lastly, we succeeded in manufacturing an organic LED (OLED) flat panel display panel driven by AZO TFTs and obtained an excellent display effect from it. We believe that AZO TFTs are a promising candidate successor to Si-based TFTs in next-generation flat panel displays.

Shan, Dongfang; Han, Dedong; Huang, Fuqing; Tian, Yu; Zhang, Suoming; Qi, Lin; Cong, Yingying; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2014-01-01

35

Self-assembled monolayers induced inter-conversion of crystal structure by vertical to lateral growth of aluminium doped zinc oxide thin films.  

PubMed

In this communication, we demonstrate the inter-conversion of crystal structure of aluminium doped zinc oxide (AZO) thin films from highly (002) plane oriented vertical growth to (103) plane oriented lateral growth by adjusting the polarity of the self-assembled monolayers (SAMs) on glass substrates at room temperature. PMID:21127799

Tai, Yian; Sharma, Jadab; Chang, Hsuan-Chun; Tien, Thieu Vo Thi; Chiou, Yi-Shiang

2011-02-14

36

Electronic structure of spinel oxides: zinc aluminate and zinc gallate  

NASA Astrophysics Data System (ADS)

The electronic structure of zinc aluminate (ZnAl2O4) and that of zinc gallate (ZnGa2O4) were studied by the self-consistent tight-binding linearized muffin-tin orbital method with the atomic sphere approximation. The calculated results predict these zinc-based spinel oxides to be direct-gap materials. The direct gap at icons/Journals/Common/Gamma" ALT="Gamma" ALIGN="TOP"/> is found to be 4.11 eV for ZnAl2O4 and 2.79 eV for ZnGa2O4. With reference to the calculated band gap of 5.36 eV for MgAl2O4, the systematic decrease in the gap is attributed to the presence of 3d orbitals of Zn and Ga and the associated p-d hybridization in the upper valence band of zinc aluminate and gallate. Comparison of the contour maps of the electron localization function of ZnAl2O4 and ZnGa2O4 with that of MgAl2O4 clearly shows the bonding to be less ionic in the zinc-based spinel oxides. Finally, the calculations yield a smaller electron effective mass for zinc gallate as compared to that for zinc aluminate, suggesting a higher mobility of electrons in gallate.

Sampath, Suresh K.; Kanhere, D. G.; Pandey, Ravindra

1999-05-01

37

Efficient inverted polymer solar cells based on ultrathin aluminum interlayer modified aluminum-doped zinc oxide electrode  

NASA Astrophysics Data System (ADS)

A convenient and economical design for inverted polymer solar cells has been developed by introducing an ultrathin aluminium (Al) interlayer to modify aluminum-doped zinc oxide (AZO) electrode as the bottom cathode. An ultrathin interlayer of Al could lower the work function of AZO electrode. Power conversion efficiency (PCE) of 3.84% was obtained for poly(3-hexyl-thiophene):phenyl-C61-butyric acid methyl ester based device and that of poly(3-hexyl-thiophene):indene-C60 bisadduct based device with such electrodes could reach to 5.52%, which was much higher than the structurally identical device based on ITO/Al(1 nm) electrode and almost the same as that of the conventional device. This indicates that the ultrathin Al modified AZO composite electrode is a strong competitor for the cathode in inverted polymer solar cells especially the large scale and low costs devices.

Shi, Ting; Zhu, Xiaoguang; Tu, Guoli

2014-03-01

38

[Clinical studies on zinc oxide ointment replacing boric acid and zinc oxide ointment (JP8)].  

PubMed

A boric acid and zinc oxide ointment (J.P. VIII) is an unique preparation in Japan, which consist of boric acid (5%), zinc oxide (10%), vegetable oil (usually soybean oil or sesame oil) and yellow wax. The ointment is widely used in the area of Hokkaido, because not only of the customary prescription but also of the characteristic clinical efficiency. However, boric acid has been recognized to be harmful in these days. Therefore, a zinc oxide ointment consisting 10% zinc oxide, soybean oil and white beeswax was tentatively made and evaluated. The zinc oxide ointment presented the same consistency as the boric acid and zinc oxide ointment, measured with penetrometer. The clinical efficiency was also confirmed on six patients with chronic eczema and seven patients with psoriasis vulgaris. The effect on wound healing of the donor site of skin graft was as good as the previous preparation. PMID:6629312

Kubota, K; Kumakiri, M; Miura, Y; Hine, K; Kori, N; Saito, H; Miyazaki, K; Arita, T

1983-07-01

39

Influence of RF power on magnetron sputtered AZO films  

SciTech Connect

Al-doped Zinc Oxide (AZO) transparent conducting films are prepared on glass substrate by RF magnetron sputtering under different RF power with a 3 inch diameter target of 2 wt%Al{sub 2}O{sub 3} in zinc oxide. The effect of RF power on the structural, optical and electrical properties of AZO films was investigated by X-ray Diffraction (XRD), Hall measurement and UV-Visible spectrophotometry. The XRD data indicates a preferential c-axis orientation for all the films. All films exhibit high transmittance (<90%) in visible region. Films deposited at 60 W power exhibit lowest resistivity of 5.7 Multiplication-Sign 10{sup -4}{omega}cm. Such low-resistivity and high-transmittance AZO films when prepared using low RF power at room temperature could find important applications in flexible electronics.

Agarwal, Mohit; Modi, Pankaj; Dusane, R. O. [Semiconductor Thin Films and Plasma Processing Laboratory, Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Mumbai 400076 (India)

2013-02-05

40

Influence of RF power on magnetron sputtered AZO films  

NASA Astrophysics Data System (ADS)

Al-doped Zinc Oxide (AZO) transparent conducting films are prepared on glass substrate by RF magnetron sputtering under different RF power with a 3 inch diameter target of 2 wt% Al2O3 in zinc oxide. The effect of RF power on the structural, optical and electrical properties of AZO films was investigated by X-ray Diffraction (XRD), Hall measurement and UV-Visible spectrophotometry. The XRD data indicates a preferential c-axis orientation for all the films. All films exhibit high transmittance (<90%) in visible region. Films deposited at 60 W power exhibit lowest resistivity of 5.7×10-4?cm. Such low-resistivity and high-transmittance AZO films when prepared using low RF power at room temperature could find important applications in flexible electronics.

Agarwal, Mohit; Modi, Pankaj; Dusane, R. O.

2013-02-01

41

21 CFR 73.2991 - Zinc oxide.  

Code of Federal Regulations, 2010 CFR

...GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION...specifications. The color additive zinc oxide shall conform...amounts consistent with good manufacturing practice. (c) Labeling. The color additive and any mixture...

2010-04-01

42

Thermal properties of semiconductor zinc oxide nanostructures  

Microsoft Academic Search

A combination of two methods — laser modulation and 3? — has been used to determine the heat capacity, heat conductivity,\\u000a and heat diffusivity of zinc oxide nanostructures. A significant difference between the thermal parameters of zinc oxide nanostructures\\u000a grown by different technological methods has been revealed. It has been shown that the relatively low heat conductivity and\\u000a heat diffusivity

Kh. T. Igamberdiev; Sh. U. Yuldashev; S. S. Kurbanov; T. W. Kang; P. K. Khabibullaev; Sh. M. Rakhimova; V. O. Pelenovich; A. G. Shashkov

2010-01-01

43

Photo-rewritable flexible LCD using indium zinc oxide/polycarbonate substrates.  

PubMed

This work presents a photo-rewritable transmissive flexible-LCD based on the alignment effect of the photo-induced adsorption of azo dye on flexible indium zinc oxide/polycarbonate (IZO/PC) substrates. Images can be displayed without applying an external field and rewritten by changing the direction of the writing laser beam while the cell temperature is controlled. By using IZO/PC substrates, the writing and erasing processes can be achieved within 1 min with a high contrast. PMID:21221146

Jau, Hung-Chang; Cheng, Ko-Ting; Lin, Tsung-Hsien; Lo, Yuan-Si; Chen, Jia-You; Hsu, Chain-Wen; Fuh, Andy Ying-Guey

2011-01-10

44

Ordered ZnO\\/AZO\\/PAM nanowire arrays prepared by seed-layer-assisted electrochemical deposition  

Microsoft Academic Search

An Al-doped ZnO (AZO) seed layer is prepared on the back side of a porous alumina membrane (PAM) substrate by spin coating followed by annealing in a vacuum at 400°C. Zinc oxide in ordered arrays mediated by a high aspect ratio and an ordered pore array of AZO\\/PAM is synthesized. The ZnO nanowire array is prepared via a 3-electrode electrochemical

Yu-Min Shen; Chih-Huang Pan; Sheng-Chang Wang; Jow-Lay Huang

45

Chemoselective reduction of aromatic nitro and azo compounds in ionic liquids using zinc and ammonium salts  

Microsoft Academic Search

Nitroarenes were chemoselectively reduced to the corresponding amines using zinc and aqueous ammonium salts in ionic liquids as a safe and recyclable reaction medium. Our results specify the effect of ammonium salts in the process; the combination of Zn\\/NH4Cl in [bmim][PF6] or Zn\\/HCO2NH4 in [bmim][BF4] were the suitable conditions for the reduction of nitroarenes. Azobenzenes were also smoothly reduced to

Faiz Ahmed Khan; Jyotirmayee Dash; Ch Sudheer; Rakesh Kumar Gupta

2003-01-01

46

Transparent conducting AZO and ITO films produced by pulsed laser ablation at 355 nm  

Microsoft Academic Search

Thin films of aluminium-doped zinc oxide (AZO) and indium tin oxide (ITO) were deposited on glass substrates by laser ablation in an oxygen environment. The electrical and optical properties of films grown at various oxygen pressures were compared. With no substrate heating, highly transparent and conducting films were obtained with oxygen pressures between 15 and 23 mTorr for both materials.

B. Thestrup; J. Schou

1999-01-01

47

Generation of fume aerosols of zinc oxide  

SciTech Connect

Fume aerosols of zinc cxide were generated by nebulization of aqueous solutions of zinc acetate (30 milligrams zinc acetate per milliliter water), with subsequent thermal vaporization and chemical degradation to the oxide. A Retec nebulizer operated with compressed air was used to generate the zinc acetate mists which were passed through a quartz tube furnace (1150/sup 0/C) to dry the droplets and degrade the acetate to the oxide form. Ultrafine particles were formed in this process, demonstrating that zinc acetate was vaporized as aerosol entered the heated tube prior to thermolysis. The few larger particles probably represent those larger droplets which do not m with completely vaporize prior to thermolysis. Cascade impactor samples indicated a mass median aerodynamic diameter (MMAD/sub ar/) of 0.8+-0.1 (SD) ..mu..m with geometric standard deviation (sigma g) of 2.9 +- 0.5 (SD). About 25% of the zinc was associated with particles smaller than 0.3 ..mu..m in aerodynamic diameter, equivalent to spherical particles smaller than 0.09 ..mu..m in geometric diameter.

Teague, S.V.; Raabe, O.G.

1980-09-01

48

A Facile Cu(I)-Catalyzed Oxidative Coupling of Anilines to Azo Compounds and Hydrazines with Diaziridinone under Mild Conditions  

PubMed Central

A mild and highly efficient Cu(I)-catalyzed oxidative coupling of anilines is described. Various primary and secondary anilines can be efficiently coupled under mild conditions to the corresponding azo compounds and hydrazines in high yields. This method provides a direct and practical access to these compounds, and is also amenable to gram scale with no special precautions to exclude air or moisture. PMID:23545123

Zhu, Yingguang; Shi, Yian

2013-01-01

49

Room temperature deposition of alumina-doped zinc oxide on flexible substrates by direct pulsed laser recrystallization  

NASA Astrophysics Data System (ADS)

In this study, a method combining room temperature pulsed laser deposition (PLD) and direct pulsed laser recrystallization (DPLR) is introduced to deposit transparent conductive oxide (TCO) layer on low melting point flexible substrates. Alumina-doped zinc oxide (AZO), as one of the most promising TCO candidates, has now been widely used in solar cells. However, to achieve optimal, electrical, and optical properties of AZO on low melting point, flexible substrate is challenging. DPLR technique is a scalable, economic, and fast process to remove crystal defects and generate recrystallization at room temperature. It features selective processing by only heating up the TCO thin film and preserve the underlying substrate at low temperature. In this study, AZO thin film is pre-deposited by PLD on flexible and rigid substrates. DPLR is then introduced to achieve a uniform TCO layer on these substrates, i.e., commercialized Kapton polyimide film, micron-thick Al-foil, and sold lime glass (SLG). Both finite element analysis simulation and designed experiments are carried out to demonstrate that DPLR is promising in manufacturing high quality AZO layers without any damage to the underlying flexible substrates. The hall mobility of AZO after DPLR on Kapton and SLG reached 198 cm2/v . s and 398 cm2/v . s respectively, while the carrier concentrations are reduced to 2.68 × 1018 and 4.3 × 1019/cm-2, respectively. These characteristics are exactly what an ideal TCO layer should carry: high conductivity and high transmission. The property changes are due to the reduction of defect density after DPLR.

Zhang, Martin Y.; Nian, Qiong; Cheng, Gary J.

2012-04-01

50

Formation of zinc oxide films using submicron zinc particle dispersions  

SciTech Connect

The thermal oxidation of submicron metallic Zn particles was studied as a method to form nanostructured ZnO films. The particles used for this work were characterized by electron microscopy, x-ray diffraction and thermal analysis to evaluate the Zn-ZnO core shell structure, surface morphology, and oxidation characteristics. Significant nanostructural changes were observed for films annealed to 400 °C or higher, where nanoflakes, nanoribbons, nanoneedles and nanorods were formed as a result of stress induced fractures arising in the ZnO outer shell due to differential thermal expansion between the metallic Zn core and the ZnO shell. Mass transport occurs through these defects due to the high vapor pressure for metallic Zn at temperatures above 230 °C, whereupon the Zn vapor rapidly oxidizes in air to form the ZnO nanostructures. The Zn particles were also incorporated into zinc indium oxide precursor solutions to form thin film transistor test structures to evaluate the potential of forming nanostructured field effect sensors using simple solution processing.

Rajachidambaram, Meena Suhanya; Varga, Tamas; Kovarik, Libor; Sanghavi, Rahul P.; Shutthanandan, V.; Thevuthasan, Suntharampillai; Han, Seungyeol; Chang, Chih-hung; Herman, Gregory S.

2012-07-27

51

Doping in zinc oxide thin films  

Microsoft Academic Search

Doping in zinc oxide (ZnO) thin films is discussed in this dissertation. The optimizations of undoped ZnO thin film growth using molecular-beam epitaxy (MBE) are discussed. The effect of the oxygen ECR plasma power on the growth rate, structural, electrical, and optical properties of the ZnO thin films were studied. It was found that larger ECR power leads to higher

Zheng Yang

2009-01-01

52

Secondary emission of nanocrystalline zinc oxide  

Microsoft Academic Search

The Raman and photoluminescence (PL) spectra of nanocrystalline zinc oxide produced by mechanochemical synthesis were measured\\u000a using a pulsed nitrogen laser (337.1 nm) and xenon lamp (360 nm) as excitation sources in PL measurements and a cw Nd:YAG\\u000a laser in Raman measurements. PL was observed in the range 400–800 nm. The Raman spectrum of nanocrystalline (90 nm) ZnO was\\u000a compared

V. S. Gorelik; S. N. Mikov; M. I. Sokolovskii; T. Tsuzuki

2006-01-01

53

Process for preparing zinc oxide-based sorbents  

DOEpatents

The disclosure relates to zinc oxide-based sorbents, and processes for preparing and using them. The sorbents are preferably used to remove one or more reduced sulfur species from gas streams. The sorbents comprise an active zinc component, optionally in combination with one or more promoter components and/or one or more substantially inert components. The active zinc component is a two phase material, consisting essentially of a zinc oxide (ZnO) phase and a zinc aluminate (ZnAl.sub.2O.sub.4) phase. Each of the two phases is characterized by a relatively small crystallite size of typically less than about 500 Angstroms. Preferably the sorbents are prepared by converting a precursor mixture, comprising a precipitated zinc oxide precursor and a precipitated aluminum oxide precursor, to the two-phase, active zinc oxide containing component.

Gangwal, Santosh Kumar (Cary, NC); Turk, Brian Scott (Durham, NC); Gupta, Raghubir Prasad (Durham, NC)

2011-06-07

54

"Magic" vicinal zinc oxide surfaces.  

PubMed

The structure of (0001) oriented ZnO single crystal surfaces is investigated by scanning tunneling microscopy. Depending on the preparation conditions, faceting of the crystals into large areas of {101¯4} surface orientation occurs. This restructuring of the surface is shown to be a consequence of dipole compensation and charge neutralization. A new stabilization mechanism of polar oxide surfaces is found which is based on the formation of vicinal surfaces with special electronic and structural properties. PMID:24010455

Zheng, Hao; Gruyters, Markus; Pehlke, Eckhard; Berndt, Richard

2013-08-23

55

Thermally oxidized zinc oxide nanowires for use as chemical sensors.  

PubMed

Zinc oxide (ZnO) mat-based conductometric devices were fabricated using a thermal oxidation technique. A metallic zinc layer was deposited on the alumina transducer and then oxidized in a controlled atmosphere, in order to obtain ZnO nanostructures. Two different batches of sensors have been prepared, and their sensing performances have been evaluated towards oxidizing and reducing gases. Functional measurements showed very good sensing performances towards ethanol and acetone at 500 °C, and NO2 at 200 °C, indirectly confirming the n-type behaviour of the material. The influence of the humidity on the response has been explored. In practical conditions the interference of humidity is very small, and could be neglected in many applications. Simultaneous measurements on different devices from the same batch confirm the high reproducibility of the response within the batch. PMID:24113169

Zappa, D; Comini, E; Sberveglieri, G

2013-11-01

56

Thermally oxidized zinc oxide nanowires for use as chemical sensors  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) mat-based conductometric devices were fabricated using a thermal oxidation technique. A metallic zinc layer was deposited on the alumina transducer and then oxidized in a controlled atmosphere, in order to obtain ZnO nanostructures. Two different batches of sensors have been prepared, and their sensing performances have been evaluated towards oxidizing and reducing gases. Functional measurements showed very good sensing performances towards ethanol and acetone at 500?° C, and NO2 at 200?° C, indirectly confirming the n-type behaviour of the material. The influence of the humidity on the response has been explored. In practical conditions the interference of humidity is very small, and could be neglected in many applications. Simultaneous measurements on different devices from the same batch confirm the high reproducibility of the response within the batch.

Zappa, D.; Comini, E.; Sberveglieri, G.

2013-11-01

57

Low-temperature solution-processed metal oxide buffer layers fulfilling large area production requirements  

NASA Astrophysics Data System (ADS)

This paper is a review of our previous work on the field of low temperature, solution processed metal oxide buffer layers published in various journals. Our work focuses on zinc oxide (ZnO) and aluminum-doped zinc oxide (AZO) as n-type and molybdenum oxide (MoO3) as p-type solution processed buffer layer. In addition to that, we investigate the surface modification of AZO using phosphonic acid-anchored aliphatic and fullerene self assembled monolayers (SAMs).

Stubhan, T.; Litzov, I.; Li, Ning; Wang, H. Q.; Krantz, J.; Machui, F.; Steidl, M.; Oh, H.; Matt, G. J.; Brabec, C. J.

2012-09-01

58

Electrical and optical properties of ultrasonically sprayed Al-doped zinc oxide thin films  

Microsoft Academic Search

Aluminium-doped ZnO (AZO) films were deposited by ultrasonic spray pyrolysis (USP) technique to investigate its potential application as antireflection coating and top contact layer for copper indium gallium diselenide (CIGS) based photovoltaic cells. The solution used to prepare AZO thin films contained 0.2M of zinc acetate and 0.2M of aluminium pentanedionate solutions in the order of 2, 3 and 4at.%

B. J. Babu; A. Maldonado; S. Velumani; R. Asomoza

2010-01-01

59

Hydrothermal synthesis of zinc oxide powders with controllable morphology  

Microsoft Academic Search

Crystalline zinc oxide powders with various morphologies have been prepared by hydrothermal treatment of zinc acetate in pure water, KOH or ammonia aqueous solution. It was found that the selected solvents play a different role in controlling the morphologies of the obtained powders. The variation of morphology of the obtained ZnO powder with solvents mainly depends on the different zinc

HaiYan Xu; Hao Wang; YongCai Zhang; WenLiang He; ManKang Zhu; Bo Wang; Hui Yan

2004-01-01

60

Mechanism of conductivity degradation of AZO thin film in high humidity ambient  

NASA Astrophysics Data System (ADS)

The conductivity stability of aluminum-doped zinc oxide (AZO) films was evaluated in the ambient with different humidity. We found that the conductivity of AZO films is sensitive to the humidity and degrades remarkably in high humidity ambient (90 ± 5% relative humidity) at 60 °C. Hall measurement results show that the conductivity degradation is due to the drop in the carrier concentration, while the carrier mobility is found to remain relatively constant in the high humidity ambient. XPS (X-ray photoelectron spectroscopy) analysis reveals that the oxygen-vacancies in the AZO thin films were greatly reduced in the high-humidity ambient. So, we believe that the high-humidity ambient causes the decrease in the oxygen vacancies and eventually resulted in the decrease in the concentration of the free carriers in the AZO thin films. In this study, a mechanism is proposed to explain the humidity-assist reduction in the oxygen vacancies in the humidity-tested AZO films. In addition, we report that the electrical properties of AZO film can be stabilized by coating a Cr layer on the AZO thin film surface.

Liu, Yen-Shuo; Hsieh, Chih-Yi; Wu, Yen-Ju; Wei, Yu-Shan; Lee, Po-Ming; Hsieh, Hsiu-Ming; Liu, Cheng-Yi

2013-10-01

61

Nitrogen and argon doped zinc oxide  

NASA Astrophysics Data System (ADS)

In this work argon and nitrogen were implanted into ZnO single crystals in order to compare the influence of these non-magnetic elements in the magnetic and electrical behaviour of zinc oxide. The results indicate that both nitrogen and argon implantations induce magnetic defects in ZnO, although these do not remain stable upon annealing. The comparison between the electrical behaviour of argon and nitrogen implanted crystals indicates that mobile charge carriers exist in the argon implanted sample after annealing, but were not detected in the nitrogen implanted sample.

Silva, C.; Costa, A. R. G.; Cruz, M. M.; da Silva, R. C.; Borges, R. P.; Alves, L. C.; Godinho, M.

2010-09-01

62

Directed spatial organization of zinc oxide nanorods.  

SciTech Connect

The ability to precisely place nanomaterials at predetermined locations is necessary for realizing applications using these new materials. Using an organic template, we demonstrate directed growth of zinc oxide (ZnO) nanorods on silver films from aqueous solution. Spatial organization of ZnO nanorods in prescribed arbitrary patterns was achieved, with unprecedented control in selectivity, crystal orientation, and nucleation density. Surprisingly, we found that caboxylate endgroups of {omega}-alkanethiol molecules strongly inhibit ZnO nucleation. The mechanism for this observed selectivity is discussed.

Simmons, Neil C.; Liu, Jun; Voigt, James A.; Hsu, Julia W. P.; Tian, Zhengrong Ryan; Matzke, Carolyn M.

2004-09-01

63

Nanocrystalline copper doped zinc oxide produced from copper doped zinc hydroxide nitrate as a layered precursor  

Microsoft Academic Search

Undoped and copper doped nanostructured zinc oxides were synthesized by using a series of synthetic layered material, undoped and copper doped zinc hydroxide nitrates at various molar percentages of copper (2–10) within the layers as precursors. The layered materials were heat-treated at 500°C to produce zinc oxide nanostructures with crystallite sizes in the range of 23–35nm. Optical studies of the

Mohammad Yeganeh Ghotbi; Narjes Bagheri; S. K. Sadrnezhaad

64

Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide.  

PubMed

The water-soluble zinc salts gluconate, sulfate, and acetate are commonly used as supplements in tablet or syrup form to prevent zinc deficiency and to treat diarrhea in children in combination with oral rehydration. Zinc citrate is an alternative compound with high zinc content, slightly soluble in water, which has better sensory properties in syrups but no absorption data in humans. We used the double-isotope tracer method with (67)Zn and (70)Zn to measure zinc absorption from zinc citrate given as supplements containing 10 mg of zinc to 15 healthy adults without food and compared absorption with that from zinc gluconate and zinc oxide (insoluble in water) using a randomized, double-masked, 3-way crossover design. Median (IQR) fractional absorption of zinc from zinc citrate was 61.3% (56.6-71.0) and was not different from that from zinc gluconate with 60.9% (50.6-71.7). Absorption from zinc oxide at 49.9% (40.9-57.7) was significantly lower than from both other supplements (P < 0.01). Three participants had little or no absorption from zinc oxide. We conclude that zinc citrate, given as a supplement without food, is as well absorbed by healthy adults as zinc gluconate and may thus be a useful alternative for preventing zinc deficiency and treating diarrhea. The more insoluble zinc oxide is less well absorbed when given as a supplement without food and may be minimally absorbed by some individuals. This trial was registered at clinicaltrials.gov as NCT01576627. PMID:24259556

Wegmüller, Rita; Tay, Fabian; Zeder, Christophe; Brnic, Marica; Hurrell, Richard F

2014-02-01

65

Influence of growth temperature on electrical, optical, and plasmonic properties of aluminum:zinc oxide films grown by radio frequency magnetron sputtering  

NASA Astrophysics Data System (ADS)

We have investigated the responsible mechanism for the observation of metallic conductivity at room temperature and metal-semiconductor transition (MST) at lower temperatures for aluminum-doped zinc oxide (AZO) films. AZO films were grown on glass substrates by radio-frequency magnetron sputtering with varying substrate temperatures (Ts). The films were found to be crystalline with the electrical resistivity close to 1.1 × 10-3 ? cm and transmittance more than 85% in the visible region. The saturated optical band gap of 3.76 eV was observed for the sample grown at Ts of 400 °C, however, a slight decrease in the bandgap was noticed above 400 °C, which can be explained by Burstein-Moss effect. Temperature dependent resistivity measurements of these highly conducting and transparent films showed a MST at ˜110 K. The observed metal-like and metal-semiconductor transitions are explained by taking into account the Mott phase transition and localization effects due to defects. All AZO films demonstrate crossover in permittivity from positive to negative and low loss in the near-infrared region, illustrating its applications for plasmonic metamaterials, including waveguides for near infrared telecommunication region. Based on the results presented in this study, the low electrical resistivity and high optical transmittance of AZO films suggested a possibility for the application in the flexible electronic devices, such as transparent conducting oxide film on LEDs, solar cells, and touch panels.

Dondapati, Hareesh; Santiago, Kevin; Pradhan, A. K.

2013-10-01

66

Piezoelectric Characterization of Individual Zinc Oxide Nanobelt Probed  

E-print Network

Piezoelectric Characterization of Individual Zinc Oxide Nanobelt Probed by Piezoresponse Force piezoelectric coefficient (d33) of an individual (0001) surface dominated zinc oxide nanobelt lying on a conductive surface. Based on references of bulk (0001) ZnO and x-cut quartz, the effective piezoelectric

Wang, Zhong L.

67

Zinc oxide microcapsules obtained via a bio-inspired approach  

Microsoft Academic Search

Hollow zinc oxide microcapsules have been synthesized by a sacrificial template route involving the chemical bath deposition of nanostructured zinc oxide thin films on sulfonate-modified polystyrene microspheres and subsequent removal of the polymer core by dissolution in a solvent or by thermolysis. Scanning electron micrographs show that uniform coating of the templates is achieved when ZnO is deposited from a

Peter Lipowsky; Michael Hirscher; Rudolf C. Hoffmann; Joachim Bill; Fritz Aldinger

2007-01-01

68

Enhanced Work Function of Al-Doped Zinc-Oxide Thin Films by Oxygen Inductively Coupled Plasma Treatment  

NASA Astrophysics Data System (ADS)

Al-doped zinc-oxide (AZO) thin films treated by oxygen and chlorine inductively coupled plasma (ICP) were compared. Kelvin probe (KP) and X-ray photoelectron spectroscopy (XPS) were employed to characterize the effect of treatment. The results of KP measurement show that the surface work function of AZO thin films can increase up to 5.92 eV after oxygen ICP (O-ICP)'s treatment, which means that the work function was increased by at least 1.1 eV. However, after the treatment of chlorine ICP (Cl-ICP), the work function increased to 5.44 eV, and the increment was 0.6 eV. And 10 days later, the work function increment was still 0.4 eV after O-ICP's treatment, while the work function after Cl-ICP's treatment came back to the original value only after 48 hours. The XPS results suggested that the O-ICP treatment was more effective than Cl-ICP for enhancing the work function of AZO films, which is well consistent with KP results.

Li, Zebin; Wu, Zhonghang; Ju, Jiaqi; He, Kongduo; Chen, Zhenliu; Yang, Xilu; Yan, Hang; Ou, Qiongrong; Liang, Rongqing

2014-01-01

69

Broadband wide-angle antireflection enhancement in AZO/Si shell/core subwavelength grating structures with hydrophobic surface for Si-based solar cells.  

PubMed

Broadband wide-angle antireflection characteristics of aluminum-doped zinc oxide (AZO)/silicon (Si) shell/core subwavelength grating (SWG) structures with a hydrophobic surface, together with theoretical prediction using a rigorous coupled-wave analysis simulation, were investigated for Si-based solar cells. The AZO films with different thicknesses were deposited on Si SWGs by rf magnetron sputtering method, which forms a shell/core structure. The AZO/Si shell/core SWGs reduced significantly the surface reflection compared to the AZO films/Si substrate. The coverage of AZO films on Si SWGs improved the antireflective property over a wider incident angle. The AZO/Si shell/core SWG structure with a 200 nm-thick AZO layer deposited at an rf power of 200 W exhibited a water contact angle of 123°. This structure also exhibited a low average reflectance of ~2% over a wide wavelength range of 300-2100 nm with a solar weighted reflectance of 2.8%, maintaining a reflectance of < 9.2% at wavelengths of 300-2100 nm up to the incident angle of ?(i) = 70°. The effective electrical properties of AZO films in AZO/Si shell/core SWGs were also analyzed. PMID:21935259

Leem, Jung Woo; Song, Young Min; Yu, Jae Su

2011-09-12

70

A modeling of the optical properties of the zinc oxide-zinc magnesium oxide double barrier system  

Microsoft Academic Search

This article investigates the correlation between the optical and transport properties of zinc oxide-zinc magnesium oxide double barrier system by investigating the localization of the energy levels in the quantum well. Effective mass approach is used to investigate this system. The degree of localization of the levels in the quantum well is also examined with respect to the width of

G. Krokidis; J. P. Xanthakis; A. A. Iliadis

2003-01-01

71

Kinetics of the reduction of the zinc oxide in zinc ferrite with iron  

SciTech Connect

Electric arc furnace (EAF) dust, which can be considered as a by-product of the steel recycling process, contains significant quantities of recoverable zinc and iron, as well as hazardous elements such as cadmium, lead and chromium, which can be leached by ground water. The zinc in the EAF dust is found almost entirely in the form of either zinc oxide or zinc ferrite, the latter accounting for 20 to 50 percent of the total zinc. It is important that an efficient process be developed which renders the dust inert, while reclaiming the valuable metals to off-set processing costs. During the conventional carbothermic reduction processes, iron is formed, and this iron can participate in the reduction of the zinc oxide in zinc ferrite. In the present work, the reduction of the zinc oxide in zinc ferrite by iron according to the following reaction: ZnO{sup {sm_bullet}}Fe{sub 2}O{sub (s.s.)} + 2 Fe{sub (s)} = Zn{sub (g)} + 4 FeO{sub (s)} was studied in an argon atmosphere using a thermogravimetric technique. First, a thermodynamic analysis was performed using the F*A*C*T computational system. Then, the effects of briquette aspect ratio (l/d), temperature, zinc ferrite particle size, amount of iron added, as well as additions such as lime, sodium chloride, and calcium fluoride were investigated.

Donald, J.R.; Pickles, C.A. [Queen`s Univ., Kingston, Ontario (Canada). Dept. of Materials and Metallurgical Engineering

1995-12-31

72

Zinc oxide thin film acoustic sensor  

SciTech Connect

This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah [Department of Physics , College of Science, Al-Mustansiriyah University, Baghdad (Iraq); Mansour, Hazim Louis [Department of Physics , College of Education, Al-Mustansiriyah University, Baghdad (Iraq)

2013-12-16

73

Optical and Luminescence Properties of Zinc Oxide  

E-print Network

We generalize and systematize basic experimental data on optical and luminescence properties of ZnO single crystals, thin films, powders, ceramics, and nanocrystals. We consider and study mechanisms by which two main emission bands occur, a short-wavelength band near the fundamental absorption edge and a broad long-wavelength band, the maximum of which usually lies in the green spectral range. We determine a relationship between the two luminescence bands and study in detail the possibility of controlling the characteristics of ZnO by varying the maximum position of the short-wavelength band. We show that the optical and luminescence characteristics of ZnO largely depend on the choice of the corresponding impurity and the parameters of the synthesis and subsequent treatment of the sample. Prospects for using zinc oxide as a scintillator material are discussed. Additionally, we consider experimental results that are of principal interest for practice.

Rodnyi, P A; 10.1134/S0030400X11120216

2012-01-01

74

Optical and Luminescence Properties of Zinc Oxide  

E-print Network

We generalize and systematize basic experimental data on optical and luminescence properties of ZnO single crystals, thin films, powders, ceramics, and nanocrystals. We consider and study mechanisms by which two main emission bands occur, a short-wavelength band near the fundamental absorption edge and a broad long-wavelength band, the maximum of which usually lies in the green spectral range. We determine a relationship between the two luminescence bands and study in detail the possibility of controlling the characteristics of ZnO by varying the maximum position of the short-wavelength band. We show that the optical and luminescence characteristics of ZnO largely depend on the choice of the corresponding impurity and the parameters of the synthesis and subsequent treatment of the sample. Prospects for using zinc oxide as a scintillator material are discussed. Additionally, we consider experimental results that are of principal interest for practice.

P. A. Rodnyi; I. V. Khodyuk

2012-03-20

75

Zinc oxide thin film acoustic sensor  

NASA Astrophysics Data System (ADS)

This paper reports the implementation of (750 nm) thickness of Zinc Oxide (ZnO) thin film for the piezoelectric pressure sensors. The film was prepared and deposited employing the spray pyrolysis technique. XRD results show that the growth preferred orientation is the (002) plane. A polycrystalline thin film (close to mono crystallite like) was obtained. Depending on the Scanning Electron Microscopy photogram, the film homogeneity and thickness were shown. The resonance frequency measured (about 19 kHz) and the damping coefficient was calculated and its value was found to be about (2.5538), the thin film be haves as homogeneous for under and over damped. The thin film pressure sensing was approximately exponentially related with frequency, the thin film was observed to has a good response for mechanical stresses also it is a good material for the piezoelectric properties.

Mohammed, Ali Jasim; Salih, Wafaa Mahdi; Hassan, Marwa Abdul Muhsien; Mansour, Hazim Louis; Nusseif, Asmaa Deiaa; Kadhum, Haider Abdullah

2013-12-01

76

Characterization of P-type zinc oxide films  

Microsoft Academic Search

Zinc Oxide falls under the classification of transparent conductive oxides. They typical optical transmittance of Zinc Oxide is 90% in the visible wavelength region. Though stoichiometric ZnO is an insulator, due to the presence of internal defects such as Zn interstitials and Oxygen vacancies, it exists as a n-type conductor. The other important property of ZnO which could be used

Madhavi Oleti Kalki Rajan

2004-01-01

77

Microwave Synthesis of Zinc Hydroxy Sulfate Nanoplates and Zinc Oxide Nanorods in the Classroom  

ERIC Educational Resources Information Center

In this hands-on, inquiry-based lab, high school and undergraduate students learn about nanotechnology by synthesizing their own nanoparticles in a single class period. This simple synthesis of zinc oxide nanorods and zinc hydroxy sulfate nanoplates can be done in 15 min using a household microwave oven. Reagent concentration, reaction…

Dziedzic, Rafal M.; Gillian-Daniel, Anne Lynn; Peterson, Greta M.; Martínez-Herna´ndez, Kermin J.

2014-01-01

78

DIRECT SOLAR THERMAL DISSOCIATION OF ZINC OXIDE: CONDENSATION AND CRYSTALLISATION OF ZINC IN THE PRESENCE OF OXYGEN  

Microsoft Academic Search

The solar thermal production of zinc from zinc oxide is part of a two-step water splitting cycle. Zinc oxide thermally dissociates into zinc vapour and oxygen at elevated temperatures;ZnO(s)=Zn(g)+0.5O2In practice, the yield of zinc depends on the kinetics of dissociation and the technical feasibility of quenching its gaseous products fast enough to avoid reoxidation. As the gaseous products cool, the

A. WEIDENKAFF; A. STEINFELD; A. WOKAUN; P. O. AUER; B. EICHLER; A. RELLER

1999-01-01

79

Ultra fast synthesis of zinc oxide nanostructures by microwaves  

NASA Astrophysics Data System (ADS)

We describe a novel route for the synthesis of nanostructured zinc oxide powder using a modified kitchen microwave. A SiC-based composite showing a very strong absorption of microwaves was used as a microwave heater. Tests showed that high temperatures exceeding 1700 ?C can be reached in less than hundred second exposure of the composite material of microwaves. Zinc oxide nanopowder was obtained by evaporation and oxidation of metallic zinc in the ambient atmosphere of the microwave oven. Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques revealed the prepared powder includes a wide variety of nanostructures including nanoparticles, nanosheets and tetrapods.

Tabet, N.; Al Ghashani, R.; Achour, S.

2009-06-01

80

Low-index metamaterials comprised of plasmonic dimers of aluminum-doped zinc oxide  

NASA Astrophysics Data System (ADS)

Transparent conducting oxides (TCO) are an interesting class of plasmonic materials, which are under intensive study for their use in low-loss metamaterials and a range of applications such as sensing, imaging and transformation optics. Here, using both full-wave simulations and an equivalent circuit model for pairs of nanoparticles of aluminum doped zinc oxide (AZO), we study the plasmonic effects for low loss low index metamaterials for infrared applications. The behavior of localized surface plasmon resonances (LSPR) of AZO nanoparticle dimers embedded in a host polymer medium is investigated for different dimer orientations with respect to the indicent electromagnetic wave. In doing this, the role of dressed polarizability to enhance and quench the plasmonic effects is also considered. The effects of the nanoparticles relative size and the spacing between them are studied. Understanding these resonances and their dependence on dimer orientations, provides a means to design metamaterial structures for use in the near infrared (NIR) region with epsilon-near-zero properties leading also to low index metamaterials. In our studies, we demonstrate how nanospheres with radii less than 100 nm that are distributed with an average spacing less than their diameter, can result in an effective medium with refractive index less than one. We utilize a full-wave frequency domain finite element method in conjunction with an equivalent-circuit model for the nanoscale dimers in order to describe the spectral response of the bulk low index properties. We also present a statistical analysis to obtain the effective refractive index for incident light having different polarizations.

Alisafaee, Hossein; Cox, P. M.; Fiddy, Michael A.

2013-09-01

81

Atomistic Simulation Study of Spinel Oxides: Zinc Aluminate and Zinc Gallate  

Microsoft Academic Search

Stoichiometric zinc aluminate (ZnAl2O4) and zinc gallate (ZnGa2O4) are simulated in the framework of the shell model, for which a new set of two-body interatomic poten- tial parameters has been developed. Using these param- eters, a reasonable prediction is made for elastic and di- electric constants of ZnAl2O4 and ZnGa2O4. Both oxides are stable against decomposition to the component oxides.

Ravindra Pandey; Julian D. Gale; Suresh K. Sampath; Jose M. Recio

1999-01-01

82

Nano-sized layered aluminium or zinc-manganese oxides as efficient water oxidizing catalysts.  

PubMed

Nano-sized layered aluminium or zinc-manganese oxides were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, dynamic light scattering and atomic absorption spectroscopy. These oxides showed efficient water oxidizing activity in the presence of cerium(IV) ammonium nitrate as a non-oxo transfer oxidant. Amounts of dissolved manganese, zinc or aluminium, and water oxidation activities of these oxides were reported and compared with other manganese oxides. A mechanism for oxygen evolution and possible roles for zinc or aluminium ions are also proposed. PMID:22565665

Najafpour, Mohammad Mahdi; Pashaei, Babak; Nayeri, Sara

2012-06-21

83

Efficient decolorization of azo dye Reactive Black B involving aromatic fragment degradation in buffered Co 2+\\/PMS oxidative processes with a ppb level dosage of Co 2+-catalyst  

Microsoft Academic Search

In order to generate powerful radicals as oxidizing species for the complete decolorization and degradation of azo dye Reactive Black B (RBB) at near neutral pH (pH 6), homogeneous activation of peroxymonosulfate (Oxone: PMS) by the trace Co2+-catalysts was explored. We not only took advantage of the high oxidation–reduction potential of produced hydroxyl and sulfite radicals but also an opportunity

Yao-Hui Huang; Yi-Fong Huang; Chun-ing Huang; Chuh-Yung Chen

2009-01-01

84

Zinc-catalyzed copolymerization of carbon dioxide and propylene oxide  

E-print Network

The zinc-catalyzed copolymerization of carbon dioxide and propylene oxide, which is one of the promising reactions for the utilization of carbon dioxide, has been investigated from various aspects. Above all, considering that supercritical carbon...

Katsurao, Takumi

2012-06-07

85

Nonstoichiometric zinc oxide and indium-doped zinc oxide: Electrical conductivity and {sup 111}In-TDPAC studies  

SciTech Connect

Indium-doped zinc oxide powders have been prepared which show room-temperature electrical conductivities as high as 30 {Omega}{sup {minus}1} cm{sup {minus}1}. The indium doping apparently occurs as Zn{sub 1-x}In{sub x}O,Zn{sub 1-y}In{sub y}O{sub 1+y/2}, or a combination of these. Optimum conductivity occurs for Zn{sub 1-x}In{sub x}O where the maximum value of x obtained was about 0.5 at%. The degrees of sample reduction were determined by iodimetric titration. Time differential perturbed angular correlation (TDPAC) spectroscopy on indium doped zinc oxide is consistent with indium substituting at normal zinc sites in the ZnO lattice. TDPAC studies on zinc oxide annealed under zinc vapors show a second environment for the {sup 111}In probe. In this case, there is an unusually high temperature dependence of the electric field gradient which may be caused by a nearby zinc interstitial. An important conclusion of this work is that zinc interstitials are not ionized and do not therefore contribute significantly to the increased conductivity of reduced zinc oxide.

Wang, R.; Sleight, A.W.; Platzer, R.; Gardner, J.A. [Oregon State Univ., Corvallis, OR (United States)] [Oregon State Univ., Corvallis, OR (United States)

1996-02-15

86

Nonstoichiometric Zinc Oxide and Indium-Doped Zinc Oxide: Electrical Conductivity and 111In-TDPAC Studies  

NASA Astrophysics Data System (ADS)

Indium-doped zinc oxide powders have been prepared which show room-temperature electrical conductivities as high as 30 ? -1cm -1. The indium doping apparently occurs as Zn 1- xIn xO, Zn 1- yIn yO 1+ y/2 , or a combination of these. Optimum conductivity occurs for Zn 1- xIn xO where the maximum value of xobtained was about 0.5 at%. This substitution results in a lattice volume expansion of 0.4%. The degrees of sample reduction were determined by iodimetric titration. Time differential perturbed angular correlation (TDPAC) spectroscopy on indium doped zinc oxide is consistent with indium substituting at normal zinc sites in the ZnO lattice. TDPAC studies on zinc oxide annealed under zinc vapors show a second environment for the 111In probe. In this case, there is an unusually high temperature dependence of the electric field gradient which may be caused by a nearby zinc interstitial. An important conclusion of this work is that zinc interstitials are not ionized and do not therefore contribute significantly to the increased conductivity of reduced zinc oxide.

Wang, Ruiping; Sleight, Arthur W.; Platzer, Roland; Gardner, John A.

1996-02-01

87

Aluminium doped zinc oxide films: formation process and optical properties  

Microsoft Academic Search

Aluminium doped zinc oxide films were prepared through a non-alcoxide sol–gel and dip-coating technique, from zinc acetate and aluminium nitrate in ethanolic solution. The acetate hydrolysis was promoted by lactic acid. The doping level of aluminium was 0.8 mol%. Acetylacetone and diethanolamine were used as additives to improve film homogeneity. The chemical processes which occur during the drying and oxide

Rodrigo Ferreira Silva; Maria Elisabete Darbello Zaniquelli

1999-01-01

88

Acetone sensor based on zinc oxide hexagonal tubes  

NASA Astrophysics Data System (ADS)

In this work hexagonal tubes of zinc oxide have been synthesized by co-precipitation method. For structural, morphological, elemental and optical analysis synthesized powders were characterized by using x-ray diffraction, field emission scanning microscope, EDX, UV-visible and FTIR techniques. For acetone sensing thick films of zinc oxide have been deposited on alumina substrate. The fabricated sensors exhibited maximum sensing response towards acetone vapour at an optimum operating temperature of 400°C.

Hastir, Anita; Singh, Onkar; Anand, Kanika; Singh, Ravi Chand

2014-04-01

89

Labyrinth patterns of zinc oxide on porous silicon substrate  

NASA Astrophysics Data System (ADS)

The substrate treatment dependent formation of different micro-morphologies of zinc oxide over PS substrate has been reported. Effect of substrate oxidation and annealing has been studied. Changes in the structural properties were seen in the form of labyrinth patterns developed on the surface and were studied with the help of scanning electron microscope (SEM), atomic force microscope (AFM). X-ray diffraction (XRD) along with UV-visible absorption and photoluminescence (PL) spectroscopy were performed for characterizing the zinc oxide film and the hybrid structure. A relatively flat film of nanostructured zinc oxide particles is found to form on the oxidized substrate as compared to the nanostructured labyrinth patterns formed on the un-oxidized substrate with enhanced aspect ratio. Such micromorphologies can be very promising for fabricating highly sensitive gas sensors.

Martínez, L.; Kumar, Y.; Mayorga, D.; Goswami, N.; Agarwal, V.

2014-03-01

90

Sliding droplets on superomniphobic zinc oxide nanostructures.  

PubMed

This study reports on liquid-repellency of zinc oxide nanostructures (ZnO NS). The ZnO NS are synthesized by an easy and fast chemical bath deposition technique. Three different nanostructured surfaces consisting of nanorods, flowers, and particles are prepared, depending on the deposition time and the presence of ethanolamine in the reaction mixture. Chemical functionalization of the ZnO NS with 1H,1H,2H,2H-perfluorodecyltrichlorosilane (PFTS) in liquid (PFTS L) and vapor phase (PFTS V) or through octafluorobutane (C(4)F(8)) plasma deposition led to the formation of superomniphobic surfaces. A comprehensive characterization of the wetting properties (static contact angle and contact angle hysteresis) has been performed using liquids composed of deionized water and various concentrations of ethanol (surface tension between 35 and 72.6 mN/m). Depending on the nanostructures morphology, coating nature and liquid employed, high static apparent contact angles ? ? 150-160°, and low contact angle hysteresis ?? ? 0° are obtained. The different ZnO NS are characterized using scanning electron microscopy (SEM) and contact angle measurements. The results reported in this work permit preparation of sliding omniphobic surfaces using a simple and low cost technique. PMID:22053956

Perry, Guillaume; Coffinier, Yannick; Thomy, Vincent; Boukherroub, Rabah

2012-01-10

91

High power pulsed magnetron sputtering of transparent conducting oxides  

Microsoft Academic Search

High power pulsed magnetron sputtering (HPPMS) has been used in order to study the deposition of transparent conducting oxides. We summarize the studies carried out on different materials (indium tin oxide-ITO and aluminium-doped zinc oxide-AZO) using rather different technological approaches, namely sputtering of ceramic targets and reactive sputtering.For the deposition of AZO reactive HPPMS for metallic targets has been used.

V. Sittinger; F. Ruske; W. Werner; C. Jacobs; B. Szyszka; D. J. Christie

2008-01-01

92

Photoelectrochemical response and stability of titanium–zinc mixed oxide films formed by thermal oxidation  

Microsoft Academic Search

The photoelectrochemical properties of titanium–zinc mixed oxide films formed by thermal oxidation of a titanium sheet with a zinc deposited overlayer were studied in pH 8.4 borate buffer solution at 298 K. The oxides were composed of ZnO (wurtzite), TiO2 (rutile), and ZnTi2O4 depending on the oxidation temperatures. Under xenon light illumination, photocurrents were observed for the oxides and these

Isao Saeki; Jun Setaka; Ryusaburo Furuichi; Hidetaka Konno

1999-01-01

93

Low resistance and transparent Ag/AZO ohmic contact to p-GaN  

NASA Astrophysics Data System (ADS)

Silver (Ag)/ aluminum-doped zinc oxide (AZO) films were deposited on p-GaN by using electronbeam evaporation. After the annealing process, current -voltage (I-V) measurements were carried out to determine the characteristic of the contacts. The Ag/AZO films annealed at 600 °C were found to present an ohmic contact behavior. The specific contact resistance was calculated to be 9.76 × 10-4 ?cm2 and the transmittance was over 80% for visibly light. The atomic force microscope was used to measure the aggregation of Ag grains which may have been the main factor in the formation of the Ag/AZO ohmic contact to p-GaN.

Han, T.; Wang, T.; Gan, X. W.; Wu, H.; Shi, Y.; Liu, C.

2014-07-01

94

Optical properties of porous nano-composites of zinc (hydr)oxide with graphite oxide  

NASA Astrophysics Data System (ADS)

The optical properties of zinc (hydr)oxide and the composites of zinc (hydr)oxide with 2% and 5% graphite oxide were investigated by three spectroscopic techniques: absorption, fluorescence and photocurrent techniques. The obtained energy gaps (from 2.85 eV to 2.95 eV) of the composites were smaller than that for zinc oxide (~3.2 eV) and zinc (hydr)oxide (~3.00 eV). The band gap narrowing of the composite materials is due to presence of defects, less confinement, and larger particles. The bonds between zinc (hydr)oxide lattice and the carbon of graphene phase also contribute to this phenomenon.

Islam, S. M. Z.; Gayen, Taposh; Seredych, Mykola; Bandosz, Teresa J.; Alfano, Robert

2013-03-01

95

Development of silver zinc oxide for general-purpose relays  

Microsoft Academic Search

The switching behavior of silver cadmium oxide (Ag\\/CdO), silver tin oxide (Ag\\/SnO2) and silver iron oxide (Ag\\/Fe2O3) contact materials is compared to silver zinc oxide (Ag\\/ZnO) materials having different amounts of additives. Endurance tests were performed in a commercial general-purpose relay, subjected to resistive, inductive and inrush current loads. Results showed the performance of Ag\\/ZnO to be significantly dependent on

Thomas J. Schoepf; Volker Behrens; Thomas Honig; Andreas Kraus

2002-01-01

96

Synthetic silver oxide and mercury-free zinc electrodes for silver-zinc reserve batteries  

NASA Astrophysics Data System (ADS)

Reserve activated silver oxide-zinc cells were constructed with synthetic silver oxide (Ag 2O) electrodes with Pb-treated zinc electrodes produced by a non-electrolytic process. The cells were tested before and after thermally accelerated aging. At discharge rates up to 80 mA cm -2, the discharge was limited by the Ag 2O electrode, with a coulombic efficiency between 89-99%. At higher rates, the cells are apparently zinc-limited. Test cells were artificially aged at 90°C for 19 h and discharged at 21°C at 80 mA cm -2. No capacity loss was measured, but a delayed activation rise time was noted (192 ms fresh vs. 567 ms aged). The delay is thought to be caused by zinc passivation due to the outgassing of cell materials.

Smith, David F.; Gucinski, James A.

97

Solvent free synthesis of chalcone and flavanone over zinc oxide supported metal oxide catalysts  

Microsoft Academic Search

Liquid phase Claisen–Schmidt condensation between 2?-hydroxyacetophenone and benzaldehyde to form 2?-hydroxychalcone, followed by intramolecular cyclisation to form flavanone was carried out over zinc oxide supported metal oxide catalysts under solvent free condition. The reaction was carried out over ZnO supported MgO, BaO, K2O and Na2O catalysts with 0.2g of each catalyst at 140°C for 3h. Magnesium oxide impregnated zinc oxide

S. Saravanamurugan; M. Palanichamy; Banumathi Arabindoo; V. Murugesan

2005-01-01

98

Optical properties of aluminum-doped zinc oxide films deposited by direct-current pulse magnetron reactive sputtering  

NASA Astrophysics Data System (ADS)

A series of <103>-oriented aluminum-doped zinc oxide (AZO) films were deposited on glass substrates via direct-current pulse magnetron reactive sputtering at different O2-to-Ar gas flow ratios (GFRs). The optical properties of the films were characterized using the fitted optical constants in the general oscillator model (which contains two Psemi-Tri oscillators) through the use of measured ellipsometric parameters. The refractive index dispersion data below the interband absorption edge were analyzed using a single-oscillator model. The fitted optical energy gap obtained using the single-oscillator model clearly shows a blue shift, followed by a red shift, as the GFR increases from 0.9/18 to 2.1/18. This shift can be attributed to the change in the free electron concentration of the film, which is closely related to the film stress. In addition, the fitted ? value indicates that the AZO film falls under the ionic class. The photoluminescence spectrum indicates a photoluminescence mechanism of the direct and wide energy gap semiconductor.

Gao, Xiao-Yong; Chen, Chao; Zhang, Sa

2014-03-01

99

Fundamentals of zinc oxide as a semiconductor  

NASA Astrophysics Data System (ADS)

In the past ten years we have witnessed a revival of, and subsequent rapid expansion in, the research on zinc oxide (ZnO) as a semiconductor. Being initially considered as a substrate for GaN and related alloys, the availability of high-quality large bulk single crystals, the strong luminescence demonstrated in optically pumped lasers and the prospects of gaining control over its electrical conductivity have led a large number of groups to turn their research for electronic and photonic devices to ZnO in its own right. The high electron mobility, high thermal conductivity, wide and direct band gap and large exciton binding energy make ZnO suitable for a wide range of devices, including transparent thin-film transistors, photodetectors, light-emitting diodes and laser diodes that operate in the blue and ultraviolet region of the spectrum. In spite of the recent rapid developments, controlling the electrical conductivity of ZnO has remained a major challenge. While a number of research groups have reported achieving p-type ZnO, there are still problems concerning the reproducibility of the results and the stability of the p-type conductivity. Even the cause of the commonly observed unintentional n-type conductivity in as-grown ZnO is still under debate. One approach to address these issues consists of growing high-quality single crystalline bulk and thin films in which the concentrations of impurities and intrinsic defects are controlled. In this review we discuss the status of ZnO as a semiconductor. We first discuss the growth of bulk and epitaxial films, growth conditions and their influence on the incorporation of native defects and impurities. We then present the theory of doping and native defects in ZnO based on density-functional calculations, discussing the stability and electronic structure of native point defects and impurities and their influence on the electrical conductivity and optical properties of ZnO. We pay special attention to the possible causes of the unintentional n-type conductivity, emphasize the role of impurities, critically review the current status of p-type doping and address possible routes to controlling the electrical conductivity in ZnO. Finally, we discuss band-gap engineering using MgZnO and CdZnO alloys.

Janotti, Anderson; Van de Walle, Chris G.

2009-12-01

100

Zinc Oxide Nanoparticles for Revolutionizing Agriculture: Synthesis and Applications  

PubMed Central

Nanotechnology is the most innovative field of 21st century. Extensive research is going on for commercializing nanoproducts throughout the world. Due to their unique properties, nanoparticles have gained considerable importance compared to bulk counterparts. Among other metal nanoparticles, zinc oxide nanoparticles are very much important due to their utilization in gas sensors, biosensors, cosmetics, drug-delivery systems, and so forth. Zinc oxide nanoparticles (ZnO NPs) also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture. As far as method of formation is concerned, ZnO NPs can be synthesized by several chemical methods such as precipitation method, vapor transport method, and hydrothermal process. The biogenic synthesis of ZnO NPs by using different plant extracts is also common nowadays. This green synthesis is quite safe and ecofriendly compared to chemical synthesis. This paper elaborates the synthesis, properties, and applications of zinc oxide nanoparticles.

Sabir, Sidra; Arshad, Muhammad

2014-01-01

101

Optical cavity modes of a single crystalline zinc oxide microsphere.  

PubMed

A detailed study on the optical cavity modes of zinc oxide microspheres under the optical excitation is presented. The zinc oxide microspheres with diameters ranging from 1.5 to 3.0 µm are prepared using hydrothermal growth technique. The photoluminescence measurement of a single microsphere shows prominent resonances of whispering gallery modes at room temperature. The experimentally observed whispering gallery modes in the photoluminescence spectrum are compared with theoretical calculations using analytical and finite element methods in order to clarify resonance properties of these modes. The comparison between theoretical analysis and experiment suggests that the dielectric constant of the ZnO microsphere is somewhat different from that for bulk ZnO. The sharp resonances of whispering gallery modes in zinc oxide microspheres cover the entire visible window. They may be utilized in realizations of optical resonators, light emitting devices, and lasers for future chip integrations with micro/nano optoelectronic circuits, and developments of optical biosensors. PMID:23481759

Moirangthem, Rakesh Singh; Cheng, Pi-Ju; Chien, Paul Ching-Hang; Ngo, Buu Trong Huynh; Chang, Shu-Wei; Tien, Chung-Hao; Chang, Yia-Chung

2013-02-11

102

Preparation and properties of transparent conducting zinc oxide and aluminium-doped zinc oxide films prepared by evaporating method  

Microsoft Academic Search

Undoped and aluminium-doped zinc oxide films have been prepared by thermal evaporation of zinc acetate [Zn(CH3COO)2 2H2O] and aluminium chloride [AlCl3] onto a heated glass substrate. The structural and optoelectrical properties of the films have been studied. The effects of heat treatment for the as-deposited films in air and vaccum are investigated. Highly transparent films with conductivity as low as

Jin Ma; Feng Ji; Hong-lei Ma; Shu-ying Li

2000-01-01

103

An evaluation of nanostructured zinc oxide as a fluorescent powder for fingerprint detection  

Microsoft Academic Search

Zinc oxide is evaluated as a fluorescent powder for the detection of fingermarks on non-porous surfaces. Pure and lithium-doped\\u000a nanostructured zinc oxide powders were characterized using scanning electron microscopy, X-ray diffraction, and fluorescence\\u000a spectroscopy. The zinc oxide powders were applied to fresh and aged fingermarks deposited on non-porous surfaces such as glass,\\u000a polyethylene and aluminium foil. Zinc oxide was found

Mi Jung Choi; Katie E. McBean; Ping Hei R. Ng; Andrew M. McDonagh; Philip J. Maynard; Chris Lennard; Claude Roux

2008-01-01

104

Volatile organic compound gas sensor based on aluminum-doped zinc oxide with nanoparticle.  

PubMed

Thick film semiconductor gas sensors based on aluminum-doped zinc oxide (AZO) with nanoparticle size were fabricated to detect volatile organic compound (VOC) existed in building, especially, formaldehyde (HCHO) gas which was known as the cause of sick building syndrome. The sensing materials for screen printing were prepared using roll milling process with binder. The crystallite sizes of prepared materials were about 15 nm through X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Gas response characteristics were examined for formaldehyde (HCHO), benzene, carbon monoxide, carbon dioxide gas existing in building. In particular, the sensors showed responses to HCHO gas at sub ppm as a function of operating temperatures and gas concentrations. Also, we investigated sensitivity, repeativity, selectivity, and response time of sensor. The transients were very sharp, taking less than 2 s for 90% response. The sensor has shown very stable response at 350 degrees C and followed a very good behavior and showed 60% response in 50 ppb HCHO concentration at 350 degrees C operating temperatures. PMID:23882782

Choi, Nak-Jin; Lee, Hyung-Kun; Moon, Seung Eon; Yang, Woo Seok; Kim, Jongdae

2013-08-01

105

Rechargeable silver--zinc batteries. [Pb oxide in Zn electrode reduces H evolution  

Microsoft Academic Search

The evolution of hydrogen in rechargeable silver--zinc batteries is reduced by the incorporation into the zinc electrode of a minor proportion of a lead oxide, e.g., either lead oxide (PbO) or lead dioxide (PbOâ). The invention further relates in general to electrodes for batteries, the electrodes consisting mainly of zinc oxide and having distributed through them.

C. Horowitz; M. Dichter

1978-01-01

106

Zinc oxide microcapsules obtained via a bio-inspired approach  

NASA Astrophysics Data System (ADS)

Hollow zinc oxide microcapsules have been synthesized by a sacrificial template route involving the chemical bath deposition of nanostructured zinc oxide thin films on sulfonate-modified polystyrene microspheres and subsequent removal of the polymer core by dissolution in a solvent or by thermolysis. Scanning electron micrographs show that uniform coating of the templates is achieved when ZnO is deposited from a solution containing zinc acetate, the polymer polyvinylpyrrolidone, and a base in methanol, and that the ZnO shells remain intact after removal of the cores. A focused ion beam is used to cut slices from the spheres and demonstrate their inner morphology and hollowness. X-ray diffraction yields evidence that the shells consist of nanocrystalline ZnO with the zincite structure.

Lipowsky, Peter; Hirscher, Michael; Hoffmann, Rudolf C.; Bill, Joachim; Aldinger, Fritz

2007-04-01

107

Effect of modifying agents on the hydrophobicity and yield of zinc borate synthesized by zinc oxide  

NASA Astrophysics Data System (ADS)

The aim of this study was to synthesize zinc borate using zinc oxide, reference boric acid, and reference zinc borate (reference ZB) as the seed, and to investigate the effects of modifying agents and reaction parameters on the hydrophobicity and yield, respectively. The reaction parameters include reaction time (1-5 h), reactant ratio (H3BO3/ZnO by mass: 2-5), seed ratio (seed crystal/(H3BO3+ZnO) by mass: 0-2wt%), reaction temperature (50-120°C), cooling temperature (10-80°C), and stirring rate (400-700 r/min); the modifying agents involve propylene glycol (PG, 0-6wt%), kerosene (1wt%-6wt%), and oleic acid (OA, 1wt%-6wt%) with solvents (isopropyl alcohol (IPA), ethanol, and methanol). The results of reaction yield obtained from either magnetically or mechanically stirred systems were compared. Zinc borate produced was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and contact angle tests to identify the hydrophobicity. In conclusion, zinc borate is synthesized successfully under the optimized reaction conditions, and the different modifying agents with various solvents affect the hydrophobicity of zinc borate.

Acarali, Nil Baran; Bardakci, Melek; Tugrul, Nurcan; Derun, Emek Moroydor; Piskin, Sabriye

2013-06-01

108

Investigations on solution derived aluminium doped zinc oxide thin films  

Microsoft Academic Search

Aluminium (Al) doped transparent zinc oxide thin films have been successfully grown on sapphire (0001) substrates by an economical chemical solution deposition technique. These films were characterized in terms of their structural, optical, and electrical properties. Detailed XPS analysis of the O1s core level spectra has been carried out for the ZnO films annealed at different temperatures. Lower binding energy

S. B Majumder; M Jain; P. S Dobal; R. S Katiyar

2003-01-01

109

Zinc oxide nanoparticles as selective killers of proliferating cells  

PubMed Central

Background: It has recently been demonstrated that zinc oxide nanoparticles (ZnO NPs) induce death of cancerous cells whilst having no cytotoxic effect on normal cells. However, there are several issues which need to be resolved before translation of zinc oxide nanoparticles into medical use, including lack of suitable biocompatible dispersion protocols and a better understanding being needed of the mechanism of their selective cytotoxic action. Methods: Nanoparticle dose affecting cell viability was evaluated in a model of proliferating cells both experimentally and mathematically. The key issue of selective toxicity of ZnO NPs toward proliferating cells was addressed by experiments using a biological model of noncancerous cells, ie, mesenchymal stem cells before and after cell differentiation to the osteogenic lineage. Results: In this paper, we report a biocompatible protocol for preparation of stable aqueous solutions of monodispersed zinc oxide nanoparticles. We found that the threshold of intracellular ZnO NP concentration required to induce cell death in proliferating cells is 0.4 ± 0.02 mM. Finally, flow cytometry analysis revealed that the threshold dose of zinc oxide nanoparticles was lethal to proliferating pluripotent mesenchymal stem cells but exhibited negligible cytotoxic effects to osteogenically differentiated mesenchymal stem cells. Conclusion: Results confirm the ZnO NP selective cytotoxic action on rapidly proliferating cells, whether benign or malignant. PMID:21698081

Taccola, Liuba; Raffa, Vittoria; Riggio, Cristina; Vittorio, Orazio; Iorio, Maria Carla; Vanacore, Renato; Pietrabissa, Andrea; Cuschieri, Alfred

2011-01-01

110

Process for fabricating doped zinc oxide microsphere gel  

DOEpatents

A new composition and method of making same for a doped zinc oxide microsphere and articles made therefrom for use in an electrical surge arrestor which has increased solid content, uniform grain size and is in the form of a gel.

Arnold, Jr., Wesley D. (Oak Ridge, TN); Bond, Walter D. (Knoxville, TN); Lauf, Robert J. (Oak Ridge, TN)

1991-01-01

111

Synthesis, characterization, and optical properties of zinc oxide nanostructures  

Microsoft Academic Search

Chapter 1. A general introduction is presented that describes the new interdisciplinary field of nanoscience. The various unique properties of nanocrystals are highlighted, and different nanocrystal synthetic techniques are discussed. The importance of a technique that achieves control over nanocrystal size and morphology is stressed. Morphological control over zinc oxide nanocrystals using the \\

Tamar Andelman

2007-01-01

112

Interfacial electron transfer dynamics of photosensitized zinc oxide nanoclusters  

SciTech Connect

The authors have prepared and characterized photosensitized zinc oxide (ZnO) nanoclusters, dispersed in methanol, using carboxylated coumarin dyes for surface adsorption. Femtosecond time-resolved emission spectroscopy allows the authors to measure the photo-induced charge carrier injection rate constant from the adsorbed photosensitizer to the n-type semiconductor nanocluster. These results are compared with other photosensitized semiconductors.

Murakoshi, Kei; Yanagida, Shozo [Osaka Univ. (Japan). Graduate School of Engineering; Capel, M. [Brookhaven National Lab., Upton, NY (United States)] [and others

1997-06-01

113

Photocatalytic degradation for methylene blue using zinc oxide prepared by codeposition and sol-gel methods.  

PubMed

Zinc oxide nanoparticle was obtained by zinc hydrate deposited on the silica nanoparticle surface and zinc hydrate was dispersed in starch gel. The structure of zinc oxide particle was characterized by nitrogen adsorption-desorption and XRD, the morphology was observed by TEM. The result showed that the zinc oxide nanoparticle deposited on the silica nanoparticle surface was well-dispersed and less than 50nm, displayed higher photocatalytic activity for methylene blue degradation. However, the zinc oxide nanoparticle in a size of 60nm was derived from starch gel and showed poorer photocatalytic activity. It provided a simple and effective route to prepare zinc oxide nanoparticle with higher photocatalytic activity through depositing zinc oxide on the silica particle surface, moreover, the catalyst is easier to recover due to its higher density. PMID:17689008

Shen, Wenzhong; Li, Zhijie; Wang, Hui; Liu, Yihong; Guo, Qingjie; Zhang, Yuanli

2008-03-21

114

Tensile strain and water vapor transport testing of flexible, conductive and transparent indium–zinc-oxide\\/silver\\/indium–zinc-oxide thin films  

Microsoft Academic Search

Thin film laminates composed of sputtered indium zinc oxide and silver, optimized for conductance and transparency, were tested for water vapor permeation as well as mechanical durability in tension. The ~82nm thick optimized indium–zinc-oxide\\/silver\\/indium–zinc-oxide (IZO\\/Ag\\/IZO) films were >80% transparent in the visible range (400nm–700nm) with measured sheet resistances less than 5?\\/sq. The water vapor permeation measurements using Ca test methods

Arrelaine A. Dameron; David C. Miller; Nathan George; Bobby To; David S. Ginley; Lin Simpson

2011-01-01

115

Process optimization of Al-doped zinc oxide films as a window layer for Cu(In,Ga)Se2 thin film solar cells  

NASA Astrophysics Data System (ADS)

Al-doped zinc oxide (AZO) thin film was deposited by an in-line pulsed-DC magnetron sputtering system for Cu(In, Ga)Se2 (CIGS) solar cell and optimum process conditions were analyzed. Of several process parameters, oxygen ratio to argon gas in the sputtering ambient was intensively investigated. As increasing the oxygen concentration from 0% to 2%, carrier concentration decreased from 4.8 × 1020 to 9.7 × 1017 cm-3 and Hall mobility reduced from 6.1 to 1.1 cm2/Vs. Resultantly, the resistivity of the AZO film increased significantly from 2.2 × 10-3 up to 5.9 × 10-1 ? cm as increasing the oxygen concentration. This was due to the effect of the scattering mechanism depending on the role of the oxygen in the AZO film. The average transmittance in the range of visible light was lowest as about 74% in the film deposited without oxygen. By the way, the optical band gap was obtained with the most large value of 3.6 eV in the film deposited without oxygen. For examining the feasibility as a window layer, the optimal AZO film deposited without oxygen was applied for making the CIGS solar cell. In this CIGS solar cell, the absorber layer was formed by using the rapid thermal annealing method of CuGa/In metal precursors. The cell was satisfactorily operated with the efficiency of 7.69% even though the cell was not optimized for the buffer layer and the composition of the absorber, and had no metal grids and anti-reflection layer.

Li, Zhao-Hui; Kwon, Sang Jik

2013-11-01

116

Structure control of sputtered zinc oxide films by utilizing zinc oxide seed layers tailored by ion beam assisted sputtering  

Microsoft Academic Search

Reactively sputtered zinc oxide thin films typically exhibit a c-oriented (0 0 0 1) texture of low crystalline order when deposited on unheated substrates. The structural order can be significantly improved upon heating the substrates during deposition. Here it will be demonstrated that by utilizing c-textured seed layers, which are grown by an ion beam assisted sputtering (IBAS) process, films

Dominik Köhl; Gomathi Natarajan; Matthias Wuttig

2012-01-01

117

Zinc sorption by iron oxides and soil samples  

E-print Network

ZINC SORPTION BY IRON OMIDES AND SOIL SAMPLES A Thesis MARKKU JUHANI YLI-HALLA Submitted to the Office of Graduate Studies Texas A&M University in a partial fulfillment of the requirements for the degree of MASTEF. OR SCIENCE May 1989 Majo...'r Subject: Soil Science ZINC SORPTION BY IRON OXIDES AND SOIL SAMPLES A Thesis by MARKKU JUHANI YLI-HALLA Approved as to style and content by: Richard H. Loeppert (Chair of Committee) A. Clearfield (Membe ) Joe B. Dixon (Member) E. C. A. Runge...

Yli-Halla, Markku Juhani

2012-06-07

118

Rapid degradation of zinc oxide nanoparticles by phosphate ions  

PubMed Central

Summary Zinc oxide nanoparticles are highly sensitive towards phosphate ions even at pH 7. Buffer solutions and cell culture media containing phosphate ions are able to destroy ZnO nanoparticles within a time span from less than one hour to one day. The driving force of the reaction is the formation of zinc phosphate of very low solubility. The morphology of the zinc oxide particles has only a minor influence on the kinetics of this reaction. Surface properties related to different production methods and the presence and absence of labelling with a perylene fluorescent dye are more important. Particles prepared under acidic conditions are more resistant than those obtained in basic or neutral reaction medium. Surprisingly, the presence of a SiO2 coating does not impede the degradation of the ZnO core. In contrast to phosphate ions, ?-glycerophosphate does not damage the ZnO nanoparticles. These findings should be taken into account when assessing the biological effects or the toxicology of zinc oxide nanoparticles. PMID:25383310

García-García, F Javier; Reller, Armin

2014-01-01

119

Differences between nanoscale structural and electrical properties of AZO:N and AZO used in polymer light-emitting diodes.  

PubMed

Conducting atomic force microscopy and scanning surface potential microscopy were adopted to investigate the nanoscale surface electrical properties of N-doped aluminum zinc oxide (AZO:N) films that were prepared by pulsed laser deposition (PLD) at various substrate temperatures. Experimental results demonstrated that when the substrate temperature is 150 degrees C and the N(2)O background pressure is 150 mTorr, the N-dopant concentration on the surface is optimal. In addition, the root-mean-square roughness value of the film surface, the low contact current (<400 nA) conducting region as a percentage of the total area, and the mean work function value are 1.43 nm, 96.9%, and 4.88 eV, respectively, all of which are better than those of the optimal AZO film made by PLD. This result indicates that N-doped AZO films are better for use as window materials in polymer light-emitting diodes. PMID:19725067

Chen, Sy-Hann; Yu, Chang-Feng

2010-03-01

120

Ultrathin oxidized Ti to increase stability and smoothness of Al doped ZnO transparent conductors for high efficiency indium-free polymer solar cells  

NASA Astrophysics Data System (ADS)

We propose a transparent electrode consisting of an aluminum doped zinc oxide (AZO) layer capped with an ultrathin oxidized Ti film for indium-free bulk-heterojunction polymer solar cells (PSCs). The oxidized Ti increases the chemical, environmental, stability and the surface smoothness of AZO while still maintaining its electrical and optical properties. The application potential of the proposed transparent electrode is demonstrated in an inverted PSC, which shows an efficiency of 6.3%, very close to the value (7%) obtained in a similar structure using indium tin oxide. This efficiency is the highest reported to date for PSCs incorporating AZO electrodes.

Formica, N.; Ghosh, D. S.; Martinez-Otero, A.; Chen, T. L.; Martorell, Jordi; Pruneri, V.

2013-10-01

121

Zinc recovery from sphalerite concentrate by direct oxidative leaching with ammonium, sodium and potassium persulphates  

Microsoft Academic Search

The recovery of zinc from sphalerite concentrate by oxidative leaching with ammonium, sodium and potassium persulphates in sulphuric acid media is reported in this investigation. Effects of particle size, reaction temperature, acid concentration, pulp density (PD) and oxidant concentration on zinc dissolution rate were determined. The results showed that leaching of 95% zinc was achieved from the concentrate of particle

M. N. Babu; K. K. Sahu; B. D. Pandey

2002-01-01

122

Supermicroporous alumina?silica zinc oxides  

SciTech Connect

A new family of porous mixed oxides with pores largely in the 8-20 {angstrom} range have been prepared. TEOS acts as a solvent and as a source of silica to which aluminum butoxide and transition metal acetates are added. Neutral amines are added as templates and to effect hydrolysis. This paper describes the ZnO-Al{sub 2}O{sub 5}-SiO{sub 2} system but similar results have been obtained with other transition metal oxides. An interesting feature of the technique is that the larger the amine template the greater is the surface area of the mixed oxide with only a slight increase in the average pore diameter. Both NMR and atomic pair distribution functional methods have been used to prove the homogeneity of the mixed oxide products. This preparative method complements our earlier report in Chemical Communications on mixed oxides prepared with ZrO{sub 2} and TiO{sub 2} incorporating transition metal oxides.

Shpeizer, Boris G.; Bakhmutov, Vladimir I.; Clearfield, Abraham (TAM)

2008-09-29

123

Aqueous pathways for the formation of zinc oxide nanoparticles.  

PubMed

We examine the effect of reactant concentrations, temperatures and feeding methods on the morphology of ZnO formed when reacting solutions of ZnSO(4) and NaOH. The catalytic effect of hydroxide in excess relative to the stoichiometric ratio is considered. It is shown that, having fixed other reaction conditions, the end-products, particle structures and size strongly depend on the mole ratio of the precursors. The presence of zinc salt hydroxide species was confirmed at sub-stoichiometric ratios in slightly acidic conditions. At the stoichiometric ratio both zinc hydroxide and zinc oxide are formed, while only zinc oxide forms in an excess of hydroxide. The method of feeding the reactants into the reaction vessel also has a strong influence on the end-product properties, as does the reaction temperature. By control of these parameters the specific surface area could be varied from 10 to 33 m(2) g(-1), the particle shape could be varied from equiaxed, through to star-like and needle-like, and the particle size may be varied from 50 to over 300 nm. PMID:21412544

Moezzi, Amir; Cortie, Michael; McDonagh, Andrew

2011-05-14

124

Electrostatic spray deposited zinc oxide films for gas sensor applications  

NASA Astrophysics Data System (ADS)

In this work, thin films of zinc oxide (ZnO) for gas-sensor applications were deposited on platinum coated alumina substrate, using electrostatic spray deposition (ESD) technique. As precursor solution zinc acetate in ethanol was used. Scanning electron microscopy (SEM) evaluation showed a porous and homogeneous film morphology and the energy dispersive X-ray analysis (EDX) confirmed the composition of the films with no presence of other impurities. The microstructure studied with X-ray diffraction (XRD) and Raman spectroscopy indicated that the ZnO oxide films are crystallized in a hexagonal wurtzite phase. The films showed good sensitivity to 1 ppm nitrogen dioxide (NO 2) at 300 °C while a much lower sensitivity to 12 ppm hydrogen sulphide (H 2S).

Ghimbeu, Camelia Matei; Schoonman, Joop; Lumbreras, Martine; Siadat, Maryam

2007-07-01

125

Influence of doping with third group oxides on properties of zinc oxide thin films  

SciTech Connect

The study of modifications in structural, optical and electrical properties of vacuum evaporated zinc oxide thin films on doping with III group oxides namely aluminum oxide, gallium oxide and indium oxide are reported. It was observed that all the films have transmittance ranging from 85 to 95%. The variation in optical properties with dopants is discussed. On doping the film with III group oxides, the conductivity of the films showed an excellent improvement of the order of 10{sup 3} {Omega}{sup -1} cm{sup -1}. The measurements of activation energy showed that all three oxide doped films have 2 donor levels below the conduction band.

Palimar, Sowmya, E-mail: sowmya0124@gmail.com; Bangera, Kasturi V.; Shivakumar, G. K. [National Institute of Technology Karnataka, Thin Film Laboratory, Physics Department (India)

2013-03-15

126

Photoresponse characteristics of nanostructured aluminum doped Zinc oxide thin films  

Microsoft Academic Search

Aluminium doped Zinc oxide (ZnO) thin films were prepared through sol gel dip coating technique with various doping concentrations from 0 to 1.5 at.%. The thin films were characterized using X-ray Diffractometer (XRD), Field Emission Scanning Electron Microscope (FESEM), UV-Vis-NIR spectrophotometer and current voltage (I-V) measurement system. From the XRD analysis, increasing of doping concentration affected structural properties of the

M. F. Malek; S. A. Arbain; M. H. Mamat; M. Z. Sahdan; M. Z. Musa; Z. Khusaimi; M. Rusop; A. S Rodzi

2011-01-01

127

Zinc oxide nanoparticle and polymer antimicrobial biomaterial composites  

Microsoft Academic Search

Particulate zinc oxide (ZnO) is a known antibacterial agent. Studies show that reducing the size of ZnO particles to nanoscale dimensions further enhances their antibacterial properties. Polymers, like all biomaterials, run the risk of harboring bacteria which may produce an antibiotic-resistant biofilm. The addition of ZnO nanoparticles, to form a composite, may reduce undesirable bacteria activity. The purpose of the

Justin T. Seil; Thomas J. Webster

2010-01-01

128

Tetrapod-like Zinc Oxide Whisker Enhancement of Resin Composite  

Microsoft Academic Search

There is an increasing demand for composite resins with both strong antibacterial activity and satisfactory mechanical properties. This study tested the hypothesis that the new antibacterial agent tetrapod-like zinc oxide whisker (T-ZnOw) could simultaneously enhance the antibacterial activity and mechanical properties of a two-component composite resin. The antibacterial activities of the materials were assessed by the broth dilution test and

L. N. Niu; M. Fang; K. Jiao; L. H. Tang; Y. H. Xiao; L. J. Shen; J. H. Chen

2010-01-01

129

Zinc Oxide Nanostructured Thin Films: Preparation and Characterization  

Microsoft Academic Search

\\u000a The preparation and characterization of zinc oxide (ZnO) nanostructured thin films have been discussed. ZnO, a wide band gap\\u000a semiconductor material, has proven to be of great interest for use in a lot of applications especially in electronics and\\u000a green technology such as solar cells, sensors and light emitting devices. With wide applications by ZnO material, it is important\\u000a to

Mohamad Hafiz Mamat; Mohamad Rusop

130

The use of aluminium doped ZnO as transparent conductive oxide for CdS\\/CdTe solar cells  

Microsoft Academic Search

CdTe\\/CdS and CdTe\\/ZnO thin film solar cells were grown with a high vacuum evaporation based low temperature process (?420°C). Aluminium doped zinc oxide (AZO) was used as transparent conducting oxide (TCO) material. AZO exhibited excellent stability during the solar cell processing, and no significant change in electrical conductivity or transparency was observed. The current density loss due to absorption in

J. Perrenoud; L. Kranz; S. Buecheler; F. Pianezzi; A. N. Tiwari

2011-01-01

131

Durable zinc oxide-containing sorbents for coal gas desulfurization  

DOEpatents

Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

Siriwardane, Ranjani V. (Morgantown, WV)

1996-01-01

132

Nearly full-dense and fine-grained AZO:Y ceramics sintered from the corresponding nanoparticles.  

PubMed

Aluminum-doped zinc oxide ceramics with yttria doping (AZO:Y) ranging from 0 to 0.2 wt.% were fabricated by pressureless sintering yttria-modified nanoparticles in air at 1,300°C. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, a physical property measurement system, and a densimeter were employed to characterize the precursor nanoparticles and the sintered AZO ceramics. It was shown that a small amount of yttria doping can remarkably retard the growth of the as-received precursor nanoparticles, further improve the microstructure, refine the grain size, and enhance the density for the sintered ceramic. Increasing the yttria doping to 0.2 wt.%, the AZO:Y nanoparticles synthetized by a coprecipitation process have a nearly sphere-shaped morphology and a mean particle diameter of 15.1 nm. Using the same amount of yttria, a fully dense AZO ceramic (99.98% of theoretical density) with a grain size of 2.2 ?m and a bulk resistivity of 4.6?×?10-3??·cm can be achieved. This kind of AZO:Y ceramic has a potential to be used as a high-quality sputtering target to deposit ZnO-based transparent conductive films with better optical and electrical properties. PMID:22929049

Yang, Ye; Lan, Pinjun; Wang, Muqin; Wei, Tiefeng; Tan, Ruiqin; Song, Weijie

2012-01-01

133

Nearly full-dense and fine-grained AZO:Y ceramics sintered from the corresponding nanoparticles  

PubMed Central

Aluminum-doped zinc oxide ceramics with yttria doping (AZO:Y) ranging from 0 to 0.2 wt.% were fabricated by pressureless sintering yttria-modified nanoparticles in air at 1,300°C. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction analysis, a physical property measurement system, and a densimeter were employed to characterize the precursor nanoparticles and the sintered AZO ceramics. It was shown that a small amount of yttria doping can remarkably retard the growth of the as-received precursor nanoparticles, further improve the microstructure, refine the grain size, and enhance the density for the sintered ceramic. Increasing the yttria doping to 0.2 wt.%, the AZO:Y nanoparticles synthetized by a coprecipitation process have a nearly sphere-shaped morphology and a mean particle diameter of 15.1 nm. Using the same amount of yttria, a fully dense AZO ceramic (99.98% of theoretical density) with a grain size of 2.2 ?m and a bulk resistivity of 4.6?×?10?3??·cm can be achieved. This kind of AZO:Y ceramic has a potential to be used as a high-quality sputtering target to deposit ZnO-based transparent conductive films with better optical and electrical properties. PMID:22929049

2012-01-01

134

Rare earth doped zinc oxide varistors  

DOEpatents

A varistor includes a Bi-free, essentially homogeneous sintered body of a ceramic composition including, expressed as nominal weight %, 0.2--4.0% oxide of at least one rare earth element, 0.5--4.0% Co{sub 3}O{sub 4}, 0.05--0.4% K{sub 2}O, 0.05--0.2% Cr{sub 2}O{sub 3}, 0--0.2% CaO, 0.00005--0.01% Al{sub 2}O{sub 3}, 0--2% MnO, 0--0.05% MgO, 0--0.5% TiO{sub 3}, 0--0.2% SnO{sub 2}, 0--0.02% B{sub 2}O{sub 3}, balance ZnO. 4 figs.

McMillan, A.D.; Modine, F.A.; Lauf, R.J.; Alim, M.A.; Mahan, G.D.; Bartkowiak, M.

1998-12-29

135

Preparation and characterization of high-transmittance AZO films using RF magnetron sputtering at room temperature  

NASA Astrophysics Data System (ADS)

Aluminum-doped zinc oxide (AZO) thin films with 250 nm thickness had been prepared on soda-lime glass substrate without heated by RF magnetron sputtering using a ceramic target. The microstructure, surface morphology, electrical and optical properties of AZO thin films had been investigated by X-ray diffraction, scanning electron microscope, four-point probe method and optical transmission spectroscopy. The results indicated that all of the films obtained were polycrystalline with a hexagonal structure and oriented with the c-axis perpendicular to the substrate. The resistivity decreased and transmittance improved with the sputtering power increase. The minimum resistivity of 2.55 × 10-3 ? cm combined with highest transmittance of 91% was obtained at a sputtering power of 400 W. The optical bandgap at different sputtering power varied among 3.81-4.04 eV.

Chen, Jian; Sun, Yihua; Lv, Xin; Li, Derong; Fang, Liang; Wang, Hailin; Sun, Xiaohua; Huang, Caihua; Yu, Haizhou; Feng, Ping

2014-10-01

136

An interrogation of the zinc oxide gallium oxide phase space by plasma enhanced chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Polycrystalline metal oxide thin films were deposited by mixing combinations of diethylzinc and trimethylgallium into an oxygen plasma. Plasma-enhanced chemical vapor deposition was shown to be a flexible tool for materials exploration, as the entire zinc-gallium-oxide phase space was explored by simply altering precursor flow rates. Film identification was performed using measurements of intrinsic optical properties as well as X-ray diffraction. The compounds synthesized included zinc oxide, gallium-doped zinc oxide (ZnO:Ga), the spinel ZnGa2O4, and amorphous gallium oxide. A phase diagram was established for PECVD synthesis as a function of the organometallic precursor composition. It was found that gallium addition had a profound impact on both the deposition rate and resistivity of the films. Small levels the gallium addition produced an order of magnitude improvement in both deposition rate and electrical properties. When the gallium fraction was >50% the deposition rate saturated and the films were insulating. Optical emission spectroscopy was used to probe the plasma chemistry of the system. It was shown to be quite complex, typified by the example that decreasing the diethylzinc fraction in the feedstream dramatically increased the density of atomic zinc in the plasma.

Robbins, J. J.; Fry, C.; Wolden, C. A.

2004-03-01

137

An image processing approach to approximating interface textures of microcrystalline silicon layers grown on existing aluminum-doped zinc oxide textures.  

PubMed

We present an algorithm for generating a surface approximation of microcrystalline silicon (?c-Si) layers after plasma enhanced chemical vapor deposition (PECVD) onto surface textured substrates, where data of the textured substrate surface are available as input. We utilize mathematical image processing tools and combine them with an ellipsoid generator approach. The presented algorithm has been tuned for use in thin-film silicon solar cell applications, where textured surfaces are used to improve light trapping. We demonstrate the feasibility of this method by means of optical simulations of generated surface textures, comparing them to simulations of measured atomic force microscopy (AFM) scan data of both Aluminum-doped zinc oxide (AZO, a transparent and conductive material) and ?c-Si layers. PMID:24514939

Hertel, Kai; Hüpkes, Jürgen; Pflaum, Christoph

2013-11-01

138

Highly conducting zinc oxide thin films achieved without postgrowth annealing  

NASA Astrophysics Data System (ADS)

Heavily doped zinc oxide thin films were grown by radio frequency magnetron sputtering. High level of Al doping has been achieved at high growth temperatures (TG), thereby avoiding the need for postgrowth annealing. It is further shown that due to ionized impurity scattering, mobility decreases with increasing TG. Optical transmission spectra show that the bandgap varies from 3.22 to 3.68 eV with increasing Al content due to the combined effect of Burstien-Moss effect and bandgap renormalization.

Singh, Budhi; Khan, Zaheer Ahmed; Khan, Imran; Ghosh, Subhasis

2010-12-01

139

Preparation and characterization of nanostructured zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Thin films of Zinc Oxide (ZnO) were deposited on slide glass substrates by the chemical bath deposition technique (CBD). The formation of nanostructured ZnO thin films have been confirmed through XRD, TEM, and SEM. The structure properties were investigated by XRD. The optical properties were measured by UV-VIS spectrophotometer. The absorption coefficient is calculated from recorded data and it is best fitted for direct band gap. The direct band gap was in range 3.8-4.0 eV.

Abd Elkader, Omar

2012-09-01

140

Diameter control of ultrathin zinc oxide nanofibers synthesized by electrospinning  

PubMed Central

Electrospinning is a versatile technique, which can be used to generate nanofibers from a rich variety of materials. We investigate the variation of a zinc oxide (ZnO)-polyvinylpyrrolidone (PVP) composite structure in morphology by electrospinning from a series of mixture solutions of ZnO sol–gel and PVP. Calcination conditions for the crystallization of ZnO nanofibers and removal of the PVP component from the ZnO-PVP composite nanofibers were also studied. The progression of the ZnO-PVP composite structure from grains to nanofibers was observed, and ZnO-PVP nanofibers as thin as 29.9?±?0.8 nm on average were successfully fabricated. The size of the resultant ZnO-PVP composite nanofibers was considerably affected by two parameters: the concentrations of zinc acetate and PVP in the precursor solution. The concentration of zinc acetate particularly influenced the diameter distribution of the ZnO-PVP nanofibers. The ZnO-PVP nanofibers could be subsequently converted into ZnO nanofibers of a pure wurtzite phase via calcination in air at 500°C for 2 h. PMID:24948890

2014-01-01

141

Preparation and gas-sensitivity of ultra-fine zinc-oxide powders from roasted zinc-blended  

Microsoft Academic Search

Ultra-fine zinc oxide is an important versatile semiconductor material, which has attracted attention for its wide range of applications such as solar cell, luminescent and chemical sensors that detect the combustible or toxic gases by virtue of their high sensitivity and stability [1]. The gas sensing mechanism involves the chemisorption of oxygen on the oxide surface followed by charge transfer

Xun Feng; Zhongjun Li; Peiyuan Wang; Yifeng Zhou

2005-01-01

142

Nonstoichiometric Zinc Oxide and Indium-Doped Zinc Oxide: Electrical Conductivity and 111In-TDPAC Studies  

Microsoft Academic Search

Indium-doped zinc oxide powders have been prepared which show room-temperature electrical conductivities as high as 30 ??1cm?1. The indium doping apparently occurs as Zn1?xInxO, Zn1?yInyO1+y\\/2, or a combination of these. Optimum conductivity occurs for Zn1?xInxO where the maximum value ofxobtained was about 0.5 at%. This substitution results in a lattice volume expansion of 0.4%. The degrees of sample reduction were

Ruiping Wang; Arthur W. Sleight; Roland Platzer; John A. Gardner

1996-01-01

143

The oxidation resistance, hardness and constitution of some intermetallic compounds containing zinc  

Microsoft Academic Search

The majority of the binary compounds of zinc with the metals from titanium to copper inclusive has been prepared, hardness\\u000a tested and oxidized in air at successively higher temperatures. A zinc-ruthenium and some zinc-gadolinium compounds have also\\u000a been tested. From the oxidation results, the temperature corresponding to a weight change of 1 mg cm?2 over 4h was determined by interpolation.

H. E. N. Stone

1976-01-01

144

The oxidation resistance, hardness and constitution of some intermetallic compounds containing zinc  

Microsoft Academic Search

The majority of the binary compounds of zinc with the metals from titanium to copper inclusive has been prepared, hardness tested and oxidized in air at successively higher temperatures. A zinc-ruthenium and some zinc-gadolinium compounds have also been tested. From the oxidation results, the temperature corresponding to a weight change of 1 mg cm-2 over 4h was determined by interpolation.

H. E. N. Stone

1976-01-01

145

Functional behaviour of paper coated with zinc oxide–soluble starch nanocomposites  

Microsoft Academic Search

Zinc oxide (ZnO) is a potential pigment material for paper coating to impart brightness and better printing properties. Nano-ZnO, due to its extremely small size, gives paper coating pigment a high covering power apart from anti-fungal and UV-protecting properties. In this work, zinc oxide–soluble starch nanocomposites (nano-ZnO) was prepared by a simple and novel wet chemical method using zinc nitrate

Virendra Prasad; A. J. Shaikh; A. A. Kathe; D. K. Bisoyi; A. K. Verma; N. Vigneshwaran

2010-01-01

146

Properties of zinc oxide at low and moderate temperatures  

NASA Astrophysics Data System (ADS)

The properties of zinc oxide are examined as an analog of gallium nitride over a wide range of temperatures and possible applications. Its economic and environmental advantages are noted, as well as its radiation hardness, compared to group III nitrides. Methods for growing films and nanostructures with high crystal perfection are proposed. In particular, a magnetron technique for layer-by-layer growth of films is implemented which makes it possible to obtain high structural perfection and substantial thicknesses unattainable by several other methods. The feasibility of producing monochromatic UV radiation from films excited by short-wavelength radiation and electrons is demonstrated; this means that they may be useable as short-wavelength radiation sources. Efficient field emission by ZnO nanostructures and films is demonstrated and opens up the prospect of their use in vacuum microelectronics equipment. Nitrogen-doped ZnO films, in particular, have been used to fabricate a phototransistor with a sensitivity two orders of magnitude higher than conventional detectors. The physical basis for creating LEDs for different colors based on ZnO films and solid solutions with CdO is discussed. The importance of studying the physics and technology of zinc oxide-based devices is emphasized.

Lashkarev, G. V.; Karpyna, V. A.; Lazorenko, V. I.; Ievtushenko, A. I.; Shtepliuk, I. I.; Khranovskyy, V. D.

2011-03-01

147

Zinc oxide nanoparticles as novel alpha-amylase inhibitors  

NASA Astrophysics Data System (ADS)

Amylase inhibitors, also known as starch blockers, contain substances that prevent dietary starches from being absorbed by the body via inhibiting breakdown of complex sugars to simpler ones. In this sense, these materials are projected as having potential applications in diabetes control. In this context, we report on zinc oxide nanoparticles as possible alpha-amylase inhibitors. Zinc oxide nanoparticles have been synthesized using soft-chemistry approach and 1-thioglycerol was used as a surfactant to yield polycrystalline nanoparticles of size ˜18 nm, stabilized in wurtzite structure. Conjugation study and structural characterization have been done using x-ray diffraction technique, Fourier transform infrared spectroscopy, UV-visible spectroscopy, and transmission electron microscopy. Cytotoxicity studies on human fibrosarcoma (HT-1080) and skin carcinoma (A-431) cell lines as well as mouse primary fibroblast cells demonstrate that up to a dose of 20 ?g/ml, ZnO nanoparticles are nontoxic to the cells. We report for the first time the alpha-amylase inhibitory activity of ZnO nanoparticles wherein an optimum dose of 20 ?g/ml was sufficient to exhibit 49% glucose inhibition at neutral pH and 35 °C temperature. This inhibitory activity was similar to that obtained with acarbose (a standard alpha-amylase inhibitor), thereby projecting ZnO nanoparticles as novel alpha-amylase inhibitors.

Dhobale, Sandip; Thite, Trupti; Laware, S. L.; Rode, C. V.; Koppikar, Soumya J.; Ghanekar, Ruchika-Kaul; Kale, S. N.

2008-11-01

148

Preparation and properties of composite particles made by nano zinc oxide coated with titanium dioxide  

Microsoft Academic Search

In this paper, composite particles of nano zinc oxide coated with titanium dioxide were prepared and characterized by TEM, XRD, XPS and FT-IR, and the properties of the composite particles for photo catalysis and light absorption were studied. Tetrabutyl titanate (TBT) was hydrolyzed in an alcoholic suspension of nano zinc oxide with diethanolamine (DEA) as an additive, resulting in a

W. Wu; Y. W. Cai; J. F. Chen; S. L. Shen; A. Martin; L.-X. Wen

2006-01-01

149

Comparative study of aluminium-doped zinc oxide and ruthenium–aluminium co-doped zinc oxide by magnetron co-sputtering  

Microsoft Academic Search

Highly oriented polycrystalline aluminium-doped (Al-doped) and ruthenium–aluminium (Ru–Al) co-doped zinc oxide are prepared on borosilicate glass and polycarbonate (PC) substrates by co-sputtering at room temperature. To investigate the effect of Ru doping, co-sputtering is achieved by varying the sputtering power of Ru target while keeping the sputtering target power of Al-doped zinc oxide unchanged. Atomic force microscopy (AFM) data shows

L. M. Wong; S. J. Wang; W. K. Chim

2010-01-01

150

Scale-up synthesis of zinc borate from the reaction of zinc oxide and boric acid in aqueous medium  

NASA Astrophysics Data System (ADS)

Synthesis of zinc borate was conducted in a laboratory and a pilot scale batch reactor to see the influence of process variables on the reaction parameters and the final product, 2ZnO·3B 2O 3·3.5H 2O. Effects of stirring speed, presence of baffles, amount of seed, particle size and purity of zinc oxide, and mole ratio of H 3BO 3:ZnO on the zinc borate formation reaction were examined at a constant temperature of 85 °C in a laboratory (4 L) and a pilot scale (85 L) reactor. Products obtained from the reaction in both reactors were characterized by chemical analysis, X-ray diffraction, particle size distribution analysis, thermal gravimetric analysis and scanning electron microscopy. The kinetic data for the zinc borate production reaction was fit by using the logistic model. The results revealed that the specific reaction rate, a model parameter, decreases with increase in particle size of zinc oxide and the presence of baffles, but increases with increase in stirring speed and purity of zinc oxide; however, it is unaffected with the changes in the amount of seed and reactants ratio. The reaction completion time is unaffected by scaling-up.

K?l?nç, Mert; Çakal, Gaye Ö.; Ye?il, Sertan; Bayram, Göknur; Ero?lu, ?nci; Özkar, Saim

2010-11-01

151

Genotoxicity and DNA repair processes of zinc oxide nanoparticles.  

PubMed

Two different sizes of zinc oxide nanoparticles (ZnO NP, ? 35 nm and 50-80 nm) were tested in the human lymphoblastoid cell line TK6 to increase our knowledge on their genotoxic potential. The comet assay was the system used, and the results obtained showed that the highest concentration tested (100 ?g/ml) for the two selected compounds was genotoxic. The percent DNA in tail obtained after treatment with ZnO NP (? 35 nm) was significantly higher than that of ZnO NP (50-80 nm) at all concentrations tested. To investigate the nature of the induced genotoxic damage, specific enzymes recognizing oxidized DNA bases were used. Treatments with endonuclease III (Endo III) and formamidopyrimidine DNA glycosylase (FPG) demonstrated that only ZnO NP (50-80 nm) were able to induce significant levels of net oxidative DNA damage. Further DNA repair kinetics studies revealed that DNA damage initially induced was removed in approximately 5 h. DNA damage induced by ZnO NP was repaired more slowly than damage following microparticulated ZnO exposure. No marked differences in repair kinetics of both forms of ZnO NP were observed. Evidence indicates that a high proportion of DNA damage induced by ZnO NP (50-80 nm) correlated with induction of oxidative damage, and that both forms of ZnO NP interfere with mechanisms involved in DNA damage repair. PMID:25268556

Demir, E?ref; Creus, Amadeu; Marcos, Ricard

2014-01-01

152

Non-injection Synthesis of Doped Zinc Oxide Plasmonic Nanocrystals.  

PubMed

Plasmonic metal oxide nanocrystals bridge the optoelectronic gap between semiconductors and metals. In this study, we report a facile, non-injection synthesis of ZnO nanocrystals doped with Al, Ga, or In. The reaction readily permits dopant/zinc atomic ratios of over 15%, is amenable to high precursor concentrations (0.2 M and greater), and provides high reaction yields (>90%). The resulting colloidal dispersions exhibit high transparency in the visible spectrum and a wavelength-tunable infrared absorption, which arises from a dopant-induced surface plasmon resonance. Through a detailed investigation of reaction parameters, the reaction mechanism is fully characterized and correlated to the optical properties of the synthesized nanocrystals. The distinctive optical features of these doped nanocrystals are shown to be readily harnessed within thin films that are suitable for optoelectronic applications. PMID:25136989

Della Gaspera, Enrico; Chesman, Anthony S R; van Embden, Joel; Jasieniak, Jacek J

2014-09-23

153

Structure-dependent mechanical properties of ultrathin zinc oxide nanowires  

PubMed Central

Mechanical properties of ultrathin zinc oxide (ZnO) nanowires of about 0.7-1.1 nm width and in the unbuckled wurtzite (WZ) phase have been carried out by molecular dynamics simulation. As the width of the nanowire decreases, Young's modulus, stress-strain behavior, and yielding stress all increase. In addition, the yielding strength and Young's modulus of Type III are much lower than the other two types, because Type I and II have prominent edges on the cross-section of the nanowire. Due to the flexibility of the Zn-O bond, the phase transformation from an unbuckled WZ phase to a buckled WZ is observed under the tensile process, and this behavior is reversible. Moreover, one- and two-atom-wide chains can be observed before the ZnO nanowires rupture. These results indicate that the ultrathin nanowire possesses very high malleability. PMID:21711876

2011-01-01

154

Doped zinc oxide window layers for dye sensitized solar cells  

NASA Astrophysics Data System (ADS)

The present paper reports the fabrication of dye sensitized solar cell (DSSC), where boron doped ZnO (BZO) and aluminum-boron co-doped ZnO (AZB) thin films were used as front window electrodes. The highly crystalline zinc oxide (ZnO) nanoparticles (NPs) synthesized by the sol-gel route were used as host material for the dye. The efficiencies of the DSSCs formed using the BZO and AZB as window layers were obtained to be 1.56 and 1.84%, respectively. The enhanced efficiency in the case of an AZB window layer based DSSC is attributed to the increase in conductivity induced by co-doping of Al and B and an increase in the number of conducting pathways between the window layer and NPs provided by the nanorods. This facilitates a new approach in the window layer (doped ZnO) for DSSC application.

Kumar, Vinod; Singh, Neetu; Kumar, Vijay; Purohit, L. P.; Kapoor, Avinashi; Ntwaeaborwa, Odireleng M.; Swart, Hendrik C.

2013-10-01

155

Size-dependent antimicrobial response of zinc oxide nanoparticles.  

PubMed

Antibacterial and antifungal activities of zinc oxide nanoparticles (ZnO NPs) were investigated against infectious microorganisms. ZnO NPs were prepared by wet chemical precipitation method varying the pH values. Particle size and morphology of the as-prepared ZnO powders were characterised by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscope. The zone of inhibition by NPs ranged from 0 to 17 mm. The lowest minimum inhibitory concentration value of NPs is 25 µg.ml(-1) against Staphylococcus epidermidis. These studies demonstrate that ZnO NPs have wide range of antimicrobial activities towards various microorganisms. The results obtained in the authors' study indicate that the inhibitory efficacy of ZnO NPs is significantly dependent on its chosen concentration and size. Significant inhibition in antibacterial response was observed for S. epidermidis when compared with control antibiotic. PMID:25014082

Palanikumar, Loganathan; Ramasamy, Sinna Nadar; Balachandran, Chandrasekaran

2014-06-01

156

Stability of zinc oxide nanofluids prepared with aggregated nanocrystalline powders.  

PubMed

Aqueous zinc oxide (ZnO) suspensions were prepared using a two-step preparation method in which an aggregated nanocrystalline ZnO powder was dispersed in water using a polyelectrolyte. The fluid showed anomalously high thermal conductivity when compared with the Maxwell and Hamilton-Crosser predictions. However, analysis of the particle size distribution showed that the fluid contained aggregated 20 nm crystallites of ZnO with a high volume fraction of particles larger than 100 nm. Sedimentation experiments revealed that particles settled out of the stationary fluid over times ranging from 0.1 hours to well over 10,000 hours. The size of the particles remaining in suspension agreed well with predictions made using Stoke's law, suggesting flocculation was not occurring in the fluids. Finally, a new concept of nanofluid stability is introduced based on the height of the fluid, sedimentation, Brownian motion and the kinetic energy of the particles. PMID:19205207

Leonard, J P; Chung, S J; Nettleship, I; Soong, Y; Martello, D V; Chyu, M K

2008-12-01

157

Green Approach for Fabrication and Applications of Zinc Oxide Nanoparticles  

PubMed Central

Zinc oxide nanoparticles (ZnO-NPs) are known to be one of the multifunctional inorganic compounds which are widely used in everyday applications. This study aims to fabricate ZnO-NPs using grapefruit (Citrus paradisi) peel extract with particle size ranging from 12 to 72?nm. Structural, morphological, and optical properties of the synthesized nanoparticles have been characterized by using UV-Vis spectrophotometer, TEM, DLS, and FTIR analysis. They show the significant photocatalytic degradation efficiency (>56%, 10?mg/L, 6?h) against methylene blue and antioxidant efficacy (?80% for 1.2?mM) against 1,1-diphenyl-2-picrylhydrazyl. From the results obtained it is suggested that green ZnO-NPs could be used effectively in environmental safety applications and also can address future medical concerns. PMID:25374484

Smita, Kumari; Cumbal, Luis

2014-01-01

158

High-voltage-gradient zinc oxide varistors: Fabrication and properties  

NASA Astrophysics Data System (ADS)

Zinc oxide varistors have many properties that make them attractive as surge arrestors or voltage limiters in high-voltage power transmission systems. The electrical characteristics are influenced by the ZnO grain size, and reducing the grain size would allow the entire device to be much smaller. The practical advantages of smaller arristors are particularly important for underground transmission lines. Advanced ceramic processing techniques were used to fabricate ZnO varistors having grain sizes in the 3- to 4-(SIGMA)m range, compared to 7 to 13 (SIGMA) m in commercial devices. The fin-grained varistors exhibited high breakdown voltage gradients, compared to commercial materials. Processing steps included synthesis of highly active powders by sol-gel techniques and hot pressing in a reducing environment to achieve high density at temperatures below about 8000 C. Heat treatment in air at temperatures up to 10000 C fully developed the nonohmic electrical properties.

Lauf, R. J.

1983-03-01

159

Zinc Oxide Nanowire Forest for Pool Boiling Heat Transfer  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanowire forest is applied for the electronics cooling by means of pool boiling heat transfer. The forest was composed of lengthwise grown backbone and branched nanowires, which were highly dense and tree-like hierarchical structures. The platinum heater and resistance temperature detector were fabricated by microfabrication on one side of silicon chips and nanowire forest was synthesized on the other side. The superheat and heat flux were evaluated at steady state while the voltage in the heater was increased gradually. The heat flux gradually increased linearly with superheat at the initial stage of heating due to convective heat transfer and abruptly increased once the coolant started to boil. It seemed that the nanowire forest played a role of increased bubble nucleation sites with superhydrophilic nature leading to enhancement of boiling heat transfer. This sheds light on application of nanostructured surface as an effective electronics cooling by boiling heat transfer.

Lee, Dongjin; Kim, Taehyun; Park, Sungsik; Lee, Seung Seob; Ko, Seung Hwan

2012-11-01

160

Physiological characterization of the Arabidopsis thaliana Oxidation-related Zinc Finger 1, a plasma membrane protein involved in oxidative stress  

Microsoft Academic Search

The CCCH-type zinc finger proteins are a superfamily containing tandem zinc-binding motifs involved in many aspects of plant\\u000a growth and development. However, the precise role of these proteins involved in plant stress tolerance is poorly understood.\\u000a This study was to examine the regulatory and functional role of the CCCH-type zinc finger protein, AtOZF1 (At2g19810), under oxidative stress. Interestingly, the AtOZF1

Ping Huang; Moon-Soo Chung; Hyun-Woo Ju; Hyun-Seok Na; Dong Ju Lee; Hyeon-Sook Cheong; Cheol Soo Kim

161

Enhanced omni-directional performance of copper zinc tin sulfide thin film solar cell by gradient index coating  

NASA Astrophysics Data System (ADS)

Many types of thin-film solar cells have a top, transparent conducting oxide (TCO) coating (such as aluminum-doped zinc oxide (AZO)) through which light is transmitted and current collected. In this paper, we demonstrate an effective antireflective coating for TCO surfaces using a gradient index coating formed from co-sputtered AZO and silicon dioxide (SiO2) targets that reduces reflection loss from the TCO. When applied to an active solar device, the power conversion efficiency of the solar cell increased by >10% when measured at normal incidence and >20% at angles 10° or greater.

Ge, Zhongyang; Rajbhandari, Pravakar; Hu, Junjie; Emrani, Amin; Dhakal, Tara P.; Westgate, Charles; Klotzkin, David

2014-03-01

162

Transparent amorphous zinc oxide thin films for NLO applications  

NASA Astrophysics Data System (ADS)

This review focuses on the growth and optical properties of amorphous zinc oxide (ZnO) thin films. A high quality ZnO films fabricated by dip-coating (sol-gel) method were grown on quartz and glass substrates at temperature equal to 350 K. The amorphous nature of the films was verified by X-ray diffraction. Atomic Force Microscopy was used to evaluate the surface morphology of the films. The optical characteristics of amorphous thin films have been investigated in the spectral range 190-1100 nm. Measurement of the polarized optical properties was shows a high transmissivity (80-99%) and low absorptivity (<5%) in the visible and near infrared regions at different angles of incidence. Linear optical properties were investigated by classic and Time-Resolved Photoluminescence (TRPL) measurements. Photoluminescence spectrum exhibits a strong ultraviolet emission while the visible emission is very weak. An innovative TRPL technique has enabled the measurement of the photoluminescence decay time as a function of temperature. TRPL measurements reveal a multiexponential decay behavior typical for amorphous thin films. Second and third harmonic generation measurements were performed by means of the rotational Maker fringe technique using Nd:YAG laser at 1064 nm in picosecond regime for investigations of the nonlinear optical properties. The obtained values of second and third order nonlinear susceptibilities were found to be high enough for the potential applications in the optical switching devices based on refractive index changes. Presented spectra confirm high structural and optical quality of the investigated zinc oxide thin films.

Zawadzka, A.; P?óciennik, P.; Strzelecki, J.; Sahraoui, B.

2014-11-01

163

Band gap energies of solar micro/meso-porous composites of zinc (hydr)oxide with graphite oxides  

NASA Astrophysics Data System (ADS)

The band gap energies of micro/meso-porous zinc (hydr)oxide and its composites with 2 wt. % and 5 wt. % graphite oxides are reported using three optical characterization techniques. The obtained energy gaps (from 2.84 eV to 2.95 eV) of the composites are smaller than that for zinc oxide (˜3.2 eV) and zinc (hydr)oxide (˜3.06 eV). The band gap narrowing of the composite materials is due to the presence of defects, larger particle size, and weaker confinement. The bonds between zinc (hydr)oxide lattice and the carbon of graphene phase also contribute to this phenomenon. The structural properties of these materials are presented using Transmission Electron Microscopy, Scanning Tunneling Electron Microscopy, X-Ray analysis, and Two-Photon Fluorescence imaging Microscopy.

Islam, SM Z.; Gayen, Taposh; Seredych, Mykola; Mabayoje, Oluwaniyi; Shi, Lingyan; Bandosz, Teresa J.; Alfano, Robert R.

2013-07-01

164

Amorphous hafnium-indium-zinc oxide semiconductor thin film transistors  

NASA Astrophysics Data System (ADS)

We developed amorphous hafnium-indium-zinc oxide (HIZO) thin films as oxide semiconductors and investigated the films electrically and physically. Adding of hafnium (Hf) element can suppress growing the columnar structure and drastically decrease the carrier concentration and hall mobility in HIZO films. The thin film transistors (TFTs) with amorphous HIZO active channel exhibit good electrical properties with field effect mobility of around 10 cm2/Vs, S of 0.23 V/decade, and high Ion/off ratio of over 108, enough to operate the next electronic devices. In particular, under bias-temperature stress test, the HIZO TFTs with 0.3 mol % (Hf content) showed only 0.46 V shift in threshold voltage, compared with 3.25 V shift in HIZO TFT (0.1 mol %). The Hf ions may play a key role to improve the instability of TFTs due to high oxygen bonding ability. Therefore, the amorphous HIZO semiconductor will be a prominent candidate as an operation device for large area electronic applications.

Kim, Chang-Jung; Kim, Sangwook; Lee, Je-Hun; Park, Jin-Seong; Kim, Sunil; Park, Jaechul; Lee, Eunha; Lee, Jaechul; Park, Youngsoo; Kim, Joo Han; Shin, Sung Tae; Chung, U.-In

2009-12-01

165

Influence Of pH On The Transport Of Nanoscale Zinc Oxide In Saturated Porous Media  

EPA Science Inventory

Widespread use of nanoscale zinc oxide (nZnO) in various fields causes subsurface environment contamination. Even though the transport of dissolved zinc ions in subsurface environments such as soils and sediments has been widely studied, the transport mechanism of nZnO in such e...

166

Bioavailability of zinc oxide added to corn tortilla is similar to that of zinc sulfate and is not affected by simultaneous addition of iron  

PubMed Central

Background Corn tortilla is the staple food of Mexico and its fortification with zinc, iron, and other micronutrients is intended to reduce micronutrient deficiencies. However, no studies have been performed to determine the relative amount of zinc absorbed from the fortified product and whether zinc absorption is affected by the simultaneous addition of iron. Objective To compare zinc absorption from corn tortilla fortified with zinc oxide versus zinc sulfate and to determine the effect of simultaneous addition of two doses of iron on zinc bioavailability. Methods A randomized, double-blind, crossover design was carried out in two phases. In the first phase, 10 adult women received corn tortillas with either 20 mg/kg of zinc oxide added, 20 mg/kg of zinc sulfate added, or no zinc added. In the second phase, 10 adult women received corn tortilla with 20 mg/kg of zinc oxide added and either with no iron added or with iron added at one of two different levels. Zinc absorption was measured by the stable isotope method. Results The mean (± SEM) fractional zinc absorption from unfortified tortilla, tortilla fortified with zinc oxide, and tortilla fortified with zinc sulfate did not differ among treatments: 0.35 ± 0.07, 0.36 ± 0.05, and 0.37 ± 0.07, respectively. The three treatment groups with 0, 30, and 60 mg/kg of added iron had similar fractional zinc absorption (0.32 ± 0.04, 0.33 ± 0.02, and 0.32 ± 0.05, respectively) and similar amounts of zinc absorbed (4.8 ± 0.7, 4.5 ± 0.3, and 4.8 ± 0.7 mg/day, respectively). Conclusions Since zinc oxide is more stable and less expensive and was absorbed equally as well as zinc sulfate, we suggest its use for corn tortilla fortification. Simultaneous addition of zinc and iron to corn tortilla does not modify zinc bioavailability at iron doses of 30 and 60 mg/kg of corn flour. PMID:23424892

Rosado, Jorge L.; Díaz, Margarita; Muñoz, Elsa; Westcott, Jamie L.; González, Karla E.; Krebs, Nancy F.; Caamaño, María C.; Hambidge, Michael

2013-01-01

167

The insert of zinc oxide thin film in indium tin oxide anode for organic electroluminescence devices q  

E-print Network

consisted of Al as a cathode, Al2O3 as an electro transport layer, Alq3 as a luminously layer, TPD as a holeThe insert of zinc oxide thin film in indium tin oxide anode for organic electroluminescence oxide films were prepared by rf magnetron sputtering on glass substrates with designed ZnO target using

Boo, Jin-Hyo

168

Chemical states and ferromagnetism in heavily Mn-substituted zinc oxide thin films  

NASA Astrophysics Data System (ADS)

A concentration of Manganese as high as 8% was successfully diluted into Zinc Oxide epitaxial films deposited by pulsed laser deposition. The films showed strong ferromagnetism with a large coercivity. Low temperature X-ray absorption spectroscopy measurements indicated that all the Manganese ions substitute for Zinc sites of the wurtzite lattice in the valency of +2. Photoluminescence measurements excluded the presence of Zinc vacancies, as well as Zn interstitials. All the magnetic moments measured were to ascribe to the formation of bound magnetic polarons, with no other contribution due to Manganese-secondary phases or Zinc vacancy-mediated double exchange interaction.

Shao, Q.; Ku, P. S.; Wang, X. L.; Zapien, J. A.; Leung, C. W.; Borgatti, F.; Gambardella, A.; Dediu, V.; Ciprian, R.; Ruotolo, A.

2014-04-01

169

Flexible and monolithic zinc oxide bionanocomposite foams by a bacterial cellulose mediated approach for antibacterial applications.  

PubMed

The use of self-assembled biomacromolecules in the development of functional bionanocomposite foams is one of the best lessons learned from nature. Here, we show that monolithic, flexible and porous zinc oxide bionanocomposite foams with a hierarchical architecture can be assembled through the mediation of bacterial cellulose. The assembly is achieved by controlled hydrolysis and solvothermal crystallization using a bacterial cellulose aerogel as a template in a non-aqueous polar medium. The bionanocomposite foam with a maximum zinc oxide loading of 70 wt% is constructed of intimately packed spheres of aggregated zinc oxide nanocrystals exhibiting a BET surface area of 92 m(2) g(-1). The zinc oxide bionanocomposite foams show excellent antibacterial activity, which give them potential value as self-supporting wound dressing and water sterilization materials. PMID:24647467

Wang, Peipei; Zhao, Jun; Xuan, Ruifei; Wang, Yun; Zou, Chen; Zhang, Zhiquan; Wan, Yizao; Xu, Yan

2014-05-14

170

Biochemistry of mobile zinc and nitric oxide revealed by fluorescent sensors  

E-print Network

Biological mobile zinc and nitric oxide (NO) are two prominent examples of inorganic compounds involved in numerous signaling pathways in living systems. In the past decade, a synergy of regulation, signaling, and translocation ...

Pluth, Michael D.

171

Room temperature fast synthesis of zinc oxide nanowires by inductive heating  

E-print Network

layer and provides rapid Joule heating for nanowire synthesis. Analytically, one can derive each coil% of the Joule heating occurs, is Room temperature fast synthesis of zinc oxide nanowires by inductive heating Lei Luo,a Brian D

Lin, Liwei

172

Transport of Zinc Oxide Nanoparticles in a Simulated Gastric Environment  

NASA Astrophysics Data System (ADS)

Recent years have seen a growing interest in the use of many types of nano sized materials in the consumer sector. Potential uses include encapsulation of nutrients, providing antimicrobial activity, altering texture, or changing bioavailability of nutrients. Engineered nanoparticles (ENP) possess properties that are different than larger particles made of the same constituents. Properties such as solubility, aggregation state, and toxicity can all be changed as a function of size. The gastric environment is an important area for study of engineered nanoparticles because of the varied physical, chemical, and enzymatic processes that are prevalent there. These all have the potential to alter those properties of ENP that make them different from their bulk counterparts. The Human Gastric Simulator (HGS) is an advanced in vitro model that can be used to study many facets of digestion. The HGS consists of a plastic lining that acts as the stomach cavity with two sets of U-shaped arms on belts that provide the physical forces needed to replicate peristalsis. Altering the position of the arms or changing the speed of the motor which powers them allows one to tightly hone and replicate varied digestive conditions. Gastric juice, consisting of salts, enzymes, and acid levels which replicate physiological conditions, is introduced to the cavity at a controllable rate. The release of digested food from the lumen of simulated stomach is controlled by a peristaltic pump. The goal of the HGS is to accurately and repeatedly simulate human digestion. This study focused on introducing foods spiked with zinc oxide ENP and bulk zinc oxide into the HGS and then monitoring how the concentration of each changed at two locations in the HGS over a two hour period. The two locations chosen were the highest point in the lumen of the stomach, which represented the fundus, and a point just beyond the equivalent of the pylorus, which represented the antrum of the stomach. These points were chosen in order to elucidate if and how two different particle sizes of the same material are transported during digestion. Results showed that particles preferentially collected at Location A; time played a minor role in the separation to the two locations while particle size did not play any role.

Mayfield, Ryan T.

173

Heterogeneous transesterification processes by using CaO supported on zinc oxide as basic catalysts  

Microsoft Academic Search

Zinc oxide, obtained by thermal decomposition of zinc oxalate, has been impregnated with different amounts of calcium oxide, and used as solid catalyst for transesterification processes. Catalysts have been characterized by chemical analysis, XRD, XPS, FT-IR, SEM, N2 adsorption–desorption at 77K and CO2-TPD. The catalytic behaviour has been evaluated by choosing two transesterification processes: a simple model such as the

Ana C. Alba-Rubio; José Santamaría-González; Josefa M. Mérida-Robles; Ramón Moreno-Tost; David Martín-Alonso; Antonio Jiménez-López; Pedro Maireles-Torres

2010-01-01

174

XPS and X-ray diffraction studies of aluminum-doped zinc oxide transparent conducting films  

Microsoft Academic Search

Aluminum-doped zinc oxide transparent conducting films are prepared by spray pyrolysis at different dopant concentrations. These films are subsequently characterized by X-ray diffractometric and X-ray photoelectron spectroscopic (XPS) techniques. The results are compared with those obtained from pure zinc oxide films prepared under identical conditions. X-ray diffraction measurements show an increase in lattice parameters (c and a) for aluminum-doped films

T. B. Ghosh; K. L. Chopra; H. N. Acharya

1996-01-01

175

Microfine zinc oxide (Z-Cote) as a photostable UVA\\/UVB sunblock agent  

Microsoft Academic Search

Background: Microfine zinc oxide (Z-Cote) is used as a transparent broad-spectrum sunblock to attenuate UV radiation (UVR), including UVA I (340-400 nm). Objective: Our purpose was to assess the suitability of microfine zinc oxide as a broad-spectrum photoprotective agent by examining those properties generally considered important in sunscreens: attenuation spectrum, sun protection factor (SPF) contribution, photostability, and photoreactivity. Methods: Attenuation

Mark A. Mitchnick; David Fairhurst; Sheldon R. Pinnell

1999-01-01

176

Hermetically sealed silver-zinc batteries operating in the silver \\/I\\/ oxide \\/Ag2O\\/ phase  

Microsoft Academic Search

A detailed report on research and development activities directed toward the production of a hermetically sealed miniature silver-zinc accumulator operating in the pure silver (I) oxide phase. Gas formation in the sealed accumulator, the effect of silver structure on the Ag2O phase size, and electric, life, and storage properties of silver-zinc accumulators operating in the silver (I) oxide phase are

L. Hajdu; J. Zahoran

1974-01-01

177

Kinetics of the reactions of carbon containing zinc oxide composites under microwave irradiation  

Microsoft Academic Search

As a fundamental study for the recycling of EAF dust using microwave heating, the reduction rate of a zinc oxide composite\\u000a by solid carbon under microwave irradiation was investigated. It was found that the reduction of zinc oxide by solid carbon\\u000a under microwave irradiation was much faster than the conventional method, and the activation energy for the reaction under\\u000a microwave

Eunju Kim; Seungyoun Cho; Joonho Lee

2009-01-01

178

Highly sensitive room temperature sensors based on the UV-LED activation of zinc oxide nanoparticles  

Microsoft Academic Search

This study describes novel work on the use of UV-light emitting diodes (LEDs) to enhance the room temperature gas sensitivity of thick film zinc oxide sensors. Sensors based on nanoparticulates of zinc oxide activated with a UV-LED of peak wavelength 400nm and incident light intensity 2.2mW\\/cm2 were capable of detecting acetone and acetaldehyde at extremely low concentrations (1vppb). The same

B. P. J. de Lacy Costello; R. J. Ewen; N. M. Ratcliffe; M. Richards

2008-01-01

179

Preparation and Desulfurization Behavior of Zinc Oxide Based Sorbent for Moderate Temperature  

Microsoft Academic Search

Zinc oxide based moderate-temperature sorbents were obtained by mixing active zinc oxide with other additives, shaping, drying and calcinating in a given order. The influences of preparation conditions on the desulfurization behaviors for the prepared ZnO based desulfurization sorbent were carried out in simulated coal gas using a fixed-bed reactor. The changes of crystal phase before and after desulfurization were

Ju Shangguan; Yousheng Zhao; Huiling Fan; Liang Litong; Fang Shen; Maoqian Miao

2010-01-01

180

Synthesis and characterization of nanostructured zinc oxide layers for sensor applications  

SciTech Connect

Fractal structures and arrays of nanowires based on zinc oxide are fabricated by two different methods, sol-gel dip-coating and chemical bath deposition combined with sol-gel synthesis. The gas-sensitive properties of the structures are analyzed. It is found that the greatest sensitivity to reducing ethanol vapor is exhibited by the structure with a lower layer in the form of an array of zinc-oxide nanowires modified by four immersions in a copper nitrate solution.

Krasteva, L. K.; Dimitrov, D. Tz.; Papazova, K. I.; Nikolaev, N. K.; Peshkova, T. V. [University of Sofia (Bulgaria); Moshnikov, V. A.; Gracheva, I. E., E-mail: iegrachova@mail.ru; Karpova, S. S. [Ul'yanov (Lenin) State Electrotechnical University LETI (Russian Federation); Kaneva, N. V. [University of Sofia (Bulgaria)

2013-04-15

181

Zinc oxide nanowire arrays for silicon core/shell solar cells.  

PubMed

The optics of core / shell nanowire solar cells was investigated. The optical wave propagation was studied by finite difference time domain simulations using realistic interface morphologies. The interface morphologies were determined by a 3D surface coverage algorithm, which provides a realistic film formation of amorphous silicon films on zinc oxide nanowire arrays. The influence of the nanowire dimensions on the interface morphology and light trapping was investigated and optimal dimensions of the zinc oxide nanowire were derived. PMID:24922370

Tamang, Asman; Pathirane, Minoli; Parsons, Rion; Schwarz, Miriam M; Iheanacho, Bright; Jovanov, Vladislav; Wagner, Veit; Wong, William S; Knipp, Dietmar

2014-05-01

182

Chemical stability and electrical performance of dual-active-layered zinc-tin-oxide/indium-gallium-zinc-oxide thin-film transistors using a solution process.  

PubMed

We investigated the chemical stability and electrical properties of dual-active-layered zinc-tin-oxide (ZTO)/indium-gallium-zinc-oxide (IGZO) structures (DALZI) with the durability of the chemical damage. The IGZO film was easily corroded or removed by an etchant, but the DALZI film was effectively protected by the high chemical stability of ZTO. Furthermore, the electrical performance of the DALZI thin-film transistor (TFT) was improved by densification compared to the IGZO TFT owing to the passivation of the pin holes or pore sites and the increase in the carrier concentration due to the effect of Sn(4+) doping. PMID:23738534

Kim, Chul Ho; Rim, You Seung; Kim, Hyun Jae

2013-07-10

183

The role of intracellular zinc release in aging, oxidative stress, and Alzheimer's disease  

PubMed Central

Brain aging is marked by structural, chemical, and genetic changes leading to cognitive decline and impaired neural functioning. Further, aging itself is also a risk factor for a number of neurodegenerative disorders, most notably Alzheimer’s disease (AD). Many of the pathological changes associated with aging and aging-related disorders have been attributed in part to increased and unregulated production of reactive oxygen species (ROS) in the brain. ROS are produced as a physiological byproduct of various cellular processes, and are normally detoxified by enzymes and antioxidants to help maintain neuronal homeostasis. However, cellular injury can cause excessive ROS production, triggering a state of oxidative stress that can lead to neuronal cell death. ROS and intracellular zinc are intimately related, as ROS production can lead to oxidation of proteins that normally bind the metal, thereby causing the liberation of zinc in cytoplasmic compartments. Similarly, not only can zinc impair mitochondrial function, leading to excess ROS production, but it can also activate a variety of extra-mitochondrial ROS-generating signaling cascades. As such, numerous accounts of oxidative neuronal injury by ROS-producing sources appear to also require zinc. We suggest that zinc deregulation is a common, perhaps ubiquitous component of injurious oxidative processes in neurons. This review summarizes current findings on zinc dyshomeostasis-driven signaling cascades in oxidative stress and age-related neurodegeneration, with a focus on AD, in order to highlight the critical role of the intracellular liberation of the metal during oxidative neuronal injury. PMID:24860495

McCord, Meghan C.; Aizenman, Elias

2014-01-01

184

Zinc-oxide charge trapping memory cell with ultra-thin chromium-oxide trapping layer  

SciTech Connect

A functional zinc-oxide based SONOS memory cell with ultra-thin chromium oxide trapping layer was fabricated. A 5 nm CrO{sub 2} layer is deposited between Atomic Layer Deposition (ALD) steps. A threshold voltage (V{sub t}) shift of 2.6V was achieved with a 10V programming voltage. Also for a 2V V{sub t} shift, the memory with CrO{sub 2} layer has a low programming voltage of 7.2V. Moreover, the deep trapping levels in CrO{sub 2} layer allows for additional scaling of the tunnel oxide due to an increase in the retention time. In addition, the structure was simulated using Physics Based TCAD. The results of the simulation fit very well with the experimental results providing an understanding of the charge trapping and tunneling physics.

El-Atab, Nazek; Rizk, Ayman; Nayfeh, Ammar [Institute Center for Microsystems – iMicro, Department of Electrical Engineering and Computer Science (EECS), Masdar Institute of Science and Technology Abu Dhabi (United Arab Emirates)] [Institute Center for Microsystems – iMicro, Department of Electrical Engineering and Computer Science (EECS), Masdar Institute of Science and Technology Abu Dhabi (United Arab Emirates); Okyay, Ali K. [Department of Electrical and Electronics Engineering, Bilkent University, 06800 Ankara (Turkey) [Department of Electrical and Electronics Engineering, Bilkent University, 06800 Ankara (Turkey); UNAM-National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara (Turkey)

2013-11-15

185

Antibacterial effect of zinc oxide nanoparticles combined with ultrasound  

NASA Astrophysics Data System (ADS)

Using Staphylococcus aureus (S. aureus), the present study investigated the antibacterial effect of ZnO nanoparticles both in the absence and presence of ultrasound stimulation. While the antibacterial effect of control nanoparticle chemistries (Al2O3) alone was either weak or unobservable under the conditions tested, the antibacterial effect of ZnO alone was significant, providing over a four log reduction (equivalent to antibiotics) compared to no treatment after just 8 h. The antibacterial effect was enhanced as ZnO particle diameter decreased. Specifically, when testing the antibacterial effect against bacteria populations relevant to infection, a 500 ?g ml-1 dose of zinc oxide nanoparticles with a diameter of 20 nm reduced S. aureus populations by four orders of magnitude after 8 and 24 h, compared to control groups with no nanoparticles. This was accomplished without the use of antibiotics, to which bacteria are developing a resistance anyway. The addition of ultrasound stimulation further reduced the number of viable colony-forming units present in a planktonic cell suspension by 76% compared to nanoparticles alone. Lastly, this study provided a mechanism for how ZnO nanoparticles in the presence of ultrasound decrease bacteria functions by demonstrating greater hydrogen peroxide generation by S. aureus compared to controls. These results indicated that small-diameter ZnO nanoparticles exhibited strong antibacterial properties that can be additionally enhanced in the presence of ultrasound and, thus, should be further studied for a wide range of medical device anti-infection applications.

Seil, Justin T.; Webster, Thomas J.

2012-12-01

186

Attachment of Quantum Dots on Zinc Oxide Nanorods  

NASA Astrophysics Data System (ADS)

ZnO nanorods grown by hydrothermal technique are of great interest for potential applications in photovoltaic and optoelectronic devices. In this study we investigate the optimization of the optical absorption properties by a low temperature, chemical bath deposition technique. Our group fabricated nanorods on indium tin oxide (ITO) substrate with precursor solution of zinc nitrate hexahydrate and hexamethylenetramine (1:1 molar ratio) at 95C for 9 hours. In order to optimize the light absorption characteristics of ZnO nanorods, CdSe/ZnS core-shell quantum dots (QDs) of various diameters were attached to the surface of ZnO nanostructures grown on ITO and gold-coated silicon substrates. Density of quantum dots was varied by controlling the number drops on the surface of the ZnO nanorods. For a 0.1 M concentration of QDs of 10 nm diameter, the PL intensity at 385 nm increased as the density of the quantum dots on ZnO nanostructures was increased. For quantum dots at 1 M concentration, the PL intensity at 385 nm increased at the beginning and then decreased at higher density. We will discuss the observed changes in PL intensity with QD concentration with ZnO-QD band structure and recombination-diffusion processes taking place at the interface.

Seay, Jared; Liang, Huan; Harikumar, Parameswar

2011-03-01

187

Biochemical responses of duckweed (Spirodela polyrhiza) to zinc oxide nanoparticles.  

PubMed

The present study focuses on the biochemical responses of the aquatic plant duckweed (Spirodela polyrhiza L.) to zinc oxide nanoparticles (ZnO NPs). Laboratory experiments were performed using a 96-h exposure to 25-nm NPs at different concentrations (0, 1, 10, and 50 mg/L). Growth, chlorophyll-to-pheophytin ratio (D665/D665a) and activities of superoxide dismutase, catalase, peroxidase (POD), and Na(+), K(+)-ATPase were determined as indices to evaluate the toxicity of NPs in the culture medium. To understand better whether the Zn(2+) released from the ZnO NP suspensions plays a key role in toxicity of the NPs, we investigated particle aggregation and dissolution in the medium. Furthermore, two exposure treatments for the group with the highest concentration (50 mg/L) were performed: (1) exposure for the full 96 h (50a treatment) and (2) the medium being replaced with culture medium without NPs after 12 h (50b treatment). Our results indicate that ZnO NPs induced adverse effects in S. polyrhiza at the concentration of 50 mg/L in the culture medium. Zn(2+) released from the NPs might be the main source of its toxicity to this species. PMID:23271345

Hu, Changwei; Liu, Yimeng; Li, Xiuling; Li, Mei

2013-05-01

188

Stability and structure of hydrogen defects in zinc oxide  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a wide band gap semiconductor with potential optical, electronic, and mechanical applications. First-principles investigations predicted that hydrogen impurities act as shallow donors in ZnO. IR spectroscopy showed that hydrogen exhibits a local vibrational mode at 3326.3 cm -1, at liquid-helium temperatures, corresponding to an O-H type bond. Results from high-pressure and polarized IR spectroscopy strongly suggest that hydrogen occupies an antibonding location with an O-H bond oriented at an angle of 110.6° from the c axis. By correlating the IR absorbance strength with free-electron concentration, it was established that the O-H complexes are shallow donors. However, the O-H donors are unstable, decaying significantly after several weeks at room temperature. The kinetics of the dissociation follow a bimolecular decay model, consistent with the formation of H2 molecules. Attempts at chemical vapor transport (CVT) growth of ZnO crystals were successful. Results varied from Zn-rich, orange-colored samples to nearly colorless ZnO polycrystals. Further analysis revealed an unknown contaminant that became apparent after annealing in hydrogen, resulting in an IR absorption peak at 3150 cm-1.

Jokela, Slade Joseph

189

Structural transformation in nickel doped zinc oxide nanostructures  

SciTech Connect

Graphical abstract: Display Omitted Highlights: ? A systematic study of 1–10% Ni doped ZnO nanostructures (Ni:ZnO NS). ? Effect of Ni concentration on properties of Ni:ZnO NS was intensively investigated. ? Structural transformation in Ni:ZnO NS demonstrated through characterizations. ? Alteration in vibrational modes of Ni:ZnO NS were meticulously analyzed. ? Intricacies of structural evolution, from particles to rods, were comprehended. -- Abstract: In this article, structural transformation in nickel doped zinc oxide nanostructures is reported. The ZnO nanostructures are synthesized with 1–10% of nickel doping through a chemical precipitation method. The undoped and doped nanostructures were systematically investigated employing X-ray diffraction (XRD), transmission and scanning electron microscopy (TEM/SEM), Fourier transform infrared (FTIR) and micro-Raman spectroscopy (?RS). The wurtzite phase of the material and associated lattice parameters were ascertained through XRD analysis. TEM/SEM images reveal the structural transformation of ZnO nanostructures with variation in nickel doping. The study of vibrational modes of nanostructures at different stages of structural transformation, as performed through FTIR and Raman spectroscopy, assist in deciphering the pivotal role of doping concentration in gradual evolution of nickel doped ZnO structure from nanoparticles to nanorods.

Goswami, Navendu, E-mail: navendugoswami@gmail.com [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP 201307 (India)] [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP 201307 (India); Sahai, Anshuman [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP 201307 (India)] [Department of Physics and Materials Science and Engineering, Jaypee Institute of Information Technology, A-10, Sector-62, Noida, UP 201307 (India)

2013-02-15

190

New fabrication of zinc oxide nanostructure thin film gas sensors  

NASA Astrophysics Data System (ADS)

The copper doped zinc oxide thin films have been prepared by sol-gel spin coating method. The structural and morphology properties of the Cu doped films were characterized by X-ray diffraction and atomic force microscope. XRD studies confirm the chemical structure of the ZnO films. The optical spectra method were used to determined optical constants and dispersion energy parameters of Cu doped Zno thin films. The optical band gap of undoped ZnO was found to be 3.16 eV. The Eg values of the films were changed with Cu doping. The refractive index dispersion of Cu doped ZnO films obeys the single oscillator model. The dispersion energy and oscillator energy values of the ZnO films were changed with Cu doping. The Cu doped ZnO nanofiber-based NH3 gas sensors were fabricated. The sensor response of the sensors was from 464.98 to 484.61 when the concentration of NH3 is changed 6600-13,300 ppm. The obtained results indicate that the response of the ZnO film based ammonia gas sensors can be controlled by copper content.

Hendi, A. A.; Alorainy, R. H.

2014-02-01

191

Zinc release from atomic layer deposited zinc oxide thin films and its antibacterial effect on Escherichia coli  

NASA Astrophysics Data System (ADS)

Zinc oxide films have been grown by atomic layer deposition (ALD) at different reaction temperatures and in various thicknesses. Zinc-ion release has been examined from the ZnO films in water and in phosphate buffered saline solution (PBS). Additionally, the antibacterial effect has been studied on Escherichia coli. The thickness of the ZnO film or its crystal orientation did not affect the rate of dissolution. ALD grown aluminum oxide films were deposited on top of the ZnO films and they acted as an effective barrier against zinc dissolution. The bacteriostatic effect was not dependent on the film thickness but both 45 nm and 280 nm thick ZnO films significantly reduced bacterial attachment and growth in dark conditions by 99.7% and 99.5%, respectively. The results indicated that photoirradiation is not required for to enhance antibacterial properties of inorganic films and that the elution of zinc ions is probably responsible for the antibacterial properties of the ZnO films. The duration of the antibacterial effect of ZnO can be controlled by accurate control of the film thickness, which is a feature of ALD, and the onset of the antibacterial effect can be delayed by a time which can be adjusted by controlling the thickness of the Al2O3 blocking layer. This gives the possibility of obtaining dual antibacterial release profiles through a nanolaminate structure of these two materials.

Kääriäinen, M.-L.; Weiss, C. K.; Ritz, S.; Pütz, S.; Cameron, D. C.; Mailänder, V.; Landfester, K.

2013-12-01

192

Total zinc in zinc battery plates by EDTA titration  

Microsoft Academic Search

Zinc battery plate electrodes are analyzed for zinc oxide, zinc chloride, zinc fluoride, zinc carbonate, zinc oxychloride, total zinc, zinc as the metal, and trace metals. A variety of methods are used to determine each of these components. The amount of zinc in each of the zinc compounds is determined by multiplying the percent of the compound by the ratio

Vernon L. Hammersley; Naval Surface

1995-01-01

193

Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell.  

PubMed

Zinc zirconate (ZnZrO(3)) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO(2)) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)(3)](PF(6))(2), [Co(pby)(3)](PF(6))(3), LiClO(4), and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO(3) as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff=56%) compared to ZnO working electrode (ff=40%) under the same condition. PMID:23266694

Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

2013-03-01

194

Device performances of organic light-emitting diodes with indium tin oxide, gallium zinc oxide, and indium zinc tin oxide anodes deposited at room temperature.  

PubMed

Thin films of Indium tin oxide (ITO), Gallium zinc oxide (GZO), and Indium zinc tin oxide (IZTO) were deposited on glass substrates by pulsed direct current magnetron sputtering at room temperature. The structural, optical, and electrical properties of the films were investigated towards evaluating their applications as flexible anodes. IZTO films exhibited the lowest resistivity (6.3 x 10(-4) Omega cm). Organic light-emitting diodes (OLEDs) were fabricated using the ITO, GZO, and IZTO films as anode layers. The turn-on voltages at a current density of 4.5 mA/cm2, 5.5 mA/cm2, 6.5 mA/cm2 were 5.5 V, 13.7 V, and 4.7 V for the devices with ITO, GZO, and IZTO anodes, respectively. The best performance was observed with the IZTO film, indicating its suitability as an alternative material for conventional ITO anodes used in OLEDs and flexible displays. PMID:24266182

Lee, Changhun; Ko, Yoonduk; Kim, Youngsung

2013-12-01

195

Novel nanostructure zinc zirconate, zinc oxide or zirconium oxide pastes coated on fluorine doped tin oxide thin film as photoelectrochemical working electrodes for dye-sensitized solar cell  

NASA Astrophysics Data System (ADS)

Zinc zirconate (ZnZrO3) (ZZ), zinc oxide (ZnO) (ZO) and zirconium oxide (ZrO2) (ZRO) nano-particles were synthesized by simple sol-gel method. ZZ, ZO and ZRO nano-particles were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and UV-Vis diffuse reflectance spectrum (DRS). Nanoporous ZZ, ZO and ZRO thin films were prepared doctor blade technique on the fluorine-doped tin oxide (FTO) and used as working electrodes in dye sensitized solar cells (DSSC). Their photovoltaic behavior were compared with standard using D35 dye and an electrolyte containing [Co(bpy)3](PF6)2, [Co(pby)3](PF6)3, LiClO4, and 4-tert-butylpyridine (TBP). The properties of DSSC have been studied by measuring their short-circuit photocurrent density (Jsc), open-circuit voltage (VOC) and fill factor (ff). The application of ZnZrO3 as working electrode produces a significant improvement in the fill factor (ff) of the dye-sensitized solar cells (ff = 56%) compared to ZnO working electrode (ff = 40%) under the same condition.

Hossein Habibi, Mohammad; Askari, Elham; Habibi, Mehdi; Zendehdel, Mahmoud

2013-03-01

196

Nanomolar concentrations of zinc pyrithione increase cell susceptibility to oxidative stress induced by hydrogen peroxide in rat thymocytes.  

PubMed

Zinc pyrithione is used as an antifouling agent. However, the environmental impacts of zinc pyrithione have recently been of concern. Zinc induces diverse actions during oxidative stress; therefore, we examined the effect of zinc pyrithione on rat thymocytes suffering from oxidative stress using appropriate fluorescent probes. The cytotoxicity of zinc pyrithione was not observed when the cells were incubated with 3 ?M zinc pyrithione for 3 h. However, zinc pyrithione at nanomolar concentrations (10 nM or more) significantly increased the lethality of cells suffering from oxidative stress induced by 3 mM H(2)O(2). The application of zinc pyrithione alone at nanomolar concentrations increased intracellular Zn(2+) level and the cellular content of superoxide anions, and decreased the cellular content of nonprotein thiols. The simultaneous application of nanomolar zinc pyrithione and micromolar H(2)O(2) synergistically increased the intracellular Zn(2+) level. Therefore, zinc pyrithione at nanomolar concentrations may exert severe cytotoxic action on cells simultaneously exposed to chemicals that induce oxidative stress. If so, zinc pyrithione leaked from antifouling materials into surrounding environments would be a risk factor for aquatic ecosystems. Alternatively, zinc pyrithione under conditions of oxidative stress may become more potent antifouling ingredient. PMID:22356860

Oyama, Tomohiro M; Saito, Minoru; Yonezawa, Takayasu; Okano, Yoshiro; Oyama, Yasuo

2012-06-01

197

Zinc  

MedlinePLUS

... condition in which the blood cannot carry enough oxygen. Some signs of copper deficiency have also occurred ... acetate lozenge, providing 9-24 mg elemental zinc, dissolved in the mouth every two hours while awake ...

198

Highly efficient inverted polymer solar cells with reduced graphene-oxide-zinc-oxide nanocomposites buffer layer  

NASA Astrophysics Data System (ADS)

In this study, we reported a 36% improvement in the performance of inverted solar cells as a result of increased short-circuit current (JSC) obtained using a composition of zinc oxide (ZnO) and reduced graphene oxide (RGO) as an n-type buffer layer. RGO-ZnO nanocomposites show higher electron conductivity than intrinsic ZnO; moreover, they show reduced contact resistance at the interface between the active layer and n-type buffer layer. These factors prevent carrier loss resulting from defects and recombinations in the device, thereby significantly increasing the JSC value for the device. Thus, an efficiency of 4.15% was achieved for inverted solar cells with a controlled RGO-ZnO nanocomposites layer.

Woo Lee, Hyun; Young Oh, Jin; Il Lee, Tae; Soon Jang, Woo; Bum Yoo, Young; Sang Chae, Soo; Ho Park, Jee; Min Myoung, Jae; Moon Song, Kie; Koo Baik, Hong

2013-05-01

199

Tunable infrared absorption and visible transparency of colloidal aluminum-doped zinc oxide nanocrystals.  

PubMed

Plasmonic nanocrystals have been attracting a lot of attention both for fundamental studies and different applications, from sensing to imaging and optoelectronic devices. Transparent conductive oxides represent an interesting class of plasmonic materials in addition to metals and vacancy-doped semiconductor quantum dots. Herein, we report a rational synthetic strategy of high-quality colloidal aluminum-doped zinc oxide nanocrystals. The presence of substitutional aluminum in the zinc oxide lattice accompanied by the generation of free electrons is proved for the first time by tunable surface plasmon absorption in the infrared region both in solution and in thin films. PMID:21970407

Buonsanti, Raffaella; Llordes, Anna; Aloni, Shaul; Helms, Brett A; Milliron, Delia J

2011-11-01

200

Impacts of humidity and temperature on the performance of transparent conducting zinc oxide.  

SciTech Connect

The impact of humidity and temperature on a zinc oxide based transparent conducting oxide (TCO) was assessed under accelerated aging conditions. An in situ electroanalytical method was used to monitor the electrical properties for a conducting zinc oxide under controlled atmospheric (humidity, temperature and irradiation) conditions. A review of thin film photovoltaic (PV) literature has shown one major failure mode of cells/modules is associated with the ingress of water into modules in the field. Water contamination has been shown to degrade the performance of the TCO in addition to corroding interconnects and other conductive metals/materials associated with the module. Water ingress is particularly problematic in flexible thin film PV modules since traditional encapsulates such as poly(ethyl vinyl acetate) (EVA) have high water vapor transmission rates. The accelerated aging studies of the zinc oxide based TCOs will allow acceleration factors and kinetic parameters to be determined for reliability purposes.

Granata, Jennifer E.; Yaklin, Melissa A.; Schneider, Duane Allen; Staiger, Chad Lynn; Norman, Kirsten

2010-06-01

201

A novel technique for the deposition of aluminium-doped zinc oxide films  

Microsoft Academic Search

Aluminium-doped zinc oxide is used in many applications as a transparent conductive oxide coating. Such coatings are often deposited by DC reactive sputtering of metallic targets, or RF sputtering of ceramic targets. Both of these techniques have their limitations. In the DC case, alloy targets are expensive and only allow a single composition per target. Additionally, in the RF case,

P. J. Kelly; Y. Zhou; A. Postill

2003-01-01

202

Molecular Orbital Studies of Zinc Oxide Chemical Vapor Deposition: Gas-Phase Radical Reactions  

E-print Network

, intermediate complexes, and products have been optimized with B3LYP/6-31G(d), and energetics have been computed were combined to give a G2(MP2)-like estimate of the enthalpy and free energy. Initiation reactions oxide nanostructures which have unique optical and electrical properties. Zinc oxide nanowires

Schlegel, H. Bernhard

203

Manganese doped Zinc oxide thin film hydrogen gas sensor at reduced operating temperature  

Microsoft Academic Search

During the pas t few decades, semiconductor metal oxide (SMO) gas sensors have become a prime technology in several domestic, commercial, and industrial gas sensing. The semiconductor properties of zinc oxide along with its dopant remain to be trapped fully in its application as gas sensor. With the advent of nanotechnology, miniaturization and high sensitivity happens to be a key

Anjali Chatterjee; Partha Bhattacharjee; P. kumbakar; Nirmal Kumar Roy

2011-01-01

204

Mechanisms of Zinc Oxide Nanocrystalline Thin Film Formation by Thermal Degradation of Metal-Loaded Hydrogels  

E-print Network

,7 Deposition of thin films of ZnO and of other metal oxides represents a key step in most-organic vapor phase epitaxy have proved to be effective in the deposition of high quality thin films of ZnOMechanisms of Zinc Oxide Nanocrystalline Thin Film Formation by Thermal Degradation of Metal

205

Al-doped and undoped zinc oxide fi lms obtained by soft chemistry  

Microsoft Academic Search

Zinc oxide with a hexagonal wurzite type structure is an unique material that exhibits semiconducting, piezo- electric and pyroelectric properties. These properties play a key role for applications in optoelectronic devices. In the present work Al-doped and undoped ZnO fi lms were obtained by soft chemistry starting with zinc acetate dihydrate and Al(III) isopropoxide in absolute ethyl alcohol. Trietanolamine was

Suzana M. Mihaiu; Alexandra Toader; Mihai Anastasescu; Mihai Gabor; Traian Petrisor Jr; Mihai Stoica; Maria Zaharescu

2009-01-01

206

Synthesis and optical properties of strongly-scattering zinc oxide powders  

Microsoft Academic Search

Zinc Oxide (ZnO) colloidal spheres comprising numerous nanocrystallites are synthesized by hydrolysis of zinc acetate dihydrate, Zn(OOCCH3) 2 · 2H2O, in diethylene glycol, HOCH2CH 2OCH2CH2OH. By varying the reaction parameters, it is possible to alter the diameter and crystallite size of the spheres. In addition to in situ control of the crystallite size, it is also possible to grow the

Eric W. Seelig

2003-01-01

207

Comparing Inhaled Ultrafine versus Fine Zinc Oxide Particles in Healthy Adults  

PubMed Central

Rationale: Zinc oxide is a common, biologically active constituent of particulate air pollution as well as a workplace toxin. Ultrafine particles (< 0.1 ?m diameter) are believed to be more potent than an equal mass of inhaled accumulation mode particles (0.1–1.0 ?m diameter). Objectives: We compared exposure–response relationships for respiratory, hematologic, and cardiovascular endpoints between ultrafine and accumulation mode zinc oxide particles. Methods: In a human inhalation study, 12 healthy adults inhaled 500 ?g/m3 of ultrafine zinc oxide, the same mass of fine zinc oxide, and filtered air while at rest for 2 hours. Measurements and Main Results: Preexposure and follow-up studies of symptoms, leukocyte surface markers, hemostasis, and cardiac electrophysiology were conducted to 24 hours post-exposure. Induced sputum was sampled 24 hours after exposure. No differences were detected between any of the three exposure conditions at this level of exposure. Conclusions: Freshly generated zinc oxide in the fine or ultrafine fractions inhaled by healthy subjects at rest at a concentration of 500 ?g/m3 for 2 hours is below the threshold for acute systemic effects as detected by these endpoints. PMID:15735058

Beckett, William S.; Chalupa, David F.; Pauly-Brown, Andrea; Speers, Donna M.; Stewart, Judith C.; Frampton, Mark W.; Utell, Mark J.; Huang, Li-Shan; Cox, Christopher; Zareba, Wojciech; Oberdorster, Gunter

2005-01-01

208

Antidiabetic Activity of Zinc Oxide and Silver Nanoparticles on Streptozotocin-Induced Diabetic Rats  

PubMed Central

The use of nanoparticles in medicine is an attractive proposition. In the present study, zinc oxide and silver nanoparticles were evaluated for their antidiabetic activity. Fifty male albino rats with weight 120 ± 20 and age 6 months were used. Animals were grouped as follows: control; did not receive any type of treatment, diabetic; received a single intraperitoneal dose of streptozotocin (100 mg/kg), diabetic + zinc oxide nanoparticles (ZnONPs), received single daily oral dose of 10 mg/kg ZnONPs in suspension, diabetic + silver nanoparticles (SNPs); received a single daily oral dose of SNP of 10 mg/kg in suspension and diabetic + insulin; received a single subcutaneous dose of 0.6 units/50 g body weight. Zinc oxide and silver nanoparticles induce a significant reduced blood glucose, higher serum insulin, higher glucokinase activity higher expression level of insulin, insulin receptor, GLUT-2 and glucokinase genes in diabetic rats treated with zinc oxide, silver nanoparticles and insulin. In conclusion, zinc oxide and sliver nanoparticles act as potent antidiabetic agents. PMID:24477262

Alkaladi, Ali; Abdelazim, Aaser Mohamed; Afifi, Mohamed

2014-01-01

209

Antidiabetic activity of zinc oxide and silver nanoparticles on streptozotocin-induced diabetic rats.  

PubMed

The use of nanoparticles in medicine is an attractive proposition. In the present study, zinc oxide and silver nanoparticles were evaluated for their antidiabetic activity. Fifty male albino rats with weight 120 ± 20 and age 6 months were used. Animals were grouped as follows: control; did not receive any type of treatment, diabetic; received a single intraperitoneal dose of streptozotocin (100 mg/kg), diabetic + zinc oxide nanoparticles (ZnONPs), received single daily oral dose of 10 mg/kg ZnONPs in suspension, diabetic + silver nanoparticles (SNPs); received a single daily oral dose of SNP of 10 mg/kg in suspension and diabetic + insulin; received a single subcutaneous dose of 0.6 units/50 g body weight. Zinc oxide and silver nanoparticles induce a significant reduced blood glucose, higher serum insulin, higher glucokinase activity higher expression level of insulin, insulin receptor, GLUT-2 and glucokinase genes in diabetic rats treated with zinc oxide, silver nanoparticles and insulin. In conclusion, zinc oxide and sliver nanoparticles act as potent antidiabetic agents. PMID:24477262

Alkaladi, Ali; Abdelazim, Aaser Mohamed; Afifi, Mohamed

2014-01-01

210

Extracellular synthesis of zinc oxide nanoparticle using seaweeds of gulf of Mannar, India  

PubMed Central

Background The biosynthesis of metal nanoparticles by marine resources is thought to be clean, nontoxic, and environmentally acceptable “green procedures”. Marine ecosystems are very important for the overall health of both marine and terrestrial environments. The use of natural sources like Marine biological resources essential for nanotechnology. Seaweeds constitute one of the commercially important marine living renewable resources. Seaweeds such as green Caulerpa peltata, red Hypnea Valencia and brown Sargassum myriocystum were used for synthesis of Zinc oxide nanoparticles. Result The preliminary screening of physico-chemical parameters such as concentration of metals, concentration of seaweed extract, temperature, pH and reaction time revealed that one seaweed S. myriocystum were able to synthesize zinc oxide nanoparticles. It was confirmed through the, initial colour change of the reaction mixture and UV visible spectrophotometer. The extracellular biosynthesized clear zinc oxide nanoparticles size 36 nm through characterization technique such as DLS, AFM, SEM –EDX, TEM, XRD and FTIR. The biosynthesized ZnO nanoparticles are effective antibacterial agents against Gram-positive than the Gram-negative bacteria. Conclusion Based on the FTIR results, fucoidan water soluble pigments present in S. myriocystum leaf extract is responsible for reduction and stabilization of zinc oxide nanoparticles. by this approach are quite stable and no visible changes were observed even after 6 months. These soluble elements could have acted as both reduction and stabilizing agents preventing the aggregation of nanoparticles in solution, extracellular biological synthesis of zinc oxide nanoparticles of size 36 nm. PMID:24298944

2013-01-01

211

Magnetic Mn substituted cobalt zinc ferrite systems: Structural, electrical and magnetic properties and their role in photo-catalytic degradation of methyl orange azo dye  

NASA Astrophysics Data System (ADS)

The present work focuses on the effect of replacement of Fe3+ ions by the Mn3+ ions in cobalt zinc ferrites (Co0.6Zn0.4MnxFe2-xO4 (0.2, 0.4, 0.6, 0.8 and 1.0) on the structural, magnetic, electrical and catalytic properties. Powder X-ray diffraction studies confirmed that all the samples possessed cubic spinel structure with Fd-3m space groups. The saturation magnetization was found to decrease with increase in Mn3+ ions concentration. The drift mobility of all compositions was found to decrease with increase in temperature which could be attributed to the semiconductor nature of nanoferrites. The photo-catalytic activity of all the nanoferrites was evaluated by the degradation of methyl orange dye and it was observed that the degradation of methyl orange dye was enhanced with increase in Mn3+ ions concentration from 0.2 to 1.0. This might be due to the octahedral site preference and higher redox potential of manganese ion as compared those of iron.

Bhukal, Santosh; Bansal, S.; Singhal, Sonal

2014-07-01

212

Oxidative degradation of acid orange 7 using Ag-doped zinc oxide thin films.  

PubMed

Ag-doped ZnO thin films with preferred c-axis orientation along (002) have been prepared by spray pyrolysis technique in aqueous medium on to the corning glass substrates. The effect of Ag-doping on to the photoelectrochemical, structural, morphological, optical, luminescence, electrical and thermal properties has been investigated. XRD and Raman study indicates that the films have hexagonal (wurtzite) crystal structure. The effect of Ag loading on the photocatalytic activity of Ag-doped ZnO in the degradation of azo dye is studied and results are compared with pure ZnO. The results show that the rate of degradation of azo dye over Ag-doped ZnO is much higher as compared to pure ZnO. Ag doping in ZnO is highly effective and can significantly enhance the photocatalytic degradation and mineralization of azo dye. The enhancement of photocatalytic activity of Ag-doped ZnO thin films is mainly due to their smaller crystallite size and capability for reducing the electron-hole pair recombination. Kinetic parameters have been investigated in terms of a first order rate equation. The rate constant (-k) for this heterogeneous photocatalysis is evaluated as a function of the initial concentration of original species. Substantial reduction in azo dye is achieved as analyzed from COD and TOC studies. PMID:23165170

Shinde, S S; Bhosale, C H; Rajpure, K Y

2012-12-01

213

Atomistic Simulation Study of Spinel Oxides: Zinc Aluminate and Zinc Gallate  

E-print Network

of the polycrystalline ZnAl2O4 is 320 nm and of the ZnGa2O4 is 295 nm. The absorbance spectra of these spinels show and tetrahedral sites in the spinel lattice, and energetics of point defects in ZnAl2O4 and ZnGa2O4. II. Method´tica, Universidad de Oviedo, 33006-Oviedo, Spain Stoichiometric zinc aluminate (ZnAl2O4) and zinc gallate (ZnGa2O4

Pandey, Ravi

214

Direct in situ measurement of dissolved zinc in the presence of zinc oxide nanoparticles using anodic stripping voltammetry.  

PubMed

The wide use of metal-based nanomaterials such as zinc oxide (ZnO) nanoparticles (NPs) has generated concerns regarding their environmental and health risks. For ZnO NPs, their toxicity in aquatic systems often depends on the release of dissolved zinc species, and the rate of dissolution is influenced by water chemistry, including the presence of zinc-chelating ligands. A challenge, however, remains in quantifying the dissolution of ZnO NPs, particularly for time scales that are short enough to determine rates. This paper reports the application of anodic stripping voltammetry (ASV) with a hanging mercury drop electrode to directly measure the concentration of dissolved zinc in ZnO NP suspensions, without separation of the ZnO NPs from the aqueous phase. The effects of the deposition time and the electrochemical potential scan rate on the ASV measurement were consistent with expectations for dissolved phase measurements. The dissolved zinc concentration measured by ASV ([Zn]ASV) was compared with that measured by inductively coupled plasma mass spectrometry (ICP-MS) after ultracentrifugation ([Zn]ICP-MS), for four types of ZnO NPs with different coatings and primary particle diameters. For small ZnO NPs (4-5 nm), [Zn]ASV was 20% higher than [Zn]ICP-MS, suggesting that these small NPs contributed to the voltammetric measurement. For larger ZnO NPs (approximately 20 nm), [Zn]ASV was (79 ± 19)% of [Zn]ICP-MS, despite the high concentrations of ZnO NPs in suspension. Using ASV, the dissolution of ZnO NPs was studied, with or without Suwannee River Fulvic Acid (SRFA). Although SRFA diminished the ASV stripping current, dissolution of 20 nm ZnO NPs was significantly promoted at high fulvic acid to ZnO NP ratios. The ASV method described in this paper provides a useful tool for studying the dissolution kinetics of ZnO NPs in complex environmental matrices. PMID:25220562

Jiang, Chuanjia; Hsu-Kim, Heileen

2014-10-20

215

Facile synthesis of zinc hydroxide carbonate flowers on zinc oxide nanorods with attractive luminescent and optochemical performance.  

PubMed

A simple synthesis route was designed to fabricate a functional composite, zinc hydroxide carbonate (ZHC) flowers on zinc oxide (ZnO) nanorods. The hydrolysis of hexamethylenetetramine (HMT) can generate various species which are slowly released and gradually change reaction modes in a Zn(NO(3))(2)/HMT solution. As a result, ZnO nanorods and ZHC flowers can be sequentially synthesized and connect very well under constant experimental conditions. The obtained composite has the advantages of both components and exhibits attractive properties. For instance, ZHC flowers on ZnO nanorods exhibit strong blue emission under the excitation of ultraviolet light, and dye-sensitized solar cells with the annealed composite as photoanode achieve much higher conversion efficiency than pure nanorod arrays. PMID:21543828

Mao, Jing; Li, Jia-Jun; Ling, Tao; Liu, Hui; Yang, Jing; Du, Xi-Wen

2011-06-17

216

Epitaxial aluminum-doped zinc oxide thin films on sapphire. 1: Effect of substrate orientation  

SciTech Connect

Epitaxial thin films of Al-doped zinc oxide have been grown on sapphire substrates by pulsed laser ablation. The effect of substrate temperature, background pressure of oxygen, and substrate orientation (A, M, R, C) on the orientation relationships between ZnO and sapphire have been evaluated using on- and off-axis X-ray diffractometry. Under all growth conditions zinc oxide, on A- and C-plane sapphire, grew with the c-axis perpendicular to the substrate. In contrast, on M and R orientations of sapphire, ZnO grew with its c-axis parallel or perpendicular to the substrate depending on the substrate temperature and background pressure employed during growth. In all cases only one unique in-plane relationship between the sapphire substrate and the zinc oxide film was found with the exception of the M-plane at high substrate temperatures.

Srikant, V.; Sergo, V.; Clarke, D.R. [Univ. of California, Santa Barbara, CA (United States). Materials Dept.

1995-07-01

217

Study of lanthanide doped zinc oxide nanoparticles synthesized via a sonochemical method  

NASA Astrophysics Data System (ADS)

In this work, lanthanide doped zinc oxide nanoparticles synthesized in room-temperature ionic liquid via a sonochemical method have been studied. Firstly, the cavitation bubble temperatures in 1-butyl-3-methylimidazolium hexafluorophosphate (ImPF6) have been estimated by the methyl radical recombination method. The temperatures measured in ImPF6 are in the range of 3000-4000 K. Secondly, a facile method has been proposed to prepare lanthanide (III) doped zinc oxide nanoparticles in ImPF6 via an ultrasonic irradiation. The nanomaterials are studied by transmission electron microscopy, X-ray diffraction, photoacoustic and luminescence techniques. The results show that the relaxation processes of the samples depend strongly on the lanthanide doping. Moreover, a mechanism is proposed to interpret the formation of lanthanide (III) doped zinc oxide nanoparticles in the ImPF6 upon ultrasonic irradiation.

Gao, Bin; Yang, YueTao; Yang, Hao; Zhang, ShuYi; Liu, XiaoJun

2013-07-01

218

Teucrium polium L. extract adsorbed on zinc oxide nanoparticles as a fortified sunscreen  

PubMed Central

Introduction: Zinc oxide nanoparticles (ZnOn) have been used as carriers and sun-protecting agents for Teucrium polium L. extract to enhance sun protection. ZnOn was synthesized by hydrolyzing zinc acetate using sodium hydroxide with mean particle diameter less than 500 nm. Materials and Methods: Top flowerings of T. polium L. were extracted by percolation method with petroleum ether, chloroform, and 80% methanol consecutively. Methanolic extract was lyophilized and used as a flavonoid-rich fraction. Sunscreen was prepared by the reconstitution of 0.5 g of the lyophilized extract in water and mixing with 0.5 to 2 g zinc-oxide (ZnO). Sun protection factor (SPF) of the aqueous extract of T. polium, the prepared gel, as well as the zinc oxide suspension alone and in combination with each other was determined spectrophotometrically based on a modified Transpore® tape method. Results and Conclusion: Obtained results showed that the T. polium extract has a wide band of ultraviolet radiation (UV) spectrum absorption ranging from 250 nm to 380 nm. SPF of the combination product in the ultraviolet B (UVB) area was greater than 80, revealing a synergistic action between ZnO and T. polium. The adsorption of flavonoids of T. polium on Zinc-oxide nanoparticles (ZnOn) slowed down their release thereby lengthening their persistence on the skin and contributing to further duration of action. PMID:24350038

Ansari, Mehdi; Sharififar, Fariba; Kazemipour, Maryam; Sarhadinejad, Zarrin; Mahdavi, Hamid

2013-01-01

219

Synthesis of Silicon and Zinc Oxide Nanowhiskers and Studies of Their Properties  

NASA Astrophysics Data System (ADS)

The conditions and mechanisms for purposeful pattern formation on the surface of single-crystal silicon wafers by building up silicon or zinc oxide by the vapor-liquid-crystal (VLC) mechanism were studied. For the polished silicon surface we developed a procedure for preparation of areas with randomly distributed nanosized gold metal particles - whisker growth initiators. The arrays of randomly distributed silicon and zinc oxide whiskers were grown. The emission cells with a pointed surface pattern were fabricated. The morphology, structure, and field electron emission properties of the fabricated structures were studied.

Gorbyk, P. P.; Dubrovin, I. V.; Dadykin, A. A.; Demchenko, Yu. A.

220

Preparation and Luminescence Properties of Rare Earth Doped Nanostructured Zinc Oxide Thin Films by Sol Gel Technique  

Microsoft Academic Search

Zinc oxide is a semiconductor cosidered promising for optoelectronic and solar cell applications. The wide bandgap nature of the zinc oxide has been a limitation in producing devices. Doping has been considered as one of the ways to reduce the band gap. In the present studies rare earth ions in the form of terbium and erbium nitatres have been introduced

Madzlan Aziz; Sunati Otoi

2009-01-01

221

Influence of the Layer Morphology on the Electrical Properties of Sol Gel Transparent Conducting Oxide Coatings  

Microsoft Academic Search

Tranparent conducting coatings have been prepared by sol gel methods either by a conventional sol-gel process (Antimony doped Tin Oxide—ATO, Aluminium doped Zinc Oxide—AZO) or a new wet chemical process using fully dispersed crystalline nanoparticles (ATO, Indium Tin Oxide—ITO). The dip coating technique has been used as deposition technique with single coating thickness varying from a few nanometer to ca.

Christian Goebbert; Guido Gasparro; Thomas Schuler; Thomas Krajewski; Michel A. Aegerter

2000-01-01

222

Effect of AZO seed layer on electrochemical growth and optical properties of ZnO nanorod arrays on ITO glass  

NASA Astrophysics Data System (ADS)

We report the structural and optical properties of ZnO nanorod arrays (NRAs) grown by an electrochemical deposition process. The ZnO NRAs were grown on indium tin oxide (ITO) coated glass substrates with a thin sputtered Al-doped ZnO (AZO) seed layer and compared with ones directly grown without the seed layer. The growth condition dependence of ZnO NRAs was investigated for various synthetic parameters. The morphology and density of the ZnO NRAs were accordingly controlled by means of zinc nitrate concentration and growth time. From photoluminescence results, the ultraviolet emission was significantly enhanced after thermal treatment. For ZnO NRAs grown on ITO glass without the seed layer, the diffuse transmittance was enhanced despite the reduction in the total transmittance, indicating a high haze value. By using a thin AZO seed layer, the well-aligned ZnO NRAs on AZO/ITO glass are controllably and reproducibly synthesized by varying the growth parameters, exhibiting a total transmittance higher than 91% in the visible wavelength range as well as good optical and crystal quality.

Lee, Hee Kwan; Kim, Myung Sub; Yu, Jae Su

2011-11-01

223

Zinc regulates iNOS-derived nitric oxide formation in endothelial cells  

PubMed Central

Aberrant production of nitric oxide (NO) by inducible NO synthase (iNOS) has been implicated in the pathogenesis of endothelial dysfunction and vascular disease. Mechanisms responsible for the fine-tuning of iNOS activity in inflammation are still not fully understood. Zinc is an important structural element of NOS enzymes and is known to inhibit its catalytical activity. In this study we aimed to investigate the effects of zinc on iNOS activity and expression in endothelial cells. We found that zinc down-regulated the expression of iNOS (mRNA+protein) and decreased cytokine-mediated activation of the iNOS promoter. Zinc-mediated regulation of iNOS expression was due to inhibition of NF-?B transactivation activity, as determined by a decrease in both NF-?B-driven luciferase reporter activity and expression of NF-?B target genes, including cyclooxygenase 2 and IL-1?. However, zinc did not affect NF-?B translocation into the nucleus, as assessed by Western blot analysis of nuclear and cytoplasmic fractions. Taken together our results demonstrate that zinc limits iNOS-derived high output NO production in endothelial cells by inhibiting NF-?B-dependent iNOS expression, pointing to a role of zinc as a regulator of iNOS activity in inflammation. PMID:25180171

Cortese-Krott, Miriam M.; Kulakov, Larissa; Oplander, Christian; Kolb-Bachofen, Victoria; Kroncke, Klaus-D.; Suschek, Christoph V.

2014-01-01

224

Laser prepared organic heterostuctures on glass/AZO substrates  

NASA Astrophysics Data System (ADS)

This paper presents some studies about the bi-layer organic heterostructures realized with zinc phthalocyanine (ZnPc) as donor layer and 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA) as acceptor layer, on substrate of glass covered by Al doped ZnO (AZO) layer. These heterostructures have been prepared using laser techniques: pulsed laser deposition (PLD) in an atmosphere of oxygen for AZO films deposition and matrix assisted pulsed laser evaporation (MAPLE) for organic films deposition. The influence of the deposition conditions on the transmission of the organic films has been analysed. The effect of the oxygen plasma treatment, with duration of 5 min and 10 min, on the surface topography, structural and optical properties of AZO layers deposited by PLD and, as consequence, on the optical and electrical properties of the single layer (ZnPc) and bi-layer (ZnPc/NTCDA) organic heterostructure, deposited by MAPLE, was investigated.

Stanculescu, Anca; Socol, Marcela; Rasoga, Oana; Mihailescu, Ion N.; Socol, Gabriel; Preda, Nicoleta; Breazu, Carmen; Stanculescu, Florin

2014-05-01

225

Doped and Undoped Zinc Oxide Nanostructures on Silicon Wafers  

NASA Astrophysics Data System (ADS)

We present results of hydrothermal deposition of undoped and Al doped ZnO nanocrystals on nanocrystalline silicon. ZnO nanocrystals were deposited in an equimolar zinc nitride and hexamethylenetetramine solution. Aluminum nitride was used as Al precursor. The difference of the morphology of doped and undoped ZnO nanocrystals is discussed. Photoluminescence properties of the obtained nanocrystals are shown.

Chubenko, E.; Bondarenko, V.

2013-05-01

226

Fabrication Process Assessment and Negative Bias Illumination Stress Study of Indium-Gallium-Zinc Oxide and Zinc-Tin Oxide Thin-Film Transistors  

NASA Astrophysics Data System (ADS)

Indium-gallium-zinc oxide (IGZO) and zinc-tin oxide (ZTO) are investigated for thin-film transistor (TFT) applications. Negative bias illumination stress (NBIS) is employed for electrical stability assessment. Unpassivated IGZO and ZTO TFTs suffer from severe NBIS instabilities. Zinc-tin-silicon oxide is found to be an effective passivation layer for IGZO and ZTO TFTs, significantly improving the NBIS stability. NBIS instabilities in unpassivated TFTs are attributed to an NBIS-induced desorption of chemisorbed oxygen from the channel layer top surface, exposing surface oxygen vacancies. A ZTSO layer protects the channel layer top surface from adsorbed gas interactions and also appears to reduce the density of oxygen vacancies. The best device architectures investigated with respect to TFT electrical performance are found to be staggered with aluminum electrodes for unpassivated TFTs and coplanar with ITO electrodes for ZTSO-passivated TFTs. Annealing in wet-O2 is not found to be effective for improving the performance of IGZO or ZTO TFTs or for reducing the post-deposition annealing temperature.

Hoshino, Ken

227

The production of zinc by thermal dissociation of zinc oxide—solar chemical reactor design  

Microsoft Academic Search

We describe the design, fabrication, and preliminary test of a novel solar chemical reactor for conducting the thermal dissociation of ZnO into zinc and oxygen at above 2000 K. The reactor configuration features a windowed rotating cavity-receiver lined with ZnO particles that are held by centrifugal force. With this arrangement, ZnO is directly exposed to high-flux solar irradiation and serves

P. Haueter; S. Moeller; R. Palumbo; A. Steinfeld

1999-01-01

228

An interrogation of the zinc oxide–gallium oxide phase space by plasma enhanced chemical vapor deposition  

Microsoft Academic Search

Polycrystalline metal oxide thin films were deposited by mixing combinations of diethylzinc and trimethylgallium into an oxygen plasma. Plasma-enhanced chemical vapor deposition was shown to be a flexible tool for materials exploration, as the entire zinc–gallium-oxide phase space was explored by simply altering precursor flow rates. Film identification was performed using measurements of intrinsic optical properties as well as X-ray

J. J. Robbins; C. Fry; C. A. Wolden

2004-01-01

229

The cytotoxic effects of titanium oxide and zinc oxide nanoparticles oh Human Cervical Adenocarcinoma cell membranes  

NASA Astrophysics Data System (ADS)

The importance of titanium dioxide (TiO2) and zinc oxide (ZnO), inorganic metal oxides nanoparticles (NPs) stems from their ubiquitous applications in personal care products, solar cells and food whitening agents. Hence, these NPs come in direct contact with the skin, digestive tracts and are absorbed into human tissues. Currently, TiO2 and ZnO are considered safe commercial ingredients by the material safety data sheets with no reported evidence of carcinogenicity or ecotoxicity, and do not classify either NP as a toxic substance. This study examined the direct effects of TiO2 and ZnO on HeLa cells, a human cervical adenocarcinonma cell line, and their membrane mechanics. The whole cell patch-clamp technique was used in addition to immunohistochemistry staining, TEM and atomic force microscopy (AFM). Additionally, we examined the effects of dexamethasone (DXM), a glucocorticoid steroid known to have an effect on cell membrane mechanics. Overall, TiO2 and ZnO seemed to have an adverse effect on cell membrane mechanics by effecting cell proliferation, altering cellular structure, decreasing cell-cell adhesion, activating existing ion channels, increasing membrane permeability, and possibly disrupting cell signaling.

Mironava, Tatsiana; Applebaum, Ariella; Applebaum, Eliana; Guterman, Shoshana; Applebaum, Kayla; Grossman, Daniel; Gordon, Chris; Brink, Peter; Wang, H. Z.; Rafailovich, Miriam

2013-03-01

230

Cytogenetic and genotoxic effects of zinc oxide nanoparticles on root cells of Allium cepa  

Microsoft Academic Search

Increasing use of zinc oxide nanoparticles (ZnO NP) in consumer products may enhance its release into the environment. Phytotoxicity study is important to understand its possible environmental impact. Allium cepa (Onion bulb) is the best model organism to study genetic toxicology of nanoparticles. Here we have reported cytogenetic and genotoxic effects of ZnO NPs on the root cells of A.

Mamta Kumari; S. Sudheer Khan; Sunandan Pakrashi; Amitava Mukherjee; Natarajan Chandrasekaran

2011-01-01

231

LASER ABLATION SYNTHESIS OF ZINC OXIDE CLUSTERS: A NEW FAMILY OF FULLERENES?  

E-print Network

1 LASER ABLATION SYNTHESIS OF ZINC OXIDE CLUSTERS: A NEW FAMILY OF FULLERENES? Alexander V to fullerenes. A local abundance minimum at n = 13 provides an additional evidence for the presence in the ablation plume of fullerene-like (ZnO)n clusters. #12;2 Recently much interest has been shown in Zn

Paris-Sud XI, Université de

232

Influence of the doping and annealing atmosphere on zinc oxide thin films deposited by spray pyrolysis  

Microsoft Academic Search

Undoped and doped (indium and aluminium) zinc oxide (ZnO) thin films have been prepared by spray pyrolysis, and the effect of the doping and annealing atmosphere on the electrical, optical and structural properties of the produced films has been investigated. The deposited films have a high resistivity. Annealing the films in an argon atmosphere or under vacuum leads to a

P Nunes; A Malik; B Fernandes; E Fortunato; P Vilarinho; R Martins

1999-01-01

233

Effect of aluminium doping on zinc oxide thin films grown by spray pyrolysis  

Microsoft Academic Search

We report the structural, optical, and electrical characterization of aluminium-doped zinc oxide thin films grown by the spray pyrolysis method. We report the effect of Al concentration on the resistivity and on the X-ray diffraction, transmittance, photoluminescence and Raman scattering spectra of the films. The minimum resistivity is obtained for the sample with nominal Al concentration of 1%. An increase

A. El Manouni; F. J. Manjón; M. Mollar; B. Marí; R. Gómez; M. C. López; J. R. Ramos-Barrado

2006-01-01

234

Degradation of wastewaters containing organic dyes photocatalysed by zinc oxide: a review  

Microsoft Academic Search

Organic dyes are one of the largest groups of pollutants discharged into wastewaters from textile and other industrial processes. Owing to the potential toxicity of the dyes and their visibility in surface waters, removal and degradation of them have attracted considerable attention worldwide. A wide range of approaches have been developed, amongst which the heterogeneous photocatalysis involving zinc oxide (ZnO)

Sze-Mun Lam; Jin-Chung Sin; Ahmad Zuhairi Abdullah; Abdul Rahman Mohamed

2012-01-01

235

Synthesis of zinc oxide nanorods in ionic liquid via ultrasonic irradiation  

Microsoft Academic Search

Zinc oxide is a versatile material that has achievable applications in piezoelectric transducers, nanogenerators, transparent electrodes and etc. Currently, sonochemical processes have been proved to be a useful technique for generating various nanostructured materials. In this work, we have developed a method for the synthesis of ZnO nanostructures, by combining the advantages of both ionic liquid and ultrasound. A simple

Hai-yan Wang; Yue-tao Yang; Xiao-jun Liu; Shu-yi Zhang

2009-01-01

236

Effect of iron oxide coatings on zinc sorption mechanisms at the clay-mineral\\/water interface  

Microsoft Academic Search

Oxide surface coatings are ubiquitous in the environment, but their effect on the intrinsic metal uptake mechanism by the underlying mineral surface is poorly understood. In this study, the zinc (Zn) sorption complexes formed at the kaolinite, goethite, and goethite-coated kaolinite surfaces, were systematically studied as a function of pH, aging time, surface loading, and the extent of goethite coating,

Maarten Nachtegaal; Donald L. Sparks

2004-01-01

237

A pillared-layered zincoborate with an anionic network containing unprecedented zinc oxide chains.  

PubMed

A semiconducting zincoborate with a pillared-layered structure, has been prepared under solvothermal conditions, showing the first example of an inorganic-organic hybrid zincoborate with an anionic network based on the interesting zinc oxide chains linked by boron atoms and B3O7H2 clusters, which are further pillared by diamine molecules to form the 3-D framework. PMID:24566611

Zhao, Pei; Lin, Zhi-En; Wei, Qi; Cheng, Lin; Yang, Guo-Yu

2014-04-01

238

The antimicrobial sensitivity of Streptococcus mutans to nanoparticles of silver, zinc oxide, and gold  

Microsoft Academic Search

Dental caries is a worldwide public health problem for which Streptococcus mutans has been identified as the possible infectious etiology. In recent years nanotechnology has permitted the development of new properties of materials. The objective of this study was to compare the bactericidal and bacteriostatic effects of nanoparticles of silver, zinc oxide, and gold on S. mutans. We used the

Juan Francisco Hernández-Sierra; Facundo Ruiz; Diana Corina Cruz Pena; Fidel Martínez-Gutiérrez; Alberto Emilio Martínez; Amaury de Jesús Pozos Guillén; Humberto Tapia-Pérez; Gabriel Martínez Castañón

2008-01-01

239

Novel Zinc Oxide Nanostructured thin Films for Volatile Organic Compaunds Gas Sensors  

Microsoft Academic Search

Novel zinc oxide nanostructured thin films have been obtained by chemical deposition technique and rapid photothermal processing (RPP). ZnO nanostructures were studied for the development of volatile organic compounds (VOC) sensors. The investigations results indicate that by RPP is possible to control the sensing properties and operating temperature. A correlation taking into account the nanostructure of the material, the effects

T. Shishiyanu; S. Shishiyanu; O. Lupan; V. Ontea; A. Bragorenco

2006-01-01

240

Aging in chemically prepared divalent silver oxide electrodes for silver\\/zinc reserve batteries  

Microsoft Academic Search

The instability of silver(II) oxide electrodes used in silver\\/zinc reserve batteries is the well known cause of capacity loss and delayed activation in reserve batteries after they are stored in the dry, unactivated state for extended periods of time. Metal contaminants in sintered\\/electroformed electrodes destabilize the oxide and the solid state reaction between AgO and elemental silver results in the

David F. Smith; Curtis Brown

2001-01-01

241

Zinc and silver recoveries from zinc–lead–iron complex sulphides by pressure oxidation  

Microsoft Academic Search

Acid pressure oxidation followed by cyanide leaching of the residue is a promising process for the treatment of complex sulphides and the recovery of precious metals along with the base metals will improve the economy of the process. However, silver is incorporated into the jarosite specie during the pressure oxidation and cyanide leaching of the residue yields very low silver

S. A Bolorunduro; D. B Dreisinger; G Van Weert

2003-01-01

242

Surface morphology and electrical transport of rapid thermal annealed chromium-doped indium zinc oxides: The influence of zinc interstitials and out-diffusion  

NASA Astrophysics Data System (ADS)

We investigate the complex impedance (CI) spectra of chromium-doped indium zinc oxide (CIZO) films with different rapid thermal annealing (RTA) temperatures. The CI spectra drawn from the impedance contributions of Zn-O and In-O bondings in CIZO films were analyzed by two sets of parallel resistance and capacitance components in series. The result demonstrates that zinc interstitials controls electron concentration and transition of electrical transport from semiconducting to metallic. At higher RTA temperature, high-density zinc interstitial promotes Zn atom diffusion from the surface, modifying surface morphology.

Hsu, C. Y.

2013-12-01

243

Surface morphology and electrical transport of rapid thermal annealed chromium-doped indium zinc oxides: The influence of zinc interstitials and out-diffusion  

SciTech Connect

We investigate the complex impedance (CI) spectra of chromium-doped indium zinc oxide (CIZO) films with different rapid thermal annealing (RTA) temperatures. The CI spectra drawn from the impedance contributions of Zn-O and In-O bondings in CIZO films were analyzed by two sets of parallel resistance and capacitance components in series. The result demonstrates that zinc interstitials controls electron concentration and transition of electrical transport from semiconducting to metallic. At higher RTA temperature, high-density zinc interstitial promotes Zn atom diffusion from the surface, modifying surface morphology.

Hsu, C. Y., E-mail: cyhsu00@gmail.com [Physics Department, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China)

2013-12-09

244

Zinc oxide and metal phthalocyanine based hybrid P-N junction diodes  

NASA Astrophysics Data System (ADS)

Hybrid p-n junction diode based on zinc oxide (ZnO) and metal phthalocyanine (MePc) has been demonstrated using highly conducting Al doped ZnO as transparent electrode. Three different MePcs: copper phthalocyanine, zinc phthalocyanine (ZnPc), and cobalt phthalocyanine are used as p-type layer in hybrid p-n junction. It is found that most desirable performance can be achieved in ZnO/ZnPc based hybrid p-n junction. The depletion region in hybrid p-n junctions has been measured using current-voltage and capacitance-voltage characteristics.

Singh, Budhi; Ghosh, Subhasis

2013-09-01

245

Morphology of nanometric size particulate aluminium-doped zinc oxide films  

Microsoft Academic Search

Aluminium-doped zinc oxide films were prepared through an alcoholic sol–gel route using Zn(CH3COO)2?·?2H2O as non-alcoxide precursor. Al(NO3)3?·?9H2O was used as dopant with an aluminium to zinc ratio of 5% (mol). Lactic acid was used as the hydrolysis promoter. Acetylacetone and diethanolamine were used as additives to improve film homogeneity. The dip-coating process was used for the sol transfer. The chemical

Rodrigo F Silva; Maria E. D Zaniquelli

2002-01-01

246

Synthesis of Styrene Carbonate from Carbon Dioxide and Styrene Oxide with Various Zinc Halide-Based Ionic Liquids  

Microsoft Academic Search

\\u000a Abstract  Various zinc halide-based ionic liquids were prepared from zinc halides and onium halides as catalysts for the synthesis of\\u000a styrene carbonate (SC) from styrene oxide and carbon dioxide. The effects of the ionic liquid catalyst composition (types\\u000a of onium cation and halide, onium cation\\/zinc ratio) and CO2 pressure on the reaction were investigated. The effectiveness of the onium cation as

Shin-ichiro Fujita; Masahiro Nishiura; Masahiko Arai

2010-01-01

247

Investigation of phosphorus and arsenic as dopants in polycrystalline thin films of zinc oxide  

NASA Astrophysics Data System (ADS)

The use of implanted phosphorus and arsenic has been systematically investigated and compared with implanted boron as n-type dopants in thin films of polycrystalline zinc oxide. For a given heat-treatment schedule and without fluorine co-doping, the steady-state resistivity of the phosphorus-doped ZnO is found to be consistently lower than that of the boron-doped ZnO. Both are in turn lower than that of the arsenic-doped ZnO. A resistivity of 3 m? cm has been obtained for a phosphorus dose of 1016/cm2, if activated at 500 °C for 5 min in nitrogen. Direct exposure to an oxidizing ambience during a heat-treatment resulted in an increase in the resistivity of the phosphorus- or arsenic-doped zinc oxide thin films. However, the kinetics of the oxidation and reduction of arsenic in zinc oxide are found to be significantly slower than those of phosphorus or boron. Thin-film transistors with self-aligned phosphorus-doped source/drain regions and channel-lengths as short as 2 ?m have been realized and characterized.

Ye, Zhi; Wong, Man

2013-01-01

248

40 CFR 721.9538 - Lithium salt of sulfophenyl azo phenyl azo disulfostilbene (generic).  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2011-07-01 false Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...Specific Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...chemical substance identified generically as lithium salt of sulfophenyl azo phenyl...

2011-07-01

249

40 CFR 721.9538 - Lithium salt of sulfophenyl azo phenyl azo disulfostilbene (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 2012-07-01 false Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...Specific Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...chemical substance identified generically as lithium salt of sulfophenyl azo phenyl...

2012-07-01

250

Nuclear microprobe investigation of the penetration of ultrafine zinc oxide into intact and tape-stripped human skin  

NASA Astrophysics Data System (ADS)

Ultrafine metal oxides, such as titanium dioxide and zinc oxide are widely used in cosmetic and health products like sunscreens. These oxides are potent UV filters and the small particle size makes the product more transparent compared to formulations containing coarser particles. In the present work the penetration of ultrafine zinc oxide into intact and tape-stripped human skin was investigated using nuclear microprobe techniques, such as proton induced X-ray spectroscopy and scanning transmission ion microscopy. Our results indicate that the penetration of ultrafine zinc oxide, in a hydrophobic basis gel with 48 h application time, is limited to the stratum corneum layer of the intact skin. Removing the stratum corneum partially or entirely by tape-stripping did not cause the penetration of the particles into the deeper dermal layers; the zinc particles remained on the surface of the skin.

Szikszai, Z.; Kertész, Zs.; Bodnár, E.; Major, I.; Borbíró, I.; Kiss, Á. Z.; Hunyadi, J.

2010-06-01

251

Electrical, electronic and optical properties of amorphous indium zinc tin oxide thin films  

NASA Astrophysics Data System (ADS)

The electrical and optical properties of amorphous indium zinc tin oxide (a-IZTO) thin films were examined as a function of chemical composition. Effects of Sn/Zn composition ratio and In content on the electrical and optical properties of a-IZTO thin films are discussed. The electron mobility of thin film transistors with higher Sn/Zn composition ratio was dramatically improved due to a shorter zinc-zinc separation distance. The thin film transistor with the composition of In:Zn:Sn = 20:48:32 exhibits a high mobility of 30.6 cm2 V-1 s-1 and a high on-off current ratio of 109.

Denny, Yus Rama; Lee, Kangil; Seo, Soonjoo; Oh, Suhk Kun; Kang, Hee Jae; Yang, Dong Seok; Heo, Sung; Chung, Jae Gwan; Lee, Jae Cheol

2014-10-01

252

Polymer light-emitting diodes with amorphous indium-zinc oxide anodes deposited at room temperature  

Microsoft Academic Search

The authors report on the performance of polymer-based light-emitting diodes, LEDs, using amorphous zinc oxide-doped indium oxide, IZO, as anode. In particular, LEDs with poly[(2-methoxy-5-(2?-ethyl-hexyloxy)-1,4-phenylene vinylene] as electroluminescent layer and aluminium cathodes, show higher efficiency with this IZO anode (0.015cd\\/A) than with indium-tin oxide (ITO) (0.010cd\\/A). Inspite of the higher resistance of this IZO electrode, compared with ITO, the fact

Gabriel Bernardo; Gonçalo Gonçalves; Pedro Barquinha; Quirina Ferreira; Graça Brotas; Luís Pereira; Ana Charas; Jorge Morgado; Rodrigo Martins; Elvira Fortunato

2009-01-01

253

Mechanistic aspects of molecular formation and crystallization of zinc oxide nanoparticles in benzyl alcohol  

NASA Astrophysics Data System (ADS)

Zinc oxide nanostructures are known to exist in a great variety of morphologies. However, the underlying mechanisms leading to these architectures are far from being fully understood. Here, we present a time dependent study of the generation of zinc oxide nanorods, which arrange into bundles with a fan- or bouquet-like structure, using the benzyl alcohol route. The structural evolution of the nanoparticles was monitored by electron microscopy techniques, whereas the progress of the chemical reaction was followed by quantification of the organic by-products using gas chromatography. With this study we give a detailed insight into the formation of the zinc oxide structures, which involves a complex pathway based on many in parallel occurring processes such as crystallization of primary particles, their oriented attachment and surface reconstruction inside the nanoparticulate agglomerates. However, in spite of such an intricate growth behavior, the ZnO nanostructures are surprisingly uniform in size and shape.Zinc oxide nanostructures are known to exist in a great variety of morphologies. However, the underlying mechanisms leading to these architectures are far from being fully understood. Here, we present a time dependent study of the generation of zinc oxide nanorods, which arrange into bundles with a fan- or bouquet-like structure, using the benzyl alcohol route. The structural evolution of the nanoparticles was monitored by electron microscopy techniques, whereas the progress of the chemical reaction was followed by quantification of the organic by-products using gas chromatography. With this study we give a detailed insight into the formation of the zinc oxide structures, which involves a complex pathway based on many in parallel occurring processes such as crystallization of primary particles, their oriented attachment and surface reconstruction inside the nanoparticulate agglomerates. However, in spite of such an intricate growth behavior, the ZnO nanostructures are surprisingly uniform in size and shape. Electronic supplementary information (ESI) available: TEM images of remaining reaction times (2, 5, 360 and 720 min). See DOI: 10.1039/c1nr11557j

Ludi, Bettina; Süess, Martin J.; Werner, Irmgard A.; Niederberger, Markus

2012-03-01

254

Atmospheric pressure based electrostatic spray deposition of transparent conductive ZnO and Al-doped ZnO (AZO) thin films: Effects of Al doping and annealing treatment  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) and Al-doped ZnO (AZO) thin films were prepared by electrostatic spray deposition method at atmospheric pressure followed by annealing. The effects of annealing and Al doping on the structural, electrical and optical properties of the films were investigated. The results show that films have random orientation with compact hexagonal wurtzite structure. It also implies that the annealing and the Al doping help to improve the electrical conductivity and optical properties as well. The minimum value of resistivity was 1.10 × 10-4 ? cm for 0.5 at. % AZO film and transmittance was greater than 96% in the visible region. The present value of resistivity is comparable to the lowest values for AZO films reported in open literatures. All the films prepared by this method have a good crystalline structure and homogenous surface. We proposed that the substitution of Al in the ZnO lattice has positive effects in terms of increasing the free electron concentration. At atmospheric pressure, the electrospraying method was confirmed to be suitable for the preparation of AZO films with low resistivity and high transmittance.

Mahmood, Khalid; Park, Seung Bin

2013-03-01

255

40 CFR 721.2095 - Chromate(3-), bis 2-[[substituted-3-[(5-sulfo-1-naphthalenyl)azo] phenyl]azo]substituted...  

Code of Federal Regulations, 2010 CFR

...5-sulfo-1-naphthalenyl)azo] phenyl]azo]substituted monocycle, trisodium...5-sulfo-1-naphthalenyl)azo] phenyl]azo]substituted monocycle, trisodium...5-sulfo-1-naphthalenyl) azo]phenyl]azo]substituted monocycle,...

2010-07-01

256

Investigation of low-zinc-solubility electrodes and electrolytes in zinc/silver oxide cells  

NASA Astrophysics Data System (ADS)

The cycle-life performance of the Zn/AgO cell is limited by high rates of Zn active material redistribution (shape change) and Zn dendrite growth. Reduced-zinc-solubility electrolytes, prepared by adding F -, CO 32-, BO 33- and PO 43- salts to aqueous KOH solutions, were used in 5 A h Zn/AgO cells to determine their effect on cell lifetimes. Ca(OH) 2 additions to the Zn electrode were also evaluated in cells of the same capacity and mass as the calcium-free cells. It was found that all of the anion additives to KOH electrolytes resulted in lower cell capacities and shorter lifetimes, which could be attributed the formation of soluble Ag-containing salts and subsequent degradation of the Ag electrode performance. The calcium-containing Zn electrode was found to significantly improve the performance of the Zn/AgO cell by promoting higher capacities, especially over the initial 20 cycles. The higher capacities could be attributed to the formation of a calcium zincate complex, crystals of which were found in the cycled Zn electrodes.

Chen, Jenn-Shing; McLarnon, Frank R.; Cairns, Elton J.

257

Gills are an initial target of zinc oxide nanoparticles in oysters Crassostrea gigas, leading to mitochondrial disruption and oxidative stress.  

PubMed

The increasing industrial use of nanomaterials during the last decades poses a potential threat to the environment and in particular to organisms living in the aquatic environment. In the present study, the toxicity of zinc oxide nanoparticles (ZnONP) was investigated in Pacific oysters Crassostrea gigas. The nanoscale of ZnONP, in vehicle or ultrapure water, was confirmed, presenting an average size ranging from 28 to 88 nm. In seawater, aggregation was detected by TEM and DLS analysis, with an increased average size ranging from 1 to 2 ?m. Soluble or nanoparticulated zinc presented similar toxicity, displaying a LC50 (96 h) around 30 mg/L. High zinc dissociation from ZnONP, releasing ionic zinc in seawater, is a potential route for zinc assimilation and ZnONP toxicity. To investigate mechanisms of toxicity, oysters were treated with 4 mg/L ZnONP for 6, 24 or 48 h. ZnONP accumulated in gills (24 and 48 h) and digestive glands (48 h). Ultrastructural analysis of gills revealed electron-dense vesicles near the cell membrane and loss of mitochondrial cristae (6 h). Swollen mitochondria and a more conspicuous loss of mitochondrial cristae were observed after 24 h. Mitochondria with disrupted membranes and an increased number of cytosolic vesicles displaying electron-dense material were observed 48 h post exposure. Digestive gland showed similar changes, but these were delayed relative to gills. ZnONP exposure did not greatly affect thiol homeostasis (reduced and oxidized glutathione) or immunological parameters (phagocytosis, hemocyte viability and activation and total hemocyte count). At 24 h post exposure, decreased (-29%) glutathione reductase (GR) activity was observed in gills, but other biochemical responses were observed only after 48 h of exposure: lower GR activity (-28%) and levels of protein thiols (-21%), increased index of lipid peroxidation (+49%) and GPx activity (+26%). In accordance with ultrastructural changes and zinc load, digestive gland showed delayed biochemical responses. Except for a decreased GR activity (-47%) at 48 h post exposure, the biochemical alterations seen in gills were not present in digestive gland. The results indicate that gills are able to incorporate zinc prior (24 h) to digestive gland (48 h), leading to earlier mitochondrial disruption and oxidative stress. Our data suggest that gills are the initial target of ZnONP and that mitochondria are organelles particularly susceptible to ZnONP in C. gigas. PMID:24745718

Trevisan, Rafael; Delapedra, Gabriel; Mello, Danielle F; Arl, Miriam; Schmidt, Éder C; Meder, Fabian; Monopoli, Marco; Cargnin-Ferreira, Eduardo; Bouzon, Zenilda L; Fisher, Andrew S; Sheehan, David; Dafre, Alcir L

2014-08-01

258

Influence of dietary carbohydrate on zinc-deficiency-induced changes in oxidative defense mechanisms and tissue oxidative damage in rats  

Microsoft Academic Search

The aim of this study was to determine the effect of dietary carbohydrate type on the expression of zinc (Zn) deficiency in\\u000a rats with respect to tissue oxidative damage and defense mechanisms. Rats were fed diets containing adequate (+Zn) or low\\u000a concentrations (-Zn) of Zn. Both fructose- and glucose-based diets were tested. Pair-fed controls were also studied to evaluate\\u000a changes

Sun H. Kim; Carl L. Keen

1999-01-01

259

Electrochemistry of the Zinc-Silver Oxide System. Part 2: Practical Measurements of Energy Conversion Using Commercial Miniature Cells.  

ERIC Educational Resources Information Center

Summarizes the quantitative relationships pertaining to the operation of electrochemical cells. Energy conversion efficiency, cycle efficiency, battery power, and energy/power density of two types of zinc-silver oxide cells are discussed. (YP)

Smith, Michael J.; Vincent, Colin A.

1989-01-01

260

Water soluble azo polymers for electronic and photonic applications  

NASA Astrophysics Data System (ADS)

The focus of this dissertation is the design and synthesis of novel water soluble azo polymers and their processing into molecular level multilayer films with unique electronic and optical phenomena. Conjugated main chain azo polymers are expected to exhibit interesting electrical and optical properties. Through an oxidative coupling reaction of 2,5-diaminobenzene sulfonic acid, a high molecular weight, conjugated, main chain azo polymer was synthesized. The polymer was soluble in water and organic solvents such as DMF and DMSO. Two classes of water soluble side chain azo polymers, one epoxy based and the other acrylic acid based, were also synthesized. The polymers were designed to contain ionizable groups in the azo chromophore. All these polymers can be processed in a manner similar to the conventional azo polymers. In addition, the water solubility of the polymers has been utilized in fabricating multilayer films through a recently reported layer-by-layer deposition process. Using the water soluble azo polymers in the ionized form and commercially available oppositely charged polyelectrolytes, multilayers were formed through an alternate deposition process. The azo chromophores in the multilayer films containing the epoxy based azo polymers self-assemble into an acentric arrangement during the deposition process. The films exhibit second order nonlinear optical (NLO) coefficients comparable to the poled, spin coated films of the same polymer. This result indicates that the chromophores in the multilayer films possess the same order of noncentrosymmetric alignment as in the case of the poled films. The self-organization of the chromophores in the multilayer films was confirmed using transmission electron microscopic (TEM) studies. Electron diffraction pattern from the films indicate that the chromophores assemble into a liquid crystal type of order with a d spacing of about 4.7 A. Additional evidence of orientational order was obtained from electroabsorption spectroscopy which is a useful technique in determining the nonlinear optical coefficients ?(3)1133 and ?(3)3333 of NLO films. The ratio ?(3)3333/?(3)1133 is an indication of the orientational order of the relevant chromophore. If the ratio is <3, it indicates that the chromophores lie preferentially in the plane of the film. If the ratio is =3, the film is isotropic. If the ratio is >3, the chromophores are predominantly oriented normal to the plane of the film. The electroabsorption results indicate that in the multilayer films the ratio is about 4, whereas in the spin coated film it is about 1.9. These results collectively indicate that we have achieved acentric ordering of azo NLO chromophores through a simple layer-by-layer deposition process. (Abstract shortened by UMI.)

Balasubramanian, Srinivasan

261

Infrared spectroscopy of zinc oxide and magnesium nanostructures  

NASA Astrophysics Data System (ADS)

Impurities in ZnO nanoparticles and Mg nanorods were investigated. ZnO nanoparticles were prepared by a reaction of zinc acetate and sodium hydrogen carbonate. The presence and source of CO2 impurities in ZnO nanoparticles were studied by infrared (IR) spectroscopy. Isotopic substitution was used to verify the vibrational frequency assignment. Isochronal annealing experiments were performed to study the formation and stability of molecular impurities. The results indicate that the molecules are much more stable than CO 2 adsorbed on bulk ZnO surfaces. IR reflectance spectra of as-grown and hydrogen-annealed ZnO nanoparticles were measured at near-normal incidence. The as-grown particles were semi-insulating and showed reflectance spectra characteristic of insulating ionic crystals. Samples annealed in hydrogen showed a significant increase in electrical conductivity and free-carrier absorption. A difference was observed in the reststrahlen line shape of the conductive sample compared to that of the as-grown sample. The effective medium approximation was applied to model the reflectance and absorption spectra. The agreement between the experimental results and the model suggests that the nanoparticles have inhomogeneous carrier concentrations. Exposure to oxygen for several hours led to a significant decrease in carrier concentration, possibly due to the adsorption of negative oxygen molecules on the nanoparticle surfaces. Cu doped ZnO nanoparticles were prepared by using a zinc acetate/copper acetate precursor. The electronic transitions of Cu2+ ions were observed in the IR absorption spectrum at low temperatures. The high resistivity property of ZnO:Cu nanoparticles was observed. Magnesium hydroxide thin layers were formed by a chemical reaction between magnesium nanorods and water. IR spectroscopy showed hydroxide (OH) vibrational modes. The assignment was verified by reactions with heavy water which produced the expected OD vibrational frequency. A Fano interference was detected for hydroxide layers formed on metallic magnesium. For hydroxide layers on insulating magnesium hydride, however, the line shape was symmetric and no Fano resonance was observed. The results show that the hydroxide layer is thin such that the vibrational motion couples to the free electron continuum of the magnesium metal.

Hlaing Oo, Win Maw

262

Carbon-Incorporated Amorphous Indium Zinc Oxide Thin-Film Transistors  

NASA Astrophysics Data System (ADS)

We propose the use of amorphous-carbon indium zinc oxide (a-CIZO) as a channel material for thin-film transistor (TFT) fabrication. This study chose a carbon dopant as a carrier suppressor and strong oxygen binder in amorphous-indium zinc oxide (a-IZO) channel material. a-CIZO thin films were deposited using radiofrequency (RF) sputtering and postannealed at 150°C. X-ray diffraction and transmission electron microscopy analysis revealed that the film remained amorphous even after postannealing. The a-CIZO TFT postannealed at 150°C exhibited saturation field-effect mobility of 16.5 cm2 V-1 s-1 and on-off current ratio of ˜4.3 × 107.

Parthiban, S.; Park, K.; Kim, H.-J.; Yang, S.; Kwon, J.-Y.

2014-11-01

263

Inductively coupled plasma etching of hafnium-indium-zinc oxide using chlorine based gas mixtures  

NASA Astrophysics Data System (ADS)

We report the etching characteristics of a stacked hafnium-indium-zinc oxide (HIZO) with a photoresist using the gas mixture of chlorine and argon (Cl2/Ar). The etching behaviors of HIZO have been investigated in terms of a source power, a bias power and a chamber pressure. As the concentration of Cl2 was increased compared to pure Ar, the etch rate of HIZO film was found slightly different from that of indium-zinc oxide (IZO) film. Moreover, to investigate the etching mechanism systematically, various inspections were carried out such as atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) depending on the portion of Cl2. Additionally, we compared the etching mechanism of HIZO film with IZO film to confirm the difference of chemical bonds caused by the influence of hafnium doping.

Choi, Yong-Hee; Jang, Ho-Kyun; Jin, Jun-Eon; Joo, Min-Kyu; Piao, Mingxing; Shin, Jong Mok; Kim, Jae-Sung; Na, Junhong; Kim, Gyu Tae

2014-04-01

264

Photodynamic effects of zinc oxide nanowires in skin cancer and fibroblast.  

PubMed

Cytotoxic effects of zinc oxide (ZnO) nanomaterials, individual and conjugated with a photosensitizer (protoporphyrin IX), were studied in the presence and absence of ultraviolet light exposure (240 nm of light wavelength for a very short time exposure) in cell cultures of human normal and cancerous skin models. Zinc Oxide nanowires (ZnO NWs) were grown on the capillary tip and conjugated with protoporphyrin IX (PpIX). This coated tip was used as tool/pointer for intracellular drug delivery protocol in suggested normal as well as carcinogenic cellular models. After true delivery of optimal drug, the labelled biological model was irradiated with UV-A, which led to a loss of mitochondrial membrane potential, as tested by neutral red assay (NRA). PMID:24338134

Fakhar-e-Alam, Muhammad; Kishwar, S; Willander, M

2014-05-01

265

Synthesis and dielectric properties of zinc oxide nanoparticles using a biotemplate  

NASA Astrophysics Data System (ADS)

Zinc Oxide nanoparticles are synthesized using DNA as capping agent. Zinc oxide nanoparticles are synthesized using DNA as a capping agent. Structural and morphological characterizations are done using SEM, FTIR and XRD. The particle size and lattice parameters are calculated from the diffraction data. The optical properties are studied using UV-Vis absorption spectroscopy and bandgap variation with temperature is determined. The dielectric property of nanoparticles is studied by varying temperature and frequency. The dielectric constant and dispersion parameters are found out. Method of Cole-Cole analysis is used to study the high temperature dispersion of relaxation time. The variation of both AC and DC conductivity are studied and activation energy calculated.

P, Sharmila P.; Tharayil, Nisha J.

2014-10-01

266

Conjugated phosphonic Acid modified zinc oxide electron transport layers for improved performance in organic solar cells.  

PubMed

Phosphonic acid modification of zinc oxide (ZnO) electron transport layers in inverted P3HT:ICBA solar cells was studied to determine the effect of conjugated linkages between the aromatic and phosphonic acid attachment groups. For example, zinc oxide treated with 2,6-difluorophenylvinylphosphonic acid, having a conjugated vinyl group connecting the aromatic moiety to the phosphonic acid group, showed a 0.78 eV decrease in the effective work function versus unmodified ZnO, whereas nonconjugated 2,6-difluorophenylethylphosphonic acid resulted in a 0.57 eV decrease, as measured by Kelvin probe. This resulted in an average power conversion efficiency of 5.89% for conjugated 2,6-difluorophenyvinylphosphonic acid modified solar cells, an improvement over unmodified (5.24%) and nonconjugated phosphonic acid modified devices (5.64%), indicating the importance of the conjugated linkage. PMID:25329245

Braid, Jennifer L; Koldemir, Unsal; Sellinger, Alan; Collins, Reuben T; Furtak, Thomas E; Olson, Dana C

2014-11-12

267

Formation of copper centers in a sensitized zinc oxide-polyvinyl alcohol system  

SciTech Connect

A substantial drop in the use of silver by the photographic industry may be brought about by replacing the conventional silver halides with low-silver and silver-free photographic materials. Of the silver-free photosensitive layers the most comparable to silver halogens in ultraviolet sensitivity is one comprising a dispersion of zinc oxide powder in polyvinyl alcohol (PVA), sensitized by components of a copper physical developer. This paper reports methods for forming latent image centers in a zinc oxide-PVA system sensitized by components of a copper physical developer. The derivatographic analysis was carried out on a Paulik Derivatograph. Electron spin resonance spectra were taken on a Bruker spectrometer at 77 K.

Gerleman, N.G.; Osipov, D.P.; Shagisultanova, G.A.

1988-11-10

268

Sensor protection using nonlinear properties of Erbium doped Zinc Oxide (EZO) thin films prepared by sol-gel method  

Microsoft Academic Search

Zinc Oxide (ZO) and Erbium doped zinc oxide (EZO) thin film were deposited on corning glass substrate by sol- gel method. Concentration of erbium is varying from 0.0 to 0.2 at.%. These films were characterized by using X-ray diffraction (XRD), UV-VIS-NIR transmission and single beam Z-scan technique under illumination of frequency doubled Nd:YAG laser. The films developed were found to

Devendra Mohan; Vinay Kumari; Purmima

2011-01-01

269

Tailoring ferromagnetism in chromium-doped zinc oxide  

NASA Astrophysics Data System (ADS)

The simultaneous manipulation of both charge and spin has made diluted magnetic semiconductors (DMS) a potential material for the fabrication of spintronic devices. We report DMSs based on ZnO doped with Cr in wurtzite (WZ) and zinc-blend (ZB) geometries. The injection of Cr impurities at a concentration of 6.25% has successfully tuned ferromagnetism in ZnO. To recognize the nature of magnetic interactions, two spatial configurations are investigated, where the impurity atoms are placed at minimum and maximum separation distances. The material favors the short-range magnetic coupling and has a tendency towards Cr clustering. The injection of a Cr impurity into ZnO strongly influences the electronic properties in terms of band structure, dependent on the impurity spatial distribution. It is half metallic for both structural geometries when impurity atoms have minimum separation and is metallic when they are placed far apart. Moreover, replacing Zn with Cr does not show a significant effect on the structural geometries. Our results endorse that Cr:ZnO can be efficiently used for spin-polarized transport and other spin-dependent applications in both hexagonal and cubic phases.

Haq, Bakhtiar Ul; Ahmed, Rashid; Goumri-Said, Souraya

2014-03-01

270

Synthesis and Characterization of Nanostructured Zinc Oxide and Tin Oxide for VOC Sensor Devices  

NASA Astrophysics Data System (ADS)

In this dissertation, nanostructured ZnO and SnOx with various forms of thin films, particles and rods were deposited and synthesized by combination of sputtering, thermolysis assisted chemical solution method, and/or dc applied electrodeposition. Different substrates such as alumina, silicon dioxide, and polyimide films were used to grow nanostructured materials in order to fabricate highly sensitive and selective VOC sensor devices. Synthesized ZnO and SnOx materials were characterized by FE-SEM, XRD, EDS, Raman spectroscopy and Keithley 2400 sourcemeter to examine the surface morphology, crystalline phase, atomic composition and electrical resistance change. Gas sensing properties of nanostructured metal oxides were studied as functions of the structural and compositional changes. Three different gases: acetone, ethanol, and ethylene, mixed with synthetic air were tested in a closed chamber by continuously flowing gases. SnO2 thin films were deposited by rf sputtering from a SnO 2 ceramic target under different argon-to-oxygen ratios to investigate the effects of oxygen stoichiometry on ethylene sensing properties. Thin film sensors exhibited higher sensitivity compared with bulk from SnO2 sensors. Post-annealing of the fabricated thin films influenced gas sensitivity while the control of argon-to-oxygen ratio during the film deposition did not affect the properties significantly due to the effective formation SnO2 by a post-annealing process. An ethylene sensing mechanism for the SnO 2 thin film sensor was also newly suggested. Significant compositional effects of tin oxide were investigated by sputter deposition from a metallic tin target. Post-annealing of the films resulted in SnO and/or SnO2 phases depending on annealing temperature. Combinatorial phases of SnOx, i.e. gradual distribution of SnO and SnO2 on the sample substrate, were fabricated by co-sputtering of tin metal and tin oxide ceramic targets. Gas sensing properties of the films were investigated with an emphasis on tin phases and microstructure. Although SnO is a p-type semiconductor and SnO2 is a n-type semiconductor, the data on sensitivity using three different gases were similar except for the direction of resistance changes during the detection of the gases. Such a combinatorial approach would enhance the selectivity of a VOC sensor by merging two different types of semiconducting materials. Geometric effects of the oxides on the gas sensing properties were investigated by constructing ZnO nanorods on ZnO thin film seed layers. A series of devices were prepared with seed layers of different thickness upon which nanorods with tuned density were grown. Quantitative analysis of the sensing mechanism shows that volumetric geometry of the nanorods such as diameter and length is a more critical factor than the thickness of the seed layer. In addition to control of the nanorod structure, the transition metal ions such as nickel, cobalt, and copper were doped into ZnO nanorods during electrodeposition. Such doping can provide the ability to operate at room temperature and to use flexible polymer substrates. Nickel was successfully doped in-situ into ZnO nanorods in aqueous solution. A doped concentration of 6% nickel revealed the most enhanced sensing property at room temperature under UV illumination. A mechanism is proposed to explain how the transition metal ions in zinc oxide play an important role in the gas sensitivity under UV illumination.

Ahn, Hosang

271

Comparison of electrodeposited and sputtered intrinsic and aluminium-doped zinc oxide thin films  

Microsoft Academic Search

Intrinsic zinc oxide (i-ZnO) and aluminium-doped ZnO (ZnO:Al) are components of high-efficiency copper indium gallium diselenide solar cells. This paper examines both of these materials grown by two different techniques, namely radio frequency sputtering and electrodeposition (ED) for comparison and a better understanding. X-ray diffraction showed all materials to be polycrystalline and hexagonal (wurtzite) ZnO. Scanning electron microscopy indicated crystallites

J S Wellings; A P Samantilleke; P Warren; S N Heavens; I M Dharmadasa

2008-01-01

272

Electrically Conductive Zinc Oxide (ZnO) Nanostructures Prepared by Sol-gel Spin-coating  

Microsoft Academic Search

The electrically conductive zinc oxide (ZnO) nanostructures prepared by sol-gel spin coating are presented. This project has been focused on electrical, optical and surface morphology properties of Al (aluminium) doped ZnO thin film. The effect of Al doping concentration at 0~5 at.% on the Al doped ZnO Thin film properties have been investigated. This project involves 3 processes which are

M. H. Mamat; A. S. Rodzi; M. Rusop

2011-01-01

273

Hydrogenated aluminium-doped zinc oxide semiconductor thin films for polymeric light-emitting diodes  

Microsoft Academic Search

Highly conducting transparent thin films of aluminium(Al)-doped zinc oxide (ZnO:Al) were deposited by a radio frequency magnetron-sputtering technique using an argon and hydrogen gas mixture at room temperature. Hydrogen serves as a shallow donor and plays a critical role in improving the Al doping efficiency to enhance the conductivity of thin films. The effect of hydrogen partial pressure on the

X T Hao; F R Zhu; K S Ong; L W Tan

2006-01-01

274

Electrically Conductive Zinc Oxide (ZnO) Nanostructures Prepared by Sol-gel Spin-coating  

Microsoft Academic Search

The electrically conductive zinc oxide (ZnO) nanostructures prepared by sol-gel spin coating are presented. This project has been focused on electrical, optical and surface morphology properties of Al (aluminium) doped ZnO thin film. The effect of Al doping concentration at 0?5 at.% on the Al doped ZnO Thin film properties have been investigated. This project involves 3 processes which are

M. H. Mamat; A. S. Rodzi; M. Rusop

2011-01-01

275

Aluminium doped zinc oxide sputtered from rotatable dual magnetrons for thin film silicon solar cells  

Microsoft Academic Search

This study addresses the electrical and optical properties as well as the surface structure after wet-chemical etching of mid-frequency magnetron sputtered aluminium doped zinc oxide (ZnO:Al) films on glass substrates from rotatable ceramic targets. Etching of an as-deposited ZnO:Al film in acid leads to rough surfaces with various feature sizes. The influence of working pressure and substrate temperature on the

H. Zhu; E. Bunte; J. Hüpkes; H. Siekmann; S. M. Huang

2009-01-01

276

Near-infrared reflection from periodically aluminium-doped zinc oxide thin films  

Microsoft Academic Search

Multilayers of aluminium-doped zinc oxide (Al:ZnO) as a heat-reflection material were prepared by a reactive sputtering method with intermittent Al doping or Al content modulation. A drop in the refractive indices n around the plasma wavelength ?p of 1456nm for the optimally-doped Al:ZnO layers formed the periodic distribution of n in the multilayers. The periodic n provided selective reflection of

Yoshiki Okuhara; Takeharu Kato; Hideaki Matsubara; Norifumi Isu; Masasuke Takata

2011-01-01

277

Evaluation of the optical axis tilt of zinc oxide films via noncollinear second harmonic generation  

SciTech Connect

We investigated noncollinear second harmonic generation form zinc oxide films, grown on glass substrates by dual ion beam sputtering technique. At a fixed incidence angle, the generated signal is investigated by scanning the polarization state of both fundamental beams. We show that the map of the generated signal as a function of polarization states of both pump beams, together with the analytical curves, allows to retrieve the orientation of the optical axis and eventually, its angular tilt, with respect to the surface normal.

Bovino, F. A. [Quantum Optics Lab., Elsag-Datamat, Via Puccini 2, 16154 Genova (Italy); Larciprete, M. C.; Belardini, A.; Sibilia, C. [Dipartimento di Energetica, Universita di Roma 'La Sapienza', Via A. Scarpa 16, 00161 Roma (Italy)

2009-06-22

278

Transparent conducting zinc oxide thin film prepared by electron beam evaporation technique with argon plasma assistance  

Microsoft Academic Search

Zinc oxide thin film has been deposited on glass substrate by electron beam evaporation with argon plasma assistance. Undoped polycrystalline ZnO pellets (purity = 99%) were used as source material. The film was characterized by atomic force microscopy, UV\\/VIS\\/NIR spectroscopy, electrical resistivity and Hall effect measurements and X-ray diffraction. The thicknesses were measured using a Dektak profilometer and the electrical

V. D. Falcao; M. E. L. Sabino; D. O. Miranda; A. S. A. C. Diniz; J. R. T. Branco

2008-01-01

279

Preparation of europium (III) doped nanocrystalline zinc oxide in ionic liquid via an ultrasonic irradiation  

Microsoft Academic Search

In this work, europium (III) doped zinc oxide nanoparitcles have been successfully prepared in room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6) via an ultrasonic irradiation. The doped nanocrystalline sample has been characterized by XRD and TEM techniques. A possible mechanism is proposed to explain the formation of Eu3+ doped ZnO nanomateirals. Additionally, the characteristic emissions of Eu3+ can be found

Yao Yang; Bin Gao; Yue-tao Yang; Xiao-jun Liu; Shu-yi Zhang

2011-01-01

280

Microbundles of zinc oxide nanorods: Assembly in ionic liquid [EMIM] +[BF 4] ?, photoluminescence and photocatalytic properties  

Microsoft Academic Search

A simple, efficient and low-temperature approach for the assembly of hierarchical Zinc oxide (ZnO) microstructures in ionic liquid [EMIM]+[BF4]? is reported. The as-obtained ZnO superstructures are composed of microbundles of nanorods from the center points, with the diameter and length in the range of 100–150nm and 2–4?m, which have been characterized by X-ray diffraction, scanning and transmission electron microscopy, and

Li Wang; Shen-Zhi Xu; Hui-Jun Li; Li-Xian Chang; Zhi-Su; Ming-Hua Zeng; Li-Na Wang; Yi-Neng Huang

2011-01-01

281

Evaluation of the cytotoxic and inflammatory potential of differentially shaped zinc oxide nanoparticles  

Microsoft Academic Search

Zinc oxide (ZnO) nanoparticles have wide-ranging applications in a diverse array of industrial and consumer products, from\\u000a ceramic manufacture and paint formulation to sunscreens and haircare products. Hence, it is imperative to rigorously characterize\\u000a the health and safety aspects of human exposure to ZnO nanoparticles. This study therefore evaluated the cellular association,\\u000a cytotoxic and inflammatory potential of spherical and sheet-shaped

Boon Chin Heng; Xinxin Zhao; Eng Chok Tan; Nurulain Khamis; Aarti Assodani; Sijing Xiong; Christiane Ruedl; Kee Woei Ng; Joachim Say-Chye Loo

282

Synthesis and characterization of zinc oxide nanoparticles: application to textiles as UV-absorbers  

Microsoft Academic Search

We report the synthesis and characterization of nanosized zinc oxide particles and their application on cotton and wool fabrics\\u000a for UV shielding. The nanoparticles were produced in different conditions of temperature (90 or 150 °C) and reacting medium\\u000a (water or 1,2-ethanediol). A high temperature was necessary to obtain small monodispersed particles. Fourier transformed infrared\\u000a spectroscopy (FTIR), transmission electron microscopy (TEM), and

Alessio Becheri; Maximilian Dürr; Pierandrea Lo Nostro; Piero Baglioni

2008-01-01

283

Enhanced field emission characteristics of zinc oxide mixed carbon nano-tubes films  

Microsoft Academic Search

A composite material of Zinc oxide and carbon nano-tubes (ZnO–CNTs) paste was synthesized by mixing multi-wall CNTs, ZnO nano-grains and organic vehicles. The microstructures and the morphologies of screen-printed films were characterized by field-emission scanning electron microscope. Results show that ZnO flakes geometrically matched with CNTs by filling into the interspaces of CNTs or directly covering upon CNTs. The field

J. Y. Pan; C. C. Zhu; Y. L. Gao

2008-01-01

284

PREPARATION OF ZINC OXIDE NANOPARTICLE VIA UNIFORM PRECIPITATION METHOD AND ITS SURFACE MODIFICATION BY METHACRYLOXYPROPYLTRIMETHOXYSILANE  

Microsoft Academic Search

Zinc oxide nanoparticles were prepared by uniform precipitation using urea hydrolysis. The ZnO precursor was slowly deposited from aqueous solution. Anionic surfactant was added into solution to block ZnO crystal growth and its agglomeration. Then ZnO nanoparticles were synthesized by the calcination of the precursor at high temperature. Transmission electron microscope (TEM) observation and particle size analyzer demonstrated that the

Erjun Tang; Baoyong Tian; Erli Zheng; Cuiyan Fu; Guoxiang Cheng

2008-01-01

285

New developments in gallium doped zinc oxide deposited on polymeric substrates by RF magnetron sputtering  

Microsoft Academic Search

Gallium-doped zinc oxide (GZO) thin films have been deposited onto polyethylene naphthalate (PEN) substrates by r.f. magnetron sputtering at room temperature. The influence of the film thickness (from 70 to 890 nm) on the electrical, structural and morphological properties are presented. The lowest resistivity obtained was 5×10?4 ? cm with a Hall mobility of 13.7 cm2\\/Vs and a carrier concentration

E. Fortunato; A. Gonçalves; A. Marques; A. Viana; H. Águas; L. Pereira; I. Ferreira; P. Vilarinho; R. Martins

2004-01-01

286

Organic solar cells incorporating buffer layers from indium doped zinc oxide nanoparticles  

Microsoft Academic Search

Monodisperse, indium doped zinc oxide (IZO) nanoparticles were prepared via the polyol-mediated synthesis and incorporated into regular and inverted poly-(3-hexylthiophene-2,5-diyl) and [6,6]-phenyl C61-butyric acid methyl ester organic photovoltaic devices as buffer layers between the active layer and the cathode. Efficient hole blocking at the particle buffer layers leads to an enhanced open-circuit voltage of the solar cells. This effect is

Andreas Puetz; Tobias Stubhan; Manuel Reinhard; Oliver Loesch; Elin Hammarberg; Silke Wolf; Claus Feldmann; Heinz Kalt; Alexander Colsmann; Uli Lemmer

2011-01-01

287

Highly stable transparent and conducting gallium-doped zinc oxide thin films for photovoltaic applications  

Microsoft Academic Search

Transparent and highly conducting gallium zinc oxide (GZO) films were successfully deposited by RF sputtering at room temperature. A lowest resistivity of ?2.8×10?4?cm was achieved for a film thickness of 1100nm (sheet resistance ?2.5?\\/?), with a Hall mobility of 18cm2\\/Vs and a carrier concentration of 1.3×1021cm?3. The films are polycrystalline with a hexagonal structure having a strong crystallographic c-axis orientation.

E. Fortunato; L. Raniero; L. Silva; A. Gonçalves; A. Pimentel; P. Barquinha; H. Águas; L. Pereira; G. Gonçalves; I. Ferreira; E. Elangovan; R. Martins

2008-01-01

288

High quality conductive gallium-doped zinc oxide films deposited at room temperature  

Microsoft Academic Search

Transparent and highly conducting gallium-doped zinc oxide films were successfully deposited by rf sputtering at room temperature. The lowest resistivity achieved was 2.6×10?4 ? cm for a thickness of 1100 nm (sheet resistance ?1.6 ?\\/sq), with a Hall mobility of 18 cm2\\/Vs and a carrier concentration of 1.3×1021 cm?3. The films are polycrystalline with a hexagonal structure and a strongly

E. Fortunato; V. Assunção; A. Gonçalves; A. Marques; H. Águas; L. Pereira; I. Ferreira; P. Vilarinho; R. Martins

2004-01-01

289

New challenges on gallium-doped zinc oxide films prepared by r.f. magnetron sputtering  

Microsoft Academic Search

Gallium-doped zinc oxide films were prepared by r.f. magnetron sputtering at room temperature as a function of the substrate–target distance. The best results were obtained for a distance of 10 cm, where a resistivity as low as 2.7×10?4 ? cm, a Hall mobility of 18 cm2\\/Vs and a carrier concentration of 1.3×1021 cm?3 were achieved. The films are polycrystalline presenting

Vitor Assunção; Elvira Fortunato; António Marques; Alexandra Gonçalves; Isabel Ferreira; Hugo Águas; Rodrigo Martins

2003-01-01

290

Thermal oxidation of n-type ZnN films made by r f sputtering from a zinc nitride target, and their conversion into p-type films  

Microsoft Academic Search

Transparent p-type thin films, containing zinc oxide phases, have been fabricated from the oxidation of n-type zinc nitride films. The zinc nitride thin films were deposited by rf-magnetron sputtering from a zinc nitride target in pure N2 and pure Ar plasma. Films deposited in Ar plasma were conductive (resistivity 4.7×10?2 ? cm and carrier concentrations around 1020 cm?3) Zn-rich ZnxNy films of low

V. Kambilafka; P. Voulgaropoulou; S. Dounis; E. Iliopoulos; M. Androulidaki; V. Šály; M. Ruzinsky; E. Aperathitis

2007-01-01

291

Gaseous species as reaction tracers in the solvothermal synthesis of the zinc oxide terephthalate MOF-5.  

PubMed

Gaseous species emitted during the zinc oxide/zinc hydroxide 1,4-benzenedicarboxylate metal organic framework synthesis (MOF-5, MOF-69c) have been used to investigate the reaction scheme that leads to the framework creation. Changes of the gas-phase composition over time indicate that the decomposition of the solvent diethylformamide occurs at least via two competing reaction pathways that can be linked to the reaction's overall water and pH management. From isotope exchange experiments, we deduce that one of the decomposition pathways leads to the removal of water from the reaction mixture, which sets the conditions when the synthesis of an oxide-based (MOF-5) instead of an hydroxide-based MOF (MOF-69c) occurs. A quantitative account of most reactants and byproducts before and after the MOF-5/MOF-69c synthesis is presented. From the investigation of the reaction intermediates and byproducts, we derive a proposal of a basic reaction scheme for the standard synthesis zinc oxide carboxylate MOFs. PMID:17455926

Hausdorf, Steffen; Baitalow, Felix; Seidel, Jürgen; Mertens, Florian O R L

2007-05-24

292

The complex interface chemistry of thin-film silicon/zinc oxide solar cell structures.  

PubMed

The interface between solid-phase crystallized phosphorous-doped polycrystalline silicon (poly-Si(n(+))) and aluminum-doped zinc oxide (ZnO:Al) was investigated using spatially resolved photoelectron emission microscopy. We find the accumulation of aluminum in the proximity of the interface. Based on a detailed photoemission line analysis, we also suggest the formation of an interface species. Silicon suboxide and/or dehydrated hemimorphite have been identified as likely candidates. For each scenario a detailed chemical reaction pathway is suggested. The chemical instability of the poly-Si(n(+))/ZnO:Al interface is explained by the fact that SiO2 is more stable than ZnO and/or that H2 is released from the initially deposited a-Si:H during the crystallization process. As a result, Zn (a deep acceptor in silicon) is "liberated" close to the silicon/zinc oxide interface presenting the inherent risk of forming deep defects in the silicon absorber. These could act as recombination centers and thus limit the performance of silicon/zinc oxide based solar cells. Based on this insight some recommendations with respect to solar cell design, material selection, and process parameters are given for further knowledge-based thin-film silicon device optimization. PMID:25363298

Gerlach, D; Wimmer, M; Wilks, R G; Félix, R; Kronast, F; Ruske, F; Bär, M

2014-12-21

293

Mechanism of azo dye degradation in Advanced Oxidation Processes: Degradation of Sulfanilic Acid Azochromotrop and its parent compounds in aqueous solution by ionizing radiation  

NASA Astrophysics Data System (ADS)

Mechanistic studies were made on hydroxyl radical and hydrated electron reaction with Sulfanilic Acid Azochromotrop (SPADNS) as model azo dye in dilute aqueous solution. SPADNS contains 4,5-dihydroxynaphthalene-2,7-disulfonic acid part and 4-sulfophenylazo group. To establish the details of the reaction mechanism the reactions of two simpler molecules without 4-sulfophenylazo part were also studied: one of them contained one (in position 4, II), the other two (in positions 4 and 5, III) -OH groups. Hydroxyl radicals react with these molecules with radical addition to the naphthalene-2,7-disulfonic acid part. The adduct hydroxycyclohexadienyl type radical decays in radical-radical reactions, or undergoes a (pH dependent) water elimination to yield naphthoxy radical. The radical decay takes place on the ms timescale. Degradation efficiencies are 0.6-0.8. Hydrated electron in the case of the two simpler molecules reacts with the rings, while in the case of dye with the azo bond. Electron scavenging is followed by protonation, this reaction in the case of II and III yields cyclohexadienyl, while with the dye hydrazo radical. The efficiency of degradation with II and III is 0.2-0.6, while for SPADNS it is close to 1.

Pálfi, Tamás; Wojnárovits, László; Takács, Erzsébet

2011-03-01

294

Zinc oxide nanoparticles toxicity to Daphnia magna: size-dependent effects and dissolution.  

PubMed

As the production of zinc oxide nanoparticles (ZnO-NPs) and other metal oxides is exponentially increasing, it is important to investigate potential environmental and health impacts of such nanoparticles. Nanoparticles' properties (e.g., size, dissolution rate) may change in different water media, and their characterization is essential to derive conclusions about toxicity results. Therefore, an aquatic model organism, Daphnia magna, was used to investigate the effect of ZnO-NPs with 2 different particle sizes (30?nm and 80-100?nm) and then compare these effects with ZnO microsized particles (>200?nm) and the ionic counterpart (in the form of ZnCl2 ) on immobilization, feeding inhibition, and reproduction endpoints. The 48-h median lethal concentration (LC50) for immobilization ranged between 0.76?mg Zn L(-1) for the ionic zinc and 1.32?mg Zn L(-1) for ZnO-NPs of 80?nm to 100?nm. For the chronic exposures, the reproduction output was impaired similarly among zinc exposures and possibly driven mainly by the zinc ionic form. The concentrations used showed a total dissolution after 48?h. On the other hand, feeding activity was more affected by the 30?nm ZnO-NPs than by the ionic zinc, showing that the particulate form was also playing an important role in the feeding inhibition of D. magna. Dissolution and particle size in the daphnia test media were found to be essential to derive conclusions on toxicity. Therefore, they can possibly be considered critical for evaluating nanoparticles' toxicity and fate. PMID:24123301

Lopes, Sílvia; Ribeiro, Fabianne; Wojnarowicz, Jacek; ?ojkowski, Witold; Jurkschat, Kerstin; Crossley, Alison; Soares, Amadeu M V M; Loureiro, Susana

2014-01-01

295

Deposition of thick zinc oxide films with a high resistivity  

NASA Astrophysics Data System (ADS)

ZnO is a well known piezoelectric material. Unfortunately, it is not easy to deposit thin films onto silicon with a high resistivity by using common deposition technologies. The use of such films is therefore strictly limited to high frequency applications. The goal of our work was to find out a new deposition technology that allows the deposition of ZnO films with a high resistivity. Furthermore we were looking for the deposition of film thicknesses in a range up to 20 micrometers for SAW-sensor and microactuator applications. The deposition of the ZnO films was carried out in a programmable RF-magnetron-sputtering-system. We sputtered from a pure zinc target with a variable gas composition that consists of argon and oxygen. We worked in an alternating mode to achieve a high resistivity of the films. After a deposition cycle at a sample temperature of about 30 degrees C with a ramp shaped power the silicon- samples were cooled during the following cycle in the gas atmosphere. The deposition rate we measured was dependent from the gas composition and the applied power in a range between 1,5 micrometers /h and 2,2 micrometers /h. We deposited films of a thickness of 20 micrometers . Between two sputtered aluminium electrodes the films had a resistivity in a range between 2*1010(Omega) cm and 2*1011(Omega) cm. The stress of the films could be influenced by the composition of the gases. The measured minimum stresses of the films were in a range of about 180 MPa. The films were also characterized by means of XRD- measurments. We found a weak < 101 > orientation of the layers perpendicular to the surface.

Schwesinger, Norbert; Bartsch, Heike; Moeller, Frank

1995-09-01

296

Liquid crystal alignment on zinc oxide nanowire arrays for LCDs applications.  

PubMed

The zinc oxide (ZnO) nanowire arrays on the indium tin oxide (ITO) glass substrates were fabricated by using the two-step hydrothermal method. A high transmittance ~92% of ZnO nanowire arrays on ITO substrate in the visible region was obtained. It was observed that the liquid crystal (LC) directors were aligned vertically to the (ZnO) nanowire arrays. The properties of ZnO nanowire arrays as vertical liquid crystal (LC) alignment layers and their applications for hybrid-aligned nematic LC modes were investigated in this work. PMID:24514480

Chen, Mu-Zhe; Chen, Wei-Sheng; Jeng, Shie-Chang; Yang, Sheng-Hsiung; Chung, Yueh-Feng

2013-12-01

297

Solution-processed indium gallium zinc oxide thin-film transistors with infrared irradiation annealing  

NASA Astrophysics Data System (ADS)

In this paper, an infrared annealing method was proposed for solution-processed indium gallium zinc oxide films. The optimized IGZO thin-film transistors (TFTs) exhibited a field-effect mobility of 2.04 cm2 (Vs)-1, on-off current ratio of 1.52×106 and subthreshold swing of 0.84 V/dec. Spectroscopic analysis confirmed that the infrared irradiation could enhance the removal of organic species and dehydroxylation. The results suggest that infrared annealing method is a potential process for low-temperature preparation of solution-processed oxide semiconductor layers and dielectric layers, and can be applied to the fabrication of TFT devices.

Pu, Haifeng; Zhou, Qianfei; Yue, Lan; Zhang, Qun

2013-10-01

298

Toxicity to woodlice of zinc and lead oxides added to soil litter  

USGS Publications Warehouse

Previous studies have shown that high concentrations of metals in soil are associated with reductions in decomposer populations. We have here determined the relation between the concentrations of lead and zinc added as oxides to soil litter and the survival and reproduction of a decomposer population under controlled conditions. Laboratory populations of woodlice (Porcellio scaber Latr) were fed soil litter treated with lead or zinc at concentrations that ranged from 100 to 12,800 ppm. The survival of the adults, the maximum number of young alive, and the average number of young alive, were recorded over 64 weeks. Lead at 12,800 ppm and zinc at 1,600 ppm or more had statistically significant (p < 0.05) negative effects on the populations. These results agree with field observations suggesting that lead and zinc have reduced populations of decomposers in contaminated forest soil litter, and concentrations are similar to those reported to be associated with reductions in natural populations of decomposers. Poisoning of decomposers may disrupt nutrient cycling, reduce the numbers of invertebrates available to other wildlife for food, and contribute to the contamination of food chains.

Beyer, W.N.; Anderson, A.

1985-01-01

299

Electrical effect of titanium diffusion on amorphous indium gallium zinc oxide  

SciTech Connect

In this work, thermal diffusion phenomenon of Ti into amorphous indium gallium zinc oxide ({alpha}-IGZO) was carefully investigated with secondary ion mass spectroscopy, I-V, and R{sub s} measurement systems and HSC chemistry simulation tool. According to the experimental and simulated results, the diffused Ti atoms were easily oxidized due to its lowest oxidation free energy. Since oxygen atoms were decomposed from the {alpha}-IGZO during the oxidation of Ti, the number of oxygen vacancies working as electron-donating sites in {alpha}-IGZO was dramatically increased, contributing to the decrease of resistivity ({rho}) from 1.96 {Omega} cm (as-deposited {alpha}-IGZO) to 1.33 Multiplication-Sign 10{sup -3}{Omega} cm (350 Degree-Sign C annealed {alpha}-IGZO).

Choi, Seung-Ha [School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Development Group of Oxide Semiconductor, Samsung Display, Yongin 446-711 (Korea, Republic of); Jung, Woo-Shik [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Park, Jin-Hong [School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of)

2012-11-19

300

The photoelectrochemistry of solution grown zinc oxide nanowire arrays  

NASA Astrophysics Data System (ADS)

ZnO nanowire arrays were synthesized by a simple wet chemical method, and the effects of substrate, solution composition, and time on the attributes of the wire arrays were explored. Optimized wire arrays were used as photoanodes for water oxidation and in dye-sensitized solar cells with fast redox couples. The results for the wire arrays as photoanodes for water oxidation were compared to single crystals. Both ZnO electrodes exhibited poor cathodic kinetics with the aqueous solution, resulting in a non-ideal behavior of the semiconductor-liquid junction and substantial losses in the fill factor. Surprisingly, the wire arrays approached the efficiency of the single crystal, 0.18% vs 0.22% respectively. In the dye senitized solar cell, the ZnO nanowires developed a Schottky junction and allowed the use of fast redox couples. Unfortunately, the efficiencies measured were low, but results suggest the potential for substantial gains in the efficiency and versatility of the dye-sensitized solar cell.

Fitch, Anthony G.

301

Effects of size and surface of zinc oxide and aluminum-doped zinc oxide nanoparticles on cell viability inferred by proteomic analyses.  

PubMed

Although the health effects of zinc oxide nanoparticles (ZnONPs) on the respiratory system have been reported, the fate, potential toxicity, and mechanisms in biological cells of these particles, as related to particle size and surface characteristics, have not been well elucidated. To determine the physicochemical properties of ZnONPs that govern cytotoxicity, we investigated the effects of size, electronic properties, zinc concentration, and pH on cell viability using human alveolar-basal epithelial A549 cells as a model. We observed that a 2-hour or longer exposure to ZnONPs induced changes in cell viability. The alteration in cell viability was associated with the zeta potentials and pH values of the ZnONPs. Proteomic profiling of A549 exposed to ZnONPs for 2 and 4 hours was used to determine the biological mechanisms of ZnONP toxicity. p53-pathway activation was the core mechanism regulating cell viability in response to particle size. Activation of the Wnt and TGF? signaling pathways was also important in the cellular response to ZnONPs of different sizes. The cadherin and Wnt signaling pathways were important cellular mechanisms triggered by surface differences. These results suggested that the size and surface characteristics of ZnONPs might play an important role in their observed cytotoxicity. This approach facilitates the design of more comprehensive systems for the evaluation of nanoparticles. PMID:25120361

Pan, Chih-Hong; Liu, Wen-Te; Bien, Mauo-Ying; Lin, I-Chan; Hsiao, Ta-Chih; Ma, Chih-Ming; Lai, Ching-Huang; Chen, Mei-Chieh; Chuang, Kai-Jen; Chuang, Hsiao-Chi

2014-01-01

302

Bacitracin zinc overdose  

MedlinePLUS

... Small amounts of bacitracin zinc are dissolved in petroleum jelly to create antibiotic ointments. Bacitracin zinc overdose ... 1-800-222-1222. See also: Bacitracin overdose Petroleum jelly overdose Zinc oxide overdose

303

Observation of the amorphous zinc oxide recrystalline process by molecular dynamics simulation  

PubMed Central

The detailed structural variations of amorphous zinc oxide (ZnO) as well as wurtzite (B4) and zinc blende (B3) crystal structures during the temperature elevation process were observed by molecular dynamics simulation. The amorphous ZnO structure was first predicted through the simulated-annealing basin-hopping algorithm with the criterion to search for the least stable structure. The density and X-ray diffraction profiles of amorphous ZnO of the structure were in agreement with previous reports. The local structural transformation among different local structures and the recrystalline process of amorphous ZnO at higher temperatures are observed and can explain the structural transformation and recrystalline mechanism in a corresponding experiment [Bruncko et al., Thin Solid Films 520, 866-870 (2011)]. PMID:23509413

Lin, Ken-Huang; Sun, Shih-Jye; Ju, Shin-Pon; Tsai, Jen-Yu; Chen, Hsin-Tsung; Hsieh, Jin-Yuan

2013-01-01

304

Hot gas desulfurization with sorbents containing oxides of zinc, iron, vanadium and copper  

SciTech Connect

The main objective of this research is to evaluate the desulfurization performance of novel sorbents consisting of different combinations of zinc, iron, vanadium and copper oxides; and to develop a sorbent which can reduce H{sub 2}S levels to less than 1 ppmv, which can stabilize zinc, making operations above 650{degrees}C possible, and which can produce economically recoverable amounts of elemental sulfur during regeneration. This objective will be accomplished by evaluating the sorbent performance using fixed-bed and TGA experiments supported by sorbent characterization at various reaction extents. In the seventh quarter, the screening of the promoted sorbents in the packed bed reactor was continued. The results of this work were presented at the 1992 University Coal Research Contractors, Review Conference at Pittsburgh, PA.

Akyurtlu, A.; Akyurtlu, J.F.

1992-01-01

305

Electron transport behavior of individual zinc oxide coated single-walled carbon nanotubes.  

PubMed

Uniform zinc oxide coated single-walled nanotubes (SWNTs) were fabricated by ultrasonic irradiation with acid-treated SWNTs, zinc acetate, and triethanolamine at low temperature in aqueous phase processing. The ZnO coating process did not decrease the dark current of the SWNTs, but a real decrease in the steady state negative photocurrent was observed after ZnO coating, suggesting a clear photosensitization effect. Transport measurements reveal that the negative photocurrent in s (semiconducting)-SWNTs@ZnO could be described by electron-hole compensation behavior attributed to the ZnO layer under ultraviolet excitation. This simple coating method for one-dimensional material can open up new possibilities for multifunctional nanodevices. PMID:19417531

Lin, Chin-Ching; Chu, Bryan T T; Tobias, Gerard; Sahakalkan, Serhat; Roth, Siegmar; Green, Malcolm L H; Chen, San-Yuan

2009-03-11

306

Electron transport behavior of individual zinc oxide coated single-walled carbon nanotubes  

NASA Astrophysics Data System (ADS)

Uniform zinc oxide coated single-walled nanotubes (SWNTs) were fabricated by ultrasonic irradiation with acid-treated SWNTs, zinc acetate, and triethanolamine at low temperature in aqueous phase processing. The ZnO coating process did not decrease the dark current of the SWNTs, but a real decrease in the steady state negative photocurrent was observed after ZnO coating, suggesting a clear photosensitization effect. Transport measurements reveal that the negative photocurrent in s (semiconducting)-SWNTs@ZnO could be described by electron-hole compensation behavior attributed to the ZnO layer under ultraviolet excitation. This simple coating method for one-dimensional material can open up new possibilities for multifunctional nanodevices.

Lin, Chin-Ching; Chu, Bryan T. T.; Tobias, Gerard; Sahakalkan, Serhat; Roth, Siegmar; Green, Malcolm L. H.; Chen, San-Yuan

2009-03-01

307

Enhancement of the electrical characteristics of thin-film transistors with indium-zinc-tin oxide/Ag/indium-zinc-tin oxide multilayer electrodes  

NASA Astrophysics Data System (ADS)

Transparent indium-zinc-tin oxide (IZTO)-based thin-film transistors (TFTs) with IZTO/Ag/IZTO multilayer electrodes were fabricated on glass substrates using a tilted dual-target radio-frequency magnetron sputtering system. The IZTO TFTs with IZTO/Ag/IZTO multilayer electrodes exhibited a high optical transmittance in a visible region. The threshold voltage, the mobility, and the on/off-current ratio of the TFTs with IZTO/Ag/IZTO multilayer electrodes were enhanced in comparison with those of the TFTs with ITO electrodes. The source/drain contact resistance of the IZTO TFTs with IZTO/Ag/IZTO multilayer electrodes was smaller than that of the IZTO TFTs with ITO electrodes, resulting in enhancement of their electrical characteristics.

Oh, Dohyun; Yun, Dong Yeol; Cho, Woon-Jo; Kim, Tae Whan

2014-08-01

308

Bio-Fabrication of zinc oxide nanoparticles using leaf extract of Parthenium hysterophorus L. and its size-dependent antifungal activity against plant fungal pathogens  

NASA Astrophysics Data System (ADS)

The study reports the synthesis and characterization of zinc oxide nanoparticles from weed plant by a novel method. The aim of this work is to synthesize zinc oxide nanoparticles from Parthenium hysterophorus L. by inexpensive, ecofriendly and simple method. Highly stable, spherical and hexagonal zinc oxide nanoparticles were synthesized by using different concentrations of 50% and 25% parthenium leaf extracts. Both the concentrations of the leaf extract act as reducing and capping agent for conversion of nanoparticles. Formation of zinc oxide nanoparticles have been confirmed by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Fourier trans-form infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis with energy dispersive X-ray analysis (EDX). SEM, TEM and EDX analysis reveals that spherical and hexagonal zinc oxide nanoparticle sizes were 27 ± 5 nm and 84 ± 2 nm respectively and chemical composition of zinc oxide were present. We synthesized different sized zinc oxide nanoparticles and explored the size-dependent antifungal activity against plant fungal pathogens. Highest zone of inhibition was observed in 25 ?g/ml of 27 ± 5 nm size zinc oxide nanoparticles against Aspergillus flavus and Aspergillus niger. Parthenium mediated zinc oxide nanoparticles were synthesized and proved to be good antifungal agents and environment friendly.

Rajiv, P.; Rajeshwari, Sivaraj; Venckatesh, Rajendran

2013-08-01

309

Metabolism of azo dyes: implication for detoxication and activation.  

PubMed

Azo dyes are consumed and otherwise utilized in varying quantities in many parts of the world. Such widely used chemicals are of great concern with regard to their potential toxicity and carcinogenic properties. Their metabolism has been studied extensively and is significant for detoxication and metabolic activation. Both oxidative and reductive pathways are involved in these processes. The majority of azo dyes undergo reduction catalyzed by enzymes of the intestinal microorganisms and/or hepatic enzymes including microsomal and soluble enzymes. The selectivity of substrate and enzyme may to a large extent be determined by the oxygen sensitivity of reduction since a normal liver is mainly aerobic in all areas, whereas the microorganisms of the lower bowel exist in an anaerobic environment. However, it should be pointed out that the pO2 of centrilobular cells within the liver is only a fraction that of air, where pO2 = 150 torr. Therefore, an azo dye reduction experiment performed aerobically may not be an accurate predictor of reductive metabolism in all areas of the liver. Many of the azo dyes in common use today have highly charged substituents such as sulfonate. These resist enzymic attack and for the most part are poorly absorbed from the intestinal tract, providing poor access to the liver, the major site of the mixed-function oxidase system. Lipophilic dyes, such as DAB, which are often carcinogenic, readily access oxidative enzymes and are activated by both mixed-function oxidase and conjugating systems. Reduction of the carcinogenic dyes usually leads to loss of carcinogenic activity. By contrast, most of the highly charged water-soluble dyes become mutagenic only after reduction. Even then, most of the fully reduced amines required oxidative metabolic activation. An outstanding example is the potent human bladder carcinogen benzidine, which derives from the reduction of several azo dyes. Many problems regarding mutagenic and carcinogenic activation remain to be solved. At the present time, it is apparent that both oxidative and reductive pathways yield toxic products. Toxicologic assessment of azo dyes must consider all pathways and particularly the oxygen sensitivity of azoreduction. This is critical in the treatment of waste from chemical plants where there is a great need for soil bacteria which catalyze reduction aerobically. Consideration of secondary pathways are also of great concern. For example, azoreduction of carcinogenic dyes such as DAB removes carcinogenic activity although oxidative metabolism of the primary amines yield mutagenic products. Such apparent dilemmas must be dealt with when considering metabolism/toxicity relationships for azo dyes. PMID:1935573

Levine, W G

1991-01-01

310

Ecotoxicological evaluation of sewage sludge contaminated with zinc oxide nanoparticles.  

PubMed

The objective of this work was to evaluate the ecotoxicological qualitative risk associated with the use of sewage sludge containing Zn oxide nanoparticles (ZnO-NPs) as soil amendment. A sludge-untreated soil and two sludge-treated soils were spiked with ZnO-NPs (0-1,000 mg/kg soil). Soil ecotoxicity was assessed with Eisenia fetida (acute and sublethal end points), and the unfilterable and filterable (0.02 ?m) soil leachates were tested with a battery of biomarkers using Chlorella vulgaris, Daphnia magna, and the fish cell line RTG-2 (Oncorhynchus mykiss). The production of E. fetida cocoons in sludge-treated soils was lower than that in sludge-untreated soils. The highest effect in the algal growth inhibition test was detected in sludge-untreated soil, most likely caused by the loss of organic matter in these samples. The D. magna results were always negative. Toxic effects (lysosomal cell function and production of reactive oxygen species) in RTG-2 cells were only observed in sludge-treated soils. In general, the toxicity of ZnO-NPs in sludge-treated soils was similar to that of sludge-untreated soil, and the filterable leachate fraction [Zn salt (Zn(2+))] did not produce greater effects than the unfilterable fraction (ZnO-NPs). Thus, after the addition of ZnO-NP-enriched sewage sludge to agricultural soil, the risk of toxic effects for soil and aquatic organisms was shown to be low. These findings are important because repeated use of organic amendments such as sewage sludge may cause more and more increased concentrations of ZnO-NPs in soils over the long-term. PMID:25185842

García-Gómez, Concepción; Fernández, María Dolores; Babin, Mar

2014-11-01

311

Property control of expanding thermal plasma deposited textured zinc oxide with focus on thin film solar cell applications  

Microsoft Academic Search

Property control of expanding thermal plasma deposited textured zinc oxide is demonstrated considering intrinsic, i.e. bulk, and extrinsic transparent conducting oxide quality relevant for application in thin film amorphous silicon pin solar cells. Particularly the interdependence of electrical conductivity, film composition and film morphology, i.e. structure, feature shape and roughness of the surface, is addressed. Control of film composition is

R. Groenen; J. Loffler; J. L. Linden; R. E. I. Schropp

2005-01-01

312

Effect of annealing temperature on the surface morphology and electrical properties of aluminum doped zinc oxide thin films prepared by sol-gel spin-coating method  

SciTech Connect

Aluminum doped zinc oxide thin films were prepared through sol gel and spin coating technique from zinc acetate dihydrate and aluminum nitrate nanohydrate in alcoholic solution. The electrical properties and surface morphology study are investigated for the thin films annealed at 350{approx}500 deg. C. Zinc oxide thin films deposited on glass and silicon substrates were characterized using electron microscopy (SEM) and current-voltage (I-V) measurement scanning for surface morphology and electrical properties study respectively. The SEM investigation shows that zinc oxide thin films are denser at higher annealing temperature. The result indicates electrical properties of aluminum doped zinc oxide thin films are improved with annealing temperatures. The resistivity of aluminum doped zinc oxide thin films are decreased with annealing temperature up to 500 deg. C.

Mamat, M. H.; Hashim, H.; Rusop, M. [Faculty of Electrical Engineering, Universiti Teknologi MARA, 40450 Shah Alam, Selangor (Malaysia)

2008-05-20

313

Metal Catalyst for Low-Temperature Growth of Controlled Zinc Oxide Nanowires on Arbitrary Substrates  

PubMed Central

Zinc oxide nanowires generated by hydrothermal method present superior physical and chemical characteristics. Quality control of the growth has been very challenging and controlled growth is only achievable under very limited conditions using homogeneous seed layers with high temperature processes. Here we show the controlled ZnO nanowire growth on various organic and inorganic materials without the requirement of a homogeneous seed layer and a high temperature process. We also report the discovery of an important role of the electronegativity in the nanowire growth on arbitrary substrates. Using heterogeneous metal oxide interlayers with low-temperature hydrothermal methods, we demonstrate well-controlled ZnO nanowire arrays and single nanowires on flat or curved surfaces. A metal catalyst and heterogeneous metal oxide interlayers are found to determine lattice-match with ZnO and to largely influence the controlled alignment. These findings will contribute to the development of novel nanodevices using controlled nanowires. PMID:24625584

Kim, Baek Hyun; Kwon, Jae W.

2014-01-01

314

Growth and characterization of zinc oxide nanowires and thin films  

NASA Astrophysics Data System (ADS)

ZnO was studied in this dissertation for use in one-dimensional nanoscale devices, optoelectronics, and electronic applications. The synthesis, structural, and optical properties of ZnO and MgO nanowires as nanoscale materials were investigated. The crystallinity, electrical, optical and magnetic properties of undoped and phosphorous doped ZnO thin films for p-type ZnO were examined. The ZnO nanowires were fabricated using catalyst-driven molecular beam epitaxy. Site specific growth of ZnO and MgO nanowires was observed on Ag coated Si and Al2O3 substrates. The structural and compositional studies indicated that the deposition of Zn and Mg resulted in two different types of radial heterostructured (Zn,Mg)O nanowires. The effect of phosphorus doping on the electrical and optical properties of ZnO grown via pulsed laser beam deposition was studied. Phosphorus doping yields enhanced n-type behavior in as-deposited films, indicating the formation of shallow donor states. Annealing in 100 mTorr of oxygen led to the conversion of n-type behavior in as-deposited films to semi-insulating behavior in the annealed films. For the annealed film, these results appear to reflect phosphorus substitution on the O sites. The characteristics of device structures that employ phosphorus-doped (Zn,Mg)O have been examined in a effort to delineate the carrier type behavior in this material. The capacitance-voltage properties of metal/insulator/P-doped (Zn,Mg)O diode structures were measured and found to exhibit a polarity consistent with the P-doped (Zn,Mg)O layer being p-type. The photo-response of ZnO doped with phosphorus was investigated. A correlation between near band-edge emission and carrier density is observed. This is similar to results found for ZnO in which the carrier density is increased via annealing in a reducing ambient. Upon annealing in an oxidizing environment, the near band-edge emission decreased for both the undoped and phosphorus doped ZnO films. The magnetic properties of phosphorus doped ZnO thin films were examined after high dose Mn implantation. Films show room temperature hysteresis in magnetization loops. The saturation magnetization and coercivity of the implanted single-phase films were both strong functions of the initial annealing temperature. (Abstract shortened by UMI.)

Heo, Young-Woo

315

Repression of Sulfate Assimilation Is an Adaptive Response of Yeast to the Oxidative Stress of Zinc Deficiency*  

PubMed Central

The Zap1 transcription factor is a central player in the response of yeast to changes in zinc status. Previous studies identified over 80 genes activated by Zap1 in zinc-limited cells. In this report, we identified 36 genes repressed in a zinc- and Zap1-responsive manner. As a result, we have identified a new mechanism of Zap1-mediated gene repression whereby transcription of the MET3, MET14, and MET16 genes is repressed in zinc-limited cells. These genes encode the first three enzymes of the sulfate assimilation pathway. We found that MET30, encoding a component of the SCFMet30 ubiquitin ligase, is a direct Zap1 target gene. MET30 expression is increased in zinc-limited cells, and this leads to degradation of Met4, a transcription factor responsible for MET3, MET14, and MET16 expression. Thus, Zap1 is responsible for a decrease in sulfate assimilation in zinc-limited cells. We further show that cells that are unable to down-regulate sulfate assimilation under zinc deficiency experience increased oxidative stress. This increased oxidative stress is associated with an increase in the NADP+/NADPH ratio and may result from a decrease in NADPH-dependent antioxidant activities. These studies have led to new insights into how cells adapt to nutrient-limiting growth conditions. PMID:19656949

Wu, Chang-Yi; Roje, Sanja; Sandoval, Francisco J.; Bird, Amanda J.; Winge, Dennis R.; Eide, David J.

2009-01-01

316

Repression of sulfate assimilation is an adaptive response of yeast to the oxidative stress of zinc deficiency.  

PubMed

The Zap1 transcription factor is a central player in the response of yeast to changes in zinc status. Previous studies identified over 80 genes activated by Zap1 in zinc-limited cells. In this report, we identified 36 genes repressed in a zinc- and Zap1-responsive manner. As a result, we have identified a new mechanism of Zap1-mediated gene repression whereby transcription of the MET3, MET14, and MET16 genes is repressed in zinc-limited cells. These genes encode the first three enzymes of the sulfate assimilation pathway. We found that MET30, encoding a component of the SCF(Met30) ubiquitin ligase, is a direct Zap1 target gene. MET30 expression is increased in zinc-limited cells, and this leads to degradation of Met4, a transcription factor responsible for MET3, MET14, and MET16 expression. Thus, Zap1 is responsible for a decrease in sulfate assimilation in zinc-limited cells. We further show that cells that are unable to down-regulate sulfate assimilation under zinc deficiency experience increased oxidative stress. This increased oxidative stress is associated with an increase in the NADP(+)/NADPH ratio and may result from a decrease in NADPH-dependent antioxidant activities. These studies have led to new insights into how cells adapt to nutrient-limiting growth conditions. PMID:19656949

Wu, Chang-Yi; Roje, Sanja; Sandoval, Francisco J; Bird, Amanda J; Winge, Dennis R; Eide, David J

2009-10-01

317

Zinc Oxide Nanorod Based Ultraviolet Detectors with Wheatstone Bridge Design  

NASA Astrophysics Data System (ADS)

This research work, for the first time, investigated metal semiconductor-metal (MSM) zine oxide (ZnO) nanorod based ultra-violet (UV) detectors having a Wheatstone bridge design with a high responsivity at room temperature and above, as well as a responsivity that was largely independent of the change in ambient conditions. The ZnO nanorods which acted as the sensing element of the detector were grown by a chemical growth technique. Studies were conducted to determine the effects on ZnO nanorod properties by varying the concentration of the chemicals used for the rod growth. These studies showed how the rod diameter and the deposition of ZnO nanorods from the solution was controlled by varying the concentration of the chemicals used for the rod growth. Conventional MSM UV detectors were fabricated with ZnO nanorods grown under optimized conditions to determine the dependence of UV response on electrode dimension and rod dimension. These studies gave insights into the dependence of UV response on the width of the electrode, spacing between the electrodes, density of the rod growth, and length and diameter of the rods. The UV responsivity was affected by varying the number of times the seed layer was spin coated, by varying the spin speed of seed layer coating and by varying the annealing temperature of the seed and rod. Based on these studies, optimum conditions for the fabrication of Wheatstone bridge UV ZnO nanorod detectors were determined. The Wheatstone bridge ZnO nanorod UV detectors were fabricated in three different configurations, namely, symmetric, asymmetric, and quasi-symmetric. The transient responses of the symmetric, asymmetric and quasi-symmetric configurations at room temperature and above showed how the response stability differed. At high temperature the responsivity of quasi-symmetric Wheatstone bridge detector configuration did not drop after saturation and the responsivity drifted by 17% to 25% from the room temperature response.The responsivity of quasisymmetric Wheatstone bridge configuration with good temperature stability was 1.16 A/W, while those of conventional MSM UV detectors were approximately 60 A/W. However, the quasi-symmetric Wheatstone bridge with responsivity 1.16 A/W was higher than the commercially available detector having responsivity of only about 0.1 A/W. Though the response of quasi-symmetric Wheatstone bridge detector was higher than the detectors available commercially, the response time was very high. The response time of quasi-symmetric Wheatstone bridge was approximately 159 seconds at room temperature, while that of commercially available detectors is of the order of microseconds. If the quasi-symmetric Wheatstone bridge has to compete with current commercially available detectors, then the response time should be brought down from seconds to microseconds. Based on these studies, an improved design of the quasi-symmetric Wheatstone bridge UV detector with the ZnO rods oriented parallel to the substrate instead of oriented vertical to the substrate was proposed.

Vasudevan, Arun

318

Synthesis and characterization of single-crystalline zinc tin oxide nanowires  

NASA Astrophysics Data System (ADS)

Crystalline zinc tin oxide (ZTO; zinc oxide with heavy tin doping of 33 at.%) nanowires were first synthesized using the electrodeposition and heat treatment method based on an anodic aluminum oxide (AAO) membrane, which has an average diameter of about 60 nm. According to the field emission scanning electron microscopy (FE-SEM) results, the synthesized ZTO nanowires are highly ordered and have high wire packing densities. The length of ZTO nanowires is about 4 ?m, and the aspect ratio is around 67. ZTO nanowires with a Zn/(Zn + Sn) atomic ratio of 0.67 (approximately 2/3) were observed from an energy dispersive spectrometer (EDS). X-ray diffraction (XRD) and corresponding selected area electron diffraction (SAED) patterns demonstrated that the ZTO nanowire is hexagonal single-crystalline. The study of ultraviolet/visible/near-infrared (UV/Vis/NIR) absorption showed that the ZTO nanowire is a wide-band semiconductor with a band gap energy of 3.7 eV.

Shi, Jen-Bin; Wu, Po-Feng; Lin, Hsien-Sheng; Lin, Ya-Ting; Lee, Hsuan-Wei; Kao, Chia-Tze; Liao, Wei-Hsiang; Young, San-Lin

2014-05-01

319

Synthesis and characterization of single-crystalline zinc tin oxide nanowires  

PubMed Central

Crystalline zinc tin oxide (ZTO; zinc oxide with heavy tin doping of 33 at.%) nanowires were first synthesized using the electrodeposition and heat treatment method based on an anodic aluminum oxide (AAO) membrane, which has an average diameter of about 60 nm. According to the field emission scanning electron microscopy (FE-SEM) results, the synthesized ZTO nanowires are highly ordered and have high wire packing densities. The length of ZTO nanowires is about 4 ?m, and the aspect ratio is around 67. ZTO nanowires with a Zn/(Zn?+?Sn) atomic ratio of 0.67 (approximately 2/3) were observed from an energy dispersive spectrometer (EDS). X-ray diffraction (XRD) and corresponding selected area electron diffraction (SAED) patterns demonstrated that the ZTO nanowire is hexagonal single-crystalline. The study of ultraviolet/visible/near-infrared (UV/Vis/NIR) absorption showed that the ZTO nanowire is a wide-band semiconductor with a band gap energy of 3.7 eV. PMID:24872800

2014-01-01

320

Nano Zinc Oxide-Loaded Calcium Alginate Films with Potential Antibacterial Properties  

Microsoft Academic Search

In this work, zinc oxide nanoparticles-loaded calcium alginate films were investigated for their moisture uptake behavior\\u000a at different temperatures. The equilibrium uptake data was interpreted quantitatively by GAB isotherm models. The monolayer\\u000a moisture contents were 0.301?±?0.003, 0.0214?±?0.092, and 0.171?±?0.102 at 20, 30, and 37°C, respectively. The water vapor\\u000a transmission rate was found to be 0.816?±?0.143, 1.42?±?0.045, and 1.632?±?0.064 g?s?1 m?2 respectively. For

Sunil K. Bajpai; Navin Chand; Varsha Chaurasia

321

Growth mechanism of atomic layer deposition of zinc oxide: A density functional theory approach  

SciTech Connect

Atomic layer deposition of zinc oxide (ZnO) using diethylzinc (DEZ) and water is studied using density functional theory. The reaction pathways between the precursors and ZnO surface sites are discussed. Both reactions proceed by the formation of intermediate complexes on the surface. The Gibbs free energy of the formation of these complexes is positive at temperatures above ?120?°C and ?200?°C for DEZ and water half-reactions, respectively. Spectroscopic ellipsometry results show that the growth per cycle changes at approximately the same temperatures.

Afshar, Amir; Cadien, Kenneth C., E-mail: kcadien@ualberta.ca [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4 (Canada)

2013-12-16

322

Constrained, aqueous growth of three-dimensional single crystalline zinc oxide structures  

SciTech Connect

We study low temperature (90?°C) aqueous growth of single crystal zinc oxide structures through patterned PMMA molds of different sizes, shapes, and orientations. We demonstrate the ability to create 3D shapes with smooth vertical sidewalls. Although the unconstrained growth is influenced by the hexagonal geometry of the underlying crystal structure, the ZnO is shown to conform exactly to any shape patterned. Using electron backscatter diffraction and scanning electron microscopy we show that the mold orientation, in conjunction with control of the growth rates of the c and m planes of the ZnO, is crucial in determining the final structure shape.

Pooley, Kathryn J., E-mail: greenber@fas.harvard.edu; Joo, John H.; Hu, Evelyn L. [School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138 (United States)

2014-01-01

323

Aluminium-doped zinc oxide films prepared by an inorganic sol–gel route  

Microsoft Academic Search

Thin films of aluminium-doped zinc oxide have been formed on glass using an inorganic sol–gel route and the dip-coating process. The films were formed by the thermal decomposition of a stable precursor colloidal sol prepared by an ethanolic reflux of Zn(CH3COO)2·2H2O and Al(NO3)3·9H2O. Lactic acid was used as hydrolysis catalyst and acetylacetone and diethanolamine were added to improve film homogeneity.

Rodrigo F. Silva; Maria E. D. Zaniquelli

2004-01-01

324

The conductivity and magnetic properties of zinc oxide thin films doped with cobalt  

SciTech Connect

The magnetic properties, temperature dependences of the resistivity, Hall constant, and magnetoresistance of epitaxial zinc oxide films doped with cobalt are studied. The ferromagnetism of the films is observed at room temperature. The conduction and magnetoresistance of the films are attributed to transport of electrons in the conduction band at high temperatures and to hopping transport at low temperatures. With increasing concentration of cobalt dopants, the resistivity of the films increases and the concentration of electrons decreases. This is due to the increase in the ionization energy of donor states because of the increase in the energy of exchange interaction between electrons at donor states and electrons of the d shell of cobaltions.

Kytin, V. G., E-mail: kytin@mig.phys.msu.ru; Kulbachinskii, V. A.; Glebov, D. S.; Burova, L. I. [Moscow State University, Faculty of Physics (Russian Federation); Kaul, A. R.; Reukova, O. V. [Moscow State University, Faculty of Chemistry (Russian Federation)

2010-02-15

325

Cu-doped zinc oxide and its polythiophene composites: preparation and antibacterial properties.  

PubMed

Cu-doped zinc oxide and its polythiophene nanocomposites were prepared by the Sol-Gel and in situ polymerization methods, respectively. The structures, morphologies and compositions of the samples were characterized. The antibacterial properties of the samples on three kinds of strains were determined by using powder inhibition zones, minimum inhibitory concentrations and minimal bactericidal concentrations. The study confirmed that the antibacterial activities of the composites were better than those of their each component. The antibacterial mechanisms of the samples were discussed further. PMID:24342360

Ma, Ge; Liang, Xiaoxi; Li, Liangchao; Qiao, Ru; Jiang, Donghua; Ding, Yan; Chen, Haifeng

2014-04-01

326

Structural and optical properties of zinc oxide film using RF-sputtering technique  

SciTech Connect

This paper reports the fabrication of zinc oxide (ZnO) film using RF-sputtering technique. Determination of the structural properties using High Resolution X-ray Diffraction (HRXRD) confirmed that ZnO film deposited on silicon (Si) substrate has a high quality. This result is in line with the Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) which were used to image the morphology of the film, in which a rough surface was demonstrated. Photoluminescence (PL) emission is included to study the optical properties of ZnO film that shows two PL peak in the UV region at 371 nm and in visible region at 530 nm respectively.

Hashim, A. J.; Jaafar, M. S.; Ghazai, Alaa J. [Nano-Optoelectronics Research and Technology Laboratory, School of Physics, Universiti Sains Malaysia, 11800 Pinang (Malaysia); Physics Department, Science College, Thi-Qar University (Iraq)

2012-11-27

327

High stability of amorphous hafnium-indium-zinc-oxide thin film transistor  

NASA Astrophysics Data System (ADS)

Time dependence of the threshold voltage (Vth) shift in amorphous hafnium-indium-zinc oxide (a-HIZO) thin film transistor has been reported under on-current bias temperature stress measured at 60 °C. X-ray photoelectron spectroscopy results show the decrease in oxygen vacancies by Hf metal cations in a-HIZO systems after annealing process. High stability of a-HIZO systems has been observed due to low charge injection from the channel layer. Hf metal cations have been effectively incorporated into the IZO thin films as a suppressor against both the oxygen deficiencies and the carrier generation.

Chong, Eugene; Jo, Kyoung Chul; Lee, Sang Yeol

2010-04-01

328

Zinc Oxide Thin-Film Transistors Fabricated at Low Temperature by Chemical Spray Pyrolysis  

NASA Astrophysics Data System (ADS)

We report the electrical behavior of undoped zinc oxide thin-film transistors (TFTs) fabricated by low-temperature chemical spray pyrolysis. An aerosol system utilizing aerodynamic focusing was used to deposit the ZnO. Polycrystalline films were subsequently formed by annealing at the relatively low temperature of 140°C. The saturation mobility of the TFTs was 2 cm2/Vs, which is the highest reported for undoped ZnO TFTs manufactured below 150°C. The devices also had an on/off ratio of 104 and a threshold voltage of -3.5 V. These values were found to depend reversibly on measurement conditions.

Jeong, Yesul; Pearson, Christopher; Lee, Yong Uk; Winchester, Lee; Hwang, Jaeeun; Kim, Hongdoo; Do, Lee-Mi; Petty, Michael C.

2014-11-01

329

Chemical Etching of Zinc Oxide for Thin-Film Silicon Solar Cells  

PubMed Central

Abstract Chemical etching is widely applied to texture the surface of sputter-deposited zinc oxide for light scattering in thin-film silicon solar cells. Based on experimental findings from the literature and our own results we propose a model that explains the etching behavior of ZnO depending on the structural material properties and etching agent. All grain boundaries are prone to be etched to a certain threshold, that is defined by the deposition conditions and etching solution. Additionally, several approaches to modify the etching behavior through special preparation and etching steps are provided. PMID:22162035

Hüpkes, Jürgen; Owen, Jorj I; Pust, Sascha E; Bunte, Eerke

2012-01-01

330

Zinc oxide integrated area efficient high output low power wavy channel thin film transistor  

SciTech Connect

We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

Hanna, A. N.; Ghoneim, M. T.; Bahabry, R. R.; Hussain, A. M.; Hussain, M. M., E-mail: muhammadmustafa.hussain@kaust.edu.sa [Integrated Nanotechnology Lab, Electrical Engineering, Computer Electrical Mathematical Science and Engineering, King Abdullah University of Science and Technology, Thuwal 23955-6900 (Saudi Arabia)

2013-11-25

331

Surfactant-modified nickel zinc iron oxide\\/polymer nanocomposites for radio frequency applications  

Microsoft Academic Search

Low loss, flexible, polymer nanocomposites with improved magneto-dielectric properties at radio frequencies (RF) were successfully\\u000a fabricated. Surfactant-modified nickel zinc iron oxide (NiZnFe2O4) nanoparticles with ferrimagnetic behavior at room temperature were synthesized by a seed-mediated growth method. The surfactant\\u000a prevented NiZnFe2O4 particle aggregation and provided compatibility with [styrene-b-ethylene\\/butylene-b-styrene] block copolymer matrices. NiZnFe2O4\\/polymer composites were prepared by a solution-casting method. Experimental results

Ta-I. Yang; Rene N. C. Brown; Leo C. Kempel; Peter Kofinas

2010-01-01

332

Origin of ferromagnetism enhancement in bi-layer chromium-doped indium zinc oxides  

SciTech Connect

This work demonstrates that by controlling the rapid thermal annealing temperature, amorphous chromium-doped indium zinc oxide films develop an amorphous-crystalline bi-layer structure and show magnetization up to {approx}30 emu/cm{sup 3}. The crystalline layer arises from significant out-diffusion of Zn from surfaces, leading to a large difference in the Zn:In ratio in amorphous and crystalline layers. Doped Cr ions in amorphous and crystalline layers form different valence configurations, creating a charge reservoir which transfers electrons through amorphous-crystalline interfaces and in turn enhances ferromagnetism.

Hsu, C. Y. [Physics Department, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China)

2012-08-06

333

Amorphous indium-gallium-zinc-oxide visible-light phototransistor with a polymeric light absorption layer  

NASA Astrophysics Data System (ADS)

This work demonstrates a real-time visible-light phototransistor comprised of a wide-band-gap amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistor (TFT) and a narrow-band-gap polymeric capping layer. The capping layer and the IGZO layer form a p-n junction diode. The p-n junction absorbs visible light and consequently injects electrons into the IGZO layer, which in turn affects the body voltage as well as the threshold voltage of a-IGZO TFT. The hysteresis behavior due to the charges at IGZO back interface is also discussed.

Zan, Hsiao-Wen; Chen, Wei-Tsung; Hsueh, Hsiu-Wen; Kao, Shih-Chin; Ku, Ming-Che; Tsai, Chuang-Chuang; Meng, Hsin-Fei

2010-11-01

334

Photoelectrochemical cell using dye sensitized zinc oxide nanowires grown on carbon fibers  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanowires (NWs) grown on carbon fibers using a vapor transport and condensation approach are used as the cathode of a photoelectrochemical cell. The carbon fibers were obtained by electrospray deposition and take the form of a flexible carbon fabric. The ZnO NW on carbon fiber anode is combined with a "black dye" photoabsorber, an electrolyte, and a platinum (Pt) counterelectrode to complete the cell. The results show that ZnO NW and carbon fibers can be used for photoinduced charge separation/charge transport and current collection, respectively, in a photoelectrochemical cell.

Unalan, Husnu Emrah; Wei, Di; Suzuki, Kenichi; Dalal, Sharvari; Hiralal, Pritesh; Matsumoto, Hidetoshi; Imaizumi, Shinji; Minagawa, Mie; Tanioka, Akihiko; Flewitt, Andrew J.; Milne, William I.; Amaratunga, Gehan A. J.

2008-09-01

335

Mapping of two-photon luminescence amplification in zinc-oxide microstructures  

SciTech Connect

The mapping of two-photon excited luminescence in aggregations of free-standing zinc oxide microrods has been carried out at room temperature. Two-photon luminescence spectra in the excitonic region for individual microrods have been recorded. The luminescence intensity exhibits a power-law dependence on the optical pump power with the exponent n > 2. This fact, along with the existence of a threshold power above which the dependence in the exciton region deviates from a quadratic one, indicates the onset of light amplification in individual ZnO microrods and the conditions preceding laser oscillation.

Semin, S. V., E-mail: sv_semin@mail.ru; Sherstyuk, N. E.; Mishina, E. D. [Moscow State Technical University of Radio Engineering, Electronics and Automation (Russian Federation); Gherman, C.; Kulyuk, L. [Academy of Sciences of Moldova, Institute of Applied Physics (Moldova, Republic of); Rasing, Th. [Radboud University Nijmegen, Institute for Molecules and Materials (Netherlands); Peng, L.-H. [National Taiwan University, Department of Electrical Engineering and Institute of Photonics and Optoelectronics (China)

2012-03-15

336

Toxicities of nano zinc oxide to five marine organisms: influences of aggregate size and ion solubility  

Microsoft Academic Search

Nano zinc oxide (nZnO) is increasingly used in sunscreen products, with high potential of being released directly into marine\\u000a environments. This study primarily aimed to characterize the aggregate size and solubility of nZnO and bulk ZnO, and to assess\\u000a their toxicities towards five selected marine organisms. Chemical characterization showed that nZnO formed larger aggregates\\u000a in seawater than ZnO, while nZnO

Stella W. Y. Wong; Priscilla T. Y. Leung; A. B. Djuriši?; Kenneth M. Y. Leung

2010-01-01

337

Preparation of surface modified zinc oxide nanoparticle with high capacity dye removal ability  

SciTech Connect

Highlights: ? Amine-functionalized zinc oxide nanoparticle (AFZON) was synthesized. ? Isotherm and kinetics data followed Langmuir isotherm and pseudo-second order kinetic model, respectively. ? Q{sub 0} of ZON for AB25, DR23 and DR31 was 20, 12 and 15 mg/g, respectively. ? Q{sub 0} of AFZON for AB25, DR23 and DR31 was 1250, 1000 and 1429 mg/g, respectively. ? AFZON was regenerated at pH 12. -- Abstract: In this paper, the surface modification of zinc oxide nanoparticle (ZON) by amine functionalization was studied to prepare high capacity adsorbent. Dye removal ability of amine-functionalized zinc oxide nanoparticle (AFZON) and zinc oxide nanoparticle (ZON) was also investigated. The physical characteristics of AFZON were studied using Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Acid Blue 25 (AB25), Direct Red 23 (DR23) and Direct Red 31 (DR31) were used as model compounds. The effect of operational parameters such as dye concentration, adsorbent dosage, pH and salt on dye removal was evaluated. The isotherm and kinetic of dye adsorption were studied. The maximum dye adsorption capacity (Q{sub 0}) was 20 mg/g AB25, 12 mg/g DR23 and 15 mg/g DR31 for ZON and 1250 mg/g AB25, 1000 mg/g DR23 and 1429 mg/g DR31 for AFZON. It was found that dye adsorption followed Langmuir isotherm. Adsorption kinetic of dyes was found to conform to pseudo-second order kinetics. Dye desorption tests (adsorbent regeneration) showed that the maximum dye release of 90% AB25, 86% for DR23 and 90% for DR31 were achieved in aqueous solution at pH 12. Based on the data of the present investigation, it can be concluded that the AFZON being an adsorbent with high dye adsorption capacity might be a suitable alternative to remove dyes from colored aqueous solutions.

Mahmoodi, Niyaz Mohammad, E-mail: nm_mahmoodi@yahoo.com [Department of Environmental Research, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of); Najafi, Farhood [Department of Resin and Additives, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of)] [Department of Resin and Additives, Institute for Color Science and Technology, Tehran (Iran, Islamic Republic of)

2012-07-15

338

Zinc oxide quantum dots embedded films by metal organic chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) quantum dots (QDs) were fabricated on silicon substrates by metal organic chemical vapor deposition. Formation of QDs is due to the vigorous reaction of the precursors when a large amount of precursors was introduced during the growth. The size of the QDs ranged from 3 to 12 nm, which was estimated by high-resolution transmission electron microscopy. The photoluminescence measured at 80 K showed that the emission of QDs embedded film ranged from 3.0 to 3.6 eV. The broad near-band-edge emission was due to the quantum confinement effect of the QDs.

Tan, S. T.; Sun, X. W.; Zhang, X. H.; Chen, B. J.; Chua, S. J.; Yong, Anna; Dong, Z. L.; Hu, X.

2006-05-01

339

Protein Tyrosine Phosphatases as Targets of the Combined Insulinomimetic Effects of Zinc and Oxidants  

Microsoft Academic Search

Zinc ions have an insulin-like (insulinomimetic) effect. A particularly sensitive target of zinc ions is protein tyrosine phosphatase 1B (PTP 1B), a key regulator of the phosphorylation state of the insulin receptor. Modulation of insulin signaling by zinc chelating agents and the recognition of temporal and spatial fluctuations of zinc suggest a physiological role of zinc in insulin signal transduction.

Hajo Haase; Wolfgang Maret

2005-01-01

340

First-principles study of negative thermal expansion in zinc oxide  

NASA Astrophysics Data System (ADS)

We present the first-principles calculations of vibrational and thermal properties for wurtzite and zinc-blende zinc oxide (ZnO) within DFT and quasi-harmonic approximation, especially for their negative thermal expansion (NTE) behavior. For the wurtzite and zinc-blende phases, negative thermal expansions are obtained at T < 95 K and T < 84 K, respectively. For the wurtzite structure, calculated phonon frequencies and mode Grüneisen parameters of low-energy modes are in good agreement with that determined experimentally. And the thermal expansion coefficient is found to be in good agreement with the experimental results. Like many other NTE semiconductors, detailed study of both phases shows that maximum contribution to NTE comes from low-frequency transverse acoustic modes, while for the wurtzite structure the contribution of longitudinal acoustic and lowest-energy optical modes is not ignorable. From the specific analysis of the vibration modes, we found that the negative thermal expansion in ZnO is dominated by the tension effect.

Wang, Zhanyu; Wang, Fei; Wang, Lei; Jia, Yu; Sun, Qiang

2013-08-01

341

Post-Deposition Induced Conductivity in Pulsed Laser Irradiated Metal Doped Zinc Oxide Films  

SciTech Connect

The optical and electrical properties of doped solution-deposited and rf sputter-deposited thin metal oxide films were investigated following post deposition pulsed laser irradiation. Solution deposited films were annealed at 450 ºC. Following the heating regiment, the transparent metal oxide films were subjected to 355 nm pulsed Nd:YAG laser irradiation (4 nsec pulsewidth) at fluences between 5 and 150 mJ/cm2. Irradiation times at pulse frequencies of 30 Hz ranged from seconds to tens of minutes. Film densification, index change and a marked increase in conductivity were observed following irradiation in air and under vacuum of Al:ZnO (AZO), Ga:ZnO (GZO), and In:ZnO (IZO) films deposited on silica substrates. Despite the measured increase in conductivity, all films continued to show high transparency on the order of 90% at wavelengths from the band edge well into the near infrared region of the spectrum. Laser energies required for turning on the conductivity of these films varied depending upon the dopant. Irradiations in air yielded resistivity measurements on the order of 16 ?.cm. Resistivities of films irradiated under vacuum were on the order of 0.1 ?.cm. The increase in conductivity can be attributed to the formation of oxygen vacancies and subsequent promotion of free carriers into the conduction band. All irradiated films become insulating after around 24 hours. Oxygen atoms in air become reduced by electrons in the metal conduction band and diffuse into the vacancies in the lattice. The rate of this reduction process depends on the type of dopant. This work also sheds light on the damage threshold, correlating the optical properties with the presence of free carriers that have been introduced into the conduction band. All films were characterized by means of UV-VIS-NIR transmission spectroscopy, visible and UV Raman spectroscopy and Hall measurements. Analysis of interference fringes in measured transmission spectra allowed film density and refractive index to be evaluated while the Raman measurements showed an increase in LO mode intensity with respect to the TO mode intensity as the films became more conducting. Results of this study are not only important for the continued development of transparent conducting oxide films that find use in photovoltaic cells and solid state lighting modules, but also provide evidence for the role of free carriers in initiating the laser damage process in these wide bandgap metal oxide films.

Wang, Lisa J.; Exarhos, Gregory J.

2009-12-03

342

Oxidative stress parameters and antioxidant response to sublethal waterborne zinc in a euryhaline teleost Fundulus heteroclitus: protective effects of salinity.  

PubMed

Zinc is an essential trace metal, but many aspects of its toxicity remain unclear. In this study, we investigated zinc effects on oxidative stress parameters and antioxidant profile in four tissues (gill, liver, kidney, and white muscle) of Fundulus heteroclitus. Possible interactive effects of salinity were also studied. Killifish were exposed to sublethal level (500 ?gL(-1)) of waterborne zinc for 96 h in 0% (fresh water), 10% (3.5 ppt), 30% (10.5 ppt) and 100% sea water (35 ppt). Salinity per se had no effect on any parameter in the control groups. Zinc exposure clearly induced oxidative stress, and responses were qualitatively similar amongst different tissues. Salinity acted as a strong protective factor, with the highest levels of reactive oxygen species (ROS) and greatest damage (protein carbonyls, lipid peroxidation as indicated by thiobarbituric acid reactive substances (TBARS) in 0 ppt, the least in 100% sea water (35 ppt), and gradations in between in many of the observed responses. Increases in total oxidative scavenging capacity (TOSC) occurred at higher salinities, correlated with increases in the activities of superoxide dismutase (SOD) and glutathione-S-tranferase (GST), as well as in tissue glutathione (GSH) concentrations. However, TOSC was depleted in zinc-exposed fish at 0 ppt, accompanied by decreases in SOD, GST, GSH, and also catalase (CAT) activity. Our results confirm that sublethal waterborne zinc is an oxidative stressor in fish, and highlight the important protective role of higher salinities in ameliorating the oxidative stress associated with zinc toxicity in this model estuarine teleost. PMID:22343464

Loro, Vania Lucia; Jorge, Mariana Basso; Silva, Kassio Rios da; Wood, Chris M

2012-04-01

343

Enhanced Oxidative Stress Resistance through Activation of a Zinc Deficiency Transcription Factor in Brachypodium distachyon.  

PubMed

Identification of viable strategies to increase stress resistance of crops will become increasingly important for the goal of global food security as our population increases and our climate changes. Considering that resistance to oxidative stress is oftentimes an indicator of health and longevity in animal systems, characterizing conserved pathways known to increase oxidative stress resistance could prove fruitful for crop improvement strategies. This report argues for the usefulness and practicality of the model organism Brachypodium distachyon for identifying and validating stress resistance factors. Specifically, we focus on a zinc deficiency B. distachyon basic leucine zipper transcription factor, BdbZIP10, and its role in oxidative stress in the model organism B. distachyon. When overexpressed, BdbZIP10 protects plants and callus tissue from oxidative stress insults, most likely through distinct and direct activation of protective oxidative stress genes. Increased oxidative stress resistance and cell viability through the overexpression of BdbZIP10 highlight the utility of investigating conserved stress responses between plant and animal systems. PMID:25228396

Glover-Cutter, Kira M; Alderman, Stephen; Dombrowski, James E; Martin, Ruth C

2014-11-01

344

Effect of nitrogen doping on wetting and photoactive properties of laser processed zinc oxide-graphene oxide nanocomposite layers  

NASA Astrophysics Data System (ADS)

Zinc oxide-graphene oxide nanocomposite layers were submitted to laser irradiation in air or controlled nitrogen atmosphere using a frequency quadrupled Nd:YAG (? = 266 nm, ?FWHM ? 3 ns, ? = 10 Hz) laser source. The experiments were performed in air at atmospheric pressure or in nitrogen at a pressure of 2 × 104 Pa. The effect of the irradiation conditions, incident laser fluence value, and number of subsequent laser pulses on the surface morphology of the composite material was systematically investigated. The obtained results reveal that nitrogen incorporation improves significantly the wetting and photoactive properties of the laser processed layers. The kinetics of water contact angle variation when the samples are submitted to laser irradiation in nitrogen are faster than that of the samples irradiated in air, the surfaces becoming super-hydrophilic under UV light irradiation.

György, E.; Pérez del Pino, A.; Logofatu, C.; Duta, A.; Isac, L.

2014-07-01

345

Dye sensitized solar cells using well-aligned zinc oxide nanotip arrays  

NASA Astrophysics Data System (ADS)

Well-aligned zinc oxide (ZnO) nanotip arrays were grown on fluorinated tin oxide coated glass using metal organic chemical vapor deposition. Dye (N719) sensitized photoelectrochemical cells comprising of ZnO nanotip arrays were fabricated and characterized. It is found that the power conversion efficiency of the cells increases with the length of the ZnO nanotips. The cells with 3.2?m ZnO nanotip array exhibited an incident photon-to-current conversion efficiency of 21.1% (at 550nm) and a power conversion efficiency of 0.55% under 1 sun irradiance. Light harvesting in ZnO nanotips also contributes to the photocurrent in the UV range.

Du Pasquier, Aurelien; Chen, Hanhong; Lu, Yicheng

2006-12-01

346

Hydrogen plasma treatment for improved conductivity in amorphous aluminum doped zinc tin oxide thin films  

NASA Astrophysics Data System (ADS)

Improving the conductivity of earth-abundant transparent conductive oxides (TCOs) remains an important challenge that will facilitate the replacement of indium-based TCOs. Here, we show that a hydrogen (H2)-plasma post-deposition treatment improves the conductivity of amorphous aluminum-doped zinc tin oxide while retaining its low optical absorption. We found that the H2-plasma treatment performed at a substrate temperature of 50 °C reduces the resistivity of the films by 57% and increases the absorptance by only 2%. Additionally, the low substrate temperature delays the known formation of tin particles with the plasma and it allows the application of the process to temperature-sensitive substrates.

Morales-Masis, M.; Ding, L.; Dauzou, F.; Jeangros, Q.; Hessler-Wyser, A.; Nicolay, S.; Ballif, C.

2014-09-01

347

Cesium-doped zinc oxide as electron selective contact in inverted organic photovoltaics  

NASA Astrophysics Data System (ADS)

Water based sol-gel processed Cesium-doped Zinc oxide (CZO) with low processing annealing temperature is introduced as an efficient electron selective contact in inverted Organic Photovoltaics (OPVs). The corresponding inverted OPVs not only demonstrate similar performance compared to the well-established sol-gel processed ZnO inverted devices but also maintain their functionality when thick layers of CZO, suitable for the up scaling scenario of OPVs have been used. The three orders of magnitude higher conductivity of CZO than ZnO in combination with the high transmittance above 80%, makes this doped oxide a suitable electron selective contact for the low-cost, roll-to-roll printing process of OPVs.

Savva, Achilleas; Choulis, Stelios A.

2013-06-01

348

Quantitative analysis of amorphous indium zinc oxide thin films synthesized by Combinatorial Pulsed Laser Deposition  

NASA Astrophysics Data System (ADS)

The use of amorphous and transparent oxides is a key for the development of new thin film transistors and displays. Recently, indium zinc oxide (IZO) was shown to exhibit high transparency in the visible range, low resistivity, and high mobility. Since the properties and the cost of these films depend on the In/(In + Zn) values, the measurement of this ratio is paramount for future developments and applications. We report on accurate analysis of the elemental composition of IZO thin films synthesized using a Combinatorial Pulsed Laser Deposition technique. The monitoring of the thin films elemental composition by Laser-Induced Breakdown Spectroscopy was chosen in view of further in situ and real-time technological developments and process control during IZO fabrication. Our analytical approach is based on plasma modeling, the recorded spectra being then compared to the spectral radiance computed for plasmas in local thermal equilibrium. The cation fractions measured were compared to values obtained by complementary measurements using energy dispersive X-ray spectroscopy and Rutherford backscattering spectrometry. Spectroscopic ellipsometry assisted the scientific discussion. A good agreement between methods was found, independently of the relative fraction of indium and zinc that varied from about 65 to 90 and 35 to 10 at%, respectively, and the measurement uncertainties associated to each analytical method.

Axente, E.; Socol, G.; Beldjilali, S. A.; Mercadier, L.; Luculescu, C. R.; Trinca, L. M.; Galca, A. C.; Pantelica, D.; Ionescu, P.; Becherescu, N.; Hermann, J.; Craciun, V.

2014-10-01

349

Protein Biosensors Based on Polymer Nanowires, Carbon Nanotubes and Zinc Oxide Nanorods  

PubMed Central

The development of biosensors using electrochemical methods is a promising application in the field of biotechnology. High sensitivity sensors for the bio-detection of proteins have been developed using several kinds of nanomaterials. The performance of the sensors depends on the type of nanostructures with which the biomaterials interact. One dimensional (1-D) structures such as nanowires, nanotubes and nanorods are proven to have high potential for bio-applications. In this paper we review these three different kinds of nanostructures that have attracted much attention at recent times with their great performance as biosensors. Materials such as polymers, carbon and zinc oxide have been widely used for the fabrication of nanostructures because of their enhanced performance in terms of sensitivity, biocompatibility, and ease of preparation. Thus we consider polymer nanowires, carbon nanotubes and zinc oxide nanorods for discussion in this paper. We consider three stages in the development of biosensors: (a) fabrication of biomaterials into nanostructures, (b) alignment of the nanostructures and (c) immobilization of proteins. Two different methods by which the biosensors can be developed at each stage for all the three nanostructures are examined. Finally, we conclude by mentioning some of the major challenges faced by many researchers who seek to fabricate biosensors for real time applications. PMID:22163892

M., Anish Kumar; Jung, Soyoun; Ji, Taeksoo

2011-01-01

350

Tuning electrical properties in amorphous zinc tin oxide thin films for solution processed electronics.  

PubMed

Solution processed zinc tin oxide (ZTO) thin film transistors (TFTs) were fabricated by varying the Zn/Sn composition. The addition of Sn to the zinc oxide (ZnO) films resulted in improved electrical characteristics, with devices of Zn0.7Sn0.3O composition showing the highest mobility of 7.7 cm(2)/(V s). An improvement in subthreshold swings was also observed, indicative of a reduction of the interfacial trap densities. Mobility studies at low temperature have been carried out, which indicated that the activation energy was reduced with Sn incorporation. Kelvin probe force microscopy was performed on the films to evaluate work function and correlated to the metal-semiconductor barrier indicating Zn0.7Sn0.3O films had the smallest barrier for charge injection. Organic-inorganic hybrid complementary inverters with a maximum gain of 10 were fabricated by integrating ZTO TFTs with poly-3-hexylthiophene (P3HT) transistors. PMID:24380364

Chandra, R Devi; Rao, Manohar; Zhang, Keke; Prabhakar, Rajiv Ramanujam; Shi, Chen; Zhang, Jie; Mhaisalkar, Subodh G; Mathews, Nripan

2014-01-22

351

Dual operation characteristics of resistance random access memory in indium-gallium-zinc-oxide thin film transistors  

NASA Astrophysics Data System (ADS)

In this study, indium-gallium-zinc-oxide thin film transistors can be operated either as transistors or resistance random access memory devices. Before the forming process, current-voltage curve transfer characteristics are observed, and resistance switching characteristics are measured after a forming process. These resistance switching characteristics exhibit two behaviors, and are dominated by different mechanisms. The mode 1 resistance switching behavior is due to oxygen vacancies, while mode 2 is dominated by the formation of an oxygen-rich layer. Furthermore, an easy approach is proposed to reduce power consumption when using these resistance random access memory devices with the amorphous indium-gallium-zinc-oxide thin film transistor.

Yang, Jyun-Bao; Chang, Ting-Chang; Huang, Jheng-Jie; Chen, Yu-Chun; Chen, Yu-Ting; Tseng, Hsueh-Chih; Chu, Ann-Kuo; Sze, Simon M.

2014-04-01

352

Improvement in the Bias Stability of Zinc-Tin Oxide Thin-Film Transistors by Hafnium Doping  

NASA Astrophysics Data System (ADS)

The influence of hafnium (Hf) doping on negative-bias temperature instability in zinc-tin oxide thin-film transistors was studied. Hafnium-zinc-tin oxide TFTs exhibited a turn-on voltage ( V ON) that shifted from 0 V to -1 V with negligible changes in the subthreshold swing and field-effect mobility after 3 h of total stresses. The enhanced improvement of the V ON shift (? V ON) was attributed to the reduction in the interface trap density, which may result from the suppression of oxygen-vacancy-related defects by the Hf ions.

Han, Dong-Suk; Park, Jae-Hyung; Kang, Yu-Jin; Park, Jong-Wan

2013-08-01

353

Reactivity of nanoparticles; interaction between zinc and copper oxide nanoparticles and iron ions in an alkaline medium  

Microsoft Academic Search

The reactivity of zinc and copper oxide nanoparticles was investigated upon their interaction with iron oxides. It was ascertained\\u000a that, depending on the reaction conditions, nanoparticles of zinc and copper ferrites (ZnFe2O4 and CuFe2O4) or core\\/shell nanoparticles (Fe3O4\\/ZnO) are produced. Size, composition, and structure of the resulting nanoparticles were determined by transmission electron\\u000a microscopy and X-ray diffraction analysis. The average

A. Ya. Shalyapina; L. A. Polyakova; M. A. Zaporozhets; E. M. Khokhlov; S. P. Gubin

2011-01-01

354

Zinc Oxide Nanoparticles for Selective Destruction of Tumor Cells and Potential for Drug Delivery Applications  

PubMed Central

Importance of the field Metal oxide nanoparticles, including zinc oxide, are versatile platforms for biomedical applications and therapeutic intervention. There is an urgent need to develop new classes of anticancer agents, and recent studies demonstrate that ZnO nanomaterials hold considerable promise. Areas covered in this review This review analyzes the biomedical applications of metal oxide and ZnO nanomaterials under development at the experimental, preclinical, and clinical levels. A discussion regarding the advantages, approaches, and limitations surrounding the use of metal oxide nanoparticles for cancer applications and drug delivery is presented. The scope of this article is focused on ZnO, and other metal oxide nanomaterial systems, and their proposed mechanisms of cytotoxic action, as well as current approaches to improve their targeting and cytotoxicity against cancer cells. Take home message Through a better understanding of the mechanisms of action and cellular consequences resulting from nanoparticles interactions with cells, the inherent toxicity and selectivity of ZnO nanoparticles against cancer may be further improved to make them attractive new anti-cancer agents. PMID:20716019

Rasmussen, John W.; Martinez, Ezequiel; Louka, Panagiota; Wingett, Denise G.

2010-01-01

355

The reduction of graphene oxide by zinc powder to produce a zinc oxide-reduced graphene oxide hybrid and its superior photocatalytic activity  

NASA Astrophysics Data System (ADS)

We have synthesized for the first time ZnO/rGO hybrids from metal zinc and GO using hydrothermal technique without adding further reducing agent. The photocatalytic property of ZnO-rGO reveals that the hybrid for 50 mg of GO has the highest activity, causing a 94% degradation of methyl orange compared to 70% by only ZnO. The consistent quenching and a gradual decrease in the decay life time of the emission at ˜500 nm as the rGO content increases indicates the interfacial charge transfer process between ZnO and rGO by the defect states responsible for green emission.

Sarkar, Sanjit; Basak, Durga

2013-03-01

356

Effect of Dietary Zinc Oxide on Morphological Characteristics, Mucin Composition and Gene Expression in the Colon of Weaned Piglets  

PubMed Central

The trace element zinc is often used in the diet of weaned piglets, as high doses have resulted in positive effects on intestinal health. However, the majority of previous studies evaluated zinc supplementations for a short period only and focused on the small intestine. The hypothesis of the present study was that low, medium and high levels of dietary zinc (57, 164 and 2,425 mg Zn/kg from zinc oxide) would affect colonic morphology and innate host defense mechanisms across 4 weeks post-weaning. Histological examinations were conducted regarding the colonic morphology and neutral, acidic, sialylated and sulphated mucins. The mRNA expression levels of mucin (MUC) 1, 2, 13, 20, toll-like receptor (TLR) 2, 4, interleukin (IL)-1?, 8, 10, interferon-? (IFN-?) and transforming growth factor-? (TGF-?) were also measured. The colonic crypt area increased in an age-depending manner, and the greatest area was found with medium concentration of dietary zinc. With the high concentration of dietary zinc, the number of goblet cells containing mixed neutral-acidic mucins and total mucins increased. Sialomucin containing goblet cells increased age-dependently. The expression of MUC2 increased with age and reached the highest level at 47 days of age. The expression levels of TLR2 and 4 decreased with age. The mRNA expression of TLR4 and the pro-inflammatory cytokine IL-8 were down-regulated with high dietary zinc treatment, while piglets fed with medium dietary zinc had the highest expression. It is concluded that dietary zinc level had a clear impact on colonic morphology, mucin profiles and immunological traits in piglets after weaning. Those changes might support local defense mechanisms and affect colonic physiology and contribute to the reported reduction of post-weaning diarrhea. PMID:24609095

Liu, Ping; Pieper, Robert; Rieger, Juliane; Vahjen, Wilfried; Davin, Roger; Plendl, Johanna; Meyer, Wilfried; Zentek, Jurgen

2014-01-01

357

Surface Composition, Work Function, and Electrochemical Characteristics of Gallium-Doped Zinc Oxide  

SciTech Connect

Gallium-doped zinc oxide (GZO) possesses the electric conductivity, thermal stability, and earth abundance to be a promising transparent conductive oxide replacement for indium tin oxide electrodes in a number of molecular electronic devices, including organic solar cells and organic light emitting diodes. The surface chemistry of GZO is complex and dominated by the hydrolysis chemistry of ZnO, which influences the work function via charge transfer and band bending caused by adsorbates. A comprehensive characterization of the surface chemical composition and electrochemical properties of GZO electrodes is presented, using both solution and surface adsorbed redox probe molecules. The GZO surface is characterized using monochromatic X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy after the following pretreatments: (i) hydriodic acid etch, (ii) potassium hydroxide etch, (iii) RF oxygen plasma etching, and (iv) high-vacuum argon-ion sputtering. The O 1s spectra for the GZO electrodes have contributions from the stoichiometric oxide lattice, defects within the lattice, hydroxylated species, and carbonaceous impurities, with relative near-surface compositions varying with pretreatment. Solution etching procedures result in an increase of the work function and ionization potential of the GZO electrode, but yield different near surface Zn:Ga atomic ratios, which significantly influence charge transfer rates for a chemisorbed probe molecule. The near surface chemical composition is shown to be the dominant factor in controlling surface work function and significantly influences the rate of electron transfer to both solution and tethered probe molecules.

Ratcliff, E. L.; Sigdel, A. K.; Macech, M. R.; Nebesny, K.; Lee, P. A.; Ginley, D. S.; Armstrong, N. R.; Berry, J. J.

2012-06-30

358

Intrinsic and interfacial effect of electrode metals on the resistive switching behaviors of zinc oxide films  

NASA Astrophysics Data System (ADS)

Exploring the role of electrode metals on the resistive switching properties of metal electrode/oxide/metal electrode sandwiched structures provides not only essential information to understand the underlying switching mechanism of the devices, but also useful guidelines for the optimization of the switching performance. A systematic study has been performed to investigate the influence of electrodes on the resistive switching characteristics of zinc oxide (ZnO) films in this contribution, in terms of both the intrinsic and interfacial effects. It has been found that the low-resistance state resistances (ΩLRS) of all the investigated devices are below 50 Ω, which can be attributed to the formation of highly conductive channels throughout the ZnO films. On the other hand, the high-resistance state resistances (ΩHRS) depend on the electronegativity and ionic size of the employed electrode metals. Devices with electrode metals of high electronegativity and large ionic size possess high ΩHRS values, while those with electrode metals of low electronegativity and small ionic size carry low ΩHRS values. A similar trend of the set voltages has also been observed, while the reset voltages are all distributed in a narrow range close to ±0.5 V. Moreover, the forming voltages of the switching devices strongly depend on the roughness of the metal/ZnO and/or ZnO/metal interface. The present work provides essential information for better understanding the switching mechanism of zinc oxide based devices, and benefits the rational selection of proper electrode metals for the device performance optimization.

Xue, W. H.; Xiao, W.; Shang, J.; Chen, X. X.; Zhu, X. J.; Pan, L.; Tan, H. W.; Zhang, W. B.; Ji, Z. H.; Liu, G.; Xu, X.-H.; Ding, J.; Li, R.-W.

2014-10-01

359

Intrinsic and interfacial effect of electrode metals on the resistive switching behaviors of zinc oxide films.  

PubMed

Exploring the role of electrode metals on the resistive switching properties of metal electrode/oxide/metal electrode sandwiched structures provides not only essential information to understand the underlying switching mechanism of the devices, but also useful guidelines for the optimization of the switching performance. A systematic study has been performed to investigate the influence of electrodes on the resistive switching characteristics of zinc oxide (ZnO) films in this contribution, in terms of both the intrinsic and interfacial effects. It has been found that the low-resistance state resistances (?LRS) of all the investigated devices are below 50 ?, which can be attributed to the formation of highly conductive channels throughout the ZnO films. On the other hand, the high-resistance state resistances (?HRS) depend on the electronegativity and ionic size of the employed electrode metals. Devices with electrode metals of high electronegativity and large ionic size possess high ?HRS values, while those with electrode metals of low electronegativity and small ionic size carry low ?HRS values. A similar trend of the set voltages has also been observed, while the reset voltages are all distributed in a narrow range close to ±0.5 V. Moreover, the forming voltages of the switching devices strongly depend on the roughness of the metal/ZnO and/or ZnO/metal interface. The present work provides essential information for better understanding the switching mechanism of zinc oxide based devices, and benefits the rational selection of proper electrode metals for the device performance optimization. PMID:25274278

Xue, W H; Xiao, W; Shang, J; Chen, X X; Zhu, X J; Pan, L; Tan, H W; Zhang, W B; Ji, Z H; Liu, G; Xu, X-H; Ding, J; Li, R-W

2014-10-24

360

Field-emission stability of hydrothermally synthesized aluminum-doped zinc oxide nanostructures.  

PubMed

The Al-doped ZnO (AZO) nanostructures field-emission arrays (FEAs) were hydrothermally synthesized on AZO/glass substrate. The samples with Al-dosage of 3 at.% show the morphology as nanowires vertically grown on the substrates and a structure of c-axis elongated single-crystalline wurtzite. The good field-emission (i.e., the large anode current and low fluctuation of 15.9%) can be found by AZO nanostructure FEAs with well-designed Al-dosage (i.e., 3 at.%) because of the vertical nanowires with the less structural defects and superior crystallinity. Moreover, the Full width at half maximum (FWHM) of near band-edge emission (NBE) decreased as the increase of annealing temperature, representing the compensated structural defects during oxygen ambient annealing. After the oxygen annealing at 500 degrees C, the hydrothermal AZO nanostructure FEAs revealed the excellent electrical characteristics (i.e., the larger anode current and uniform distribution of induced fluorescence) and enhanced field-emission stability (i.e., the lowest current fluctuation of 5.97%). PMID:22966589

Hsieh, Tsang-Yen; Wang, Jyh-Liang; Yang, Po-Yu; Hwang, Chuan-Chou; Shye, Der-Chi

2012-07-01

361

Sol-Gel Zinc Oxide Humidity Sensors Integrated with a Ring Oscillator Circuit On-a-Chip.  

PubMed

The study develops an integrated humidity microsensor fabricated using the commercial 0.18 ?m complementary metal oxide semiconductor (CMOS) process. The integrated humidity sensor consists of a humidity sensor and a ring oscillator circuit on-a-chip. The humidity sensor is composed of a sensitive film and branch interdigitated electrodes. The sensitive film is zinc oxide prepared by sol-gel method. After completion of the CMOS process, the sensor requires a post-process to remove the sacrificial oxide layer and to coat the zinc oxide film on the interdigitated electrodes. The capacitance of the sensor changes when the sensitive film adsorbs water vapor. The circuit is used to convert the capacitance of the humidity sensor into the oscillation frequency output. Experimental results show that the output frequency of the sensor changes from 84.3 to 73.4 MHz at 30 °C as the humidity increases 40 to 90%RH. PMID:25353984

Yang, Ming-Zhi; Dai, Ching-Liang; Wu, Chyan-Chyi

2014-01-01

362

Analysis of dose-dependent effect of zinc oxide nanoparticles on the oxidative stress and antioxidant enzyme activity in adipocytes.  

PubMed

The present study aimed to synthesize Zinc oxide (ZnO) nanoparticles and to analyze the dose-dependent effect on the oxidative stress and antioxidant enzyme activities in 3T3-L1 adipocytes. ZnO is widely used in the several cosmetic lotions and biomedical products. There are several studies that have reported the ZnO nanoparticle-mediated cytotoxicity on various tissues. However, there are no studies carried out on dose-dependent effect of ZnO nanoparticles in the adipose tissue. ZnO nanoparticle was synthesized by chemical pyrolysis method and characterized by the SEM. A cytotoxicity assay was carried out to determine 3T3-L1 cell viability. 3T3-L1 cell morphology was significantly altered, and most of the cells are dead at higher concentration of ZnO nanoparticles. ZnO nanoparticles increased reactive oxygen species (ROS), lipid peroxidation (MDA), and reduced glutathione (GSH) in 3T3-L1 adipocytes. In addition, antioxidant enzyme activity and its mRNA expression were also upregulated in 3T3-L1 adipocytes. In conclusion, the present study showed that ZnO nanoparticles significantly altered oxidative stress and antioxidant enzyme activity in 3T3-L1 adipocytes on a dose-dependent manner. PMID:25234395

Muthuraman, Pandurangan; Ramkumar, Kothandam; Kim, Doo Hwan

2014-12-01

363

Hydrogen sulfide adsorption on nano-sized zinc oxide/reduced graphite oxide composite at ambient condition  

NASA Astrophysics Data System (ADS)

This paper presents new insights on the synthesis of nano-ZnO on reduced graphite oxide (rGO) composite via a microwave-assisted route and its use as a potential sorbent to adsorb hydrogen sulfide (H2S) at ambient conditions. Depending on the synthesis methods, the nano-sized ZnO on rGO presents different characteristics, in particular the degree of nano-ZnO dispersion on the surface of the rGO. Microwave-assisted reduction was able to offer a mild reduction to the oxygen-containing functional groups attached on the surface of graphite oxide (GO). Those oxygen-containing functional groups provide the bridge and the terminal groups between zinc oxide and the rGO surface. Because those functional groups act as anchor sites for metal ions, it was possible to achieve uniformly distributed nano-sized ZnO particles on the surface of the rGO sheets. In addition, they accelerate oxygen activation for H2S adsorption. H2S adsorption tests at ambient conditions were conducted. The 1-D carbon nanotubes (CNTs) had been used for reference in order to investigate the functionality of 2-D rGO substrate. Also, the effects of the different synthesis methods (microwave vs. reflux) were evaluated for H2S adsorption. The adsorption capacity increased dramatically for the microwave-assisted composite compared to the composite manufactured using the reflux method.

Song, Hoon Sub; Park, Moon Gyu; Kwon, Soon Jin; Yi, Kwang Bok; Croiset, Eric; Chen, Zhongwei; Nam, Sung Chan

2013-07-01

364

Mineral filters in sunscreen products--comparison of the efficacy of zinc oxide and titanium dioxide by in vitro method.  

PubMed

European legislation currently authorizes 26 sun filters among which, there is only one mineral filter: titanium dioxide. In the United States, two mineral filters are authorized: titanium dioxide in a maximum dose of 25% and zinc oxide. Zinc oxide is authorized in Europe, but its concentration level is not limited. A large number of commercial products are containing one of these mineral filters. The difference between these products lies in the percentage of the active substance, the way they are incorporated into the final product and the size of the primary particles. Depending on the ingredient used, there is a large variation in efficacy. The efficacy of the products tested was determined by an in vitro method using a spectrophotometer equipped with an integration sphere. Titanium dioxide was thus seen to be much more effective than zinc oxide; indeed no commercial form of zinc oxide tested can give a sun protection factor (SPF) higher than 10 at its maximum dose of use, unlike titanium dioxide which in its coated form (coated with alumina and with stearic acid, amongst others) gives a SPF of 38. This study has also allowed us to dispel the theory that talc--a raw material which has been used empirically for years in foundation in the belief that it has photoprotective effects--has an effect against sun rays. Talc proved to be particularly ineffective, as when it is used at a level of 25%, it only gives a totally negligible SPF of one unit. PMID:18271305

Couteau, C; Alami, S; Guitton, M; Paparis, E; Coiffard, L J M

2008-01-01

365

Effect of doping level and spray time on zinc oxide thin films produced by spray pyrolysis for transparent electrodes applications  

Microsoft Academic Search

In this paper, we present the results of optical, electrical and structural properties of zinc oxide (ZnO) semiconductors thin layers with various aluminium (Al) doping level and deposited at different spray time using the spray pyrolysis technique in atmospheric pressure. The study of optical properties from reflection and transmission spectra shows a high transmission value a band gap energy of

Z. Ben Achour; T. Ktari; B. Ouertani; O. Touayar; B. Bessais; J. Ben Brahim

2007-01-01

366

Optical investigations in a PEM controlled reactive magnetron sputter process for aluminium doped zinc oxide layers using metallic alloy targets  

Microsoft Academic Search

The use of aluminium doped zinc oxide (ZAO) as transparent conductive layer (TCO) has growing importance especially for production of solar modules. A significant cost reduction of TCO thin film production is expected by use of much less expensive metallic alloy targets. ZAO films with good TCO properties can be achieved only in the transition mode of the reactive sputter

Till Wallendorf; Swen Marke; Christian May; Johannes Strümpfel

2003-01-01

367

The characteristics of aluminium-doped zinc oxide films prepared by pulsed magnetron sputtering from powder targets  

Microsoft Academic Search

Mixed zinc oxide and alumina powder targets have been used to prepare transparent semi-conductive films on glass by pulsed magnetron sputtering. The structure, crystallinity, optical properties, electrical properties and adhesion of the films were investigated using a range of techniques, including SEM, XRD, spectrophotometry, four-point probe and scratch adhesion testing. Also, the properties of the coatings before and after annealing

Y. Zhou; P. J. Kelly; A. Postill; O. Abu-Zeid; A. A. Alnajjar

2004-01-01

368

Gas sensing properties of a clad modified fiber optic sensor with Ce, Li and Al doped nanocrystalline zinc oxides  

Microsoft Academic Search

Spectral characteristics of a clad modified fiber optic gas sensor are studied for various concentrations (0–500ppm) of ammonia, methanol and ethanol at room temperature. Cerium, aluminum and lithium doped (6at.%) nanocrystalline zinc oxides are replaced with a clad and used as gas sensing materials. The study shows that the spectral intensity increases linearly with concentration for ammonia whereas it decreases

B. Renganathan; D. Sastikumar; G. Gobi; N. Rajeswari Yogamalar; A. Chandra Bose

2011-01-01

369

Surface textured molybdenum doped zinc oxide thin films prepared for thin film solar cells using pulsed direct current magnetron sputtering  

Microsoft Academic Search

In this study, we examined the effect of etching on the electrical properties, transmittance, and scattering of visible light in molybdenum doped zinc oxide, ZnO:Mo (MZO) thin films prepared by pulsed direct current magnetron sputtering. We used two different etching solutions – KOH and HCl – to alter the surface texture of the MZO thin film so that it could

Y. C. Lin; B. L. Wang; W. T. Yen; C. H. Shen

2011-01-01

370

Epitaxial growth of aluminium-doped zinc oxide films by magnetron sputtering on (001), (110), and (012) oriented sapphire substrates  

Microsoft Academic Search

Highly aluminium-doped zinc oxide (ZnO) films have been grown on differently oriented sapphire substrates by magnetron sputtering from an oxidic target. Rocking curve measurements, Rutherford backscattering analysis and transmission electron microscopy show that the films exhibit a disturbed film growth. However, despite the large nominal lattice mismatch between ZnO and sapphire (-31%), the films grow epitaxially on every sapphire orientation,

P. Kuppusami; G. Vollweiler; D. Rafaja; K. Ellmer

2005-01-01

371

Mechanisms underlying the protective effect of zinc and selenium against cadmium-induced oxidative stress in zebrafish Danio rerio  

Microsoft Academic Search

The present study was designed to elucidate the protective effect mechanism of Zinc (Zn) and Selenium (Se) on cadmium (Cd)-induced\\u000a oxidative stress in zebrafish. For this purpose we investigate the response of oxidative stress markers, metallothionein accumulation\\u000a and gene expression in liver and ovary of female zebrafish exposed to 0,4 mg\\/l Cd in water and supplemented with Zn (5 mg\\u000a kg?1) and\\/or

Mohamed Banni; Lina Chouchene; Khaled Said; Abdelhamid Kerkeni; Imed Messaoudi

372

A novel approach reveals that zinc oxide nanoparticles are bioavailable and toxic after dietary exposures  

USGS Publications Warehouse

If engineered nanomaterials are released into the environment, some are likely to end up associated with the food of animals due to aggregation and sorption processes. However, few studies have considered dietary exposure of nanomaterials. Here we show that zinc (Zn) from isotopically modified 67ZnO particles is efficiently assimilated by freshwater snails when ingested with food. The 67Zn from nano-sized 67ZnO appears as bioavailable as 67Zn internalized by diatoms. Apparent agglomeration of the zinc oxide (ZnO) particles did not reduce bioavailability, nor preclude toxicity. In the diet, ZnO nanoparticles damage digestion: snails ate less, defecated less and inefficiently processed the ingested food when exposed to high concentrations of ZnO. It was not clear whether the toxicity was due to the high Zn dose achieved with nanoparticles or to the ZnO nanoparticles themselves. Further study of exposure from nanoparticles in food would greatly benefit assessment of ecological and human health risks. ?? 2011 Informa UK, Ltd.

Croteau, M.-N.; Dybowska, A.D.; Luoma, S.N.; Valsami-Jones, E.

2011-01-01

373

Transparent conductive indium zinc oxide films prepared by pulsed plasma deposition  

SciTech Connect

Transparent conductive indium zinc oxide films were prepared by pulsed plasma deposition from a ceramic target (90 wt. % In{sub 2}O{sub 3} and 10 wt. % ZnO). The dependences of film properties upon the substrate temperature was investigated using characterization methods including x-ray diffraction, atomic force microscope, Hall measurement, ultraviolet-visible spectroscopy, and x-ray photoelectron spectroscopy. The films grown at room temperature had a rather smooth surface due to the amorphous structure, with a root mean square roughness of less than 1 nm. The atomic ratio of Zn/(Zn + In) in these films is 15.3 at. %, which is close to that in the target, and the chemical states of indium and zinc atoms were In{sup 3+} and Zn{sup 2+}, respectively. The films deposited on a substrate with a temperature of 200 Degree-Sign C exhibited polycrystalline structure and a preferred growth orientation along the (222) plane. Here the electrical properties were improved due to the better crystallinity, with the films exhibiting a minimum resistivity value of 4.2 Multiplication-Sign 10{sup -4}{Omega} cm, a maximum carrier mobility of 45 cm{sup 2} V{sup -1} s{sup -1}, and an optical transmittance over 80% in the visible region.

Wan Runlai; Yang Ming; Zhou Qianfei; Zhang Qun [Department of Materials Science, Fudan University, Shanghai 200433 (China)

2012-11-15

374

Chromium and Ruthenium-Doped Zinc Oxide Thin Films for Propane Sensing Applications  

PubMed Central

Chromium and ruthenium-doped zinc oxide (ZnO:Cr) and (ZnO:Ru) thin solid films were deposited on soda-lime glass substrates by the sol-gel dip-coating method. A 0.6 M solution of zinc acetate dihydrate dissolved in 2-methoxyethanol and monoethanolamine was used as basic solution. Chromium (III) acetylacetonate and Ruthenium (III) trichloride were used as doping sources. The Ru incorporation and its distribution profile into the films were proved by the SIMS technique. The morphology and structure of the films were studied by SEM microscopy and X-ray diffraction measurements, respectively. The SEM images show porous surfaces covered by small grains with different grain size, depending on the doping element, and the immersions number into the doping solutions. The sensing properties of ZnO:Cr and ZnO:Ru films in a propane (C3H8) atmosphere, as a function of the immersions number in the doping solution, have been studied in the present work. The highest sensitivity values were obtained for films doped from five immersions, 5.8 and 900, for ZnO:Cr and ZnO:Ru films, respectively. In order to evidence the catalytic effect of the chromium (Cr) and ruthenium (Ru), the sensing characteristics of undoped ZnO films are reported as well. PMID:23482091

Gomez-Pozos, Heberto; Gonzalez-Vidal, Jose Luis; Torres, Gonzalo Alberto; Rodriguez-Baez, Jorge; Maldonado, Arturo; de la Luz Olvera, Maria; Acosta, Dwight Roberto; Avendano-Alejo, Maximino; Castaneda, Luis

2013-01-01

375

Effects of physicochemical properties of zinc oxide nanoparticles on cellular uptake  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanoparticles have been used as a source of zinc, an essential trace element in food industry and also widely applied to various cosmetic products. However, there are few researches demonstrating that the cellular uptake behaviours of ZnO with respect to the physicochemical characteristics such as particle size and surface charge in human cells. In this study, we evaluated the cellular uptake of ZnO with two different sizes (20 and 70 nm) and different charges (positive and negative). Human lung epithelial cells were exposed to ZnO for a given time, and then the uptake amount of ZnO was measured with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The results showed that the smaller sized ZnO could more easily enter the cells than the larger sized ZnO. In terms of surface charge, positively charged ZnO showed high cellular uptake compared to ZnO with negative charge. The internalization pathway of positively charged ZnO nanoparticles was determined to be primarily related to the energy-dependent endocytosis. It is, therefore, concluded that the particle size and surface charge of ZnO nanoparticles are critical factors influencing on their cellular uptake. Understanding the cellular uptake behaviours of nanoparticles with respect to physicochemical properties may be important to predict their toxicity potential on human.

Yu, J.; Baek, M.; Chung, H. E.; Choi, S. J.

2011-07-01

376

Chromium and ruthenium-doped zinc oxide thin films for propane sensing applications.  

PubMed

Chromium and ruthenium-doped zinc oxide (ZnO:Cr) and (ZnO:Ru) thin solid films were deposited on soda-lime glass substrates by the sol-gel dip-coating method. A 0.6 M solution of zinc acetate dihydrate dissolved in 2-methoxyethanol and monoethanolamine was used as basic solution. Chromium (III) acetylacetonate and Ruthenium (III) trichloride were used as doping sources. The Ru incorporation and its distribution profile into the films were proved by the SIMS technique. The morphology and structure of the films were studied by SEM microscopy and X-ray diffraction measurements, respectively. The SEM images show porous surfaces covered by small grains with different grain size, depending on the doping element, and the immersions number into the doping solutions. The sensing properties of ZnO:Cr and ZnO:Ru films in a propane (C3H8) atmosphere, as a function of the immersions number in the doping solution, have been studied in the present work. The highest sensitivity values were obtained for films doped from five immersions, 5.8 and 900, for ZnO:Cr and ZnO:Ru films, respectively. In order to evidence the catalytic effect of the chromium (Cr) and ruthenium (Ru), the sensing characteristics of undoped ZnO films are reported as well. PMID:23482091

Gómez-Pozos, Heberto; González-Vidal, José Luis; Torres, Gonzalo Alberto; Rodríguez-Baez, Jorge; Maldonado, Arturo; Olvera, María de la Luz; Acosta, Dwight Roberto; Avendaño-Alejo, Maximino; Castañeda, Luis

2013-01-01

377

40 CFR 721.8780 - Substituted pyridine azo substituted phenyl.  

Code of Federal Regulations, 2010 CFR

... Substituted pyridine azo substituted phenyl. 721.8780 Section 721.8780 ...Substituted pyridine azo substituted phenyl. (a) Chemical substance and significant...as substituted pyridine azo substituted phenyl (PMNs P-96-767 and...

2010-07-01

378

Preventive effects of zinc against psychological stress-induced iron dyshomeostasis, erythropoiesis inhibition, and oxidative stress status in rats.  

PubMed

Psychological stress (PS) could cause decreased iron absorption and iron redistribution in body resulting in low iron concentration in the bone marrow and inhibition of erythropoiesis. In the present study, we investigated the effect of zinc supplementation on the iron metabolism, erythropoiesis, and oxidative stress status in PS-induced rats. Thirty-two rats were divided into two groups randomly: control group and zinc supplementation group. Each group was subdivided into two subgroups: control group and PS group. Rats received zinc supplementation before PS exposure established by a communication box. We investigated the serum corticosterone (CORT) level; iron apparent absorption; iron contents in liver, spleen, cortex, hippocampus, striatum, and serum; hematological parameters; malondialdehyde (MDA); reduced glutathione (GSH); and superoxide dismutase (SOD). Compared to PS-treated rats with normal diet, the PS-treated rats with zinc supplementation showed increased iron apparent absorption, serum iron, hemoglobin, red blood cell, GSH, and SOD activities; while the serum CORT; iron contents in liver, spleen, and regional brain; and MDA decreased. These results indicated that dietary zinc supplementation had preventive effects against PS-induced iron dyshomeostasis, erythropoiesis inhibition, and oxidative stress status in rats. PMID:22274754

Li, Yingjie; Zheng, Yuanyuan; Qian, Jianxin; Chen, Xinmin; Shen, Zhilei; Tao, Liping; Li, Hongxia; Qin, Haihong; Li, Min; Shen, Hui

2012-06-01

379

Polarity-dependent photoemission spectra of wurtzite-type zinc oxide  

SciTech Connect

The polar surfaces of wurtzite-type zinc oxide (ZnO) were characterized by x-ray photoemission spectroscopy to identify the origin of the polarity dependence of the valence band spectra. A characteristic sub-peak always appeared in the valence band spectra of the (0001) face regardless of the surface preparation conditions. It also appeared in the valence band spectra of the (1012) face, but only when the photoelectron take-off angle was parallel to the c-axis of ZnO. Our analysis demonstrates that this take-off angle dependency originates not from the surface state, photoelectron diffraction, or the presence of surfactants but from the crystal polarity.

Williams, Jesse [International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan); NIMS Saint-Gobain Center of Excellence for Advanced Materials, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Yoshikawa, Hideki; Ueda, Shigenori; Yamashita, Yoshiyuki; Kobayashi, Keisuke [Synchrotron X-ray Station at SPring-8, NIMS, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5198 (Japan); Adachi, Yutaka; Ohashi, Naoki [NIMS Saint-Gobain Center of Excellence for Advanced Materials, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Haneda, Hajime; Ohgaki, Takeshi [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Miyazaki, Hiroki [Optical and Electronic Materials Unit, NIMS, 1-1 Namiki, Tsukuba 305-0044 (Japan); Department of Materials Chemistry, Graduate School of Engineering, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584 (Japan); Ishigaki, Takamasa [Department of Materials Chemistry, Graduate School of Engineering, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584 (Japan)

2012-01-30

380

Polarization insensitivity in epsilon-near-zero metamaterial from plasmonic aluminum-doped zinc oxide nanoparticles  

NASA Astrophysics Data System (ADS)

We investigated the optical characteristics and polarization insensitivity of an epsilon-near-zero metamaterial structure comprising aluminum-doped zinc oxide nanoparticles (NPs) hosted by a medium of ligands. By the use of an equivalent circuit model for the pairs of NPs, or dimers, and also of fullwave simulations, we studied the response of this self-assembled metamaterial for near-infrared applications. Considering the coupling of localized surface plasmons, we demonstrated the dominance of a certain dimer configuration and then applied this result to the whole medium as a simplifying approximation for a random structure. The consequent results showed a polarization insensitivity and also a general redshift in the plasmon resonance of the structure.

Alisafaee, Hossein; Fiddy, Michael A.

2014-01-01

381

Contact resistance improvement using interfacial silver nanoparticles in amorphous indium-zinc-oxide thin film transistors  

NASA Astrophysics Data System (ADS)

We describe an approach to reduce the contact resistance at compositional conducting/semiconducting indium-zinc-oxide (IZO) homojunctions used for contacts in thin film transistors (TFTs). By introducing silver nanoparticles (Ag NPs) at the homojunction interface between the conducting IZO electrodes and the amorphous IZO channel, we reduce the specific contact resistance, obtained by transmission line model measurements, down to ˜10-2 ? cm2, ˜3 orders of magnitude lower than either NP-free homojunction contacts or solid Ag metal contacts. The resulting back-gated TFTs with Ag NP contacts exhibit good field effect mobility of ˜27 cm2/V s and an on/off ratio >107. We attribute the improved contact resistance to electric field concentration by the Ag NPs.

Xu, Rui; He, Jian; Song, Yang; Li, Wei; Zaslavsky, A.; Paine, D. C.

2014-09-01

382

Zinc Oxide Thin Films Fabricated with Direct Current Magnetron Sputtering Deposition Technique  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a very promising material for emerging large area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 100 nm to 1020 nm were deposited on silicon (Si) substrate. The deposition pressure was varied from 12 mTorr to 25 mTorr. The influences of the film thickness and the deposition pressure on structural properties of the ZnO films were investigated using Mahr surface profilometer and atomic force microscopy (AFM). The experimental results reveal that the film thickness and the deposition pressure play significant role in the structural formation of the deposited ZnO thin films. ZnO films deposited on Si substrates are promising for variety of thin-film sensor applications.

Hoon, Jian-Wei; Chan, Kah-Yoong; Krishnasamy, Jegenathan; Tou, Teck-Yong

2011-03-01

383

High sensitive formaldehyde graphene gas sensor modified by atomic layer deposition zinc oxide films  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin films with various thicknesses were fabricated by Atomic Layer Deposition on Chemical Vapor Deposition grown graphene films and their response to formaldehyde has been investigated. It was found that 0.5 nm ZnO films modified graphene sensors showed high response to formaldehyde with the resistance change up to 52% at the concentration of 9 parts-per-million (ppm) at room temperature. Meanwhile, the detection limit could reach 180 parts-per-billion (ppb) and fast response of 36 s was also obtained. The high sensitivity could be attributed to the combining effect from the highly reactive, top mounted ZnO thin films, and high conductive graphene base network. The dependence of ZnO films surface morphology and its sensitivity on the ZnO films thickness was also investigated.

Mu, Haichuan; Zhang, Zhiqiang; Zhao, Xiaojing; Liu, Feng; Wang, Keke; Xie, Haifen

2014-07-01

384

Microbundles of zinc oxide nanorods: Assembly in ionic liquid [EMIM] +[BF 4] -, photoluminescence and photocatalytic properties  

NASA Astrophysics Data System (ADS)

A simple, efficient and low-temperature approach for the assembly of hierarchical Zinc oxide (ZnO) microstructures in ionic liquid [EMIM] +[BF 4] - is reported. The as-obtained ZnO superstructures are composed of microbundles of nanorods from the center points, with the diameter and length in the range of 100-150 nm and 2-4 ?m, which have been characterized by X-ray diffraction, scanning and transmission electron microscopy, and photoluminescence spectroscopy. The ZnO microstructures exhibit significant defect-related green-yellow emission and high photodegradation of dye Methyl Orange (5×10 -5 mol/L) under UV excitation within 80 min.

Wang, Li; Xu, Shen-Zhi; Li, Hui-Jun; Chang, Li-Xian; Zhi-Su; Zeng, Ming-Hua; Wang, Li-Na; Huang, Yi-Neng

2011-03-01

385

General mobility and carrier concentration relationship in transparent amorphous indium zinc oxide films  

NASA Astrophysics Data System (ADS)

We report the dependence of the electronic properties on the metal composition and oxygen content of transparent conducting amorphous indium zinc oxide (a-IZO) films deposited by dc magnetron sputtering. a-IZO shows a clear Burstein-Moss shift with an effective optical band gap of 3.1eV independent of the metal composition. A metal-composition-independent dependence of the mobility (?) on carrier concentration (N) is also found for a-IZO with ?max=54cm2/Vs at N=1.3×1020cm-3 . The electron transport, thermally activated at N?1019cm-3 , becomes limited by lattice scattering at N?1020cm-3 and then by ionized impurity scattering at N>5×1020cm-3 .

Leenheer, Andrew J.; Perkins, John D.; van Hest, Maikel F. A. M.; Berry, Joseph J.; O'Hayre, Ryan P.; Ginley, David S.

2008-03-01

386

High voltage hybrid organic photovoltaics using a zinc oxide acceptor and a subphthalocyanine donor.  

PubMed

We demonstrate hybrid organic photovoltaic (HOPV) bilayer devices with very high open circuit voltages (VOC) of 1.18 V based on a sol-gel processed zinc oxide (ZnO) acceptor and a vacuum deposited boron subphthalocyanine chloride (SubPc) donor layer. X-ray photoelectron spectroscopy (XPS) and Kelvin Probe (KP) measurements of the ZnO/SubPc interface show that the ZnO preparation conditions have a significant impact on the film composition and the electronic properties of the interface, in particular the work function and interface gap energy. Low temperature processing at 120 °C resulted in a ZnO work function of 3.20 eV and the highest VOC of 1.18 V, a consequence of the increased interface gap energy. PMID:25092380

Dearden, Chloe Argent; Walker, Marc; Beaumont, Nicola; Hancox, Ian; Unsworth, Natalie K; Sullivan, Paul; McConville, Chris F; Jones, Tim S

2014-09-21

387

Complex impedance spectroscopy of Mn-doped zinc oxide nanorod films  

NASA Astrophysics Data System (ADS)

The frequency-dependent properties of Mn-doped (3-5 at.%) aligned zinc oxide (Mn-ZnO) nanorods, synthesized by hybrid wet chemical route onto glass substrates, were investigated by bias-dependent impedance spectroscopy. No peak of Mn cluster/secondary phases was detected in the X-ray diffraction traces of the samples. XPS studies show the presence of oxygen vacancies in Mn-ZnO nanorods and Mn in Mn 2+ and Mn 4+ charge states. Although X-ray diffraction/X-ray photoelectron spectroscopy does not give any indication of the presence of metal clusters in the samples, bias-dependent impedance spectroscopy demonstrates significant sensitivity to the formation of Mn clusters in Mn-ZnO nanorods.

Sharma, M. K.; Gayen, R. N.; Pal, A. K.; Kanjilal, D.; Chatterjee, Ratnamala

2011-09-01

388

Detection of orexin A neuropeptide in biological fluids using a zinc oxide field effect transistor.  

PubMed

Biomarkers which are indicative of acute physiological and emotional states are studied in a number of different areas in cognitive neuroscience. Currently, many cognitive studies are conducted based on programmed tasks followed by timed biofluid sampling, central laboratory processing, and followed by data analysis. In this work, we present a sensor platform capable of rapid biomarker detection specific for detecting neuropeptide orexin A, found in blood and saliva and known as an indicator of fatigue and cognitive performance. A peptide recognition element that selectively binds to orexin A was designed, characterized, and functionalized onto a zinc oxide field effect transistor to enable rapid detection. The detection limit using the sensor platform was sub-picomolar in water, and picomolar to nanomolar levels in saliva and serum. The transistor and recognition element sensor platform can be easily expanded, allowing for multiple biomarkers to be detected simultaneously, lending itself to complex biomarker analysis applicable to rapid feedback for neuroscience research and physiological monitoring. PMID:23509980

Hagen, Joshua; Lyon, Wanda; Chushak, Yaroslav; Tomczak, Melanie; Naik, Rajesh; Stone, Morley; Kelley-Loughnane, Nancy

2013-03-20

389

Biofunctionalized zinc oxide field effect transistors for selective sensing of riboflavin with current modulation.  

PubMed

Zinc oxide field effect transistors (ZnO-FET), covalently functionalized with single stranded DNA aptamers, provide a highly selective platform for label-free small molecule sensing. The nanostructured surface morphology of ZnO provides high sensitivity and room temperature deposition allows for a wide array of substrate types. Herein we demonstrate the selective detection of riboflavin down to the pM level in aqueous solution using the negative electrical current response of the ZnO-FET by covalently attaching a riboflavin binding aptamer to the surface. The response of the biofunctionalized ZnO-FET was tuned by attaching a redox tag (ferrocene) to the 3' terminus of the aptamer, resulting in positive current modulation upon exposure to riboflavin down to pM levels. PMID:22163977

Hagen, Joshua A; Kim, Sang N; Bayraktaroglu, Burhan; Leedy, Kevin; Chávez, Jorge L; Kelley-Loughnane, Nancy; Naik, Rajesh R; Stone, Morley O

2011-01-01

390

Density functional theory description of electronic properties of wurtzite zinc oxide  

NASA Astrophysics Data System (ADS)

We report calculated, electronic properties of wurtzite zinc oxide (w-ZnO). We solved self-consistently the two inherently coupled equations of density functional theory (DFT), following the Bagayoko, Zhao, and Williams (BZW) method as enhanced by the work of Ekuma and Franklin (BZW-EF). We employed a local density approximation (LDA) potential and the linear combination of atomic orbitals (LCAO). Most of the calculated, electronic properties of w-ZnO are in excellent agreement with experiment, including our zero temperature band gap of 3.39 eV and the electron effective mass. The doubly self-consistent approach utilized in this work points to the ability of theory to predict accurately key properties of semiconductors and hence to inform and to guide the design and fabrication of semiconductor-based devices.

Franklin, L.; Ekuma, C. E.; Zhao, G. L.; Bagayoko, D.

2013-05-01

391

Coherent diffractive imaging of solid state reactions in zinc oxide crystals  

NASA Astrophysics Data System (ADS)

We investigated the doping of zinc oxide (ZnO) microcrystals with iron and nickel via in situ coherent x-ray diffractive imaging (CXDI) in vacuum. Evaporated thin metal films were deposited onto the ZnO microcrystals. A single crystal was selected and tracked through annealing cycles. A solid state reaction was observed in both iron and nickel experiments using CXDI. A combination of the shrink wrap and guided hybrid-input-output phasing methods were applied to retrieve the electron density. The resolution was 33 nm (half order) determined via the phase retrieval transfer function. The resulting images are nevertheless sensitive to sub-angstrom displacements. The exterior of the microcrystal was found to degrade dramatically. The annealing of ZnO microcrystals coated with metal thin films proved an unsuitable doping method. In addition the observed defect structure of one crystal was attributed to the presence of an array of defects and was found to change upon annealing.

Leake, Steven J.; Harder, Ross; Robinson, Ian K.

2011-11-01

392

Cholesterol biosensor based on rf sputtered zinc oxide nanoporous thin film  

SciTech Connect

Cholesterol oxidase (ChOx) has been immobilized onto zinc oxide (ZnO) nanoporous thin films grown on gold surface. A preferred c-axis oriented ZnO thin film with porous surface morphology has been fabricated by rf sputtering under high pressure. Optical studies and cyclic voltammetric measurements show that the ChOx/ZnO/Au bioelectrode is sensitive to the detection of cholesterol in 25-400 mg/dl range. A relatively low value of enzyme's kinetic parameter (Michaelis-Menten constant) {approx}2.1 mM indicates enhanced enzyme affinity of ChOx to cholesterol. The observed results show promising application of nanoporous ZnO thin film for biosensing application without any functionalization.

Singh, S. P.; Arya, Sunil K.; Pandey, Pratibha; Malhotra, B. D.; Saha, Shibu; Sreenivas, K.; Gupta, Vinay [BECPRG, National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi 110012 (India); Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2007-08-06

393

The E3 center in zinc oxide: Evidence for involvement of hydrogen  

NASA Astrophysics Data System (ADS)

Proton implantation is shown to increase the concentration of the so called and commonly observed E3 defect level in zinc oxide (ZnO). Box and single profiles of protons with doses ranging from 6×1010 cm-2 to 4.3×1012 cm-2 were implanted into hydrothermally grown ZnO samples with original concentrations of E3 below 5×1014 cm-3. Capacitance-Voltage profiling and junction spectroscopy measurements showed that the charge carrier concentration and absolute concentration of E3 centers increase by more than one order of magnitude compared to the as-grown samples as well as control samples implanted with He ions. The results provide strong evidence for the involvement of H in the formation of the E3 center, and a complex involving interstitial H and an oxygen sub-lattice primary defect are discussed.

Hupfer, A.; Bhoodoo, C.; Vines, L.; Svensson, B. G.

2014-03-01

394

Electron-induced surface reactivity modification in Zinc oxide-based thin films  

SciTech Connect

Chemical surface reactivity is a key parameter in modern microelectronic and display technology that is defined by basic physical interactions at the liquid etcher/material surface interface. We apply recently developed low-energy electron irradiation method for surface modification of zinc oxide-based thin films affording to vary physical processes at the liquid agent/material surface interface/and widely tune its chemical reactivity. Electron irradiation leads to the formation of ultrathin layer on irradiated surface, without generation of volumetric defects, and preserves original optical and conductive properties. The method allows fabrication of high-resolution patterned templates with modified chemical etching resistance for the fabrication of three-dimensional patterned arrays.

Sabayev, V.; Aronov, D.; Rosenman, G. [Department of Physical Electronics, School of Electrical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv 69978 (Israel); Oster, L. [Sami Shamoon Academic College of Engineering, Beer-Sheva 84100 (Israel)

2008-10-06

395

Impact of temperature on zinc oxide particle size by using sol-gel process  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanoparticles were prepared and synthesized via sol-gel method, by using citric acid as a precursor. The impact of annealing on the particle size was investigated. Based on the results from the Thermogravimetric Analysis (TGA), three different annealing temperature which is 500, 600 and 700 °C were chosen followed by the characterization of the ZnO nanoparticle by using Powder X-Ray Diffraction (PXRD), Transmission Electron Microscopy (TEM) and Field Emission Scanning Electron Microscopy (FESEM). Results showed that the crystallite size estimated from PXRD increased with the annealing temperature which was hexagonal structure for ZnO. TEM further revealed the same tendency which the Zn NPs size also increased with the annealing temperature.

Lee, Keanchuan; Saipolbahri, Zulhilmi Akmal bin; Guan, Beh Hoe; Soleimani, Hassan; Ching, Dennis Ling Chuan

2014-10-01

396

Laser stimulated light reflection reduction for silver nanoparticle-attached aluminum-doped zinc oxide substrate  

NASA Astrophysics Data System (ADS)

A principal possibility to operate the light reflection within the 350 nm-680 nm spectra wavelength range and related extinction efficiency of silver nanoparticle-attached aluminum-doped zinc oxide substrate using an external laser light was shown. The treatment was performed by a nanosecond Nd:YAG (1064 nm) and Er:glass (1540 nm) lasers and by the corresponding bicolor regime. The principal role of the interfaces separating the ZnO:Al substrate and topology of Ag NP is established using AFM analysis of the Ag NP possessing 20 nm, 40 nm and 60 nm average sizes. Different possible physical mechanisms are discussed including quadrupolar interaction of the electromagnetic wave and nanocomposites following the overlap between the surface plasmon resonance and the nano-trapping levels. The high selectivity to the photoexcited wavelength is explored. The sensitivity to the observed photoinducing laser wavelengths is discussed.

Kityk, I. V.; Chen, X.; Oyama, M.; Gondek, E.; Armatys, P.; Karasinski, P.

2014-02-01

397

Zinc Oxide Thin Films Fabricated with Direct Current Magnetron Sputtering Deposition Technique  

SciTech Connect

Zinc oxide (ZnO) is a very promising material for emerging large area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 100 nm to 1020 nm were deposited on silicon (Si) substrate. The deposition pressure was varied from 12 mTorr to 25 mTorr. The influences of the film thickness and the deposition pressure on structural properties of the ZnO films were investigated using Mahr surface profilometer and atomic force microscopy (AFM). The experimental results reveal that the film thickness and the deposition pressure play significant role in the structural formation of the deposited ZnO thin films. ZnO films deposited on Si substrates are promising for variety of thin-film sensor applications.

Hoon, Jian-Wei; Chan, Kah-Yoong; Krishnasamy, Jegenathan; Tou, Teck-Yong [Centre for Advanced Devices and Systems (CADS), Faculty of Engineering, Multimedia University, Selangor Darul Ehsan (Malaysia)

2011-03-30

398

Ultra-long multicolor belts and unique morphologies of tin-doped zinc oxide nanostructures  

NASA Astrophysics Data System (ADS)

We demonstrate the synthesis, characterization and application of pure and tin (Sn) doped zinc oxide (ZnO) nanostructures with unique optical properties. Pencil-shaped nanorods were synthesized using a mixture of pure ZnO and carbon as starting material. The growth mechanism of these nanorods is discussed in detail. Sn-doped ultra-long belt-shape ZnO structures show many different colors in a single belt under fluorescent light in an optical microscope. These different colors are attributed to the presence of different defects in the ZnO lattice. X-ray diffraction and UV-VIS spectroscopy results are in good agreement with each other. A major application for these belts is likely to be in a single-particle sensor. A single belt based UV sensor is also fabricated and the results suggest that these photoconducting belts can serve as highly sensitive UV-light detectors.

Zia, S.; Amin, M.; Manzoor, U.; Bhatti, A. S.

2014-04-01

399

Detection of Orexin A Neuropeptide in Biological Fluids Using a Zinc Oxide Field Effect Transistor  

PubMed Central

Biomarkers which are indicative of acute physiological and emotional states are studied in a number of different areas in cognitive neuroscience. Currently, many cognitive studies are conducted based on programmed tasks followed by timed biofluid sampling, central laboratory processing, and followed by data analysis. In this work, we present a sensor platform capable of rapid biomarker detection specific for detecting neuropeptide orexin A, found in blood and saliva and known as an indicator of fatigue and cognitive performance. A peptide recognition element that selectively binds to orexin A was designed, characterized, and functionalized onto a zinc oxide field effect transistor to enable rapid detection. The detection limit using the sensor platform was sub-picomolar in water, and picomolar to nanomolar levels in saliva and serum. The transistor and recognition element sensor platform can be easily expanded, allowing for multiple biomarkers to be detected simultaneously, lending itself to complex biomarker analysis applicable to rapid feedback for neuroscience research and physiological monitoring. PMID:23509980

2013-01-01

400

Simultaneous Diffusion of Oxygen Tracer and Lithium Impurity in Aluminum Doped Zinc Oxide  

NASA Astrophysics Data System (ADS)

Aluminum-doped zinc oxide ceramics were used to study oxygen self-diffusion by the vapor-solid exchange method. The diffusion profile and the quantitative analysis of impurities (H, Li, and Al) were performed by secondary ion mass spectrometry. The concentrations of Al and H in ZnO were evaluated to be 3.2×1019 and below 1.5×1017/cm3, respectively. The simultaneous diffusion of oxygen tracer and Li impurity were detected in the analysis, and the diffusion profiles were analyzed to evaluate the diffusion coefficients. Enhanced oxygen diffusivity and increased Li impurity concentration was obtained in Al-doped ZnO. We discuss the defect equations for enhancing oxygen diffusivity and increasing Li concentration in Al-doped ZnO.

Sakaguchi, Isao; Watanabe, Ken; Adachi, Yutaka; Ohgaki, Takeshi; Hishita, Shunichi; Ohashi, Naoki; Haneda, Hajime

2011-12-01

401

Inverted polymer solar cells with amorphous indium zinc oxide as the electron-collecting electrode  

SciTech Connect

We report on the fabrication and performance of polymer-based inverted solar cells utilizing amorphous indium zinc oxide (a-IZO) as the electron-collecting electrode. Amorphous IZO films of 200 nm thickness were deposited by room temperature sputtering in a high-purity argon atmosphere. The films possessed a high optical transmittance in the visible region (? 80%), a low resistivity (3.3 × 10{sup ?4} ?cm), a low surface roughness (root mean square = 0.68 nm), and a low work function (4.46 ± 0.02 eV). Inverted solar cells with the structure a-IZO/P3HT: PCBM/PEDOT:PSS/Ag exhibited a power conversion efficiency of 3% estimated for AM 1.5G, 100 mW/cm{sup 2} illumination.

Cheun, Hyeunseok; Kim, Jungbae; Zhou, Yinhua; Fang, Yunnan; Dindar, Amir; Shim, Jae Won; Fuentes-Hernandez, Canek; Sandhage, Kenneth H.; Kippelen, Bernard

2010-01-01

402

Biofunctionalized Zinc Oxide Field Effect Transistors for Selective Sensing of Riboflavin with Current Modulation  

PubMed Central

Zinc oxide field effect transistors (ZnO-FET), covalently functionalized with single stranded DNA aptamers, provide a highly selective platform for label-free small molecule sensing. The nanostructured surface morphology of ZnO provides high sensitivity and room temperature deposition allows for a wide array of substrate types. Herein we demonstrate the selective detection of riboflavin down to the pM level in aqueous solution using the negative electrical current response of the ZnO-FET by covalently attaching a riboflavin binding aptamer to the surface. The response of the biofunctionalized ZnO-FET was tuned by attaching a redox tag (ferrocene) to the 3? terminus of the aptamer, resulting in positive current modulation upon exposure to riboflavin down to pM levels. PMID:22163977

Hagen, Joshua A.; Kim, Sang N.; Bayraktaroglu, Burhan; Leedy, Kevin; Chavez, Jorge L.; Kelley-Loughnane, Nancy; Naik, Rajesh R.; Stone, Morley O.

2011-01-01

403

Improved Stability Of Amorphous Zinc Tin Oxide Thin Film Transistors Using Molecular Passivation  

SciTech Connect

The role of back channel surface chemistry on amorphous zinc tin oxide (ZTO) bottom gate thin film transistors (TFT) have been characterized by positive bias-stress measurements and x-ray photoelectron spectroscopy. Positive bias-stress turn-on voltage shifts for ZTO-TFTs were significantly reduced by passivation of back channel surfaces with self-assembled monolayers of n-hexylphosphonic acid (n-HPA) when compared to ZTO-TFTs with no passivation. These results indicate that adsorption of molecular species on exposed back channel of ZTO-TFTs strongly influence observed turn-on voltage shifts, as opposed to charge injection into the dielectric or trapping due to oxygen vacancies.

Rajachidambaram, Meena Suhanya; Pandey, Archana; Vilayur Ganapathy, Subramanian; Nachimuthu, Ponnusamy; Thevuthasan, Suntharampillai; Herman, Gregory S.

2013-10-21

404

Coating and enhanced photocurrent of vertically aligned zinc oxide nanowire arrays with metal sulfide materials.  

PubMed

Hybrid nanostructures combining zinc oxide (ZnO) and a metal sulfide (MS) semiconductor are highly important for energy-related applications. Controlled filling and coating of vertically aligned ZnO nanowire arrays with different MS materials was achieved via the thermal decomposition approach of single-source precursors in the gas phase by using a simple atmospheric-pressure chemical vapor deposition system. Using different precursors allowed us to synthesize multicomponent structures such as nanowires coated with alloy shell or multishell structures. Herein, we present the synthesis and structural characterization of the different structures, as well as an electrochemical characterization and a photovoltaic response of the ZnO-CdS system, in which the resulting photocurrent upon illumination indicates charge separation at the interface. PMID:25133933

Volokh, Michael; Diab, Mahmud; Magen, Osnat; Jen-La Plante, Ilan; Flomin, Kobi; Rukenstein, Pazit; Tessler, Nir; Mokari, Taleb

2014-08-27

405

Improved electrical properties of zinc-tin oxide TFTs by inkjet process optimization  

NASA Astrophysics Data System (ADS)

Inkjet printing process was optimized to improve the electrical properties of inkjet-printed zinc-tin oxide thin-film transistors. Among the process conditions evaluated, inkjet voltage and substrate temperature were found to be the key factors for obtaining uniform thin-films and good thin-film transistors. The optimization process with a jetting voltage of 60 V and substrate temperature of 50°C gave good electrical properties, such as a field-effect mobility of 5.11 cm2/V s, a threshold voltage of 2.83 V, a subthreshold slope of 1.33 V/dec, and an on-to-off current ratio of 108. The electrical properties of the inkjet-optimized TFTs were superior to those of the unoptimized inkjet TFTs. A positive bias stability was also investigated.

Lee, Seung-Hyun; Choi, Woon-Seop

2014-07-01

406

Effect of active zinc oxide dispersion on reduced graphite oxide for hydrogen sulfide adsorption at mid-temperature  

NASA Astrophysics Data System (ADS)

Composites of Zinc oxide (ZnO) with reduced graphite oxide (rGO) were synthesized and used as adsorbents for hydrogen sulfide (H2S) at 300 °C. Various characterization methods (TGA, XRD, FT-IR, TEM and XPS) were performed in order to link their H2S adsorption performance to the properties of the adsorbent's surface. Microwave-assisted reduction process of graphite oxide (GO) provided mild reduction environment, allowing oxygen-containing functional groups to remain on the rGO surface. It was confirmed that for the ZnO/rGO synthesize using the microwave-assisted reduction method, the ZnO particle size and the degree of ZnO dispersion remained stable over time at 300 °C, which was not the case for only the ZnO particles themselves. This stable highly dispersed feature allows for sustained high surface area over time. This was confirmed through breakthrough experiments for H2S adsorption where it was found that the ZnO/rGO composite showed almost four times higher ZnO utilization efficiency than ZnO itself. The effect of the H2 and CO2 on H2S adsorption was also investigated. The presence of hydrogen in the H2S stream had a positive effect on the removal of H2S since it allows a reducing environment for Znsbnd O and Znsbnd S bonds, leading to more active sites (Zn2+) to sulfur molecules. On the other hand, the presence of carbon dioxide (CO2) showed the opposite trend, likely due to the oxidation environment and also due to possible competitive adsorption between H2S and CO2.

Song, Hoon Sub; Park, Moon Gyu; Croiset, Eric; Chen, Zhongwei; Nam, Sung Chan; Ryu, Ho-Jung; Yi, Kwang Bok

2013-09-01

407

Synthesis Mechanism of Low-Voltage Praseodymium Oxide Doped Zinc Oxide Varistor Ceramics Prepared Through Modified Citrate Gel Coating  

PubMed Central

High demands on low-voltage electronics have increased the need for zinc oxide (ZnO) varistors with fast response, highly non-linear current-voltage characteristics and energy absorption capabilities at low breakdown voltage. However, trade-off between breakdown voltage and grain size poses a critical bottle-neck in the production of low-voltage varistors. The present study highlights the synthesis mechanism for obtaining praseodymium oxide (Pr6O11) based ZnO varistor ceramics having breakdown voltages of 2.8 to 13.3 V/mm through employment of direct modified citrate gel coating technique. Precursor powder and its ceramics were examined by means of TG/DTG, FTIR, XRD and FESEM analyses. The electrical properties as a function of Pr6O11 addition were analyzed on the basis of I-V characteristic measurement. The breakdown voltage could be adjusted from 0.01 to 0.06 V per grain boundary by controlling the amount of Pr6O11 from 0.2 to 0.8 mol%, without alteration of the grain size. The non-linearity coefficient, ?, varied from 3.0 to 3.5 and the barrier height ranged from 0.56 to 0.64 eV. Breakdown voltage and ? lowering with increasing Pr6O11 content were associated to reduction in the barrier height caused by variation in O vacancies at grain boundary. PMID:22606043

Abdullah, Wan Rafizah Wan; Zakaria, Azmi; Ghazali, Mohd Sabri Mohd

2012-01-01

408

Effect of thermal processing on silver thin films of varying thickness deposited on zinc oxide and indium tin oxide  

SciTech Connect

Silver films of varying thicknesses (25, 45, and 60 nm) were deposited on indium tin oxide (ITO) on silicon and zinc oxide (ZnO) on silicon. The films were annealed in vacuum for 1 h at different temperatures (300-650 deg. C). Four-point-probe measurements were used to determine the resistivity of the films. All films showed an abrupt change in resistivity beyond an onset temperature that varied with thickness. Rutherford backscattering spectrometry measurements revealed agglomeration of the Ag films upon annealing as being responsible for the resistivity change. X-ray pole figure analysis determined that the annealed films took on a preferential <111> texturing; however, the degree of texturing was significantly higher in Ag/ZnO/Si than in Ag/ITO/Si samples. This observation was accounted for by interface energy minimization. Atomic force microscopy (AFM) measurements revealed an increasing surface roughness of the annealed films with temperature. The resistivity behavior was explained by the counterbalancing effects of increasing crystallinity and surface roughness. Average surface roughness obtained from the AFM measurements were also used to model the agglomeration of Ag based on Ostwald ripening theory.

Sivaramakrishnan, K.; Ngo, A. T.; Alford, T. L. [School of Materials and Flexible Display Center at ASU, Arizona State University, Tempe, Arizona 85287 (United States); Iyer, S. [Department of Electrical and Computer Engineering, North Carolina Agricultural and Technical State University, Greensboro, North Carolina 27411 (United States)

2009-03-15

409

Physiological hepatic response to zinc oxide nanoparticle exposure in the white sucker, Catostomus commersonii.  

PubMed

Liver toxicity of commercially relevant zinc oxide nanoparticles (nZnO) was assessed in a benthic freshwater cypriniform, the white sucker (Catostomus commersonii). Exposure to nZnO caused several changes in levels of liver enzyme activity, antioxidants, and lipid peroxidation end products consistent with an oxidative stress response. Aconitase activity decreased by ~65% but tended to be restored to original levels upon supplementation with Fe(2+), indicating oxidative inactivation of the 4Fe-4S cluster. Furthermore, glucose-6-phosphate dehydrogenase activity decreased by ~29%, and glutathione levels increased by ~56%. Taken together, these suggest that nZnO induces hepatic physiological stress. Each assay was then validated by using a single liver homogenate or plasma sample that was partitioned and treated with nZnO or Zn(2+), the breakdown product of nZnO. It was found that Zn(2+), but not nZnO, increased detected glutathione reductase activity by ~14% and decreased detected malondialdehyde by ~39%. This indicates that if appreciable nZnO dissolution occurs in liver samples during processing and assay, it may skew results, with implications not only for this study, but also for a wide range of nanotoxicology studies focusing on nZnO. Finally, in vitro incubations of cell-free rat blood plasma with nZnO failed to generate any significant increase in malondialdehyde or protein carbonyl levels, or any significant decrease in ferric reducing ability of plasma. This suggests that at the level tested, any oxidative stress caused by nZnO is the result of a coordinated physiological response by the liver. PMID:24704545

Dieni, Christopher Anthony; Callaghan, Neal Ingraham; Gormley, Patrick Thomas; Butler, Kathryn Marie Alison; Maccormack, Tyson James

2014-05-01

410

COMPARISON OF THE EFFICIENCY OF ZINC INJECTED AS METAL OR OXIDE  

E-print Network

un témoin. La libération du zinc injecté sous forme d'oxyde est plus brutale et provoque une to bovine, the delayed effect could be too long in ovine. Therefore it was interesting to compare, in sheep a more intensive effect but a shorter delayed effect. In fact, with zinc metal, plasma zinc is still

Boyer, Edmond

411

Zinc and Energy Requirements in Induction of Oxidative Stress to Retinal Pigmented Epithelial Cells  

Microsoft Academic Search

In age-related macular degeneration (AMD), retinal pigmented epithelium (RPE) cells are believed to be detrimentally affected. It is thought that zinc may play a part in this process. In the past, therefore, zinc supplementation has been suggested as a treatment for AMD. Experimental data shown here confound this view by indicating that whereas low amounts of zinc do protect RPE

John P. M. Wood; Neville N. Osborne

2003-01-01

412

Nanostructured zinc oxide films synthesized by successive chemical solution deposition for gas sensor applications  

E-print Network

synthesis D. Electrical properties A B S T R A C T Nanostructured ZnO thin films have been deposited using ZnO thin films [21,22,26]. The SCSD is a simple and flexible method which offers an easy way to dope be realized [25­27,9]. However, the SCSD synthesis of Al-doped ZnO (AZO) films and effect of post-grown rapid

Kik, Pieter

413

Total zinc in zinc battery plates by EDTA titration  

SciTech Connect

At present, zinc battery plate electrodes are analyzed for zinc oxide, zinc chloride, zinc fluoride, zinc carbonate, zinc oxychloride, total zinc, zinc as the metal, and trace metals. A variety of methods are used to determine each of these components. The amount of zinc in each of the zinc compounds is determined by multiplying the percent of the compound by the ratio of the molecular weights of zinc to the zinc compound. This percent zinc is subtracted from percent total zinc and the operation is performed for every zinc compound determined. The remaining zinc value after these subtractions represents zinc as the metal. Zinc metal is the charged state on the anode. Percent total zinc is required in all these calculations. The importance of these components cannot be overemphasized. The presence, or absence, of certain components in the zinc electrode can influence its behavior in a zinc-silver oxide primary battery. Passivation layers, tendency to dendritic growth, corrosion rates, voltage rise times, current density, porosity, surface area, electrochemical capacity, and other considerations make it imperative that the chemical composition of the zinc electrode be known. The focus of this project was to evaluate the present method for total zinc and to develop a better method.

Hammersley, V.L. [Naval Surface Warfare Center, Crane, IN (United States)

1995-07-01

414

Optimizing amorphous indium zinc oxide film growth for low residual stress and high electrical conductivity  

NASA Astrophysics Data System (ADS)

With recent advances in flexible electronics, there is a growing need for transparent conductors with optimum conductivity tailored to the application and nearly zero residual stress to ensure mechanical reliability. Within amorphous transparent conducting oxide (TCO) systems, a variety of sputter growth parameters have been shown to separately impact film stress and optoelectronic properties due to the complex nature of the deposition process. We apply a statistical design of experiments (DOE) approach to identify growth parameter-material property relationships in amorphous indium zinc oxide (a-IZO) thin films and observed large, compressive residual stresses in films grown under conditions typically used for the deposition of highly conductive samples. Power, growth pressure, oxygen partial pressure, and RF power ratio (RF/(RF + DC)) were varied according to a full-factorial test matrix and each film was characterized. The resulting regression model and analysis of variance (ANOVA) revealed significant contributions to the residual stress from individual growth parameters as well as interactions of different growth parameters, but no conditions were found within the initial growth space that simultaneously produced low residual stress and high electrical conductivity. Extrapolation of the model results to lower oxygen partial pressures, combined with prior knowledge of conductivity-growth parameter relationships in the IZO system, allowed the selection of two promising growth conditions that were both empirically verified to achieve nearly zero residual stress and electrical conductivities >1480 S/cm. This work shows that a-IZO can be simultaneously optimized for high conductivity and low residual stress.

Kumar, Mukesh; Sigdel, A. K.; Gennett, T.; Berry, J. J.; Perkins, J. D.; Ginley, D. S.; Packard, C. E.

2013-10-01

415

Rational doping for zinc oxide and its influences on morphology and optical properties  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanopowders doped with different metal ions (Me, Me = Sn4+, In3+, Mn2+, and Co2+) are prepared by a simple sol—gel method. Influences of the ion doping on morphology and optical properties of the resulting ZnxMeyO are investigated by scanning electron microscopy, X-ray diffraction, UV-vis absorption spectrum, and photoluminescence. The morphology of ZnO can be tailored by ion doping, which is closely related not only to the ionic radii and electronegativities of the doped ions, but also to their oxidation states and electron configurations. The optical band gap and photoluminescence of ZnO can also be modulated by ion doping, which results from a combination of different effects, Burstein—Moss, band tail, charge compensation, sp—d exchange, non-radiative recombination, and blocking barrier. This may offer us a viable approach to tuning the (optical) properties of ZnO-based materials via rational ion doping.

Xia, Yu-Jing; Guan, Zi-Sheng; He, Tao

2014-08-01

416

Zinc immobilization and magnetite formation via ferric oxide reduction by Shewanella putrefaciens 200  

SciTech Connect

Long-term batch experiments in an artificial groundwater medium indicated that microbial reduction of synthetic, high-surface-area goethite and lepidocrocite by Shewanella putrefaciens 200 can act to immobilize surface-associated zinc into a new mineral phase that is not soluble in 0.5 M HCl. While Zn was incorporated in siderite grains in experiments with goethite, additional Zn immobilization may result from incorporation into as yet unidentified biogenic minerals or into a more crystalline goethite. Experiments with an oxide mixture primarily composed of lepidocrocite resulted in the production of magnetite, biphasic immobilization of Zn, and an enhanced overall degree of Zn immobilization. When NO{sub 3}{sup {minus}} was present as an alternate electron acceptor, microbial production of Fe(II) was inhibited, and the degree of Zn immobilization was subsequently reduced. These data indicate that (i) biologically induced mineralization can play a key role in the cycling of trace elements in natural systems, (ii) the nature of the oxide surface plays an important role in biologically induced mineralization, and (iii) conditions associated with Fe(II) production are necessary for these processes to immobilize surface-bound Zn within these new mineral phases.

Cooper, D.C.; Picardal, F.; Rivera, J.; Talbot, C.

2000-01-01

417

Enhancement of oxygen vacancies and solar photocatalytic activity of zinc oxide by incorporation of nonmetal  

NASA Astrophysics Data System (ADS)

B-doped ZnO and N-doped ZnO powders have been synthesized by mechanochemical method and characterized by TG-DTA, XRD, SEM-EDX, XPS, UV-visible and photoluminescence (PL) spectra. X-ray diffraction data suggests the hexagonal wurtzite structure for modified ZnO crystallites and the incorporation of nonmetal expands the lattice constants of ZnO. The room temperature PL spectra suggest more number of oxygen vacancies exist in nonmetal-doped ZnO than that of undoped zinc oxide. XPS analysis shows the substitution of some of the O atoms of ZnO by nonmetal atoms. Solar photocatalytic activity of B-doped ZnO, N-doped ZnO and undoped ZnO was compared by means of oxidative photocatalytic degradation (PCD) of Bisphenol A (BPA). B-doped ZnO showed better solar PCD efficiency as compare to N-doped ZnO and undoped ZnO. The PCD of BPA follows first order reaction kinetics. The detail mechanism of PCD of Bisphenol A was proposed with the identification of intermediates such as hydroquinone, benzene-1,2,4-triol and 4-(2-hydroxypropan-2-yl) phenol.

Patil, Ashokrao B.; Patil, Kashinath R.; Pardeshi, Satish K.

2011-12-01

418

Supplementation with Vitamin C, Vitamin E or b-Carotene Influences Osmotic Fragility and Oxidative Damage of Erythrocytes of Zinc-Deficient Rats1  

Microsoft Academic Search

Dietary zinc deficiency in rats causes increased osmotic fragility of their erythrocytes. In this study, the influence of supplementary antioxidants (vitamin C, vitamin E or b-carotene) on osmotic fragility, oxidative damage and components of the primary defense system of erythrocytes of zinc-deficient rats was investigated. Indicators of hemolysis in vivo were also examined. Five groups of 12 male rats were

Anton Kraus; Hans-Peter Roth; Manfred Kirchgessner

419

Aluminum-nitride codoped zinc oxide films prepared using a radio-frequency magnetron cosputtering system  

SciTech Connect

Al-N codoped zinc oxide films were prepared using a radio-frequency magnetron cosputtering system at room temperature. AlN and ZnO materials were employed as the cosputtered targets. The as-deposited cosputtered films at various theoretical atomic ratios [Al/(Al+Zn) at. %] showed n-type conductive behavior in spite of the N atoms exceeding that of the Al dopants, indicating that the N-related acceptors were still inactive. The crystalline structure was obviously correlated with the cosputtered AlN contents and eventually evolved into an amorphous structure for the Al-N codoped ZnO film at a theoretical Al doping level reaching 60%. With an adequate postannealing treatment, the N-related acceptors were effectively activated and the p-type ZnO conductive behavior achieved. The appearance of the Zn{sub 3}N{sub 2} phase in the x-ray diffraction pattern of the annealed Al-N codoped ZnO film provided evidence of the nitrification of zinc ions. The redshift of the shallow level transition and the apparent suppression of the oxygen-related deep level emission investigated from the photoluminescence spectrum measured at room temperature were concluded to be influenced by the activated N-related acceptors. In addition, the activation of the N acceptors denoted as N-Zn bond and the chemical bond related to the Zn{sub 3}N{sub 2} crystalline structure were also observed from the associated x-ray photoelectron spectroscopy spectra.

Liu, D.-S.; Sheu, C.-S.; Lee, C.-T. [Institute of Electro-Optical and Materials Science, National Formosa University, Huwei, Taiwan 63201 (China); Institute of Microelectronics, Department of Electrical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

2007-08-01

420

Microwave-assisted hydrothermal synthesis of zinc oxide particles starting from chloride precursor  

SciTech Connect

Graphical abstract: Schematic of the mechanism for ZnO nanoparticles obtained by the calcination. Highlights: Black-Right-Pointing-Pointer Nanocrystalline ZnO particles were successfully prepared by a microwave-assisted method. Black-Right-Pointing-Pointer Sponge-like morphology of ZnO change to a net-like structure after thermal treatment. Black-Right-Pointing-Pointer The PL spectra exhibited a nearband-edge emission at 393 nm. -- Abstract: Zinc oxide (ZnO) was synthesized using a microwave assisted hydrothermal (MAH) process based on chloride/urea/water solution and under 800 W irradiation for 5 min. In the bath, Zn{sup 2+} ions reacted with the complex carbonate and hydroxide ions to form zinc carbonate hydroxide hydrate (Zn{sub 4}CO{sub 3}(OH){sub 6}{center_dot}H{sub 2}O), and the conversion from Zn{sub 4}CO{sub 3}(OH){sub 6}{center_dot}H{sub 2}O to ZnO was synchronously achieved by a MAH process. The as-prepared ZnO has a sponge-like morphology. However, the initial sponge-like morphology of ZnO could change to a net-like structure after thermal treatment, and compact nano-scale ZnO particles were finally obtained when the period of thermal treatment increased to 30 min. Pure ZnO nanoparticles was obtained from calcination of loose sponge-like ZnO particles at 500 Degree-Sign C. The analysis of optical properties of these ZnO nanoparticles showed that the intensity of 393 nm emission increased with the calcination temperature because the defects were reduced and the crystallinity was improved.

Tseng, Chun-Chieh [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan, ROC (China)] [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan, ROC (China); Chou, Yu-Hsien [Nanopowder and Thin Film Technology Center, ITRI-South Industrial Technology Research Institute, Tainan 709, Taiwan, ROC (China)] [Nanopowder and Thin Film Technology Center, ITRI-South Industrial Technology Research Institute, Tainan 709, Taiwan, ROC (China); Liu, Chung-Ming [Department of Chemical and Material Engineering, LungHwa University of Science and Technology, Taoyuan 306, Taiwan, ROC (China)] [Department of Chemical and Material Engineering, LungHwa University of Science and Technology, Taoyuan 306, Taiwan, ROC (China); Liu, Yih-Ming [Department of Chemical and Materials Engineering, Chung Cheng Institute of Technology, National Defense University, Ta-His, Tao-Yuan 335, Taiwan, ROC (China)] [Department of Chemical and Materials Engineering, Chung Cheng Institute of Technology, National Defense University, Ta-His, Tao-Yuan 335, Taiwan, ROC (China); Ger, Ming-Der, E-mail: mingderger@gmail.com [Department of Chemical and Materials Engineering, Chung Cheng Institute of Technology, National Defense University, Ta-His, Tao-Yuan 335, Taiwan, ROC (China)] [Department of Chemical and Materials Engineering, Chung Cheng Institute of Technology, National Defense University, Ta-His, Tao-Yuan 335, Taiwan, ROC (China); Shu, Youn-Yuen, E-mail: shuyy@nknucc.nknu.edu.tw [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan, ROC (China)] [Environmental Analysis Laboratory, Department of Chemistry, National Kaohsiung Normal University, Kaohsiung 802, Taiwan, ROC (China)

2012-01-15

421

Zinc oxide nanoparticles, a novel candidate for the treatment of allergic inflammatory diseases.  

PubMed

Zinc (Zn) is an essential trace metal for eukaryotes. The roles of Zn in the numerous physiological functions have been elucidated. Bamboo salt contains Zn that was shown to have anti-inflammatory effect and other health benefits. Nanoparticles of various types have found application in the biology, medicine, and physics. Here we synthesized tetrapod-like, zinc oxide nanoparticles (ZO-NP; diameter 200 nm, source of Zn) using a radio frequency thermal plasma system and investigated its effects on mast cell-mediated allergic inflammatory reactions. ZO-NP was found to inhibit the productions and mRNA expressions of inflammatory cytokines such as interleukin (IL)-1?, IL-6, and tumor necrosis factor-? on the phorbol 12-myristate 13-acetate plus A23187 (PMACI)-stimulated human mast cell line, HMC-1 cells. In these stimulated cells, caspase-1 and nuclear factor-?B activations were abolished by ZO-NP, and the expressions of receptor interacting protein2 (RIP2) and I?B kinase? (IKK?) induced by PAMCI were reduced. On the other hand, ZO-NP alone increased the expressions of RIP2 and IKK? in normal condition. ZO-NP inhibited the phosphorylation of extracellular signal-regulated protein kinase in the PMACI-stimulated HMC-1 cells. Furthermore, ZO-NP significantly inhibited passive cutaneous anaphylaxis activated by anti-dinitrophenyl IgE. These findings indicate that ZO-NP effectively ameliorates mast cell-mediated allergic inflammatory reaction, and suggest that ZO-NP be considered a potential therapeutic for the treatment of mast cell-mediated allergic diseases. PMID:24877691

Kim, Min-Ho; Seo, Jun-Ho; Kim, Hyung-Min; Jeong, Hyun-Ja

2014-09-01

422

Effect of iron oxide coatings on zinc sorption mechanisms at the clay-mineral/water interface.  

PubMed

Oxide surface coatings are ubiquitous in the environment, but their effect on the intrinsic metal uptake mechanism by the underlying mineral surface is poorly understood. In this study, the zinc (Zn) sorption complexes formed at the kaolinite, goethite, and goethite-coated kaolinite surfaces, were systematically studied as a function of pH, aging time, surface loading, and the extent of goethite coating, using extended X-ray absorption fine structure (EXAFS) spectroscopy. At pH 5.0, Zn partitioned to all sorbents by specific chemical binding to hydroxyl surface sites. At pH 7.0, the dominant sorption mechanism changed with reaction time. At the kaolinite surface, Zn was incorporated into a mixed metal Zn-Al layered double hydroxide (LDH). At the goethite surface, Zn initially formed a monodentate inner-sphere adsorption complex, with typical Zn-Fe distances of 3.18 A. However, with increasing reaction time, the major Zn sorption mechanism shifted to the formation of a zinc hydroxide surface precipitate, with characteristic Zn-Zn bond distances of 3.07 A. At the goethite-coated kaolinite surface, Zn initially bonded to FeOH groups of the goethite coating. With increasing aging time however, the inclusion of Zn into a mixed Zn-Al LDH took over as the dominant sorption mechanism. These results suggest that the formation of a precipitate phase at the kaolinite surface is thermodynamically favored over adsorption to the goethite coating. These findings show that the formation of Zn precipitates, similar in structure to brucite, at the pristine kaolinite, goethite, and goethite-coated kaolinite surfaces at near neutral pH and over extended reaction times is an important attenuation mechanism of metal contaminants in the environment. PMID:15219425

Nachtegaal, Maarten; Sparks, Donald L

2004-08-01

423

Preparation and Luminescence Properties of Rare Earth Doped Nanostructured Zinc Oxide Thin Films by Sol Gel Technique  

NASA Astrophysics Data System (ADS)

Zinc oxide is a semiconductor cosidered promising for optoelectronic and solar cell applications. The wide bandgap nature of the zinc oxide has been a limitation in producing devices. Doping has been considered as one of the ways to reduce the band gap. In the present studies rare earth ions in the form of terbium and erbium nitatres have been introduced in the zinc oxide structure by the sol gel technique. Homogeneous thin film of nanostructured oxide and the doped homologue of the size range 30 to 80 nm were produced as characterized by scanning electron microscopy. The luminescence properties were investigated and the doped samples showed enhanced results. The enhancement were characterized as the extra energy levels produced by the dopants allowing more transitions to the lower states to take place. The dominant transitions were attributed to the 5D4 to 7Fj (J = 6-3) for the terbium doped systems and (4F7/2) to the ground state 4I15/2) for the erbium systems.

Aziz, Madzlan; Otoi, Sunati

2009-06-01

424

The interaction of 193-nm excimer laser irradiation with single-crystal zinc oxide: Neutral atomic zinc and oxygen emission  

SciTech Connect

We report mass-resolved time-of-flight measurements of neutral particles from the surface of single-crystal ZnO during pulsed 193-nm irradiation at laser fluences below the threshold for avalanche breakdown. The major species emitted are atomic Zn and O. We examine the emissions of atomic Zn as a function of laser fluence and laser exposure. Defects at the ZnO surface appear necessary for the detection of these emissions. Our results suggest that the production of defects is necessary to explain intense sustained emissions at higher fluence. Rapid, clean surface etching and high atomic zinc kinetic energies seen at higher laser fluences are also discussed.

Kahn, E. H. [Washington State University; Langford, S. C. [Washington State University; Dickinson, J. T. [Washington State University; Boatner, Lynn A [ORNL

2013-01-01

425

Zinc oxide as an economical and efficient catalyst for the one-pot preparation of ?-acetamido ketones via a four-component condensation reaction  

Microsoft Academic Search

A new, efficient, one-pot, four-component condensation of benzaldehyde derivatives, acetophenone derivatives, acetyl chloride and acetonitrile in the presence of zinc oxide as catalyst is described for the synthesis of ?-acetamido ketones.

Malek Taher Maghsoodlou; Asadollah Hassankhani; Hamid Reza Shaterian; Sayyed Mostafa Habibi-Khorasani; Elaheh Mosaddegh

2007-01-01

426

A Highly Efficient Method for the Silylation of Alcohols, Phenols, and Naphthols Using HMDS in the Presence of Zinc Oxide (ZnO) as Economical Heterogeneous Catalyst  

Microsoft Academic Search

Variety alcohols, phenols, and naphthols were effectively converted into their corresponding trimethylsilyl ether with hexamethyldisilazane in the presence of zinc oxide under very mild and ambient conditions with short reaction time in good to excellent yields.

Hamid Reza Shaterian; Majid Ghashang

2007-01-01

427

Preparation and Characterization of Silver and Zinc-Oxide Heat Mirrors.  

NASA Astrophysics Data System (ADS)

A heat mirror is a spectrally selective coating for windows which transmits solar radiation and highly reflects infrared radiation. When applied to the inside surface of a window the heat mirror maintains the visibility of the window yet suppresses the radiative heat loss. The heat mirror thus functions as a transparent heat insulation. We have developed the techniques for preparing two types of heat mirrors which utilize two different mechanisms for achieving high infrared reflectivity. The first type of heat mirrors consists of a very thin(70A) silver film prepared by resistive evaporation. The highly visible transparent and infrared reflective silver film is deposited onto a water cooled polyester substrate through a helium plasma which acts to provide a uniform film without clustering of the silver layer into isolated islands. An antireflecting dielectric coating of Al _2O_3 enhances the visible transparency and protects the delicate silver film. We have made an excellent silver heat mirror with a visible transmittance of 86% and an emissivity of.13 but these films have poor long term stability. The second type of heat mirrors consists of a thick(2000A) layer of zinc oxide prepared by reactive triode D.C. magnetron sputtering. High infrared reflectance is obtained by making the zinc oxide slightly nonstoichiometric which introduces free carriers into the otherwise empty conduction band of the ZnO. The stoichiometry was controlled by holding the sputtering rate constant and regulating the oxygen flow rate into the system. Films were made with and without a secondary plasma generated near the substrate. The free carrier concentration and the electron mobility of films made with and without the secondary plasma are comparable and the addition of the secondary plasma results in no improvement of the heat mirror qualities of the films. We were able to make good heat mirrors with 80% visible transmittance and.20 emissivity without a secondary plasma or intentional impurity doping or post deposition annealing. These films show excellent stability and durability and are good candidates for commercial development. Samples were characterized through Hall effect, X-ray diffraction, optical transmission, Rutherford backscattering and Scanning Electron Microscope measurements.

Min, Yuhua Lee

428

Stable, self-ballasting field emission from zinc oxide nanowires grown on an array of vertically aligned carbon nanofibers  

NASA Astrophysics Data System (ADS)

A structure composed of zinc oxide nanowires (ZNWs) grown hydrothermally on an array of vertically aligned carbon nanofibers (CNFs) was fabricated and its field emission properties determined and compared with bare CNF arrays. The combination produced a macroscopic turn-on field of 1.2 V/?m which was found to be the lowest reported from ZNWs deposited on a two-dimensional substrate and much less than the equivalent CNFs array (5.2 V/?m). Crucially, field emission was found to be much more stable at higher pressures of 5×10-6 mbar without exhibiting current degradation for a fixed external field, while emitting with a current density of 1 mA/cm2, the current density typically required for backlighting and field emission displays. We propose a self-ballasting mechanism, in which the low carrier density in the zinc oxide prevents current runaway in the presence of adsorbed species.

Li, C.; Zhang, Y.; Mann, M.; Hiralal, P.; Unalan, H. E.; Lei, W.; Wang, B. P.; Chu, D. P.; Pribat, D.; Amaratunga, G. A. J.; Milne, W. I.

2010-04-01

429

Interaction between nanoparticles generated by zinc chloride treatment and oxidative responses in rat liver.  

PubMed

The aim of the present study was to investigate the interaction of zinc chloride (3 mg/kg, intraperitoneally [ip]) in rat liver in terms of the biosynthesis of nanoparticles. Zinc treatment increased zinc content in rat liver. Analysis of fluorescence revealed the presence of red fluorescence in the liver following zinc treatment. Interestingly, the co-exposure to zinc (3 mg/kg, ip) and selenium (0.20 mg/L, per os [by mouth]) led to a higher intensity of red fluorescence compared to zinc-treated rats. In addition, X-ray diffraction measurements carried out on liver fractions of zinc-treated rats point to the biosynthesis of zinc sulfide and/or selenide nanocomplexes at nearly 51.60 nm in size. Moreover, co-exposure led to nanocomplexes of about 72.60 nm in size. The interaction of zinc with other mineral elements (S, Se) generates several nanocomplexes, such as ZnS and/or ZnSe. The nanocomplex ZnX could interact directly with enzyme activity or indirectly by the disruption of mineral elements' bioavailability in cells. Subacute zinc or selenium treatment decreased malondialdehyde levels, indicating a drop in lipid peroxidation. In addition, antioxidant enzyme assays showed that treatment with zinc or co-treatment with zinc and selenium increased the activities of glutathione peroxidase, catalase, and superoxide dismutase. Consequently, zinc complexation with sulfur and/or selenium at nanoscale level could enhance antioxidative responses, which is correlated to the ratio of number of ZnX nanoparticles (X=sulfur or X=selenium) to malondialdehyde level in rat liver. PMID:24403828

Azzouz, Inès; Trabelsi, Hamdi; Hanini, Amel; Ferchichi, Soumaya; Tebourbi, Olfa; Sakly, Mohsen; Abdelmelek, Hafedh

2014-01-01

430

Interaction between nanoparticles generated by zinc chloride treatment and oxidative responses in rat liver  

PubMed Central

The aim of the present study was to investigate the interaction of zinc chloride (3 mg/kg, intraperitoneally [ip]) in rat liver in terms of the biosynthesis of nanoparticles. Zinc treatment increased zinc content in rat liver. Analysis of fluorescence revealed the presence of red fluorescence in the liver following zinc treatment. Interestingly, the co-exposure to zinc (3 mg/kg, ip) and selenium (0.20 mg/L, per os [by mouth]) led to a higher intensity of red fluorescence compared to zinc-treated rats. In addition, X-ray diffraction measurements carried out on liver fractions of zinc-treated rats point to the biosynthesis of zinc sulfide and/or selenide nanocomplexes at nearly 51.60 nm in size. Moreover, co-exposure led to nanocomplexes of about 72.60 nm in size. The interaction of zinc with other mineral elements (S, Se) generates several nanocomplexes, such as ZnS and/or ZnSe. The nanocomplex ZnX could interact directly with enzyme activity or indirectly by the disruption of mineral elements’ bioavailability in cells. Subacute zinc or selenium treatment decreased malondialdehyde levels, indicating a drop in lipid peroxidation. In addition, antioxidant enzyme assays showed that treatment with zinc or co-treatment with zinc and selenium increased the activities of glutathione peroxidase, catalase, and superoxide dismutase. Consequently, zinc complexation with sulfur and/or selenium at nanoscale level could enhance antioxidative responses, which is correlated to the ratio of number of ZnX nanoparticles (X=sulfur or X=selenium) to malondialdehyde level in rat liver. PMID:24403828

Azzouz, Ines; Trabelsi, Hamdi; Hanini, Amel; Ferchichi, Soumaya; Tebourbi, Olfa; Sakly, Mohsen; Abdelmelek, Hafedh

2014-01-01

431

Synthesis of Phytosteryl Esters by Using Alumina-Supported Zinc Oxide (ZnO\\/Al 2 O 3 ) from Esterification Production of Phytosterol with Fatty Acid  

Microsoft Academic Search

The feasibility of zinc oxide-catalyzed esterification of natural phytosterols with oleic acid was investigated well by a\\u000a chemical process. The influences of various reaction parameters were evaluated. Basic solid zinc oxide is the most desirable\\u000a catalyst due to its high selectivity (more than 90%), reusability, activity and less corrosivity, whereas sterol selectivity\\u000a with other catalysts, such as H2SO4, NaHSO4 and

Xianghe Meng; Qiuyue Pan; Tiankui Yang

2011-01-01

432

Effect of doping concentration on the properties of aluminium doped zinc oxide thin films prepared by spray pyrolysis for transparent electrode applications  

Microsoft Academic Search

Zinc oxide possesses many interesting properties, such as modifiable conductivity, wide band gap, high excitonic binding energy, piezo-electric polarisation and cathodoluminiscence. In this study transparent conducting aluminium doped zinc oxide (ZnO:Al) thin films were deposited on float glass substrates by tailor made spray pyrolysis with adaptation for measuring the actual temperature of the substrate surface during deposition. The films were

C. M. Muiva; T. S. Sathiaraj; K. Maabong

2011-01-01

433

Examination of zinc oxide, copper chromium oxide, and copper scandium oxide properties for use in transparent electronics and chemical sensors  

Microsoft Academic Search

Greater progress in the field of TCO (transparent oxide semiconductor) research has been hampered by a lack of availability of p-type candidates. Though the n-type TCO's are well documented and easily produced only one well documented oxide has spurred continued efforts at producing robust, p-type behavior, namely ZnO. Though p-ZnO has been produced, a coterminous research effort into improving the

Patrick Sadik

2009-01-01

434

Recovery of manganese oxides from spent alkaline and zinc-carbon batteries. An application as catalysts for VOCs elimination.  

PubMed

Manganese, in the form of oxide, was recovered from spent alkaline and zinc-carbon batteries employing a biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO4 solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnOx synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn2O3 in the EMO and the CMO samples, together with some Mn(4+) cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn3O4. The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200°C, while heptane requires more than 400°C. The CMO has the highest oxide selectivity to CO2. The results show that manganese oxides obtained using spent alkaline and zinc-carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs. PMID:23562448

Gallegos, María V; Falco, Lorena R; Peluso, Miguel A; Sambeth, Jorge E; Thomas, Horacio J

2013-06-01

435

Structural and optical properties of undoped and aluminium doped zinc oxide nanoparticles via precipitation method at low temperature  

Microsoft Academic Search

Zinc oxide (ZnO) and aluminium doped ZnO nanoparticles with grain size in the nanometer range have been successfully synthesized by alkali precipitation method. The grain size and morphology of nanoparticles have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The smallest size of about 25–30nm with a spherical shape has been measured from

S. Suwanboon; P. Amornpitoksuk; A. Haidoux; J. C. Tedenac

2008-01-01

436

Facile synthesis of highly oriented p-type aluminum co-doped zinc oxide film with aqua ammonia  

Microsoft Academic Search

Zinc oxide (ZnO) is a wide band-gap material with excellent optoelectronic properties. However, the application of ZnO to optoelectronic devices using ZnO has been hindered by the difficulty in obtaining a stable p-type doping. The paper demonstrates that, with a proper selection of the nitrogen precursor, a solution processable, highly c-axis oriented, stable, and p-type aluminium co-doped ZnO (NZO) formation

Ian Y. Y. Bu

2011-01-01

437

High-rate, room temperature plasma-enhanced deposition of aluminum-doped zinc oxide nanofilms for solar cell applications  

Microsoft Academic Search

A custom-designed inductively coupled plasma (ICP)-assisted radio-frequency magnetron sputtering deposition system has been employed to synthesize aluminium-doped zinc oxide (ZnO:Al) nanofilms on glass substrates at room temperature. The effects of film thickness and ZnO target (partially covered by Al chips) power on the structural, electrical and optical properties of the ZnO:Al nanofilms are studied. A high growth rate (?41nm\\/min), low

B. S. Chua; S. Xu; Y. P. Ren; Q. J. Cheng; K. Ostrikov

2009-01-01

438

High deposition rate aluminium-doped zinc oxide films with highly efficient light trapping for silicon thin film solar cells  

Microsoft Academic Search

Aluminium-doped zinc oxide films were deposited on glass substrates at high rates by reactive mid-frequency sputtering. The in-line sputter system allows oxygen influx along the middle and sides of a dual-cathode system. The effect of varying the oxygen flow from the sides on the electrical and optical properties together with the surface morphology after wet chemical etching was investigated. Increasing

S. Calnan; J. Hupkes; B. Rech; H. Siekmann; A. N. Tiwari

2008-01-01

439

Zinc oxide thin-film chemical sensors in conjunction with neural network pattern recognition for trimethylamine and dimethylamine gases  

Microsoft Academic Search

Transient response curves for exposure to several gases are observed using zinc oxide (ZnO) thin-film gas sensors. It is found that an aluminium-doped ZnO (ZnO::Al) sensor exhibits a high sensitivity and an excellent selectivity for amine gases. In order to discriminate between gas species such as trimethylamine (TMA), dimethylamine (DMA) and other gases pattern recognition analysis using a neural network

H. Nanto; S. Tsubakino; T. Kawai; M. Ikeda; S. Kitagawa; M. Habara

1994-01-01

440

Preparation, structural characterization, semiconductor and photoluminescent properties of zinc oxide nanoparticles in a phosphonium-based ionic liquid  

Microsoft Academic Search

A convenient microwave method in preparation of zinc oxide nanoparticles (ZnONPs) using an ionic liquid, trihexyltetradecylphosphonium bis{(trifluoromethyl)sulfonyl}-imide, [P66614][NTf2], as a green solvent is described in this paper. To the best of our knowledge, there is no report for synthesizing any nanoparticle using this ionic liquid. Trihexyltetradecylphosphonium bis{(trifluoromethyl)sulfonyl}-imide has low interface tension and thus it can enhance the nucleation rate, which

Elaheh K. Goharshadi; Maryam Abareshi; Roya Mehrkhah; Sara Samiee; Majid Moosavi; Abbas Youssefi; Paul Nancarrow

2011-01-01

441

A study on the ultrasonic preparation of nanocrystalline zinc oxide in room temperature ionic liquid and triethylene glycol  

Microsoft Academic Search

A fast and green approach has been developed for the preparation of nanocrystalline zinc oxide (ZnO) in room-temperature ionic liquid (RTIL) via ultrasonic irradiation. For comparison, ZnO nanoparticles have been prepared under the same experimental condition in triethylene glycol (TEG). The results show that ZnO nanorods can be prepared in RTIL, while spherical nanoparticles are obtained in TEG. A possible

Hao Yang; Hai-yan Wang; Yue-tao Yang; Xiao-jun Liu; Shu-yi Zhang

2010-01-01

442

The short-term effects of antioxidant and zinc supplements on oxidative stress biomarker levels in plasma: a pilot investigation  

PubMed Central

Purpose To determine if short-term Age-Related Eye Disease Study (AREDS) antioxidant and zinc supplementation affects biomarkers of oxidative stress, possibly serving as a predictor of their efficacy. Design Prospective interventional case series Methods Nineteen subjects, 12 with intermediate or advanced age-related macular degeneration (AMD) (AREDS categories 3 or 4) and 7 non-AMD controls, were admitted to the Vanderbilt General Clinical Research Center and placed on a controlled diet for 7 days. Antioxidant and zinc supplements were stopped two weeks prior to study enrollment. Dietary supplementation with 500 mg vitamin C, 400 IU vitamin E, 15 mg ?-carotene, 80 mg zinc oxide, and 2 mg cupric oxide per day was instituted on Study Day 2. Blood was drawn on Study Days 2 and 7, and plasma concentrations of cysteine (Cys), cystine (CySS), glutathione (GSH), isoprostane (IsoP), and isofuran (IsoF) were determined. Results Short-term AREDS supplementation significantly lowered mean plasma levels of CySS in participants on a regulated diet (p = 0.034). No significant differences were observed for Cys, GSH, IsoP, or IsoF. There were no significant differences between AMD patients and controls. Conclusions This pilot interventional study shows that a 5-day course of antioxidant and zinc supplements can modify plasma levels of CySS, suggesting that this oxidative stress biomarker could help predict how likely an individual is to benefit from AREDS supplementation. Further, CySS may be useful for the evaluation of new AMD therapies, particularly those hypothesized to affect redox status. PMID:22381365

Brantley, Milam A.; Osborn, Melissa P.; Sanders, Barton J.; Rezaei, Kasra A.; Lu, Pengcheng; Li, Chun; Milne, Ginger L.; Cai, Jiyang; Sternberg, Paul

2012-01-01

443

Growth and characterization of zinc oxide nano\\/micro-fibers by thermal chemical reactions and vapor transport deposition in air  

Microsoft Academic Search

Zinc oxide (ZnO) crystal fibers were prepared on silicon (100) substrate via a simple thermal chemical reactions vapor transport deposition method in air with a mixture of ZnO and carbon powders as reactants. The growth process was carried out at 1100°C in a quartz tube with one side opened to the air. There is no other metal catalyst and carrier

B. J. Chen; X. W. Sun; C. X. Xu; B. K. Tay

2004-01-01