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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

Aluminum doped zinc oxide for organic photovoltaics  

SciTech Connect

Aluminum doped zinc oxide (AZO) was grown via magnetron sputtering as a low-cost alternative to indium tin oxide (ITO) for organic photovoltaics (OPVs). Postdeposition ozone treatment resulted in devices with lower series resistance, increased open-circuit voltage, and power conversion efficiency double that of devices fabricated on untreated AZO. Furthermore, cells fabricated using ozone treated AZO and standard ITO displayed comparable performance.

Murdoch, G. B.; Hinds, S.; Sargent, E. H.; Tsang, S. W.; Mordoukhovski, L.; Lu, Z. H. [Department of Materials Science and Engineering, University of Toronto, 184 College St., Toronto, Ontario M5S 3E4 (Canada)

2009-05-25

3

Light extraction enhancement of organic light-emitting diodes using aluminum zinc oxide embedded anodes.  

PubMed

Aluminum zinc oxide (AZO) has been embedded onto indium tin oxide (ITO) anode to enhance the light extraction from an organic light-emitting diode (OLED). The embedded AZO provides deflection and scattering interfaces on the newly generated AZO/organics and AZO/ITO interfaces rather than the conventional ITO/organic interface. The current efficiency of AZO embedded OLEDs was enhanced by up to 64%, attributed to the improved light extraction by additionally created reflection and scattering of emitted light on the AZO/ITO interfaces which was roughed in AZO embedding process. The current efficiency was found to increase with the increasing AZO embedded area ratio, but limited by the accompanying increases in haze and electrical resistance of the AZO embedded ITO film. PMID:25607483

Hsu, Ching-Ming; Lin, Bo-Ting; Zeng, Yin-Xing; Lin, Wei-Ming; Wu, Wen-Tuan

2014-12-15

4

Zinc oxide overdose  

MedlinePLUS

Zinc oxide is an ingredient in many products, including certain creams and ointments used to prevent or treat minor skin burns and irritation. Zinc oxide overdose occurs when someone accidentally or intentionally ...

5

An Evaluation of Zinc Oxide Photovoltaic Devices  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is attractive for photovoltaic applications due to its conductivity when doped with aluminum and transparency to the visible range of sunlight, i.e. minimized optical and electrical loss. Zinc oxide can form a stable n-n isotype heterojunction with silicon, which is comparable with conventional p-n junctions. The performance of such a junction heavily relies on the Fermi energy tuning of ZnO by Al doping. As an n-type dopant to ZnO, Al greatly improves the conductivity of ZnO. Moreover, Al-doped ZnO (AZO) is relatively abundant and cheap compared to other transparent conductive oxides (TCO), so that potentially the cost of electricity generation ($/KW) can be decreased. In order to boost the poor open circuit voltages resulted from the structures such as ITO/n-Si and AZO/n-Si, a thin 40 nm AZO film was introduced in our design as a buffer layer between the emitter and base. Our goal is to discover what Al content in the buffer layer achieves the optimum performance. Aluminum doped ZnO films were grown by a co-sputtering method which was a combination of RF sputtered ZnO with a fixed power of 300 W and DC sputtered Al with varied powers of 15-40 W. The Al content in AZO increases with increasing power used in Al sputtering. In this research, two types of heterojunction solar cells, ITO/AZO/n-Si and AZO/AZO/n-Si, were fabricated, analyzed and compared. The middle layer of AZO is the buffer layer which has varied Al doping and plays a key role in improving open circuit voltage. For the structure AZO/AZO/n-Si, the top emitter AZO layer has a fixed Al doping of 6.12 wt% at which AZO demonstrates the highest conductivity. With Al doping of the buffer AZO layer ranging from 0-7 wt.%, 6.34 wt.% of Al doping yields the best performance for both types of solar cell structures. At its best performance, ITO/AZO/n-Si demonstrates an open circuit voltage (Voc) of 0.42 V, a short circuit current density (J sc) of 26.0 mA/cm2, and a conversion efficiency of 5.03%, while AZO/AZO/n-Si shows a Voc of 0.3 V, a Jsc of 24.7 mA/cm2 and a conversion efficiency of 3.99%. The device ITO/AZO/n-Si which has 6.34% Al doped ZnO buffer improves the Voc up to 0.42V from 0.2V for the cell without a ZnO buffer layer. Similarly, AZO/AZO/n-Si improves the Voc to 0.3 V from 0.26 V for the cell without a buffer layer. The research results have shown that both types of structure provide higher Voc than the structure without a buffer layer. The increase of Voc can be attributed to the fact that the buffer layer engineers the Fermi level of ZnO to heighten the isotype junction barrier. Our capacitance-voltage (C-V) measurements showed that the junction formed with ZnO and intrinsic Si has the highest barrier height compared to ZnO/nSi or ZnO/pSi junctions. This could imply that reducing the doping density of Si can possibly improve the barrier height at the ZnO/Si interface and therefore improve the open-circuit voltage. To study the carrier transport mechanisms at ZnO/nSi junctions, current-voltage-temperature (I-V-T) measurements were conducted. As a result, in the forward direction, AZO(6.34 wt%)/nSi junction shows a combination of thermionic emission and recombination at intermediate voltages and an existence of space charge limited current (SCLC) at high voltages. On the other hand, AZO(3.49 wt%)/nSi junction has a mechanism of a combination of tunneling and recombination at intermediate voltages and SCLC in the ballistic regime at high voltages.

Wang, Jun

6

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

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. 4 figures.

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

1993-12-14

8

Zinc oxide varistors  

Microsoft Academic Search

An overview is given of zinc oxide varistors, which are made of semiconducting ceramics with highly nonohmic current-voltage characteristics, which originate at the grain boundaries. These varistors are widely utilized to protect electric power lines and electronic components against dangerous voltage surges. This overview covers electrical characteristics, fabrication methods, effects of additives, microstructures, the conduction mechanism, degradation, and applications.<>

K. Eda

1989-01-01

9

The physical properties of Al-doped zinc oxide films prepared by RF magnetron sputtering  

Microsoft Academic Search

Al-doped zinc oxide (AZO) films are prepared by RF magnetron sputtering on glass and Si substrates with specifically designed ZnO targets containing different amounts of Al2O3 powder as a doping source. The physical properties of the AZO films are investigated in terms of the preparation conditions, such as Al2O3 content in the target, RF power (PRF), substrate temperature (Ts) and

Ki Cheol Park; Dae Young Ma; Kun Ho Kim

1997-01-01

10

Zinc Oxide for Weanling Piglets  

Microsoft Academic Search

Digestive disorders and impaired performance are common problems among weanling piglets. The purpose of the present study was to examine the effect on health and performance of feeding different levels of zinc (as zinc oxide) for one, two or three weeks after weaning to piglets weaned at 28 days of age. A supplement of 2500 ppm zinc for two weeks

Hanne Damgaard Poulsen

1995-01-01

11

Arsenic doped zinc oxide  

SciTech Connect

As-doping of zinc oxide has been approached by ion implantation and chemical vapor deposition. The effect of thermal annealing on the implanted samples has been investigated by using secondary ion mass spectrometry and Rutherford backscattering/channeling geometry. The crystal damage, the distribution of the arsenic, the diffusion of impurities, and the formation of secondary phases is discussed. For the thin films grown by vapor deposition, the composition has been determined with regard to the growth parameters. The bonding state of arsenic was investigated for both series of samples using x-ray photoelectron spectroscopy.

Volbers, N.; Lautenschlaeger, S.; Leichtweiss, T.; Laufer, A.; Graubner, S.; Meyer, B. K. [Physics Institute, Justus-Liebig-Universitaet Giessen, Heinrich-Buff-Ring 16, 35392 Giessen (Germany); Potzger, K.; Zhou Shengqiang [Institute for Ion Beam Physics and Materials Research, Forschungszentrum Dresden-Rossendorf, P.O. Box 51 01 19, D-01314 Dresden (Germany)

2008-06-15

12

Zinc Oxide Nanostructures by Solvothermal Synthesis .  

E-print Network

??The synthesis, characterization, and properties of three types of one-dimensional zinc oxide nanostructures are described. They were obtained by solvothermal treatment of nanometric zinc oxide… (more)

Segovia, M.

2012-01-01

13

Highly stable inverted organic photovoltaics using aluminum-doped zinc oxide as electron transport layers  

NASA Astrophysics Data System (ADS)

In this paper, we demonstrate highly stable inverted bulk heterojunction organic solar cells using aluminum-doped zinc oxide (AZO) as electron transport layers fabricated via a non-toxic so-gel process. The conductivity of the AZO layers can be enhanced fourfold as compared to that of intrinsic zinc oxide (ZnO) layers. The transmittance of AZO films is improved and the Haze value of the films is reduced by more than 50% in comparison to that of ZnO. The power conversion efficiency of the device reaches 6.51% and still has approximately 98% of the initial power conversion efficiency (PCE) after over 900 h without encapsulation.

Chen, Mei-Hsin; Kuo, Ya-Ching; Lin, Hung-Hsuan; Chao, Yi-Ping; Wong, Ming-Show

2015-02-01

14

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

NASA Astrophysics Data System (ADS)

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 0.01 M 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 showed that the degradation of AZO films was due to compositional and structural changes with the treatment of water electrolysis, which resulted from the reduction reaction of atomic hydrogen generated in the electrolysis of water. This optical degradation reflects the stability degradation of AZO films under water electrolysis environment.

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

2006-12-01

15

Self-assembled monolayers assisted thin film growth of aluminum doped zinc oxide by spray pyrolysis method  

NASA Astrophysics Data System (ADS)

In this work, aluminum doped zinc oxide (AZO) were deposited on pristine and self-assembled monolayer (SAM) modified glass substrates by chemical spray pyrolysis technique. The measurements of different parameters showed that modifying the surface of the glass substrates with the different SAMs resulted in excellent nucleation sites for the crystal growth of the AZO thin film. Among the different functional groups, SAMs with sbnd CH3 terminal group improves the quality of the film remarkably, while the other groups improve the quality moderately. From the results we observed that our finding suggests a novel approach of improving the quality of AZO films deposited by spray pyrolysis technique.

Aklilu, Muluken; Tai, Yian

2013-04-01

16

Journal of the Korean Physical Society, Vol. 49, December 2006, pp. S584S588 Deposition-Temperature Effects on AZO Thin Films Prepared by RF  

E-print Network

- electronic devices, we investigated aluminum-doped zinc oxide (AZO) thin films prepared by radio- frequency-Temperature Effects on AZO Thin Films Prepared by RF Magnetron Sputtering and Their Physical Properties Jeung Hun Park of deposition temperature. The structural, electrical, and optical properties of AZO thin films were studied

Pak, Hyuk Kyu

17

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

18

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

19

Study of zinc oxide ceramics  

SciTech Connect

The authors determined the elemental and phase composition of zinc oxide ceramic (ZOC) by emission spectral (ESA), x-ray phase (XPA), and micro x-ray spectral (MXSA) analysis as well as by the method of electron spectroscopy for chemical analysis (ESCA). They studied the microstructure on metallographic and scanning electron microscopes using MXSA and ESCA data. Samples of ZOC were synthesized in the system of oxides Zn, Bi, Sb, Co, Mn, Sn, Si, Ni, Mg, Cr and B. The authors found that several mechanisms are responsible for the changes in the parameters of varistors based on zinc oxide ceramic, each of whose contribution depends on the operating conditions of the varistor.

Petvkhov, A.P.; Fedotova, O.I.; Rumyantseva, I.A.; Teslenko, S.P.

1986-01-01

20

Zinc Oxide Nanowires by Oxidation of Zinc Powder for Ethanol Gas Sensor Application  

Microsoft Academic Search

Zinc oxide nanowires were prepared by oxidation of zinc powder. The oxidation of zinc was performed by heating a tube of zinc powder at various duration times and temperatures. Field Emission Scanning Electron Microscopy (FE-SEM), Energy Disper- sive Spectrometry (EDS) and Transmission Electron Microscopy (TEM) were used to char- acterize the tube. It was found that the diameter of zinc

Chanchai Viriyaworasakul; Sombat Kittikunodom; Supab Choopun; Torranin Chairuangsri; Pongsri Mangkorntong; Nikorn Mangkorntong

21

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

SciTech Connect

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. [Dipartimento di Energia and NEMAS, Center for Nanoengineered Materials and Surfaces, Politecnico di Milano, via Ponzio 34/3, I-20133 Milano (Italy); Casari, C. S.; Li Bassi, A. [Dipartimento di Energia and NEMAS, Center for Nanoengineered Materials and Surfaces, Politecnico di Milano, via Ponzio 34/3, I-20133 Milano (Italy); Center for Nano Science and Technology PoliMI, Istituto Italiano di Tecnologia, Via Pascoli 70/3, I-20133 Milano (Italy)

2014-02-21

22

21 CFR 73.1991 - Zinc oxide.  

Code of Federal Regulations, 2011 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...

2011-04-01

23

21 CFR 73.1991 - Zinc oxide.  

Code of Federal Regulations, 2010 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...

2010-04-01

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.  

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

26

21 CFR 73.1991 - Zinc oxide.  

Code of Federal Regulations, 2014 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...

2014-04-01

27

21 CFR 582.5991 - Zinc oxide.  

Code of Federal Regulations, 2013 CFR

... ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary Supplements 1 § 582.5991 Zinc oxide. (a) Product. Zinc oxide. (b) Conditions of use. This...

2013-04-01

28

Comparison of carrier transport mechanism under UV/Vis illumination in an AZO photodetector and an AZO/p-Si heterojunction photodiode produced by spray pyrolysis  

NASA Astrophysics Data System (ADS)

In this study, Aluminum doped Zinc Oxide (AZO) layer is deposited on p-type silicon (p-Si) by spray pyrolysis method to fabricate ultraviolet-visible (UV/Vis) photodetector as Al doping process can have positive effect on the photodetector performance. Morphology, crystalline structure, and Al concentration of AZO layer are investigated by SEM, XRD, and EDX. The goal of this study is to analyze the mechanism of carrier transport by means of current-voltage characteristics under UV/Vis illumination in two cases: (a) electrodes connected to the surface of AZO layer and (b) electrodes connected to cross section of heterojunction (AZO/p-Si). Measurements indicate that the AZO/p-Si photodiode exhibits a higher photocurrent and lower photoresponse time under visible illumination with respect to AZO photodetector; while under UV illumination, the above result is inversed. Besides, the internal junction field of AZO/p-Si heterojunction plays an important role on this mechanism.

Shasti, M.; Mortezaali, A.; Dariani, R. S.

2015-01-01

29

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

30

Efficient indium-tin-oxide free inverted organic solar cells based on aluminum-doped zinc oxide cathode and low-temperature aqueous solution processed zinc oxide electron extraction layer  

NASA Astrophysics Data System (ADS)

Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C61 butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150 °C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100 °C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.

Chen, Dazheng; Zhang, Chunfu; Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue

2014-06-01

31

Efficient indium-tin-oxide free inverted organic solar cells based on aluminum-doped zinc oxide cathode and low-temperature aqueous solution processed zinc oxide electron extraction layer  

SciTech Connect

Indium-tin-oxide (ITO) free inverted organic solar cells (IOSCs) based on aluminum-doped zinc oxide (AZO) cathode, low-temperature aqueous solution processed zinc oxide (ZnO) electron extraction layer, and poly(3-hexylthiophene-2, 5-diyl):[6, 6]-phenyl C{sub 61} butyric acid methyl ester blend were realized in this work. The resulted IOSC with ZnO annealed at 150?°C shows the superior power conversion efficiency (PCE) of 3.01%, if decreasing the ZnO annealing temperature to 100?°C, the obtained IOSC also shows a PCE of 2.76%, and no light soaking issue is observed. It is found that this ZnO film not only acts as an effective buffer layer but also slightly improves the optical transmittance of AZO substrates. Further, despite the relatively inferior air-stability, these un-encapsulated AZO/ZnO IOSCs show comparable PCEs to the referenced ITO/ZnO IOSCs, which demonstrates that the AZO cathode is a potential alternative to ITO in IOSCs. Meanwhile, this simple ZnO process is compatible with large area deposition and plastic substrates, and is promising to be widely used in IOSCs and other relative fields.

Chen, Dazheng; Zhang, Chunfu, E-mail: cfzhang@xidian.edu.cn; Wang, Zhizhe; Zhang, Jincheng; Tang, Shi; Wei, Wei; Sun, Li; Hao, Yue, E-mail: yhao@xidian.edu.cn [State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology, School of Microelectronics, Xidian University, No. 2 South Taibai Road, Xi'an 710071 (China)

2014-06-16

32

Transmittance from visible to mid infra-red in AZO films grown by atomic layer deposition system  

E-print Network

Deposition; Transmittance of AZO; IR transmittance 1. Introduction Aluminum-doped zinc oxide (AZO´n-Sua´rez et al., 2002; Islam et al., 1996), thermal evaporation (Jin et al., 1999; Ma et al., 2000), pulsed

Tanner, David B.

33

Solution grown antimony doped zinc oxide films.  

E-print Network

??Zinc oxide is an extensively studied semiconducting material due to its versatile properties applicable to many technologies such as electronics, optoelectronics, sensing and renewable energy.… (more)

Riley, Conor T.

2012-01-01

34

Bidirectional reflectance of zinc oxide  

NASA Technical Reports Server (NTRS)

This investigation was undertaken to determine original and useful information about the bidirection reflectance of zinc oxide. The bidirectional reflectance will be studied for the spectra between .25-2.5 microns and the hemisphere above the specimen. The following factors will be considered: (1) surface conditions; (2) specimen preparation; (3) specimen substrate, (4) polarization; (5) depolarization; (6) wavelength; and (7) angles of incident and reflection. The bidirectional reflectance will be checked by experimentally determined angular hemispherical measurements or hemispherical measurements will be used to obtain absolute bidirectional reflectance.

Scott, R.

1973-01-01

35

Electrical and structural properties of multicomponent transparent conducting oxide films prepared by co-sputtering of AZO and ITO  

Microsoft Academic Search

Multicomponent transparent conducting oxide (TCO) films were deposited on glass substrates by co-sputtering of Al-doped ZnO (AZO) and Sn-doped In2O3 (ITO) targets. Changes in the electrical and structural properties of the films were investigated as a function of the power on ITO target at a constant AZO power. The addition of limited amounts of ITO (cation ratio of [In]\\/[Al+Zn+In+Sn], ?<0.28)

Dong-Ho Kim; Hye-Ri Kim; Sung-Hun Lee; Eungsun Byon; Gun-Hwan Lee

2010-01-01

36

Directed spatial organization of zinc oxide nanostructures  

DOEpatents

A method for controllably forming zinc oxide nanostructures on a surface via an organic template, which is formed using a stamp prepared from pre-defined relief structures, inking the stamp with a solution comprising self-assembled monolayer (SAM) molecules, contacting the stamp to the surface, such as Ag sputtered on Si, and immersing the surface with the patterned SAM molecules with a zinc-containing solution with pH control to form zinc oxide nanostructures on the bare Ag surface.

Hsu, Julia (Albuquerque, NM); Liu, Jun (Richland, WA)

2009-02-17

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

ELECTROCHEMICAL REDUCTION PRIOR TO ELECTRO-FENTON OXIDATION OF AZO DYES. IMPACT OF THE PRE-TREATMENT ON  

E-print Network

1 ELECTROCHEMICAL REDUCTION PRIOR TO ELECTRO-FENTON OXIDATION OF AZO DYES. IMPACT OF THE PRE dyes, Orange II, Methyl red and Biebrich Scarlet by electro-Fenton and the effect : 10.1007/s11270-012-1385-0 #12;2 by the Fenton reaction led to the oxidation of by-products from

Paris-Sud XI, Université de

39

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

40

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

41

Comparative study of zinc oxide and aluminum doped zinc oxide transparent thin films grown by direct current magnetron sputtering  

E-print Network

Comparative study of zinc oxide and aluminum doped zinc oxide transparent thin films grown January 2007 Abstract Pure and aluminum (Al) doped zinc oxide (ZnO and ZAO) thin films have been grown.V. All rights reserved. Keywords: Zinc oxide; dc magnetron sputtering; Surface morphology; Sensors 1

42

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

43

21 CFR 73.2991 - Zinc oxide.  

Code of Federal Regulations, 2011 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...

2011-04-01

44

21 CFR 73.2991 - Zinc oxide.  

Code of Federal Regulations, 2013 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...

2013-04-01

45

21 CFR 73.2991 - Zinc oxide.  

Code of Federal Regulations, 2012 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...

2012-04-01

46

21 CFR 73.2991 - Zinc oxide.  

Code of Federal Regulations, 2014 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...

2014-04-01

47

Pulsed laser deposition of ITO/AZO transparent contact layers for GaN LED applications  

NASA Astrophysics Data System (ADS)

In this study, indium-tin oxide (ITO)/Al-doped zinc oxide (AZO) composite films were fabricated by pulsed laser deposition and used as transparent contact layers (TCLs) in GaN-based blue light emitting diodes (LEDs). The ITO/AZO TCLs were composed of the thin ITO (50 nm) films and AZO films with various thicknesses from 200 to 1000 nm. Conventional LED with ITO (200 nm) TCL prepared by E-beam evaporation was fabricated and characterized for comparison. From the transmittance spectra, the ITO/AZO films exhibited high transparency above 90 at wavelength of 465 nm. The sheet resistance of ITO/AZO TCL decreased as the AZO thickness increased, which could be attributed to the increase in a carrier concentration, leading to a decrease in the forward bias of LED. The LEDs with ITO/AZO composite TCLs showed better light extraction as compared to LED with ITO TCL in compliance with simulation. When an injection current of 20 mA was applied, the output power for LEDs fabricated with ITO/AZO TCLs had 45%, 63%, and 71% enhancement as compared with those fabricated using ITO (200 nm) TCL for the AZO thicknesses of 200, 460, and 1000 nm, respectively.

Ou, Sin Liang; Wuu, Dong Sing; Liu, Shu Ping; Fu, Yu Chuan; Huang, Shih Cheng; Horng, Ray Hua

2011-08-01

48

Azo dye Acid Red 27 decomposition kinetics during ozone oxidation and adsorption processes.  

PubMed

To elucidate the effects of ozone dosage, catalysts, and temperature on azo dye decomposition rate in treatment processes, the decomposition kinetics of Acid Red 27 by ozone was investigated. Acid Red 27 decomposition rate followed the first-order reaction with complete dye discoloration in 20 min of ozone reaction. The dye decay rate increases as ozone dosage increases. Using Mn, Zn and Ni as transition metal catalysts during the ozone oxidation process, Mn displayed the greatest catalytic effect with significant increase in the rate of decomposition. The rate of decomposition decreases with increase in temperature and beyond 40 degrees C, increase in decomposition rate was followed by a corresponding increase in temperature. The FT-IR spectra in the range of 1,000-1,800 cm(-1) revealed specific band variations after the ozone oxidation process, portraying structural changes traceable to cleavage of bonds in the benzene ring, the sulphite salt group, and the C-N located beside the -N = N- bond. From the (1)H-NMR spectra, the breaking down of the benzene ring showed the disappearance of the 10 H peaks at 7-8 ppm, which later emerged with a new peak at 6.16 ppm. In a parallel batch test of azo dye Acid Red 27 adsorption onto activated carbon, a low adsorption capacity was observed in the adsorption test carried out after three minutes of ozone injection while the adsorption process without ozone injection yielded a high adsorption capacity. PMID:19337926

Beak, Mi H; Ijagbemi, Christianah O; Kim, Dong S

2009-05-01

49

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

E-print Network

Atomistic Simulation Study of Spinel Oxides: Zinc Aluminate and Zinc Gallate Ravindra Pandey+ in the spinel oxides considered here. The calculated formation energies of the native defects suggestGa2O4), and intermediate zinc aluminogallate spinel oxides have been investigated recently.1 Both

Pandey, Ravi

50

Photoemission studies of wurtzite zinc oxide.  

NASA Technical Reports Server (NTRS)

The electronic structure of wurtzite zinc oxide, investigated over the widest possible photon energy range by means of photoemission techniques, is described. Of particular interest among the results of the photoemission study are the location of the Zn 3rd core states, the width of the upper valence bands, and structure in the conduction-band and valence-band density of states.

Powell, R. A.; Spicer, W. E.; Mcmenamin, J. C.

1972-01-01

51

Effect of solvent volume on the physical properties of aluminium doped nanocrystalline zinc oxide thin films deposited using a simplified spray pyrolysis technique  

NASA Astrophysics Data System (ADS)

Aluminium doped zinc oxide (AZO) thin films were deposited by employing a low cost and simplified spray technique using a perfume atomizer from starting solutions having different volumes (10, 20, … , 50 mL) of solvent. The effect of solvent volume on the structural, electrical, optical, photoluminescence (PL) and surface morphological properties was studied. The electrical resistivity of the AZO films is remarkably influenced by the variation in the solvent volume. The X-ray diffraction profiles clearly showed that all the films have preferential orientation along the (0 0 2) plane irrespective of the solvent volume. The crystallite size was found to be in the nano range of 35-46 nm. The optical transmittance in the visible region is desirably high (>85%). The AFM images show columnar morphology with varying grain size. The PL studies revealed that the AZO film deposited from 50 mL of solvent volume has good quality with lesser defect density.

Jabena Begum, N.; Mohan, R.; Ravichandran, K.

2013-01-01

52

Molecular Orbital Studies of Zinc Oxide Chemical Vapor Deposition: Gas-Phase Hydrolysis of Diethyl Zinc,  

E-print Network

region.1,2 Doping with indium, gallium, or aluminum improves these properties.3-5 These characteristicsMolecular Orbital Studies of Zinc Oxide Chemical Vapor Deposition: Gas-Phase Hydrolysis of Diethyl deposition of zinc oxide thin films can be carried out with diethyl zinc and water vapor. The present study

Schlegel, H. Bernhard

53

LPG sensing performance of nanostructured zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Nanostructured zinc oxide thin films were prepared using ultrasonic spray pyrolysis technique. Zinc acetate was used as a starting precursor. As prepared thin films were characterized using different analytical techniques. The sensing performance of the nanostructured zinc oxide thin films was studied on exposure of various gases. The films were observed to be most sensitive (S= 1727) to LPG at 300°C.

Bari, A. R.; Patil, L. A.

2013-06-01

54

Novel Zinc Oxide Nanostructures Discovery by Electron Zhong Lin Wang  

E-print Network

Novel Zinc Oxide Nanostructures Discovery by Electron Microscopy Zhong Lin Wang School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332-0245, USA Abstract. Zinc oxide fabricated based on individual nanobelts. Thermal transport along a nanobelt has been measured [7]. Zinc

Wang, Zhong L.

55

Kinetic study of electro-Fenton oxidation of azo dyes on boron-doped diamond electrode.  

PubMed

The present work compares electrochemical degradation of red and blue azo textile dyes in single- and two-compartment electrochemical cells in the presence of Fenton reagent (Fe2+) and using a boron-doped diamond anode. Degradation of both dyes was related to the concentration of dye, applied current density and the concentration of FeSO4 catalyst. Complete colour removal and approximately 91% of organic matter oxidation was achieved in a two-compartment electrochemical cell at an applied current density of 20 mA x cm(-2), pH of 3 and Fe(2+) ion concentration of 0.02 mM. Higher current density and reaction time were required to achieve the same removals in a one-compartment electrochemical cell. Dye degradation kinetics as well as chemical oxygen demand removal rate were successfully modelled to pseudo first-order kinetics. The apparent first-order rate constants (k(o)) for degradation of red dye with an initial concentration of 20, 40 and 60 ppm were found to be 2.67 +/- 0.16, 2.19 +/- 0.09 and 1.5 +/- 0.03 min(-1), and for blue dye at the same initial concentrations were 1.99 +/- 0.2, 0.95 +/- 0.02 and 0.71 +/- 0.030 min(-1), respectively. PMID:24191481

Almomani, Fares; Baranova, Elena A

2013-01-01

56

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

57

Calculated Electronic Properties of Zinc Oxide  

Microsoft Academic Search

We performed ab-initio, self-consistent calculations of the electronic and related properties of zinc oxide (ZnO). Our computations employed a local density potential and the linear combination of atomic orbital (LCAO) formalism within the Bagayoko, Zhao, and Williams (BZW) procedure. The calculated equilibrium lattice parameters, energy bands, and band gap (3.2 eV) of wurtzite ZnO agree very well with experiment. We

D. Bagayoko; G. L. Zhao; E. G. Wang

2003-01-01

58

Zinc oxide-based diluted magnetic semiconductors  

Microsoft Academic Search

The current experimental situation on the occurrence or absence of ferromagnetism in diluted magnetic semiconductors based on wurtzite zinc oxide hosts is presented, focusing mainly on the many recent experiments which have been performed on bulk systems. Numerous reports have suggested that partial (typically less than 10at.%) substitution of Zn2+ in ZnO by magnetic transition metal (tM) ions, particularly Mn2+

Ram Seshadri

2005-01-01

59

Zinc oxide nanostructures: growth, properties and applications  

Microsoft Academic Search

Zinc oxide is a unique material that exhibits semiconducting and piezoelectric dual properties. Using a solid–vapour phase thermal sublimation technique, nanocombs, nanorings, nanohelixes\\/nanosprings, nanobelts, nanowires and nanocages of ZnO have been synthesized under specific growth conditions. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The

Zhong Lin Wang

2004-01-01

60

Photoconductivity of Ultrathin Zinc Oxide Films  

Microsoft Academic Search

Electrical and photoelectrical properties of nondoped and doped zinc oxide films coated on glass plates by the dip-coating method are investigated at room temperature in various ambient atmospheres. The dark conductivity of the nondoped films exponentially decreased with decreasing film thickness while the conductivity under illumination of 350 nm light was almost constant at 100 S·cm-1 irrespective of the film

Yasutaka Takahashi; Masaaki Kanamori; Akiko Kondoh; Hideki Minoura; Yutaka Ohya

1994-01-01

61

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

62

Electrode patterning and annealing processes of aluminum-doped zinc oxide thin films using a UV laser system  

NASA Astrophysics Data System (ADS)

This study presents the hybrid processing (patterning and annealing) of aluminum-doped zinc oxide (AZO) films in a one-step process using a diode-pumped-solid-state (DPSS) ultraviolet (UV) laser system. The focused laser beam had a diameter of 30 ?m and the positive defocused laser beam had a diameter of 1 mm. Both beams were adjusted using a UV laser-processing system. AZO films were deposited on Corning Eagle 2000® optical glass sheets with a thickness of 0.7 mm using a sputtering method. The deposited films were approximately 200 nm. The optoelectronic properties of machined (patterning and annealing) AZO films depend on the laser pulse frequency and galvanometer scanning speed. The surface morphology, roughness, optical transmittance, and resistivity of the films after the laser patterning and annealing processes were measured using a three-dimensional confocal laser scanning microscope, a field emission scanning electron microscope (FE-SEM), a spectrophotometer, and a four-point probe instrument, respectively. Experimental results indicate that the ablation depth increased as the pulse repetition frequency increased. The ablation depth also decreased as the galvanometric scanning speed increased. The transmittance spectra of the film changes slightly after laser annealing, and the average transmittance in the visible region is approximately 83%. All resistivity values of laser-patterned and annealed AZO films decreased significantly. The structural properties grain size was calculated firm the X-ray diffraction (XRD) spectra using the Scherrer equation that increased from 7.4 nm to 12 nm as the annealing scanning speed decreased from 800 mm/s to 400 mm/s. The root mean square (RMS) values of annealed AZO films treated with a laser scanning speed of 500 mm/s with a pulse repetition frequency of 40 kHz, 55 kHz, and 70 kHz were 1.1 nm, 1.2 nm, and 1.8 nm, respectively.

Hsiao, Wen-Tse; Tseng, Shih-Feng; Huang, Kuo-Cheng; Chiang, Donyau

2013-01-01

63

Characterization of Amorphous Zinc Tin Oxide Semiconductors  

SciTech Connect

Amorphous zinc tin oxide (ZTO) was investigated to determine the effect of deposition and post annealing conditions on film structure, composition, surface contamination, and thin film transistor (TFT) device performance. X-ray diffraction results indicated that the ZTO films remain amorphous even after annealing to 600 °C. We found that the bulk Zn:Sn ratio of the sputter deposited films were slightly tin rich compared to the composition of the ceramic sputter target, and there was a significant depletion of zinc at the surface. X-ray photoelectron spectroscopy also indicated that residual surface contamination depended strongly on the sample post-annealing conditions where water, carbonate and hydroxyl species were absorbed to the surface. Electrical characterization of ZTO films, using TFT test structures, indicated that mobilities as high as 17 cm2/Vs could be obtained for depletion mode devices.

Rajachidambaram, Jaana Saranya; Sanghavi, Shail P.; Nachimuthu, Ponnusamy; Shutthanandan, V.; Varga, Tamas; Flynn, Brendan T.; Thevuthasan, Suntharampillai; Herman, Gregory S.

2012-06-12

64

Zinc oxide nanostructures and nanoengineering  

NASA Astrophysics Data System (ADS)

ZnO is a large band-gap (3.37 eV) semiconductor, a potentially important material for numerous optoelectronic applications. Nanostructures, by definition are the structures having at least one dimension between 1--100 nm. In this thesis we will investigate a brief account of the strategies to grow ZnO nanostructures. Since invariably nanomaterial properties tend to change significantly during scale-up from development on limited volume equipment. Goal of this study is to demonstrate a practical technique which is able to synthesize large quantities of nanowires while keeping the unique properties of nano-sized materials. Using ZnO as an example, we discussed a strategy to produce nanowires in gram quantity. Ability to define position, size, and density of nanostructures on surfaces enable detailed studies of the properties of individual sites as well as collective properties of the assembly. These periodic structures are usually manufactured using electron beam lithography, photolithography, or x-ray lithography techniques. These methods allow fabrication of nanostructures and provide highly reproducible results. However, they are mostly not scalable to large areas, and are limited by a multistage, time-consuming, and expensive preparation procedure. We described an unique technique combining nanosphere self-assembly lithography and vapor-liquid-solid (VLS) approach of fabricating periodic array of catalyst dots in various geometry and subsequently grow vertically aligned ZnO nanowires in a large area hoping to achieve enhanced ultraviolet lasing and many other photonic devices. ZnO being a transparent conducting oxide, the fabrication of ZnO field emitters can be easily integrated with ITO and ZnO thin film fabrication process. Thus a low cost solution for fabrication of field emission display can be realized using ZnO nanowires as field emitters. There have been several demonstrations of using ZnO nanowires as field emitters. However no significant improvement in terms of field enhancement factor or turn on voltage has been achieved. Most of these nanowires were grown on smooth substrate. We will discuss effect of substrate geometry on field emission properties of nanostructures. We choose carbon cloth as an example, where the woven cloth geometry combined with the high aspect ratio of the nanowires significantly improved the field emission property.

Banerjee, Debasish

65

Microstructure of Nonohmic Zinc Oxide Ceramics  

Microsoft Academic Search

The existing and distributing states of crystal phases in the nonohmic zinc oxide ceramics with five additives, 0.5Bi2O3, 1.0Sb2O3, 0.5Co2O3, 0.5MnO2 and 0.5Cr2O3 (mol.%) were investigated by using various analytical techniques. The ceramics consist of the ZnO and spinel phases and mixed phases of beta-and delta-Bi2O3. The ZnO phase corresponds to the main constituent grains, which are single crystals 10

Masanori Inada

1978-01-01

66

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

67

Preparation of Naturally Textured Aluminum-Doped Zinc Oxide Films on Flexible Poly(ether sulfone) Substrate by Radio Frequency Magnetron Sputtering  

NASA Astrophysics Data System (ADS)

Transparent conducting oxide (TCO) layers of naturally textured aluminum-doped zinc oxide (AZO) were prepared on flexible poly(ether sulfone) (PES) substrates by controlling the radio frequency (RF) magnetron sputtering power without chemical wet etching, and their morphological, optical, and electrical properties were characterized. Layers with crater structures were formed at a single RF power; whereas at high RF power (2000 W), their surfaces resembled that of chemically wet-etched AZO. Layers were also formed by dual RF sputtering powers: sputtering a 0.15-µm-thick layer at high power and a subsequent 0.45-µm-thick layer at low power produced flakes with larger grains or crater-like structures. The measured visible transmittance of all the layers was >85% - sufficient for use in amorphous silicon (a-Si) thin-film solar cells. The measured optical and electrical properties of the naturally textured AZO layers are comparable to those of chemically wet-etched AZO layers, suggesting a possible method for fabricating inexpensive flexible a-Si thin-film solar cells in fewer steps.

An, Jae Seok; Koog Shin, Jin; Lee, Jong Ho; Choi, Bum Ho

2013-03-01

68

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

SciTech Connect

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 (T{sub s}). The films were found to be crystalline with the electrical resistivity close to 1.1 × 10{sup ?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 T{sub s} 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. [Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)] [Center for Materials Research, Norfolk State University, 700 Park Avenue, Norfolk, Virginia 23504 (United States)

2013-10-14

69

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

NASA Astrophysics Data System (ADS)

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 prepared at high temperature was composed of moderate sized grains with a regular shape. A secondary phase of ZnO2 was also observed for the film deposited at low substrate temperature. The cross-sectional TEM study of the AZO film showed that prior to the well-aligned columnar growth an initial interfacial zone with nano crystallites were formed. The nano crystallites formed initially with a large tilt angle normal to the substrate surface and during the growth of the transition zone, the tilt angle decreased until it vanished. The evolution of the film structure is discussed in terms of evolutionary selection model and the dynamic deposition process.

Hong, R. J.; Jiang, X.

2006-07-01

70

Piezoelectric Nanogenerators Based on Zinc Oxide Nanowire Arrays  

Microsoft Academic Search

We have converted nanoscale mechanical energy into electrical energy by means of piezoelectric zinc oxide nanowire (NW) arrays. The aligned NWs are deflected with a conductive atomic force microscope tip in contact mode. The coupling of piezoelectric and semiconducting properties in zinc oxide creates a strain field and charge separation across the NW as a result of its bending. The

Zhong Lin Wang; Jinhui Song

2006-01-01

71

Zinc Oxide Nanomaterials for Biomedical Fluorescence Detection  

PubMed Central

One-dimensional zinc oxide nanomaterials have been recently developed into novel, extremely effective, optical signal-enhancing bioplatforms. Their usefulness has been demonstrated in various biomedical fluorescence assays. Fluorescence is extensively used in biology and medicine as a sensitive and noninvasive detection method for tracking and analyzing biological molecules. Achieving high sensitivity via improving signal-to-noise ratio is of paramount importance in fluorescence-based, trace-level detection. Recent advances in the development of optically superior one-dimensional materials have contributed to this important biomedical area of detection. This review article will discuss major research developments that have so far been made in this emerging and exciting topical field. The discussion will cover a broad range of subjects including synthesis of zinc oxide nanorods (ZnO NRs), various properties differentiating them as suitable optical biodetection platforms, their demonstrated applicability in DNA and protein detection, and the nanomaterial characteristics relevant for biomolecular fluorescence enhancement. This review will then summarize the current status of ZnO NR-based biodetection and further elaborate future utility of ZnO NR platforms for advanced biomedical assays, based on their proven advantages. Lastly, present challenges experienced in this topical area will be identified and focal subject areas for future research will be suggested as well. PMID:24730276

Hahm, Jong-in

2014-01-01

72

UV irradiation-induced zinc dissociation from commercial zinc oxide sunscreen and its action in human epidermal keratinocytes  

E-print Network

UV irradiation-induced zinc dissociation from commercial zinc oxide sunscreen and its action Summary Zinc oxide (ZnO) is an active ingredient in sunscreen owing to its properties of broadly filtering of solar radiation on the skin. This study investigated the dissociation of zinc (Zn2+ ) from Zn

Li, Yang V.

73

COMPARISON OF THE EFFICIENCY OF ZINC INJECTED AS METAL OR OXIDE  

E-print Network

COMPARISON OF THE EFFICIENCY OF ZINC INJECTED AS METAL OR OXIDE FOR ZINC DEFICIENCY TREATMENT, the speed of liberation out of the injection site of zinc from zinc dust or zinc oxide. Materials as oxide (ZnO). All animals received hay ad libitum without any mineral mix. Plasma samples were analysed

Boyer, Edmond

74

Antifouling properties of zinc oxide nanorod coatings.  

PubMed

In laboratory experiments, the antifouling (AF) properties of zinc oxide (ZnO) nanorod coatings were investigated using the marine bacterium Acinetobacter sp. AZ4C, larvae of the bryozoan Bugula neritina and the microalga Tetraselmis sp. ZnO nanorod coatings were fabricated on microscope glass substrata by a simple hydrothermal technique using two different molar concentrations (5 and 10?mM) of zinc precursors. These coatings were tested for 5?h under artificial sunlight (1060?W?m(-2) or 530?W?m(-2)) and in the dark (no irradiation). In the presence of light, both the ZnO nanorod coatings significantly reduced the density of Acinetobacter sp. AZ4C and Tetraselmis sp. in comparison to the control (microscope glass substratum without a ZnO coating). High mortality and low settlement of B. neritina larvae was observed on ZnO nanorod coatings subjected to light irradiation. In darkness, neither mortality nor enhanced settlement of larvae was observed. Larvae of B. neritina were not affected by Zn(2+) ions. The AF effect of the ZnO nanorod coatings was thus attributed to the reactive oxygen species (ROS) produced by photocatalysis. It was concluded that ZnO nanorod coatings effectively prevented marine micro and macrofouling in static conditions. PMID:25115521

Al-Fori, Marwan; Dobretsov, Sergey; Myint, Myo Tay Zar; Dutta, Joydeep

2014-01-01

75

Zinc Adsorption Effects on Arsenite Oxidation Kinetics at the  

E-print Network

Zinc Adsorption Effects on Arsenite Oxidation Kinetics at the Birnessite-Water Interface L A U R oxidation of As(III) to As(V). Previous studies showed that manganese oxides, such as birnessite (-MnO2), directly oxidized As(III). However, these studies did not explore the role that cation adsorption has on As

Sparks, Donald L.

76

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

77

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

78

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

79

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

80

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

81

Influence of phytase, EDTA, and polyphenols on zinc absorption in adults from porridges fortified with zinc sulfate or zinc oxide.  

PubMed

Fortification of cereal staples with zinc is recommended to combat zinc deficiency. To optimize zinc absorption, strategies are needed to overcome the inhibitory effect of phytic acid (PA) and perhaps polyphenols. Five zinc absorption studies were conducted in young adults consuming maize or sorghum porridges fortified with 2 mg zinc as zinc sulfate (ZnSO4) or zinc oxide (ZnO) and containing combinations of PA or polyphenols as potential inhibitors and EDTA and phytase as potential enhancers. Fractional absorption of zinc (FAZ) was measured by using the double isotopic tracer ratio method. Adding phytase to the maize porridge immediately before consumption or using phytase for dephytinization during meal preparation both increased FAZ by >80% (both P < 0.001). Adding Na2EDTA at an EDTA:zinc molar ratio of 1:1 increased FAZ from maize porridge fortified with ZnSO4 by 30% (P = 0.01) but had no influence at higher EDTA ratios or on absorption from ZnO. FAZ was slightly higher from ZnSO4 than from ZnO (P = 0.02). Sorghum polyphenols had no effect on FAZ from dephytinized sorghum porridges but decreased FAZ by 20% from PA-rich sorghum porridges (P < 0.02). The combined inhibitory effect of polyphenols and PA was overcome by EDTA. In conclusion, ZnSO4 was better absorbed than ZnO, phytase used to degrade PA during digestion or during food preparation substantially increased zinc absorption from zinc-fortified cereals, EDTA at a 1:1 molar ratio modestly enhanced zinc absorption from ZnSO4-fortified cereals but not ZnO-fortified cereals, and sorghum polyphenols inhibited zinc absorption in the presence, but not absence, of PA. This trial was registered at clinicaltrials.gov as NCT01210794. PMID:24966411

Brni?, Marica; Wegmüller, Rita; Zeder, Christophe; Senti, Gabriela; Hurrell, Richard F

2014-09-01

82

Solvent extraction of zinc by trilaurylamine N-oxide  

Microsoft Academic Search

The solvent extraction behaviour of zinc from aqueous hydrochloric acid solutions using trilaurylamine N-oxide in toluene has been studied. The distribution ratios have been studied as a function of concentration of acid and extractant. The effects of foreign agents such as nitrate, sulphate, chloride, acetate, citrate, oxalate, and ascorbic acid on the extraction of zinc from hydrochloric acid solution are

A. Bari

1988-01-01

83

Bioavailability of Zinc in Wistar Rats Fed with Rice Fortified with Zinc Oxide  

PubMed Central

The study of zinc bioavailability in foods is important because this mineral intake does not meet the recommended doses for some population groups. Also, the presence of dietary factors that reduce zinc absorption contributes to its deficiency. Rice fortified with micronutrients (Ultra Rice®) is a viable alternative for fortification since this cereal is already inserted into the population habit. The aim of this study was to evaluate the bioavailability of zinc (Zn) in rice fortified with zinc oxide. During 42 days, rats were divided into four groups and fed with diets containing two different sources of Zn (test diet: UR® fortified with zinc oxide, or control diet: zinc carbonate (ZnCO3)), supplying 50% or 100%, respectively, of the recommendations of this mineral for animals. Weight gain, food intake, feed efficiency ratio, weight, thickness and length of femur; retention of zinc, calcium (Ca) and magnesium (Mg) in the femur and the concentrations of Zn in femur, plasma and erythrocytes were evaluated. Control diet showed higher weight gain, feed efficiency ratio, retention of Zn and Zn concentration in the femur (p < 0.05). However, no differences were observed (p > 0.05) for dietary intake, length and thickness of the femur, erythrocyte and plasmatic Zn between groups. Although rice fortified with zinc oxide showed a lower bioavailability compared to ZnCO3, this food can be a viable alternative to be used as a vehicle for fortification. PMID:24932657

Della Lucia, Ceres Mattos; Santos, Laura Luiza Menezes; Rodrigues, Kellen Cristina da Cruz; Rodrigues, Vivian Cristina da Cruz; Martino, Hércia Stampini Duarte; Pinheiro Sant’Ana, Helena Maria

2014-01-01

84

Toxicokinetics of zinc oxide nanoparticles in rats  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanoparticle have been extensively applied to diverse industrial fields because they possess UV light absorption, catalytic, semi-conducting, and magnetic characteristics as well as antimicrobial property. However, up to date, toxicological effects of ZnO nanoparticles in animal models have not been completely determined. Moreover, little information is available about kinetic behaviors of ZnO nanoparticles in vivo, which will be crucial to predict their potential chronic toxicity after long-term exposure. The aim of this study was, therefore, to evaluate the pharmacokinetics and toxicokinetics of ZnO nanoparticles after single-dose and repeated dose 90-day oral administration in male and female rats, respectively. The blood samples were collected following administration of three different doses (125, 250, and 500 mg/kg) and ZnO concentration was assessed by measuring zinc level with inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The result showed that the plasma ZnO concentration significantly increased in a dose-dependent manner, but decreased within 24 h after single-dose oral administration up to 500 mg/kg, without any significant difference between gender. However, when repeated dose 90-day oral toxicity study was performed, the elevated plasma concentrations did not return to normal control levels in all the cases, indicating their toxicity potential. These findings suggest that repeated oral exposure to ZnO nanoparticles up to the dose of 125 mg/kg could accumulate in the systemic circulation, thereby implying that the NOAEL values could be less than 125 mg/kg via oral intake.

Chung, H. E.; Yu, J.; Baek, M.; Lee, J. A.; Kim, M. S.; Kim, S. H.; Maeng, E. H.; Lee, J. K.; Jeong, J.; Choi, S. J.

2013-04-01

85

Acetone sensor based on zinc oxide hexagonal tubes  

SciTech Connect

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, E-mail: anitahastir@gmail.com; Singh, Onkar, E-mail: anitahastir@gmail.com; Anand, Kanika, E-mail: anitahastir@gmail.com; Singh, Ravi Chand, E-mail: anitahastir@gmail.com [Department of Physics, Guru Nanak Dev University, Amritsar-143005, Punjab (India)

2014-04-24

86

Electrodeposition of semiconductors for optoelectronic devices: results on zinc oxide  

Microsoft Academic Search

Electrodeposition of polycrystalline semiconductor thin films is mainly used for photovoltaic applications. Most of the work concerns chalcogenide compounds like CdTe, CuInSe2, CdS… This route is also emerging for semiconductor oxide preparation. Results concerning the electrodeposition of zinc oxide layers by reduction of dissolved oxygen in presence of Zn(II) ions are presented. Epitaxial growth can be achieved in zinc chloride

Thierry Pauporté; Daniel Lincot

2000-01-01

87

Zinc oxide nanoflowers make new blood vessels  

NASA Astrophysics Data System (ADS)

It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood vessels formation. Additionally, it helps to promote endothelial cell (EA.hy926 cells) migration in wound healing assays. Formation of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2)--a redox signaling molecule, might be the plausible mechanism for nanoflower-based angiogenesis. Angiogenesis by nanoflowers may provide the basis for the future development of new alternative therapeutic treatment strategies for cardiovascular and ischemic diseases, where angiogenesis plays a significant role.It is well established that angiogenesis is the process of formation of new capillaries from pre-existing blood vessels. It is a complex process, involving both pro- and anti-angiogenic factors, and plays a significant role in physiological and pathophysiological processes such as embryonic development, atherosclerosis, post-ischemic vascularization of the myocardium, tumor growth and metastasis, rheumatoid arthritis etc. This is the first report of zinc oxide (ZnO) nanoflowers that show significant pro-angiogenic properties (formation of new capillaries from pre-existing blood vessels), observed by in vitro and in vivo angiogenesis assays. The egg yolk angiogenesis assay using ZnO nanoflowers indicates the presence of matured blood vessels formation. Additionally, it helps to promote endothelial cell (EA.hy926 cells) migration in wound healing assays. Formation of reactive oxygen species (ROS), especially hydrogen peroxide (H2O2)--a redox signaling molecule, might be the plausible mechanism for nanoflower-based angiogenesis. Angiogenesis by nanoflowers may provide the basis for the future development of new alternative therapeutic treatment strategies for cardiovascular and ischemic diseases, where angiogenesis plays a significant role. Electronic supplementary information (ESI) available: See DOI: 10.1039/c2nr32369a

Barui, Ayan Kumar; Veeriah, Vimal; Mukherjee, Sudip; Manna, Joydeb; Patel, Ajay Kumar; Patra, Sujata; Pal, Krishnendu; Murali, Shruthi; Rana, Rohit K.; Chatterjee, Suvro; Patra, Chitta Ranjan

2012-11-01

88

Zinc oxide nanostructures: morphology derivation and evolution.  

PubMed

Zinc oxide nanostructures of various types, including nanobelts, nanoplatelets, nanowires, and nanorods, have been synthesized via well-developed routes by many research groups. However, so far, the underlying mechanism for the morphology derivation and evolution of the nanostructures has not been elucidated in depth. In this article, we report the systematic investigation of the morphology evolution characteristics of ZnO nanostructures from dense rods to dense nanoplatelets, nanoplatelet flowers, dense nanobelt flowers, and nanowire flowers in an evaporation-physical transport-condensation approach. Through the use of crystal growth theory, the determining factors for the formation of different nanostructural morphologies were found to be gas-phase supersaturation and the surface energy of the growing surface planes. Other experimental parameters such as the temperature at the source and the substrate, the temperature difference and the distance between the source and the substrate, the heating rate of the furnace, the gas flow rate, the ceramic tube diameter, and the starting material are all correlated with supersaturation and impose an effect on the morphology evolution. This finding may have an important impact on the qualitative understanding of the morphology evolution of nanostructures and the achieving of desired nanostructures controllably. PMID:16853555

Ye, Changhui; Fang, Xiaosheng; Hao, Yufeng; Teng, Xuemei; Zhang, Lide

2005-10-27

89

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

90

Construction of triglyceride biosensor based on nickel oxide-chitosan/zinc oxide/zinc hexacyanoferrate film.  

PubMed

A method is described for construction of an amperometric triglyceride (TG) biosensor based on co-immobilization of lipase, glycerol kinase (GK) and glycerol-3-phosphate oxidase (GPO) onto nickel oxide nanoparticles (NiONPs)-chitosan (CHIT) nanocomposite adsorbed onto zinc oxide/zinc hexacyanoferrate (ZnO-ZnHCF) hybrid film electrodeposited on the surface of an Au electrode. The NiONPs-CHIT/ZnO-ZnHCF hybrid film was characterized by cyclic voltammetry (CV), atomic force microscopy (AFM) and electrochemical impedance spectroscopy (EIS). The biosensor showed optimum response within 4 s at pH 6.0 and 35 °C, when polarized at +0.4 V against Ag/AgCl. There was a linear relationship between sensor response and triolein concentration in the range 50-700 mg/dl with sensitivity of 0.05 ?A/mg/dl. The sensor was employed for determination of TG in serum. The detection limit of the biosensor was 10 mg/dl. The biosensor was evaluated with 95-96% recovery of added triolein in sera and 2% and 3% within and between batch coefficients of variation (CVs) respectively. There was a good correlation (r=0.99) between serum TG values by standard enzymic colorimetric method and the present method. The biosensor lost 50% of its initial activity after its 100 uses over a period of 180 days, when stored at 4 °C. PMID:23707748

Narang, J; Chauhan, N; Pundir, C S

2013-09-01

91

The enhanced conductivity and stability of AZO thin films with a TiO2 buffer layer  

NASA Astrophysics Data System (ADS)

Aluminum doped zinc oxide (AZO) films were substitutes of the SnO2:F films on soda lime glass substrate in the amorphous thin-film solar cells due to good properties and low cost. In order to improve properties of AZO films, the TiO2 buffer layer had been introduced. AZO films with and without TiO2 buffer layer were deposited on soda lime glass substrates by r.f. magnetron sputtering. Subsequently, one group samples were annealed in vacuum (0.1 Pa) at 500 °C for 120 s using the RTA system, and the influence of TiO2 thickness on the properties of AZO films had been discussed. The XRD measurement results showed that all the films had a preferentially oriented (0 0 2) peak, and the intensity of (0 0 2) peak had been enhanced for the AZO films with TiO2 buffer layer. The resistivity of TiO2 (3.0 nm)/AZO double-layer film is 4.76×10-4 ? cm with the maximum figure merit of 1.92×10-2 ?-1, and the resistivity has a remarkable 28.7% decrease comparing with that of the single AZO film. The carrier scattering mechanism of TiO2 (3.0 nm)/AZO double-layer film had been described by Hall measurement in different temperatures. The average transmittance of all the films exceeded 92% in the visible spectrum. Another group samples were heat treated in the quartz tube in air atmosphere, and the effect of TiO2 thickness on thermal stability of AZO films had been discussed.

Yang, Tianlin; Song, Shumei; Li, Yanhui; Xin, Yanqing; Du, Guiqiang; Lv, Maoshui; Han, Shenghao

2012-12-01

92

Solarthermal and solar quasi-electrolytic processing and separations: Zinc from zinc oxide as an example  

Microsoft Academic Search

The advantages of using the high thermodynamic potential of sunlight for energy-intensive industrial solar thermochemical and thermoelectrochemical processing and the concomitant need for high-temperature separation methods are discussed. Example applications are introduced. The production of zinc from zinc oxide is used as an explicit illustrative example to show some opportunities and problems that solar energy presents. The use of quasi-electrolysis,

Edward A. Fletcher

1999-01-01

93

Electrolyte optimization for cathodic growth of zinc oxide films  

Microsoft Academic Search

Zinc oxide is of considerable interest to the optical and electronic industries, because of its electrical, optical, and acoustic characteristics. ZnO films can be prepared by several techniques, such as radio frequency (RF) magnetron sputtering, chemical vapor deposition, and molecular beam epitaxy. Preparation of oxide films by electrodeposition from aqueous solutions has several potential advantages over the other techniques. However,

Masanobu Izaki; Takashi Omi

1996-01-01

94

Nitric oxide and zinc homeostasis in pulmonary endothelium.  

PubMed

We have shown that zinc-thiolate moieties of the metal binding protein metallothionein (MT) are critical targets for nitric oxide (NO) with resultant increases in intracellular labile zinc. Such an NO-MT-Zn signaling pathway appears to participate in important cardiovascular functions associated with biosynthesis of NO including hypoxic vasoconstriction in the lung. Although downstream effector signaling molecules and critical contractile targets remain unclear, current investigations reveal a contributory role for zinc dependent protein kinases and cytoskeletal proteins in mediating hypoxic induced constriction of pulmonary endothelial cells. PMID:20716286

Li, Huihua; Cao, Rong; Wasserloos, Karla J; Bernal, Paula; Liu, Zhao-Qian; Pitt, Bruce R; St Croix, Claudette M

2010-08-01

95

Biodecolorization of azo dye Remazol orange by Pseudomonas aeruginosa BCH and toxicity (oxidative stress) reduction in Allium cepa root cells.  

PubMed

In this report a textile azo dye Remazol orange was degraded and detoxified by bacterium Pseudomonas aeruginosa BCH in plain distilled water. This bacterial decolorization performance was found to be pH and temperature dependent with maximum decolorization observed at pH 8 and temperature 30 °C. Bacterium tolerated higher dye concentrations up to 400 mg?l(-1). Effect of initial cell mass showed that higher cell mass concentration can accelerate decolorization process with maximum of 92 % decolorization observed at 2.5 g?l(-1) cell mass within 6.5 h. Effect of various metal ions showed Mn has inducing effect whereas Zn strongly inhibited the decolorization process at 5 mM concentration. Analysis of biodegradation products carried out with UV-vis spectroscopy, HPTLC and FTIR confirmed the decolorization and degradation of Remazol orange. Possible route for the degradation of dye was proposed based on GC-MS analysis. During toxicological scrutiny in Allium cepa root cells, induction in the activities of superoxide dismutase (SOD), guaiacol peroxidase (GPX) and inhibition of catalase (CAT) along with raised levels of lipid peroxidation and protein oxidation in dye treated samples were detected which conclusively indicated the generation of oxidative stress. Less toxic nature of the dye degraded products was observed after bacterial treatment. PMID:22948606

Jadhav, Shekhar B; Surwase, Shripad N; Kalyani, Dayanand C; Gurav, Ranjit G; Jadhav, Jyoti P

2012-11-01

96

Plasma in-liquid method for reduction of zinc oxide in zinc nanoparticle synthesis  

NASA Astrophysics Data System (ADS)

Metal air-batteries with high-energy density are expected to be increasingly applied in electric vehicles. This will require a method of recycling air batteries, and reduction of metal oxide by generating plasma in liquid has been proposed as a possible method. Microwave-induced plasma is generated in ethanol as a reducing agent in which zinc oxide is dispersed. Analysis by energy-dispersive x-ray spectrometry (EDS) and x-ray diffraction (XRD) reveals the reduction of zinc oxide. According to images by transmission electron microscopy (TEM), cubic and hexagonal metallic zinc particles are formed in sizes of 30 to 200 nm. Additionally, spherical fiber flocculates approximately 180 nm in diameter are present.

Amaliyah, Novriany; Mukasa, Shinobu; Nomura, Shinfuku; Toyota, Hiromichi; Kitamae, Tomohide

2015-02-01

97

Heterostructured nanohybrid of zinc oxide-montmorillonite clay.  

PubMed

We have synthesized heterostructured zinc oxide-aluminosilicate nanohybrids through a hydrothermal reaction between the colloidal suspension of exfoliated montmorillonite nanosheets and the sol solution of zinc acetate. According to X-ray diffraction, N2 adsorption-desorption isotherm, and field emission-scanning electron microscopic analyses, it was found that the intercalation of zinc oxide nanoparticles expands the basal spacing of the host montmorillonite clay, and the crystallites of the nanohybrids are assembled to form a house-of-cards structure. From UV-vis spectroscopic investigation, it becomes certain that calcined nanohybrid contains two kinds of the zinc oxide species in the interlayer space of host lattice and in mesopores formed by the house-of-cards type stacking of the crystallites. Zn K-edge X-ray absorption near-edge structure/extended X-ray absorption fine structure analyses clearly demonstrate that guest species in the nanohybrids exist as nanocrystalline zinc oxides with wurzite-type structure. PMID:16471722

Hur, Su Gil; Kim, Tae Woo; Hwang, Seong-Ju; Hwang, Sung-Ho; Yang, Jae Hun; Choy, Jin-Ho

2006-02-01

98

Analysis of cellular responses of macrophages to zinc ions and zinc oxide nanoparticles: a combined targeted and proteomic approach  

NASA Astrophysics Data System (ADS)

Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations.Two different zinc oxide nanoparticles, as well as zinc ions, are used to study the cellular responses of the RAW 264 macrophage cell line. A proteomic screen is used to provide a wide view of the molecular effects of zinc, and the most prominent results are cross-validated by targeted studies. Furthermore, the alteration of important macrophage functions (e.g. phagocytosis) by zinc is also investigated. The intracellular dissolution/uptake of zinc is also studied to further characterize zinc toxicity. Zinc oxide nanoparticles dissolve readily in the cells, leading to high intracellular zinc concentrations, mostly as protein-bound zinc. The proteomic screen reveals a rather weak response in the oxidative stress response pathway, but a strong response both in the central metabolism and in the proteasomal protein degradation pathway. Targeted experiments confirm that carbohydrate catabolism and proteasome are critical determinants of sensitivity to zinc, which also induces DNA damage. Conversely, glutathione levels and phagocytosis appear unaffected at moderately toxic zinc concentrations. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr00319e

Triboulet, Sarah; Aude-Garcia, Catherine; Armand, Lucie; Gerdil, Adèle; Diemer, Hélène; Proamer, Fabienne; Collin-Faure, Véronique; Habert, Aurélie; Strub, Jean-Marc; Hanau, Daniel; Herlin, Nathalie; Carrière, Marie; van Dorsselaer, Alain; Rabilloud, Thierry

2014-05-01

99

Sealed silver oxide zinc cells for orbiting and planetary missions.  

NASA Technical Reports Server (NTRS)

Several test programs were carried out to determine the performance and limitations of sealed, silver oxide zinc cells for (1) 24-hr synchronous orbits, (2) orbits that would require a maximum of six cycles per day, and (3) missions to other planets requiring maintenance of maximum capacity for probe operations during planet encounter. The results are summarized to provide power system designers with guidelines bearing on capacity maintenance during cycling, cycle life, charged stand effects, and internal pressure characteristics. The life of zinc silver oxide cells is shown to be limited to one to two years over the temperature range of 0 to 24 C.

Hennigan, T. J.; Palandati, C. F.

1972-01-01

100

Electrolyte optimization for cathodic growth of zinc oxide films  

SciTech Connect

Zinc oxide is of considerable interest to the optical and electronic industries, because of its electrical, optical, and acoustic characteristics. ZnO films can be prepared by several techniques, such as radio frequency (RF) magnetron sputtering, chemical vapor deposition, and molecular beam epitaxy. Preparation of oxide films by electrodeposition from aqueous solutions has several potential advantages over the other techniques. However, the formation of oxide films through electrochemical reactions have been demonstrated only on thallic oxide by Switzer and zirconium oxide by Gal-Or. In this work, the authors have prepared transparent ZnO films with optical bandgap energy of 3.3 eV by electrodeposition from an aqueous, 0.1 mol/liter zinc nitrate electrolyte. The deposition technology is still being developed. This paper reports the effects of the electrolyte concentration on the electrodeposition and properties of the ZnO films.

Izaki, Masanobu [Osaka Municipal Technical Research Inst. (Japan); Omi, Takashi [Osaka Prefecture Univ., Sakai (Japan). Coll. of Engineering

1996-03-01

101

Hydrogen Reduction of Zinc and Iron Oxides Containing Mixtures  

NASA Astrophysics Data System (ADS)

Zinc is a metal of significant technological importance and its production from secondary sources has motivated the development of alternative processes, such as the chemical treatment of electrical arc furnace (EAF) dust. Currently, the extraction of zinc from the mentioned residue using a carbon-containing reducing agent is in the process of being established commercially and technically. In the current study, the possibility of reducing zinc from an EAF dust sample through a H2 constant flux in a horizontal oven is studied. The reduction of a synthetic oxide mixture of analogous composition is also investigated. The results indicated that the reduction process is thermodynamically viable for temperatures higher than 1123 K (850 °C), and all zinc metal produced is transferred to the gas stream, enabling its complete separation from iron. The same reaction in the presence of zinc crystals was considered for synthesizing FeZn alloys. However, for the experimental conditions employed, although ZnO reduction was indeed thermodynamically hindered because of the presence of zinc crystals (the metal's partial pressure was enhanced), the zinc metal's escape within the gaseous phase could not be effectively avoided.

de Siqueira, Rogério Navarro C.; de Albuquerque Brocchi, Eduardo; de Oliveira, Pamela Fernandes; Motta, Marcelo Senna

2013-10-01

102

J Am Cerom Soc 73 [lo] 3026-32 (19901 Electrical Properties of Individual Zinc Oxide  

E-print Network

J Am Cerom Soc 73 [lo] 3026-32 (19901 Electrical Properties of Individual Zinc Oxide Grain properties of single interfaces and grain boundaries. [Keywords: grain boundaries, zinc oxide, varistors semiconductor, zinc oxide (ZnO), which is used commercially as a varistor material. This is an excellent

Rohrer, Gregory S.

103

Zinc oxide nanostructures: epitaxially growing from hexagonal zinc nanostructures  

NASA Astrophysics Data System (ADS)

The epitaxial growth of ZnO nanosheets and nanoneedles from a Zn/ZnO core/shell structure is verified by an experiment in which the ZnO nanoneedles and nanosheets are synthesized in air within an ultra-low temperature range from 250 to 400 °C by thermal oxidation of Zn films made up of hexagonal nanodiscs or nanoprisms. The hexagonal Zn structures are oxidized to form a Zn/ZnO core/shell structure with an epitaxial relationship; ZnO nanoneedles and nanosheets are found to grow epitaxially from the ZnO shell, along sixfold symmetric \\langle \\bar {2}110\\rangle directions, showing the same lattice orientation as the Zn core. The stability difference among different facets of hexagonal Zn crystal structures plays a key role in the formation of ZnO nanosheets, nanoneedles and the Zn/ZnO core/shell structure, as well as ZnO hollow structures. A vapor solid mechanism is suggested to explain the epitaxial growth process of the ZnO products. Photoluminescence properties of the ZnO nanostructures are also explored.

Guo, Chuan Fei; Wang, Yongsheng; Jiang, Peng; Cao, Sihai; Miao, Junjie; Zhang, Zhuwei; Liu, Qian

2008-11-01

104

Resputtering of zinc oxide films prepared by radical assisted sputtering  

SciTech Connect

Sputtering losses of zinc oxide films prepared by radical assisted sputtering were studied. It was found that the sputtering loss can be very severe in oxygenous sputtering processes of zinc oxide films. In general, resputtering caused by negative oxygen ions dominates the sputtering loss, while diffuse deposition plays a minor role. Resputtering is strongly correlated with the sputtering threshold energy of the deposited films and the concentration of O{sup -} in the sputtering zone. The balance between the oxygen concentration in the sputtering zone and the oxidation degree of the growing films depends on the sputtering rate. Our research suggests that a lower oxygen concentration in the sputtering zone and a higher oxidation degree of the growing films are favorable for reducing the resputtering losses. The sputtering loss mechanisms discussed in this work are also helpful for understanding the deposition processes of other magnetron sputtering systems.

Song Qiuming [Hefei National Laboratory for Physical Science at Microscale and USTC-SHINCRON Joint Laboratory, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); CAS/CUHK Shenzhen Institute of Advanced Integration Technology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, Guangdong 518054 (China); Wu Bingjun; Xie Bin; Huang Feng; Li Ming; Wang Haiqian [Hefei National Laboratory for Physical Science at Microscale and USTC-SHINCRON Joint Laboratory, University of Science and Technology of China, 96 Jinzhai Road, Hefei, Anhui 230026 (China); Jiang Yousong; Song Yizhou [Shincron Co., LTD., Shinagawa-Ku, Tokyo 140-0011 (Japan)

2009-02-15

105

Application of zinc oxide quantum dots in food safety  

Technology Transfer Automated Retrieval System (TEKTRAN)

Zinc oxide quantum dots (ZnO QDs) are nanoparticles of purified powdered ZnO. The ZnO QDs were directly added into liquid foods or coated on the surface of glass jars using polylactic acid (PLA) as a carrier. The antimicrobial activities of ZnO QDs against Listeria monocytogenes, Salmonella Enteriti...

106

Preparation and characterization of lead doped zinc oxide thin films  

NASA Astrophysics Data System (ADS)

Undoped and Lead doped Zinc Oxide thin films were prepared by low-cost Spray pyrolysis technique. XRD and UV-Vis spectroscopy techniques were employed for characterizing the films, as the doping is increased the change in structural properties and optical transmittance is noted.

Valan, I. Inigo; Gokulakrishnan, V.; Stephen, A.; Ramamurthi, K.

2013-02-01

107

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

108

Nanocomposite electrical generator based on piezoelectric zinc oxide nanowires  

E-print Network

Nanocomposite electrical generator based on piezoelectric zinc oxide nanowires K. Momeni, G. M October 2010; published online 1 December 2010 A nanocomposite electrical generator composed of an array the finalization of this paper, it was found out that a nanocomposite electrical generator was built experimentally

Endres. William J.

109

Process for fabricating doped zinc oxide microsphere gel  

DOEpatents

Disclosed are 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.

1991-11-05

110

Potassium silicate-zinc oxide solution for metal finishes  

NASA Technical Reports Server (NTRS)

Examples of zinc dust formulations, which are not subject to cracking or crazing, are fire retardant, and have high adhesive qualities, are listed. The potassium silicate in these formulations has mol ratios of dissolved silica potassium oxide in the range 4.8 to 1 - 5.3 to 1.

Schutt, J. B.

1970-01-01

111

Electrode effects on gas sensing properties of nanocrystalline zinc oxide  

Microsoft Academic Search

Electrode effects on gas sensing properties have been examined by nanocrystalline zinc oxide sensor in this study. Nanocrystalline Zn is grown by the gas condensation method in a 5 mbar helium atmosphere on the surface of gold or silver electrodes and then undergoes step sintering to form nanocrystalline ZnO. The response of nanocrystalline ZnO in CO gas shows the decreasing

Hong-Ming Lin; Shah-Jye Tzeng; Peng-Jan Hsiau; Wen-Li Tsai

1998-01-01

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

Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet  

E-print Network

1 Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet Richard Claeyssen1,2 , Maud Andriollo-Sanchez1 , Josiane Arnaud2,3 , Laurence Touvard1 Cedex 9, France. Keywords: Burn injury, zinc intakes, zinc status, oxidative stress, rat model

Paris-Sud XI, Université de

114

Rapid degradation of zinc oxide nanoparticles by phosphate ions.  

PubMed

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

Herrmann, Rudolf; García-García, F Javier; Reller, Armin

2014-01-01

115

Doping in zinc oxide thin films  

NASA Astrophysics Data System (ADS)

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 growth rate, better crystallinity, lower electron carrier concentration, larger resistivity, and smaller density of non-radiative luminescence centers in the ZnO thin films. Low-temperature photoluminescence (PL) measurements were carried out in undoped and Ga-doped ZnO thin films grown by molecular-beam epitaxy. As the carrier concentration increases from 1.8 x 1018 to 1.8 x 1020 cm-3, the dominant PL line at 9 K changes from I1 (3.368--3.371 eV), to IDA (3.317--3.321 eV), and finally to I8 (3.359 eV). The dominance of I1, due to ionized-donor bound excitons, is unexpected in n-type samples, but is shown to be consistent with the temperature-dependent Hall fitting results. We also show that IDA has characteristics of a donor-acceptor-pair transition, and use a detailed, quantitative analysis to argue that it arises from GaZn donors paired with Zn-vacancy (VZn) acceptors. In this analysis, the GaZn0/+ energy is well-known from two-electron satellite transitions, and the VZn0/- energy is taken from a recent theoretical calculation. Typical behaviors of Sb-doped p-type ZnO are presented. The Sb doping mechanisms and preference in ZnO are discussed. Diluted magnetic semiconducting ZnO:Co thin films with above room-temperature TC were prepared. Transmission electron microscopy and x-ray diffraction studies indicate the ZnO:Co thin films are free of secondary phases. The magnetization of the ZnO:Co thin films shows a free electron carrier concentration dependence, which increases dramatically when the free electron carrier concentration exceeds ˜1019 cm -3, indicating a carrier-mediated mechanism for ferromagnetism. The anomalous Hall effect was observed in the ZnO:Co thin films. The anomalous Hall coefficient and its dependence on longitudinal resistivity were analyzed. The presence of a side-jump contribution further supports an intrinsic origin for ferromagnetism in ZnO:Co thin films. These observations together with the magnetic anisotropy and magnetoresistance results, supports an intrinsic carrier-mediated mechanism for ferromagnetic exchange in ZnO:Co diluted magnetic semiconductor materials. Well-above room temperature and electron-concentration dependent ferromagnetism was observed in n-type ZnO:Mn films, indicating long-range ferromagnetic order. Magnetic anisotropy was also observed in these ZnO:Mn films, which is another indication for intrinsic ferromagnetism. The electron-mediated ferromagnetism in n-type ZnO:Mn contradicts the existing theory that the magnetic exchange in ZnO:Mn materials is mediated by holes. Microstructural studies using transmission electron microscopy were performed on a ZnO:Mn diluted magnetic semiconductor thin film. The high-resolution imaging and electron diffraction reveal that the ZnO:Mn thin film has a high structual quality and is free of clustering/segregated phases. High-angle annular dark field imaging and x-ray diffraction patterns further support the absence of phase segregation in the film. Magnetotransport was studied on the ZnO:Mn samples, and from these measurements, the temperature dependence of the resistivity and magnetoresistance, electron carrier concentration, and anomalous Hall coefficient of the sample is discussed. The anomalous Hall coefficient depends on the resistivity, and from this relation, the presence of the quadratic dependence term supports the intrinsic spin-obit origin of the anomalous Hall effect in the ZnO:Mn thin film.

Yang, Zheng

116

Analytic bond-order potential for atomistic simulations of zinc oxide  

E-print Network

Analytic bond-order potential for atomistic simulations of zinc oxide Paul Erhart1 , Niklas Juslin2 for zinc oxide and its elemental constituents is derived based on an analytical bond-order formalism. The model potential provides a good description of the bulk properties of various solid structures of zinc

Nordlund, Kai

117

Authigenic iron oxide proxies for marine zinc over geological time and implications for eukaryotic metallome  

E-print Network

Authigenic iron oxide proxies for marine zinc over geological time and implications for eukaryotic, Germany ABSTRACT Here, we explore enrichments in paleomarine Zn as recorded by authigenic iron oxides linked to biologically intrinsic evolutionary factors. In this case, zinc`s geochemical and biological

Konhauser, Kurt

118

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

119

Solvothermal routes for synthesis of zinc oxide nanorods.  

SciTech Connect

Control of the synthesis of nanomaterials to produce morphologies exhibiting quantized properties will enable device integration of several novel applications including biosensors, catalysis, and optical devices. In this work, solvothermal routes to produce zinc oxide nanorods are explored. Much previous work has relied on the addition of growth directing/inhibiting agents to control morphology. It was found in coarsening studies that zinc oxide nanodots will ripen to nanorod morphologies at temperatures of 90 to 120 C. The resulting nanorods have widths of 9-12 nm average dimension, which is smaller than current methods for nanorod synthesis. Use of nanodots as nuclei may be an approach that will allow for controlled growth of higher aspect ratio nanorods.

Bell, Nelson Simmons

2005-03-01

120

Zinc in a +III oxidation state  

E-print Network

The possibility of Group 12 elements, such as Zn, Cd, and Hg existing in an oxidation state of +III or higher and hence transforming them into transition metals has fascinated chemists for decades. It took nearly 20 years before experiment could confirm the theoretical prediction that Hg indeed can exist in an oxidation state of +IV. While this unusual property of Hg is attributed to the relativistic effects, Zn being much lighter than Hg has not been expected to have an oxidation state higher than +II. Using density functional theory we show that an oxidation state of +III for Zn can be realized by choosing specific ligands with large electron affinities. We demonstrate this by a systematic study of the interaction of Zn with F, BO2, and AuF6 ligands whose electron affinities are progressively higher, namely, 3.4 eV, 4.5 eV, and 8.6 eV, respectively. Discovery of higher oxidation states of elements can help in the formulation of new reactions and hence in the development of new chemistry.

Samanta, Devleena

2012-01-01

121

Decolorization of the azo dye Reactive Black 5 by Fenton and photo-Fenton oxidation  

Microsoft Academic Search

The oxidative decolorization of Reactive Black 5 (RB5) in aqueous solution has been studied using Fenton (H2O2\\/Fe2+) and photo-Fenton (H2O2\\/Fe2+\\/UV) processes. This investigation reveals that both methods can remove the color of RB5. Batch experiments were carried out to investigate the process's optimal operational conditions: pH, H2O2 dosage, Fe2+ dosage, RB5 concentration and optimal [Fe2+]0\\/[H2O2]0\\/[RB5]0 ratio, to obtain the bests

Marco S. Lucas; José A. Peres

2006-01-01

122

Fabrication and characterization of the electrical and optical properties of n-type thin film transparent conducting oxides deposited by neutralized ion beam sputtering and pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Transparent conducting oxides have become a fundamental electronic material for numerous current technologies and are optimally deposited as a uniform thin film with low electrical resistivity and high optical transmission. The purpose of this study is to characterize the electrical and optical characteristics of three TCO: Indium Tin Oxide (ITO) (95%, 5%), Zinc Oxide (ZnO), and Aluminum doped Zinc Oxide (AZO) (98%, 2%). The deposition techniques of neutralized ion beam sputtering and pulsed laser deposition will be investigated. ITO will be deposited from commercially available sintered targets whereas ZnO and AZO will be deposited from powder pressed targets. The results have shown that AZO deposit AZO from a powder pressed target with comparable electrical and optical properties to that of ITO deposited from a sintered target.

Vanderford, John D.

123

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

124

Zinc-oxide-based sorbents and processes for preparing and using same  

DOEpatents

Zinc oxide-based sorbents, and processes for preparing and using them are provided. 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 Prasael (Durham, NC)

2010-03-23

125

Band-Gap Engineering of Zinc Oxide Colloids via Lattice Substitution with Sulfur Leading to Materials with Advanced Properties for  

E-print Network

Band-Gap Engineering of Zinc Oxide Colloids via Lattice Substitution with Sulfur Leading requires a precise control over electronic properties. Zinc oxide is favorable for large such as zinc oxide (ZnO).3,4 At first sight, ZnO is a simple material. Unlike typical transition metals, zinc

Nabben, Reinhard

126

Zinc ion and neutral emission from single crystal zinc oxide during 193-nm excimer laser exposure  

SciTech Connect

Mass resolved time-of-flight measurements on neutral zinc atoms and zinc ions show energetic ions and neutrals during 193-nm irradiation of single crystals of semiconducting zinc oxide. Typical Zn+ kinetic energies are 3-5 eV. At fluences (energy per unit area per pulse) below 200 mJ/cm2, the ion intensities (per laser pulse) decrease monotonically to low values with laser pulse number. The depletion kinetics change from exponential to second order near 50 mJ/cm2. We attribute this change to the annihilation of defects yielding Zn+ emission when Zn+ or other surface defects become mobile. At fluences between 200 and 300 mJ/cm2, Zn+ emission becomes more sustained due to defects created by the laser. In this same fluence range, we observe the onset of detectable neutral atomic zinc emission. These neutral atoms display Maxwell-Boltzmann kinetic energy distributions w th effective surface temperatures that approach 5000 K as the fluence is raised to 350 mJ/cm2. These high surface temperatures are remarkable given the low etch rates observed at these fluences, suggesting that heated layer is extremely thin. We propose emission mechanisms and experiments to resolve outstanding questions.

Kahn, E. H. [Washington State University] [Washington State University; Langford, S. C. [Washington State University] [Washington State University; Boatner, Lynn A [ORNL] [ORNL; Dickinson, J. T. [Washington State University] [Washington State University

2011-01-01

127

Enterococcus faecalis zinc-responsive proteins mediate bacterial defence against zinc overload, lysozyme and oxidative stress.  

PubMed

Two Enterococcus faecalis genes encoding the P-type ATPase EF1400 and the putative SapB protein EF0759 were previously shown to be strongly upregulated in the presence of high concentrations of zinc. In the present work, we showed that a Zn(2+)-responsive DNA-binding motif (zim) is present in the promoter regions of these genes. Both proteins were further studied with respect to their involvement in zinc homeostasis and invasion of the host. EF0759 contributed to intramacrophage survival by an as-yet unknown mechanism(s). EF1400, here renamed ZntAEf, is an ATPase with specificity for zinc and plays a role in dealing with several host defences, i.e. zinc overload, oxidative stress and lysozyme; it provides E. faecalis cells with the ability to survive inside macrophages. As these three host defence mechanisms are important at several sites in the host, i.e. inside macrophages and in saliva, this work suggested that ZntAEf constitutes a crucial E. faecalis defence mechanism that is likely to contribute to the ability of this bacterium to endure life inside its host. PMID:25312746

Abrantes, Marta C; Kok, Jan; Silva Lopes, Maria de Fátima

2014-12-01

128

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

129

Synthesis and characterization of zinc oxide nanoparticles by laser ablation of zinc in liquid  

NASA Astrophysics Data System (ADS)

We report formation of colloidal suspension of zinc oxide nanoparticles by pulsed laser ablation of a zinc metal target at room temperature in different liquid environment. We have used photoluminescence, atomic force microscopy and X-ray diffraction to characterize the nanoparticles. The sample ablated in deionized water showed the photoluminescence peak at 384 nm (3.23 eV), whereas peaks at 370 nm (3.35 eV) were observed for sample prepared in isopropanol. The use of water and isopropanol as a solvent yielded spherical nanoparticles of 14-20 nm while in acetone we found two types of particles, one spherical nanoparticles with sizes around 100 nm and another platelet-like structure of 1 ?m in diameter and 40 nm in width. The absorption peak of samples prepared in deionized water and isopropanol are seen to be substantially blue shifted relative to that of the bulk zinc oxide due to the strong confinement effect. The technique offers an alternative for preparing the nanoparticles of active metal.

Thareja, R. K.; Shukla, Shobha

2007-09-01

130

Nonohmic Properties of Zinc Oxide Ceramics  

Microsoft Academic Search

Nonohmic properties of ZnO ceramics with five additives of Bi2O3, CoO, MnO, Cr2O3, and Sb2O3 are studied in relation to sintering temperature, additive content, and temperature dependence. The observation of electron photomicrographs and X-ray microanalysis proves a ceramic microstructure such that ZnO and these five oxides form, at the grain boundaries, segregation layers which are responsible for the nonohmic properties.

Michio Matsuoka

1971-01-01

131

Anisotropic Ferromagnetism in Substituted Zinc Oxide  

Microsoft Academic Search

Room-temperature ferromagnetism is observed in (110) oriented ZnO films\\u000acontaining 5 at % of Sc, Ti, V, Fe, Co or Ni, but not Cr, Mn or Cu ions. There\\u000aare large moments, 1.9 and 0.5 muB\\/atom for Co- and Ti-substituted oxides,\\u000arespectively. Sc-substituted ZnO shows also a moment of 0.3 muB\\/Sc.\\u000aMagnetization is very anisotropic, with variations of up to

M. Venkatesan; C. B. Fitzgerald; J. G. Lunney; J. M. D. Coey

2004-01-01

132

Formation Mechanism of Nonohmic Zinc Oxide Ceramics  

Microsoft Academic Search

For the formation of nonohmic ZnO ceramics based on the system ZnO-Bi2O3-Sb2O3, the reactions on heating (-->) and on slow cooling (<=ftarrow), {2PY+17ZnO}\\\\xleftarrow{\\\\xrightarrow{950{\\\\degree}˜ 1050{\\\\degC}}}{3Xzso+3Bi2O3} [L] \\\\ding{172}, and {Xzso}\\\\xleftarrow{\\\\xrightarrow≳ 1300{\\\\degC}}}{SP} \\\\ding{173}, play important roles, where PY is Zn2Bi3Sb3O14 pyrochlore, Xzso a polymorph of Zn7Sb2O12 [SP] and L is a liquid. Oxide additives markedly influence these reactions and consequently the phases and

Masanori Inada

1980-01-01

133

Zinc-histidine complex protects cultured cortical neurons against oxidative stress-induced damage.  

PubMed

The levels of zinc in the brain are directly affected by dietary zinc and deficiency has been associated with alcohol withdrawal seizures, excitotoxicity, impaired learning and memory and an accelerated rate of dysfunction in aged brain. Although zinc is essential for a healthy nervous system, high concentrations of zinc are neurotoxic, thus it is important to identify the most effective forms of zinc for treatment of conditions of the central nervous system. Accumulating evidence suggests that zinc-histidine complex (Zn(His)(2)) has greater biological potency and enhanced bioavailability compared with other zinc salts and also has antioxidant potential. Therefore, in this study we investigated the ability of zinc-histidine to protect cultured cortical neurons against hydrogen peroxide-induced damage. Pre-treating neurons for 18 h with subtoxic concentrations of zinc-histidine (5-25 microM) improved neuronal viability and strongly inhibited hydrogen peroxide-induced (75 microM, 30 min) cell damage as assessed by MTT turnover and morphological analysis 24h later. Low concentrations of zinc-histidine were more neuroprotective than zinc chloride. There was evidence of an anti-apoptotic mechanism of action as zinc-histidine inhibited hydrogen peroxide-induced caspase-3 activation and c-jun-N-terminal kinase phosphorylation. In summary, zinc supplementation with zinc-histidine protects cultured neurons against oxidative insults and inhibits apoptosis which suggests that zinc-histidine may be beneficial in the treatment of diseases of the CNS associated with zinc deficiency. PMID:15519738

Williams, Robert J; Spencer, Jeremy P E; Goni, Faisal M; Rice-Evans, Catherine A

2004-11-23

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

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.

McMillan, April D. (Knoxville, TN); Modine, Frank A. (Oak Ridge, TN); Lauf, Robert J. (Oak Ridge, TN); Alim, Mohammad A. (Medina, OH); Mahan, Gerald D. (Oak Ridge, TN); Bartkowiak, Miroslaw (Oak Ridge, TN)

1998-01-01

136

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

137

Zinc oxide thin film synthesized by combustion chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin film was prepared on quartz substrate by combustion chemical vapor deposition. Its surface morphology, crystal structure, chemical stoichiometry and optical properties were investigated using scanning electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Some small hexagonal ZnO sheets were observed on top of the ZnO thin film. XPS data showed that as-prepared ZnO thin film is of high O deficiency. Zinc hydroxide species was detected on the surface due to the reaction of interstitial Zn with H 2O in air. XRD and Raman spectroscopic results indicated that the ZnO film is polycrystalline and dominant in a hexagonal wurtzite phase.

Li, Zhi-Yang; Xu, Fuchun; Wu, Qi-Hui; Li, Jing

2008-12-01

138

Zinc-oxide-based planar nanodiodes operating at 50 MHz  

NASA Astrophysics Data System (ADS)

Nanometer-scale self-switching devices (SSDs) fabricated in polycrystalline zinc oxide have been demonstrated up to at least 51.5 MHz, functioning as rectifiers to generate DC voltage. The SSDs require only a single nanolithography step and hence are of interest to low-cost printed electronics. The devices showed stable performance within the frequency range tested. The as-fabricated devices possessed strongly nonlinear current-voltage characteristics, resembling those of conventional diodes. After coating the devices with poly methyl methacrylate and poly vinylidene fluoride to enhance the electric field coupling, the nonlinear behavior was maintained while the device current increased dramatically.

Irshaid, Mustafa Y.; Balocco, Claudio; Luo, Yi; Bao, Peng; Brox-Nilsen, Christian; Song, A. M.

2011-08-01

139

Biofunctionalization of zinc oxide nanowires for DNA sensory applications  

PubMed Central

We report on the biofunctionalization of zinc oxide nanowires for the attachment of DNA target molecules on the nanowire surface. With the organosilane glycidyloxypropyltrimethoxysilane acting as a bifunctional linker, amino-modified capture molecule oligonucleotides have been immobilized on the nanowire surface. The dye-marked DNA molecules were detected via fluorescence microscopy, and our results reveal a successful attachment of DNA capture molecules onto the nanowire surface. The electrical field effect induced by the negatively charged attached DNA molecules should be able to control the electrical properties of the nanowires and gives way to a ZnO nanowire-based biosensing device. PMID:21867525

2011-01-01

140

Cancer-Targeted Optical Imaging with Fluorescent Zinc Oxide Nanowires  

PubMed Central

Herein we demonstrate that intrinsically fluorescent zinc oxide (ZnO) nanowires (NWs) can be adopted for molecularly targeted imaging of cancer cells, after they are functionalized to render water solubility, biocompatibility, and low cellular toxicity. Optical imaging of integrin ?v?3 on U87MG human glioblastoma cells was achieved with RGD peptide-conjugated green fluorescent ZnO NWs, which opened up new avenues of research for investigating ZnO NW-based agents in tumor vasculature-targeted molecular imaging and drug delivery. PMID:21823599

Hong, Hao; Shi, Jian; Yang, Yunan; Zhang, Yin; Engle, Jonathan W.; Nickles, Robert J.; Wang, Xudong; Cai, Weibo

2011-01-01

141

Role of zinc oxide nanomorphology on Schottky diode properties  

NASA Astrophysics Data System (ADS)

Here, we present the solvothermal synthesis of surfactant guided rod and sphere like zinc-oxide (ZnO) nanoparticles and their application in ITO/ZnO/Al based Schottky diode. Morphology dependent device parameters like ideality factor, barrier potential and series resistance have been analyzed on the basis of charge transport phenomena. The effect of ZnO nanomorphology on device performance has been explained on the basis of multi generation-recombination via interface traps. Carrier mobility, carrier concentration and density of states near Fermi level were also evaluated to see the morphological effect on device property. Finally device performance has been correlated with ZnO morphology.

Middya, Somnath; Layek, Animesh; Dey, Arka; Datta, Joydeep; Das, Mrinmay; Banerjee, Chandan; Ray, Partha Pratim

2014-08-01

142

Diameter control of ultrathin zinc oxide nanofibers synthesized by electrospinning  

NASA Astrophysics Data System (ADS)

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.

Liao, Yingjie; Fukuda, Takeshi; Kamata, Norihiko; Tokunaga, Makoto

2014-05-01

143

Nanoscale Chemical Imaging of Zinc Oxide Nanowire Corrosion  

SciTech Connect

Nanoscale chemical images of individual bare and alumina-coated zinc oxide nanowires (NWs) were recorded using tip-enhanced second harmonic generation (SHG) spectroscopy before and after exposure to carbon dioxide and water vapor. The NWs were exposed for 0, 2, 4 and 6 days, and images were collected for the same bare nanowire after each two-day exposure period. Corrosion of the bare ZnO NW to zinc carbonate was evident from far-field and near-field SHG images and simultaneously recorded AFM data. The expected zinc carbonate corrosion product is SHG inactive. The AFM profile of the NW showed vertical and lateral expansion in different regions of the nanowire. The lower resolution far-field SHG signal decreased gradually and uniformly. The near-field SHG signal provided a profile of the evolving NW under investigation with a spatial resolution of ~100 nm which is in agreement with the AFM results. In contrast, alumina-coated ZnO NWs that were exposed in the same gas environment showed reduced, but still observable, degradation. The 3-nm thick alumina protective layer may have been insufficient to fully protect the NW, or the coating may have been incomplete. Thicker coatings preclude the tip-enhanced method. Nevertheless, the ability to monitor corrosion on a nanometer scale is a powerful tool for a fundamental understanding of surface chemical processes and should lead to the discovery of protective layers to prevent or delay degradation.

Cimatu, Katherine A [ORNL; Mahurin, Shannon Mark [ORNL; Meyer, Kent A [ORNL; Shaw, Robert W [ORNL

2012-01-01

144

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

145

A combined marginal deficiency of copper and zinc does not exacerbate oxidant stress asssociated with copper or zinc deficiency  

Technology Transfer Automated Retrieval System (TEKTRAN)

Both copper deficiency (Cu-def) and zinc deficiency (Zn-def) result in oxidative stress. Thus, an experiment was conducted to determine whether a marginal Zn-def amplified oxidative stress responses to a marginal Cu-def, or vice versa. Weanling male Sprague-Dawley rats were assigned to groups of 10 ...

146

Reduction of aromatic nitro compounds with hydrazine hydrate in the presence of an iron oxide\\/hydroxide catalyst. III. The selective reduction of nitro groups in aromatic azo compounds  

Microsoft Academic Search

The study on the range of applications of a cheap iron oxide\\/hydroxide modification as a H-transfer catalyst opened up a promising new route for the selective reduction of nitro groups in aromatic azo compounds. A series of monosubstituted 3- and 4-nitrophenylazobenzenes were reduced selectively by hydrazine hydrate in the presence of the iron oxide\\/hydroxide catalyst. The selectivity for the nitro

Max Lauwiner; Ronny Roth; Paul Rys

1999-01-01

147

Antibacterial, Deodorizing, and UV Absorbing Materials Obtained with Zinc Oxide (ZnO) Coated Fabrics  

Microsoft Academic Search

Ultra fine particle zinc oxide from Sumitomo Cement Co. is a multi functional material with antibacterial, deodorizing, and UV absorbing properties. The company has dispersed ultra fine zinc oxide into various types of vehicles that are classified into water-based and organic solvent-based types.

Mitumasa Saito

1993-01-01

148

Modified zinc oxide thick film resistors as NH 3 gas sensor  

Microsoft Academic Search

Screen printed thick films of pure and RuO2-doped zinc oxide were prepared. Pure zinc oxide films were also surface modified with ruthenium chloride. Gas sensing properties of the pure, doped and surface modified films were studied. The films were observed to be most sensitive to NH3 gas. The results are discussed and interpreted.

M. S. Wagh; G. H. Jain; D. R. Patil; S. A. Patil; L. A. Patil

2006-01-01

149

Characterization of clinical tolerance to inhaled zinc oxide in naive subjects and sheet metal workers.  

PubMed

Clinical tolerance to the acute effects of zinc oxide inhalation develops in workers during periods of repeated exposure. The aims of this study were to determine whether clinical tolerance is accompanied by a reduction in the acute pulmonary inflammatory and cytokine responses to zinc oxide exposure and whether tolerance can be demonstrated in sheet metal workers who chronically inhale low levels of zinc oxide. Naive (never-exposed) subjects inhaled 5 mg/m3 zinc oxide on 1 or 3 days and underwent bronchoalveolar lavage 20 hours after the final exposure. Sheet metal workers inhaled zinc oxide on 1 day and control furnace gas on another day. Among naive subjects in whom tolerance was induced, bronchoalveolar lavage fluid percent neutrophils and interleukin-6 (IL-6) levels were significantly decreased compared with subjects who underwent only a single exposure. Sheet metal workers were much less symptomatic, but they still experienced a significant increase in plasma IL-6. The results indicate that clinical tolerance to zinc oxide is accompanied by reduced pulmonary inflammation and that chronically exposed sheet metal workers are not clinically affected by exposure to zinc oxide fume at the Occupational Safety and Health Administration Permissible Exposure Limit. The increase in IL-6 levels observed in the clinically responsive, and to a lesser extent, tolerant, states following zinc oxide inhalation is consistent with the dual role of IL-6 as a pyrogen and anti-inflammatory agent. PMID:11094787

Fine, J M; Gordon, T; Chen, L C; Kinney, P; Falcone, G; Sparer, J; Beckett, W S

2000-11-01

150

Degradation of azo dye with horse radish peroxidase (HRP)  

Microsoft Academic Search

Azo dyes are recalcitrant carcinogenic compounds and have dermal and immunological effect on human beings. Conventional methods are not effective in the treatment of azo dyes. The oxidation capability of horse radish per- oxidase (HRP) and hydrogen peroxide (H2O2) on direct yellow 12 dye was investigated and was found to be very effective treatment methodology. HRP was extracted from horse

VASANTHA LAXMI MADDHINNI; HIMA BINDU VURIMINDI; ANJANEYULU YERRAMILLI; Trent Lott

2006-01-01

151

H? sensing properties of two-dimensional zinc oxide nanostructures.  

PubMed

In this work we have grown particular zinc oxide two-dimensional nanostructures which are essentially a series of hexagonal very thin sheets. The hexagonal wurtzite crystal structure gives them their peculiar shape, whose dimensions are few microns wide, with a thickness in the order of 25 nm. Such kind of nanostructure, grown by thermal oxidation of evaporated metallic zinc on a silica substrate, has been used to fabricate conductometric gas sensors, investigated then for hydrogen gas detection. The "depletion layer sensing mechanism" is clarified, explaining how the geometrical factors of one- and two-dimensional nanostructures affect their sensing parameters. The comparison with one-dimensional ZnO nanowires based structures shows that two-dimensional nanostructures are ideal for gas sensing, due to their tiny thickness, which is comparable to the depletion-layer thickness, and their large cross-section, which increases the base current, thus lowering the limit of detection. The response to H? has been found good even to sub-ppm concentrations, with response and recovery times shorter than 18s in the whole range of H? concentrations investigated (500 ppb-10 ppm). The limit of detection has been found around 200 ppb for H? gas even at relatively low working temperature (175 °C). PMID:24720984

Tonezzer, Matteo; Iannotta, Salvatore

2014-05-01

152

Nanosized Zinc Oxide Induces Toxicity in Human Lung Cells  

PubMed Central

Zinc oxide nanoparticles (ZnO-NPs) are increasingly used in sunscreens, biosensors, food additives, pigments, rubber manufacture, and electronic materials. With the wide application of ZnO-NPs, concern has been raised about its unintentional health and environmental impacts. This study investigates the toxic effects of ZnO-NPs in human lung cells. In order to assess toxicity, human lung epithelial cells (L-132) were exposed to dispersion of 50?nm ZnO-NPs at concentrations of 5, 25, 50, and 100??g/mL for 24?h. The toxicity was evaluated by observing changes in cell morphology, cell viability, oxidative stress parameters, DNA damage analysis, and gene expression. Exposure to 50?nm ZnO-NPs at concentrations between 5 and 100??g/mL decreased cell viability in a concentration-dependent manner. Morphological examination revealed cell shrinkage, nuclear condensation, and formation of apoptotic bodies. The oxidative stress parameters revealed significant depletion of GSH level and increase in ROS levels suggesting generation of oxidative stress. ZnO-NPs exposure caused DNA fragmentation demonstrating apoptotic type of cell death. ZnO-NPs increased the expression of metallothionein gene, which is considered as a biomarker in metal-induced toxicity. To summarize, ZnO-NPs cause toxicity in human lung cells possibly through oxidative stress-induced apoptosis. PMID:23997968

Sahu, Devashri; Kannan, G. M.; Vijayaraghavan, R.; Anand, T.; Khanum, Farhath

2013-01-01

153

An assessment of zinc oxide nanosheets as a selective adsorbent for cadmium  

PubMed Central

Zinc oxide nanosheet is assessed as a selective adsorbent for the detection and adsorption of cadmium using simple eco-friendly extraction method. Pure zinc oxide nanosheet powders were characterized using field emission scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy. The zinc oxide nanosheets were applied to different metal ions, including Cd(II), Cu(II), Hg(II), La(III), Mn(II), Pb(II), Pd(II), and Y(III). Zinc oxide nanosheets were found to be selective for cadmium among these metal ions when determined by inductively coupled plasma-optical emission spectrometry. Moreover, adsorption isotherm data provided that the adsorption process was mainly monolayer on zinc oxide nanosheets. PMID:24011201

2013-01-01

154

Myeloperoxidase-derived oxidants rapidly oxidize and disrupt zinc-cysteine/histidine clusters in proteins.  

PubMed

Zinc is an abundant cellular transition metal ion, which binds avidly to protein cysteine (Cys) and histidine (His) residues to form zinc-Cys/His clusters; these play a key role in the function of many proteins (e.g., DNA binding and repair enzymes, transcription factors, nitric oxide synthase). Leukocyte-derived myeloperoxidase generates powerful oxidants including hypochlorous (HOCl), hypobromous (HOBr), and hypothiocyanous (HOSCN) acids from H(2)O(2) and (pseudo)halide ions. Excessive or misplaced formation of these species is associated with cellular dysfunction, apoptosis and necrosis, and multiple inflammatory diseases. HOCl and HOBr react rapidly with sulfur-containing compounds, and HOSCN reacts specifically with thiols. Consequently, we hypothesized that zinc-Cys/His clusters would be targets for these oxidants, and the activity of such enzymes would be perturbed. This hypothesis has been tested using yeast alcohol dehydrogenase (YADH), which contains a well-characterized Zn(1)Cys(2)His(1) cluster. Incubation of YADH with pathologically relevant concentrations of HOSCN, HOCl, and HOBr resulted in rapid oxidation of the protein (rate constants, determined by competition kinetics, for reaction of HOCl and HOSCN with YADH being (3.3±0.9)×10(8) and (2.9±0.4)×10(4) M(-1) s(-1) per YADH monomer, respectively), loss of enzyme activity, Zn(2+) release, changes in protein structure (particularly formation of disulfide cross-links), and oxidation of Cys residues. The loss of enzyme activity correlated with Zn(2+) release, loss of thiols, and changes in protein structure. We conclude that exposure of zinc-Cys/His clusters to inflammatory oxidants can result in impaired protein activity, thiol oxidation, and Zn(2+) release. These reactions may contribute to inflammation-induced tissue damage. PMID:23032100

Cook, Naomi L; Pattison, David I; Davies, Michael J

2012-12-01

155

ZINC  

EPA Science Inventory

This report summarizes the available information on zinc as it relates to its effects on man and his environment. Zinc is found in most soils, but some areas are deficient in it. Metallurgic operations contribute to zinc contamination in air, water and soil. Trace amounts of zinc...

156

Solar Energy Materials & Solar Cells 91 (2007) 924930 Plasma-enhanced chemical vapor deposition of zinc oxide at  

E-print Network

of zinc oxide at atmospheric pressure and low temperature M.D. Barankin, E. Gonzalez II, A.M. Ladwig, R vapor deposition of aluminum-doped zinc oxide has been demonstrated for the first time at 800 Torr reserved. Keywords: Transparent-conducting oxide (TCO); Al/ZnO; PECVD 1. Introduction Aluminum-doped zinc

Hicks, Robert F.

157

1-Dimensional Zinc Oxide Nanomaterial Growth and Solar Cell Applications  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) has attracted much interest during last decades as a functional material. Furthermore, ZnO is a potential material for transparent conducting oxide material competing with indium tin oxide (ITO), graphene, and carbon nanotube film. It has been known as a conductive material when doped with elements such as indium, gallium and aluminum. The solubility of those dopant elements in ZnO is still debatable; but, it is necessary to find alternative conducting materials when their form is film or nanostructure for display devices. This is a consequence of the ever increasing price of indium. In addition, a new generation solar cell (nanostructured or hybrid photovoltaics) requires compatible materials which are capable of free standing on substrates without seed or buffer layers and have the ability introduce electrons or holes pathway without blocking towards electrodes. The nanostructures for solar cells using inorganic materials such as silicon (Si), titanium oxide (TiO2), and ZnO have been an interesting topic for research in solar cell community in order to overcome the limitation of efficiency for organic solar cells. This dissertation is a study of the rational solution-based synthesis of 1-dimentional ZnO nanomaterial and its solar cell applications. These results have implications in cost effective and uniform nanomanufacturing for the next generation solar cells application by controlling growth condition and by doping transition metal element in solution.

Choi, Hyung Woo

158

Zinc deficiency induces oxidative stress and AP1 activation in 3T3 cells  

Microsoft Academic Search

It has been postulated that one mechanism underlying zinc deficiency–induced tissue alterations is excessive cellular oxidative damage. In the present study we investigated if zinc deficiency can induce oxidative stress in 3T3 cells and trigger select intracellular responses that have been associated to oxidative stress. Cells were exposed to control media or to chelated media containing 0.5, 5, or 50

Patricia I Oteiza; Michael S Clegg; M. Paola Zago; Carl L Keen

2000-01-01

159

Effect of morphology and solvent on two-photon absorption of nano zinc oxide  

SciTech Connect

Highlights: ? ZnO nanospheres and triangular structures synthesis by novel precipitation technique. ? The effect of precursor concentration on the size and shape of nano ZnO. ? Open aperture Z-scan measurements of the ZnO nanoparticle dispersions. ? Nanospheres exhibit higher two photon absorption coefficient than triangular nanostructures. ? Nanospheres dispersed in water exhibit higher two photon absorption coefficient than its dispersion in 2-propanol. - Abstract: In this paper, we report the effect of morphology and solvent on the two-photon absorption of nano zinc oxide. Zinc oxide nanoparticles in two different morphologies like nanospheres and triangular nanostructures are synthesized by novel precipitation technique and their two-photon absorption coefficient is measured using open aperture Z-scan technique. Experimental results show that the zinc oxide nanospheres exhibit higher two-photon absorption coefficient than the zinc oxide triangular nanostructures. The zinc oxide nanospheres dispersed in water exhibit higher two-photon absorption coefficient than that of its dispersion in 2-propanol. The zinc oxide nanospheres dispersed in water shows a decrease in two-photon absorption coefficient with an increase in on-axis irradiance. The result confirms the dependence of shape and solvent on the two-photon absorption of nano zinc oxide.

Kavitha, M.K. [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695547, Kerala (India); Haripadmam, P.C.; Gopinath, Pramod; Krishnan, Bindu [Department of Physics, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695547, Kerala (India); John, Honey, E-mail: honey@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram 695547, Kerala (India)

2013-05-15

160

Photophysical Behaviors of Single Fluorophores Localized on Zinc Oxide Nanostructures  

PubMed Central

Single-molecule fluorescence spectroscopy has now been widely used to investigate complex dynamic processes which would normally be obscured in an ensemble-averaged measurement. In this report we studied photophysical behaviors of single fluorophores in proximity to zinc oxide nanostructures by single-molecule fluorescence spectroscopy and time-correlated single-photon counting (TCSPC). Single fluorophores on ZnO surfaces showed enhanced fluorescence brightness to various extents compared with those on glass; the single-molecule time trajectories also illustrated pronounced fluctuations of emission intensities, with time periods distributed from milliseconds to seconds. We attribute fluorescence fluctuations to the interfacial electron transfer (ET) events. The fluorescence fluctuation dynamics were found to be inhomogeneous from molecule to molecule and from time to time, showing significant static and dynamic disorders in the interfacial electron transfer reaction processes. PMID:23109903

Fu, Yi; Zhang, Jian; Lakowicz, Joseph R.

2012-01-01

161

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

162

Adsorption of isopropanol and cyclohexane on zinc oxide  

NASA Astrophysics Data System (ADS)

Adsorption isotherms of isopropanol and cyclohexane are obtained in the range of 234-303 K on an initial surface of zinc oxide and after its treatment with glow-discharge plasma in O2 and high-frequency plasma in Ar. The values of isosteric heat and adsorption entropy are shown to be only slightly affected by these treatments. It is found that the acidity of the surface increases by 38 and 97%, respectively, and the acidic sites are not adsorption sites for either adsorbate. At low degrees of occupation, the adsorption isotherms of (CH3)2CHOH are described by an equation of induced adsorption whose parameters are dependent on the plasma-chemical treatments. It is concluded that adsorbed isopropanol particles exist in positively and negatively charged forms. The adsorption of cyclohexane is described by the Hill-de Boer equation for the initial ZnO surface, and by the Langmuir equation after plasma-chemical treatments.

Bratchikova, I. G.; Pylinina, A. I.; Platonov, E. A.; Danilova, M. N.; Isaeva, N. Yu.; Yagodovskii, V. D.

2015-01-01

163

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

164

Gold coated zinc oxide nanonecklaces as a SERS substrate.  

PubMed

Faceted zinc oxide nanonecklace (ZnO NN) arrays were grown on r-plane sapphires along one direction (ZnO [0001] II sapphire [10-11] and ZnO (-12-10) II sapphire (01-12)) using chemical vapor deposition. After coated with 45 nm gold films and annealed at 250 degrees C for 30 seconds, the coated ZnO NNs exhibit satisfactory and stable surface enhanced Raman scattering (SERS) effects when tested with melamine and other chemicals. The limit of detection of melamine is 10(-5) mol/L and the analytical enhancement factor is 10(4), which is competitive to a commercial substrate. This study indicates that gold coated ZnO NN substrates have a great potential as SERS-active substrates in rapid detection of trace amount food contaminants such as melamine and other chemicals. PMID:21776731

He, Lili; Shi, Jian; Sun, Xin; Lin, Mengshi; Yu, Ping; Li, Hao

2011-04-01

165

Prenatal development toxicity study of zinc oxide nanoparticles in rats  

PubMed Central

This study investigated the potential adverse effects of zinc oxide nanoparticles ([ZnOSM20(+) NPs] zinc oxide nanoparticles, positively charged, 20 nm) on pregnant dams and embryo–fetal development after maternal exposure over the period of gestational days 5–19 with Sprague-Dawley rats. ZnOSM20(+) NPs were administered to pregnant rats by gavage at 0, 100, 200, and 400 mg/kg/day. All dams were subjected to a cesarean section on gestational day 20, and all of the fetuses were examined for external, visceral, and skeletal alterations. Toxicity in the dams manifested as significantly decreased body weight after administration of 400 mg/kg/day NPs; reduced food consumption after administration of 200 and 400 mg/kg/day NPs; and decreased liver weight and increased adrenal glands weight after administration of 400 mg/kg/day NPs. However, no treatment-related difference in: number of corpora lutea; number of implantation sites; implantation rate (%); resorption; dead fetuses; litter size; fetal deaths and placental weights; and sex ratio were observed between the groups. On the other hand, significant decreases between treatment groups and controls were seen for fetal weights after administration of 400 mg/kg/day NPs. Morphological examinations of the fetuses demonstrated significant differences in incidences of abnormalities in the group administered 400mg/kg/day. Meanwhile, no significant difference was found in the Zn content of fetal tissue between the control and high-dose groups. These results showed that oral doses for the study with 15-days repeated of ZnOSM20(+) NPs were maternotoxic in the 200 mg/kg/day group, and embryotoxic in the 400 mg/kg/day group. PMID:25565834

Hong, Jeong-Sup; Park, Myeong-Kyu; Kim, Min-Seok; Lim, Jeong-Hyeon; Park, Gil-Jong; Maeng, Eun-Ho; Shin, Jae-Ho; Kim, Meyoung-Kon; Jeong, Jayoung; Park, Jin-A; Kim, Jong-Choon; Shin, Ho-Chul

2014-01-01

166

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

167

Zinc  

MedlinePLUS

... generally increase zinc absorption, although a protein in cow's milk slows absorption down. Soy proteins also reduce ... the most zinc from mother's milk, less from cow's milk, and even less from soy-based milk. ...

168

Electrochemical Quartz Crystal Microbalance Studies of Electron Addition at Nanocrystalline Tin Oxide/Water and Zinc Oxide/Water Interfaces: Evidence for  

E-print Network

Oxide/Water and Zinc Oxide/Water Interfaces: Evidence for Band-Edge-Determining Proton Uptake Buford I at nanocrystalline zinc oxide/ water and tin oxide/water interfaces is similarly accompanied by uptake of charge intercalation is a general mode of reactivity for metal oxide semiconductors. Finally, the new observations

169

Aligned ZnO Nanorod Arrays Grown Directly on Zinc Foils and Zinc Spheres by a Low-Temperature Oxidation Method.  

SciTech Connect

Vertically aligned, dense ZnO nanorod arrays were grown directly on zinc foils by a catalyst-free, low-temperature (450-500 C) oxidization method. The zinc foils remain conductive even after the growth of ZnO nanorods on its surface. The success of this synthesis largely relies on the level of control over oxygen introduction. By replacing zinc foils with zinc microspheres, unique and sophisticated urchin-like ZnO nanorod assemblies can be readily obtained.

Gu, Dr Zhanjun [University of Georgia, Athens, GA; Paranthaman, Mariappan Parans [ORNL; Xu, Jun [ORNL; Pan, Zhengwei [University of Georgia, Athens, GA

2009-01-01

170

Enhanced ultraviolet sensitivity of zinc oxide nanoparticle photoconductors by surface passivation  

NASA Astrophysics Data System (ADS)

Zinc oxide nanoparticles were created by a top-down wet-chemical etching process and then coated with polyvinyl-alcohol (PVA), exhibiting sizes ranging from 10 to 120 nm with an average size approximately 80 nm. The PVA layer provides surface passivation of zinc oxide nanoparticles. As a result of PVA coating, enhancement in ultraviolet emission and suppression of parasitic green emission is observed. Photoconductors fabricated using the PVA coated zinc oxide nanoparticles exhibited a ratio of ultraviolet photo-generated current to dark current as high as 4.5 × 104, 5 times better than that of the devices fabricated using uncoated ZnO nanoparticles.

Qin, Liqiao; Shing, Christopher; Sawyer, Shayla; Dutta, Partha S.

2011-01-01

171

Thermal Degradation of Single Crystal Zinc Oxide and the Growth of Nanostructures  

SciTech Connect

Heat treatment of (0001) single crystal zinc oxide (ZnO) seems to degrade the surface morphology at high temperature. The degradation, however, does not suppress the growth of ZnO nanostructures on selective regions of the single crystal ZnO that have been sputtered with metallic zinc (Zn) and annealed at 800 degree sign C. On the uncoated regions, no growth occurs but the presence of pits suggests material loss from the surface. The formation of ZnO nanostructures on the selective regions could be aided by the preferential loss of oxygen as well as zinc suboxides from the uncoated regions. Indirect evidence of the role of oxygen and zinc suboxides can be inferred from the formation of nickel zinc oxide Ni{sub 0.9}Zn{sub 0.1}O and nickel oxide NiO{sub 2} when Zn is replaced by Ni and annealed under similar conditions.

Saw, K. G.; Tan, G. L. [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 Penang (Malaysia); Hassan, Z.; Yam, F. K.; Ng, S. S. [Schools of Physics, Universiti Sains Malaysia, 11800 Penang (Malaysia)

2010-07-07

172

Optical properties of zinc peroxide and zinc oxide multilayer nanohybrid films  

NASA Astrophysics Data System (ADS)

Zinc peroxide and zinc oxide nanoparticles were prepared and self-assembled hybrid nanolayers were built up using layer-by-layer (LbL) technique on the surface of glass substrate using the layer silicate hectorite and an anionic polyelectrolyte, sodium polystyrene sulfonate (PSS). Light absorption, interference and morphological properties of the hybrid films were studied to determine their thickness and refractive index. The influence of layer silicates and polymers on the self-organizing properties of ZnO 2 and ZnO nanoparticles was examined. X-ray diffraction revealed that ZnO 2 powders decomposed to ZnO (zincite phase) at relatively low temperatures (less than 200 °C). The optical thickness of the films ranged from 190 to 750 nm and increased linearly with the number of layers. Band gap energies of the ZnO 2/hectorite films were independent from the layer thickness and were larger than that of pure ZnO 2 nanodispersion. Decomposition of ZnO 2 to ZnO and O 2 at 400 °C resulted in the decrease of the band gap energy from 3.75 to 3.3 eV. Concomitantly, the refractive index increased in correlation with the formation of the zincite ZnO phase. In contrast, the band gap energies of the ZnO 2/PSS hybrid films decreased with the thickness of the nanohybrid layers. We ascribe this phenomenon to the steric stabilization of primary ZnO 2 particles present in the confined space between adjacent layers of hectorite sheets.

Seb?k, Dániel; Szabó, Tamás; Dékány, Imre

2009-05-01

173

Journal of the Korean Physical Society, Vol. 50, No. 3, March 2007, pp. 622625 Al-ZnO Thin Films as Transparent Conductive Oxides : Synthesis,  

E-print Network

conductive oxide, Al-doped ZnO, OLED, Anode, RF magnetron sputtering I. INTRODUCTION Zinc oxide is recognized being: magnetron sputtering [5,6], pulsed laser deposition [7], chemical vapor deposition [8-to-substrate dis- tance (Dts) by RF magnetron sputtering. Moreover, the AZO films were used as an anode material

Boo, Jin-Hyo

174

High Rate Zinc Oxide Film Deposition by Atmospheric TPCVD Using Ar\\/Air Plasma Jets  

Microsoft Academic Search

In order to develop a functional film deposition process with a high deposition rate, as a basic study, deposition of zinc oxide film by atmospheric thermal plasma CVD (TPCVD) was carried out. As feedstock, working gas and substrate, ethanol diluted zinc acetate solution, Ar and 430 stainless steel were used. As for the deposition conditions, Ar gas flow rate was

ANDO Yasutaka; KOBAYASHI Akira; TOBE Shogo; TAHARA Hirokazu

175

Rapid hydrothermal synthesis of zinc oxide nanorods on single crystal sapphire substrate  

Microsoft Academic Search

For development of ZnO nanorods-based heterostructures an environmentally benign synthesis process and fabrication route are required. Zinc oxide nanorod arrays have been grown on (0001) sapphire substrates by a rapid hydrothermal method (in 15 min) from a solution of zinc sulfate and sodium hydroxide. Two different synthesis regimes have been identified which give different morphologies of depositions shown by SEM.

O. Lupan; L. Chow; Y. Rudzevich; Y. Lin; A. Schulte; E. Monaico; L. Ghimpu; V. Sontea; V. Trofim; S. Railean; V. Cretu; I. Pocaznoi

2011-01-01

176

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...

177

Zinc poisoning  

MedlinePLUS

... other materials to make industrial items such as paint, dyes, and more. These combination substances can be ... Compounds used to make paint, rubber, dyes, wood preservatives, and ... Zinc chloride Zinc oxide (relatively nonharmful) Zinc ...

178

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

E-print Network

oxide films were prepared by rf magnetron sputtering on glass substrates with designed ZnO target using high-purity of zinc oxide (99.99%) powder. Systematic study on dependence of target to a hole-transporting layer and an Indium tin oxide (ITO) outerlayer. We tried to bring low the barrier

Boo, Jin-Hyo

179

Controlled Co(II) Doping of Zinc Oxide Nanocrystals  

SciTech Connect

Dopants are non-native atoms commonly used to modify the properties of bulk semiconductors. In this paper we demonstrate that by controlling the addition of cobalt(II) to growing zinc oxide nanocrystals (ZnO NCs) it is possible to modulate the resulting properties. We show that the environment of cobalt may be controlled by varying the synthetic conditions, mainly through varying the time of dopant-precursor addition and concentration. These conditions prove critical to the resulting Co(II) configuration, which affects both the luminescent and photocatalytic properties of the ZnO NCs. Presynthetic doping with 2% Co(II) results in a 98% quenching of the visible emission of ZnO, whereas the same quantity doped post synthesis results in only a 60% quenching. The environment of cobalt in the ZnO wurtzite lattice is identified through UV-vis spectroscopy. The wurtzite structure of the ZnO lattice for all nanocrystalline species is confirmed through X-ray diffraction patterns obtained from a synchrotron radiation source. Postsynthetically doped Co(II) in ZnO NC is demonstrated to have potential applications as an 'on-off' sensor, as exemplified with nitric oxide.

S Bohle; C Spina

2011-12-31

180

Understanding the defect structure of solution grown zinc oxide  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a wide bandgap semiconducting oxide with many potential applications in various optoelectronic devices such as light emitting diodes (LEDs) and field effect transistors (FETs). Much effort has been made to understand the ZnO structure and its defects. However, one major issue in determining whether it is Zn or O deficiency that provides ZnO its unique properties remains. X-ray absorption spectroscopy (XAS) is an ideal, atom specific characterization technique that is able to probe defect structure in many materials, including ZnO. In this paper, comparative studies of bulk and aqueous solution grown (?90 °C) ZnO powders using XAS and x-ray pair distribution function (XPDF) techniques are described. The XAS Zn-Zn correlation and XPDF results undoubtedly point out that the solution grown ZnO contains Zn deficiency, rather than the O deficiency that were commonly reported. This understanding of ZnO short range order and structure will be invaluable for further development of solid state lighting and other optoelectronic device applications.

Liew, Laura-Lynn; Sankar, Gopinathan; Handoko, Albertus D.; Goh, Gregory K. L.; Kohara, Shinji

2012-05-01

181

CSA doped polypyrrole-zinc oxide thin film sensor  

NASA Astrophysics Data System (ADS)

The polypyrrole-zinc oxide (PPy-ZnO) hybrid sensor doped with different weight ratios of camphor sulphonic acid (CSA) were prepared by spin coating technique. These CSA doped PPy-ZnO hybrids were characterized by field emission scanning electron microscope (FESEM) and fourier transform infrared (FTIR) which proved the formation of polypyrrole, PPy-ZnO and the interaction between polypyrrole - ZnO (PPy-ZnO) hybrid with CSA doping. The gas sensing properties of the PPy-ZnO hybrid films doped with CSA have been studied for oxidizing (NO2) as well as reducing (H2S, NH3, CH4OH and CH3OH) gases at room temperature. We demonstrate that CSA doped PPy-ZnO hybrid films are highly selective to NO2 along with high-sensitivity at low concentration (80% to 100 ppm) and better stability, which suggested that the CSA doped PPy-ZnO hybrid films are potential candidate for NO2 detection at room temperature.

Chougule, M. A.; Jundale, D. M.; Raut, B. T.; Sen, Shashwati; Patil, V. B.

2013-02-01

182

Effect of aluminum oxide doping on the structural, electrical, and optical properties of zinc oxide (AOZO) nanofibers synthesized by electrospinning  

Microsoft Academic Search

Zinc oxide nanofibers doped with aluminum oxide were prepared by sol–gel processing and electrospinning techniques using polyvinylpyrrolidone (PVP), zinc acetate and aluminum acetate as precursors. The resulting nanofibers were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV–Vis spectroscopy, and current–voltage (I–V) properties. The nanofibers had diameters in the range of 60–150nm. The incorporation of

A. F. Lotus; Y. C. Kang; J. I. Walker; R. D. Ramsier; G. G. Chase

2010-01-01

183

Atmospheric pressure chemical vapor deposition of transparent conducting films of fluorine doped zinc oxide and their application  

E-print Network

crystal flat panel displays, energy efficient windows, gas sensors, surface acoustic wave devices loss or diffusion, which can lead to degra- dation in solar cell efficiency. Zinc oxide is more stable conducting oxides. This suggests zinc oxide may lead to higher solar cell efficiency than tin oxide

184

Phosphate-enhanced cytotoxicity of zinc oxide nanoparticles and agglomerates.  

PubMed

Zinc oxide (ZnO) nanoparticles (NPs) have been found to readily react with phosphate ions to form zinc phosphate (Zn3(PO4)2) crystallites. Because phosphates are ubiquitous in physiological fluids as well as waste water streams, it is important to examine the potential effects that the formation of Zn3(PO4)2 crystallites may have on cell viability. Thus, the cytotoxic response of NIH/3T3 fibroblast cells was assessed following 24h of exposure to ZnO NPs suspended in media with and without the standard phosphate salt supplement. Both particle dosage and size have been shown to impact the cytotoxic effects of ZnO NPs, so doses ranging from 5 to 50 ?g/mL were examined and agglomerate size effects were investigated by using the bioinert amphiphilic polymer polyvinylpyrrolidone (PVP) to generate water-soluble ZnO ranging from individually dispersed 4 nm NPs up to micron-sized agglomerates. Cell metabolic activity measures indicated that the presence of phosphate in the suspension media can led to significantly reduced cell viability at all agglomerate sizes and at lower ZnO dosages. In addition, a reduction in cell viability was observed when agglomerate size was decreased, but only in the phosphate-containing media. These metabolic activity results were reflected in separate measures of cell death via the lactate dehydrogenase assay. Our results suggest that, while higher doses of water-soluble ZnO NPs are cytotoxic, the presence of phosphates in the surrounding fluid can lead to significantly elevated levels of cell death at lower ZnO NP doses. Moreover, the extent of this death can potentially be modulated or offset by tuning the agglomerate size. These findings underscore the importance of understanding how nanoscale materials can interact with the components of surrounding fluids so that potential adverse effects of such interactions can be controlled. PMID:24362007

Everett, W Neil; Chern, Christina; Sun, Dazhi; McMahon, Rebecca E; Zhang, Xi; Chen, Wei-Jung A; Hahn, Mariah S; Sue, H-J

2014-02-10

185

Pharmacokinetics, tissue distribution, and excretion of zinc oxide nanoparticles  

PubMed Central

Background This study explored the pharmacokinetics, tissue distribution, and excretion profile of zinc oxide (ZnO) nanoparticles with respect to their particle size in rats. Methods Two ZnO nanoparticles of different size (20 nm and 70 nm) were orally administered to male and female rats, respectively. The area under the plasma concentration-time curve, tissue distribution, excretion, and the fate of the nanoparticles in organs were analyzed. Results The plasma zinc concentration of both sizes of ZnO nanoparticles increased during the 24 hours after administration in a dose-dependent manner. They were mainly distributed to organs such as the liver, lung, and kidney within 72 hours without any significant difference being found according to particle size or rat gender. Elimination kinetics showed that a small amount of ZnO nanoparticles was excreted via the urine, while most of nanoparticles were excreted via the feces. Transmission electron microscopy and x-ray absorption spectroscopy studies in the tissues showed no noticeable ZnO nanoparticles, while new Zn-S bonds were observed in tissues. Conclusion ZnO nanoparticles of different size were not easily absorbed into the bloodstream via the gastrointestinal tract after a single oral dose. The liver, lung, and kidney could be possible target organs for accumulation and toxicity of ZnO nanoparticles was independent of particle size or gender. ZnO nanoparticles appear to be absorbed in the organs in an ionic form rather than in a particulate form due to newly formed Zn-S bonds. The nanoparticles were mainly excreted via the feces, and smaller particles were cleared more rapidly than the larger ones. ZnO nanoparticles at a concentration below 300 mg/kg were distributed in tissues and excreted within 24 hours. These findings provide crucial information on possible acute and chronic toxicity of ZnO nanoparticles in potential target organs. PMID:22811602

Baek, Miri; Chung, Hae-Eun; Yu, Jin; Lee, Jung-A; Kim, Tae-Hyun; Oh, Jae-Min; Lee, Won-Jae; Paek, Seung-Min; Lee, Jong Kwon; Jeong, Jayoung; Choy, Jin-Ho; Choi, Soo-Jin

2012-01-01

186

Hydrothermal synthesis of zinc oxide nanoparticles using rice as soft biotemplate  

PubMed Central

Background Rice as a renewable, abundant bio-resource with unique characteristics can be used as a bio-template to synthesize various functional nanomaterials. Therefore, the effect of uncooked rice flour as bio-template on physico-chemical properties, especially the morphology of zinc oxide nanostructures was investigated in this study. The ZnO particles were synthesized through hydrothermal-biotemplate method using zinc acetate-sodium hydroxide and uncooked rice flour at various ratios as precursors at 120°C for 18 hours. Results The results indicate that rice as a bio-template can be used to modify the shape and size of zinc oxide particles. Different morphologies, namely flake-, flower-, rose-, star- and rod-like structures were obtained with particle size at micro- and nanometer range. Pore size and texture of the resulting zinc oxide particles were found to be template-dependent and the resulting specific surface area enhanced compared to the zinc oxide synthesized without rice under the same conditions. However, optical property particularly the band gap energy is generally quite similar. Conclusion Pure zinc oxide crystals were successfully synthesized using rice flour as biotemplate at various ratios of zinc salt to rice. The size- and shape-controlled capability of rice to assemble the ZnO particles can be employed for further useful practical applications. PMID:23919386

2013-01-01

187

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

188

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.

189

Nanohybrids of ultrathin titania nanosheets and zinc oxide nanoparticles by an electrostatic interaction.  

PubMed

We synthesized ultrathin titania nanosheets and zinc oxide nanoparticles, and formed the nanohybrids of them by an electrostatic interaction. The titania nanosheets were prepared by soft chemical processes: intercalation, exfoliation, and reassembly. The zinc oxide nanoparticles were prepared by the sol-gel method. And two nano-scale inorganic materials were hybridized to form nanohybrids using an electrostatic interaction as a driving force. According to the X-ray diffraction pattern and high-resolution transmission electron microscope images, it is revealed that the nanohybrid of the titania nanosheets and zinc oxide nanoparticles has a house of cards structure in which zinc oxide nanoparticles are randomly attached to layered titania nanosheets. PMID:20352811

Kim, Sunmi; Paek, Seungwoo; Lee, Seonghoon

2010-01-01

190

Thioredoxin 2, an Oxidative Stress-induced Protein, Contains a High Affinity Zinc Binding Site*  

E-print Network

Thioredoxin 2, an Oxidative Stress-induced Protein, Contains a High Affinity Zinc Binding Site, the gene coding for Trx2 is under control of the oxidative stress transcrip- tion factor OxyR in E. coli. This suggests that Trx2 may play a role in the cellular defense against oxidative stress. We show here that Trx2

Bardwell, James

191

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

192

Characterization and optimization of zinc oxide films by r.f. magnetron sputtering  

Microsoft Academic Search

Zinc oxide films were deposited by a r.f. magnetron sputtering using a zinc oxide target. The deposited films were characterized as a function of deposition temperature, pressure, argon-oxygen gas flow ratio, target-substrate distance. The deposition conditions were optimized to give good quality films suitable for the fabrication of surface acoustic wave device. The films deposited at temperatures as low as

K. B. Sundaram; A. Khan

1997-01-01

193

Description of industrial technology for production of active zinc oxide for production of sulfur purification catalysts  

Microsoft Academic Search

Physicochemical and technological tests have shown that by means of sufficiently thorough chemical processing of various inactive feedstocks using ammonia-carbonate solutions (ACS's) it is possible to produce a finely divided zinc oxide with dispersity d\\/sub ZnO\\/ = 200 to 350 A and capacity of 30 to 32%. For example, muffle-furnace zinc oxide with d\\/sub ZnO\\/ = 1300 A and sulfur

M. L. Dantsig; E. V. Turcheninova; G. A. Dantsig; V. S. Sobolevsky; V. N. Menshov; V. V. Zhavoronkov; T. A. Kondrashchenko; Z. E. Ermina

1980-01-01

194

Burn-induced oxidative stress is altered by a low zinc status: kinetic study in burned rats fed a low zinc diet  

PubMed Central

As an initial subdeficient status of zinc, considered as an essential antioxidant trace element, is frequent in burned patients, we aim to assess the effects of low zinc dietary intakes on burn induced oxidative stress, in an animal model. After eight weeks of conditioning diets containing 80 ppm (control group) or 10 ppm of zinc (depleted group), Wistar rats were 20% TBSA burned and sampled one to ten days after injury. Kinetic evolutions of zinc status, plasma oxidative stress parameters and antioxidant enzymes were also studied in blood and organs. The zinc depleted diet induced, before injury, a significant decrease in zinc bone level and the increase of oxidative stress markers without stimulation of antioxidant enzyme activity. After burn, more markedly in zinc depleted animals than in controls, zinc levels decreased in plasma and bone, while increasing in liver. The decrease of thiol groups and GSH/GSSG ratio and the depression of GPx activity in liver are also moderately emphasized. Nevertheless, depleted zinc status could not be considered as determining for oxidative damages after burn injury. Further investigations must also be done to enlighten the mechanism of beneficial effects of zinc supplementation reported in burned patients. PMID:18773151

Claeyssen, Richard; Andriollo-Sanchez, Maud; Arnaud, Josiane; Touvard, Laurence; Alonso, Antonia; Chancerelle, Yves; Roussel, Anne-Marie; Agay, Diane

2008-01-01

195

Ordered Nucleation Sites for the Growth of Zinc Oxide Nanofibers  

SciTech Connect

Organic photovoltaics (OPVs) offer a promising route to low cost photovoltaic (PV) technology that can be inexpensively manufactured on a large scale for use in power generation and commercial products. Solar power conversion efficiencies of laboratory scale OPV devices have recently reached ~5%; however, projected efficiencies of at least 10% will be required for commercialization. An analogous approach that has arisen recently that can potentially increase efficiencies employs metal oxide semiconductors as the electron acceptor, creating a hybrid organic-inorganic device. This approach offers the advantage that the conduction band of the oxide can be tuned in a systematic way through doping, thus potentially achieving higher photovoltages in the device. Additionally, nanostructures of these materials can be easily grown from precursor solutions, providing a technique to precisely control the nanoscale geometry. This work focuses on using ZnO, which is known to have high electron mobility (>100 cm2/Vs), as the electron acceptor. Nanofibers of ZnO can be grown from precursors such as zinc acetate or zinc nitrate to form arrays of nanofibers into which a conjugated polymer can be intercalated to form a composite PV device. The morphology of the nanofiber array is critical to the performance of the device, but current methods of nanofiber growth from a flat, polycrystalline nucleation layer allow for little morphological control. To overcome this limitation, we have created ordered arrays of ZnO nucleation sites with controllable size and spacing. Toluene solutions of diblock copolymer micelles with ZnCl2 incorporated into the micellar cores were spin-coated onto glass substrates and etched with an O2 plasma to yield hexagonally ordered arrays of ZnO nanoparticles that functioned as nucleation sites. Changing the concentration of ZnCl2 and the molecular weight and ratio of the diblock copolymer resulted in systematic variation in the size and spacing of the nucleation sites. Thermal anneal treatment provided further modification of the nucleation layer, from which ZnO nanofibers were successfully grown from solution, although at present it is not known if the geometry of the as-grown ZnO nanofibers precisely reflects that of the underlying nucleation layer. This work provides a simple and useful method for potentially controlling the nucleation of ZnO nanofibers to be used in hybrid ZnO/organic nanocomposite PV devices.

Wang, J.; Ginley, D.S.; Shaheen, S.

2006-01-01

196

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.

197

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

198

Degradation efficiencies of azo dye Acid Orange 7 by the interaction of heat, UV and anions with common oxidants: persulfate, peroxymonosulfate and hydrogen peroxide.  

PubMed

In this paper, the degradation of azo dye Acid Orange 7 (AO7) by three common peroxides (persulfate (PS), peroxymonosulfate (PMS) or hydrogen peroxide (H(2)O(2))) under various activation conditions, i.e., heat (25-80 degrees C), UV light (254 nm), or anions (SO(4)(2-), NO(3)(-), CO(3)(2-), HCO(3)(-), HPO(4)(2-), and Cl(-)), was investigated. The order of AO7 degradation efficiencies by heat activation is PS>PMS>H(2)O(2). PS oxidation activated by heat (>50 degrees C) is an effective degradation technology, while PMS and H(2)O(2) are hardly activated. When assisted by UV, peroxides could all be activated and degrade AO7 quickly. The order is PS>H(2)O(2)>PMS. We activated peroxides, for the first time, by using some anions and compared the subsequently degradation efficiencies of AO7. It was found that PMS could be activated by some anions, but PS and H(2)O(2) cannot. The activation efficiencies of PMS by SO(4)(2-) and NO(3)(-) are negligible, whereas remarkable by HCO(3)(-), HPO(4)(2-), Cl(-) and CO(3)(2-). For HCO(3)(-), HPO(4)(2-) and Cl(-), the activation efficiencies become higher with the increase of anion concentration. For CO(3)(2-), however, the activation efficiency is higher at lower concentration. PMID:20371151

Yang, Shiying; Wang, Ping; Yang, Xin; Shan, Liang; Zhang, Wenyi; Shao, Xueting; Niu, Rui

2010-07-15

199

Study for double-layered AZO/ATO transparent conducting thin film  

NASA Astrophysics Data System (ADS)

The purpose of this study is to provide transparent conductive composite films, used for such as dye-sensitized solar cells (DSSCs). In this work, transparent conductive oxide films with double-layer structure, ATO(antimony doped tin oxide)films covered on AZO(aluminum doped zinc oxide)films, were prepared on glass substrates by RF magnetron sputtering method. Subsequently the films were post-annealed at different temperature. The structure, surface morphology, optical and electrical properties of the films were investigated as a function of annealing temperature. Our results indicate that the composite films can maintain good electrical and optical properties at a temperature higher than 450°C compared to that of single-layer film.

Cao, Miaomiao; Li, Yudong; Yang, Jing; Chen, Yigang

2013-03-01

200

Investigation of electrical and optoelectronic properties of zinc oxide nanowires  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) nanowires have been synthesized by using tubular furnace chemical vapor deposition technique. The morphology, chemical composition and crystal structure of as-synthesized ZnO nanowires were examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) techniques. Four-terminal current-voltage ( I- V) measurements were employed to study the electrical conductance of ZnO nanowires under various testing gas environments for gas sensing purpose. The I- V curves at temperature ranging from 150 to 300 K were recorded in the testing chamber under vacuum. The Arrhenius plot shows perfect linear relationship between the logarithm of the current I and inverse temperature 1/ T. The donor level of the semiconducting nanowires is about 326 meV. The I- V behaviors were found to be reversible and repeatable with testing gases. The electrical conductivity was enhanced by a factor of four with ambient CO gas compared to that in vacuum and other testing gases. The optoelectronic properties of the ZnO nanowires were obtained by two-terminal I- V measurement method while the nanowires were illuminated by a ruby laser. The electrical conductivity was increased by 60% when the laser was present in comparison to that when the laser was off. Those significant changes suggest that nano-devices constructed by the ZnO nanowires could be used in gas sensing and optical switching applications.

Zhang, D.; Lee, S. K.; Chava, S.; Berven, C. A.; Katkanant, V.

2011-10-01

201

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

202

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

203

Epitaxial Zinc Oxide Semiconductor Film deposited on Gallium Nitride Substrate  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a wide bandgap semiconductor which is very promising for making efficient electronic and optical devices. The goal of this research was to produce high quality ZnO film on gallium nitride (GaN) substrate by optimizing the substrate temperature. The GaN substrates were chemically cleaned and mounted on a ceramic heater and loaded into a vacuum deposition chamber that was pumped down to a base pressure of 3 x 10-7 Torr. The film deposition was preceded by a 30 minute thermal desorption carried in vacuum at 500 ^oC. The ZnO thin film was then sputter-deposited using an O2/Ar gas mixture onto GaN substrates heated at temperatures varying from 20 ^oC to 500 ^oC. Post-deposition annealing was done in a rapid thermal processor at 900 ^oC for 5 min in an ultrapure N2 ambient to improve the crystal quality of the films. The films were then optically characterized using photoluminescence (PL) measurement with a UV laser excitation. Our measurements reveal that ZnO films deposited on GaN substrate held at 200 ^oC gave the best film with the highest luminous intensity, with a peak energy of 3.28 eV and a full width half maximum of 87.4 nm. Results from low temperature (10 K) PL measurements and from x-ray diffraction will also be presented.

McMaster, Michael; Oder, Tom

2011-04-01

204

Prevention of retinal light damage by zinc oxide combined with rosemary extract  

PubMed Central

Purpose Zinc oxide effectively reduces visual cell loss in rats exposed to intense visible light and is known to slow the rate of disease progression in advanced stages of age-related macular degeneration. Our goal was to determine the efficacy of zinc oxide in combination with novel and well-established antioxidants in an animal model of light-induced oxidative retinal damage. Methods One group of male Sprague-Dawley rats was pretreated with zinc oxide with or without a detergent extract of rosemary powder and then exposed to intense visible light for 4–24 h. Another group of animals received zinc oxide combined with rosemary oil diluted with a mixture of polyunsaturated fatty acids (ROPUFA) and a third group was given an antioxidant mineral mix containing zinc oxide, as recommended by the Age Related Eye Disease Study group's first clinical trial (AREDS1). Visual cell survival was determined 2 weeks after intense light treatment by measuring rhodopsin and photoreceptor cell DNA levels and confirmed by retinal histology and agarose gel electrophoresis of DNA. Western analysis was used to determine the effects of zinc and antioxidants on the oxidative stress markers, glial fibrillary acidic protein (GFAP), heme-oxygenase-1 (HO-1), and carboxyethylpyrrole (CEP). Rod and cone opsin and arrestin levels were used as markers of photoreceptor cell function. Results Dark-reared rats treated with 1.3 mg/kg zinc oxide and 17 mg/kg rosemary extract, or with one-half those doses, and exposed to moderate intensity green light retained 75%–85% of the rhodopsin and retinal DNA measured in unexposed rats. These levels were significantly higher than found for zinc oxide or rosemary treatment alone. Rosemary oil was also effective when combined with zinc oxide, but ROPUFA alone was no more effective than the detergent vehicle. Prolonged intense green light led to increases in retinal GFAP and HO-1 levels and to decreases in cone cell opsin and rod and cone arrestins. Rosemary plus zinc treatment reduced the expression of oxidative stress protein markers and enhanced visual cell survival, as shown by improved photoreceptor cell morphology and by decreased retinal DNA degradation. Using higher intensity white light for exposures in cyclic light-reared rats, treatment with an AREDS antioxidant/mineral mixture was found to be ineffective, whereas rosemary extract plus an equivalent dose of zinc oxide was significantly more effective in preserving visual cells. CEP protein adduct formation was reduced by all antioxidant treatments, but rosemary plus zinc oxide also prevented the loss of cone cell opsin and arrestin more effectively than AREDS. Conclusions In the rat model of acute retinal light damage, zinc oxide combined with a detergent extract of rosemary powder or rosemary oil is more effective than treatment with either component alone and significantly more effective than an AREDS mixture containing a comparable dose of zinc oxide. Light-induced oxidative stress in animal models of retinal degeneration can be a useful preclinical paradigm for screening novel antioxidants and for testing potential therapeutics designed to slow the progression of age-related ocular disease. PMID:23825923

Darrow, R. M.; Rapp, C. M.; Smuts, J.P.; Armstrong, D.W.; Lang, J. C.

2013-01-01

205

Rambutan peels promoted biomimetic synthesis of bioinspired zinc oxide nanochains for biomedical applications  

NASA Astrophysics Data System (ADS)

A naturally occurring rambutan peel waste was employed to synthesis bioinspired zinc oxide nanochains. Rambutan peels has the ability of ligating zinc ions as a natural ligation agent resulting in zinc oxide nanochains formation due to its extended polyphenolic system over incubation period. Successful formation of zinc oxide nanochains was confirmed employing transmission electron microscopy studies. About 60% and ?40% cell viability was lost and 50% and 10% morphological change was observed in 7 and 4 days incubated ZnO treated cells compared with control. Moreover, 50% and 55% of cell death was observed at 24 and 48 h incubation with 7 days treated ZnO cells and hence alters and disturbs the growth of cancer cells and could be used for liver cancer cell treatment.

Yuvakkumar, R.; Suresh, J.; Saravanakumar, B.; Joseph Nathanael, A.; Hong, Sun Ig; Rajendran, V.

2015-02-01

206

Rambutan peels promoted biomimetic synthesis of bioinspired zinc oxide nanochains for biomedical applications.  

PubMed

A naturally occurring rambutan peel waste was employed to synthesis bioinspired zinc oxide nanochains. Rambutan peels has the ability of ligating zinc ions as a natural ligation agent resulting in zinc oxide nanochains formation due to its extended polyphenolic system over incubation period. Successful formation of zinc oxide nanochains was confirmed employing transmission electron microscopy studies. About 60% and ?40% cell viability was lost and 50% and 10% morphological change was observed in 7 and 4days incubated ZnO treated cells compared with control. Moreover, 50% and 55% of cell death was observed at 24 and 48h incubation with 7days treated ZnO cells and hence alters and disturbs the growth of cancer cells and could be used for liver cancer cell treatment. PMID:25228035

Yuvakkumar, R; Suresh, J; Saravanakumar, B; Joseph Nathanael, A; Hong, Sun Ig; Rajendran, V

2015-02-25

207

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

208

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

209

Structural Properties of Ultrasonically Sprayed Al-Doped ZnO (AZO) Thin Films: Effect of ZnO Buffer Layer on AZO  

NASA Astrophysics Data System (ADS)

Transparent aluminium-doped ZnO (AZO)-conducting oxide films were deposited on a glass substrate, using an ultrasonic spray pyrolysis (USP) system at 475°C. We investigated the effects of the Al/Zn atomic ratios on the structural properties of the AZO films. All the deposited AZO thin films presented hexagonal wurtzite structure. As Al doping increased in the film, the preferential orientation switched from [002] to [101], and crystallite sizes varied from 31.90 nm to 34.5 nm. Field emission scanning electron microscopy showed a change in the surface morphology of the AZO films with respect to the Al/Zn ratio, and secondary ion mass spectroscopy showed that the amount of Al incorporated into the films was proportional to the concentration of the starting solution. A fast Fourier transform of the AZO film measurements confirmed the presence of (100), (102), and (200) reflections, corresponding to a wurtzite structure of the AZO thin films. The plane corresponding to AZO was simulated, and matched the experimental pattern obtained from high-resolution transmission electron microscopy. An un-doped ZnO layer was deposited onto the AZO film using USP at 400°C, and a bilayer of AZO/ZnO was annealed in vacuum for 20 min at 350°C. The resistivity of these bilayer films was lower than that of a single-layered AZO film, and it further decreased by vacuum annealing.

Babu, B. J.; Velumani, S.; Arenas-Alatorre, J.; Kassiba, A.; Chavez, Jose; Park, Hyeonsik; Hussain, Shahzada Qamar; Yi, Junsin; Asomoza, R.

2015-02-01

210

Structural Properties of Ultrasonically Sprayed Al-Doped ZnO (AZO) Thin Films: Effect of ZnO Buffer Layer on AZO  

NASA Astrophysics Data System (ADS)

Transparent aluminium-doped ZnO (AZO)-conducting oxide films were deposited on a glass substrate, using an ultrasonic spray pyrolysis (USP) system at 475°C. We investigated the effects of the Al/Zn atomic ratios on the structural properties of the AZO films. All the deposited AZO thin films presented hexagonal wurtzite structure. As Al doping increased in the film, the preferential orientation switched from [002] to [101], and crystallite sizes varied from 31.90 nm to 34.5 nm. Field emission scanning electron microscopy showed a change in the surface morphology of the AZO films with respect to the Al/Zn ratio, and secondary ion mass spectroscopy showed that the amount of Al incorporated into the films was proportional to the concentration of the starting solution. A fast Fourier transform of the AZO film measurements confirmed the presence of (100), (102), and (200) reflections, corresponding to a wurtzite structure of the AZO thin films. The plane corresponding to AZO was simulated, and matched the experimental pattern obtained from high-resolution transmission electron microscopy. An un-doped ZnO layer was deposited onto the AZO film using USP at 400°C, and a bilayer of AZO/ZnO was annealed in vacuum for 20 min at 350°C. The resistivity of these bilayer films was lower than that of a single-layered AZO film, and it further decreased by vacuum annealing.

Babu, B. J.; Velumani, S.; Arenas-Alatorre, J.; Kassiba, A.; Chavez, Jose; Park, Hyeonsik; Hussain, Shahzada Qamar; Yi, Junsin; Asomoza, R.

2014-12-01

211

Zinc  

MedlinePLUS

... as most children in the United States. The common cold Some studies suggest that zinc lozenges or syrup ( ... in pill form) help speed recovery from the common cold and reduce its symptoms if taken within 24 ...

212

High performance organic photovoltaics with zinc oxide and graphene oxide buffer layers  

NASA Astrophysics Data System (ADS)

We report air stable inverted organic photovoltaics (OPVs) incorporating graphene oxide (GO) and solution processed zinc oxide (ZnO) as hole transport and electron transport layers, respectively. Both the hole transport layer and the electron transport layer (HTL and ETL) are of advantage in high transparency and environmental stability. The use of GO and ZnO in poly(2,7-carbazole) derivative (PCDTBT):fullerene derivative (PC70BM)-based inverted OPVs leads to an improved device stability and enhanced high open circuit voltage (Voc) of 0.81 V, a short-circuit current density (Jsc) of 14.10 mA cm-2, and a fill factor (FF) of 54.44 along with a power conversion efficiency of 6.20%.

Mohd Yusoff, Abd Rashid Bin; Kim, Hyeong Pil; Jang, Jin

2014-01-01

213

High performance organic photovoltaics with zinc oxide and graphene oxide buffer layers.  

PubMed

We report air stable inverted organic photovoltaics (OPVs) incorporating graphene oxide (GO) and solution processed zinc oxide (ZnO) as hole transport and electron transport layers, respectively. Both the hole transport layer and the electron transport layer (HTL and ETL) are of advantage in high transparency and environmental stability. The use of GO and ZnO in poly(2,7-carbazole) derivative (PCDTBT):fullerene derivative (PC??BM)-based inverted OPVs leads to an improved device stability and enhanced high open circuit voltage (V(oc)) of 0.81 V, a short-circuit current density (J(sc)) of 14.10 mA cm(-2), and a fill factor (FF) of 54.44 along with a power conversion efficiency of 6.20%. PMID:24323233

Yusoff, Abd Rashid bin Mohd; Kim, Hyeong Pil; Jang, Jin

2014-01-01

214

Hydrothermal synthesis and characterization of a series of novel zinc vanadium oxides as cathode materials  

SciTech Connect

The authors report here the hydrothermal synthesis of a series of novel zinc vanadium oxides, using tetramethyl ammonium ion in order to stabilize the layered structure of vanadium oxide during electrochemical redox reactions with lithium. The compounds were synthesized by the reaction of zinc chloride, vanadium (V) oxide, and tetramethyl ammonium hydroxide at 165 C for 60 hours. Four new zinc vanadium oxide compounds were discovered, only one of which contained the organic cation; another was found to have a layered structure with bridging V-O-V groups analogous to that of beta alumina. These compounds were characterized by X-ray powder diffraction, and IR. Three of the compounds reacted readily with lithium, and their electrochemical behavior in lithium cells were determined.

Zhang, F.; Zavalij, P.Y.; Whittingham, M.S.

1998-07-01

215

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

216

Antibacterial Activity of Dental Composites Containing Zinc Oxide Nanoparticles  

PubMed Central

The resin-based dental composites commonly used in restorations result in more plaque accumulation than other materials. Bacterial biofilm growth contributes to secondary caries and failure of resin-based dental composites. Methods to inhibit biofilm growth on dental composites have been sought for several decades. It is demonstrated here that zinc oxide nanoparticles (ZnO-NPs) blended at 10% (w/w) fraction into dental composites display antimicrobial activity and reduce growth of bacterial biofilms by roughly 80% for a single-species model dental biofilm. Antibacterial effectiveness of ZnO-NPs was assessed against Streptococcus sobrinus ATCC 27352 grown both planktonically and as biofilms on composites. Direct contact inhibition was observed by scanning electron microscopy and confocal laser scanning microscopy while biofilm formation was quantified by viable counts. An 80% reduction in bacterial counts was observed with 10% ZnO-NP-containing composites compared with their unmodified counterpart, indicating a statistically significant suppression of biofilm growth. Although, 20% of the bacterial population survived and could form a biofilm layer again, 10% ZnO-NP-containing composites maintained at least some inhibitory activity even after the third generation of biofilm growth. Microscopy demonstrated continuous biofilm formation for unmodified composites after one day growth, but only sparsely distributed biofilms formed on 10% ZnO-NP-containing composites. The minimum inhibitory concentration of ZnO-NPs suspended in S. sobrinus planktonic culture was 50 ?g/ml. 10% ZnO-NP-containing composites qualitatively showed less biofilm after one day anaerobic growth of a three-species initial colonizer biofilm after when compared to unmodified composites, but did not significantly reduce growth after three days. PMID:20225252

Sevinç, Berdan Aydin; Hanley, Luke

2010-01-01

217

Alveolar Epithelial Cell Injury Due to Zinc Oxide Nanoparticle Exposure  

PubMed Central

Rationale: Although inhalation of zinc oxide (ZnO) nanoparticles (NPs) is known to cause systemic disease (i.e., metal fume fever), little is known about mechanisms underlying injury to alveolar epithelium. Objectives: Investigate ZnO NP–induced injury to alveolar epithelium by exposing primary cultured rat alveolar epithelial cell monolayers (RAECMs) to ZnO NPs. Methods: RAECMs were exposed apically to ZnO NPs or, in some experiments, to culture fluid containing ZnCl2 or free Zn released from ZnO NPs. Transepithelial electrical resistance (RT) and equivalent short-circuit current (IEQ) were assessed as functions of concentration and time. Morphologic changes, lactate dehydrogenase release, cell membrane integrity, intracellular reactive oxygen species (ROS), and mitochondrial activity were measured. Measurements and Main Results: Apical exposure to 176 ?g/ml ZnO NPs decreased RT and IEQ of RAECMs by 100% over 24 hours, whereas exposure to 11 ?g/ml ZnO NPs had little effect. Changes in RT and IEQ caused by 176 ?g/ml ZnO NPs were irreversible. ZnO NP effects on RT yielded half-maximal concentrations of approximately 20 ?g/ml. Apical exposure for 24 hours to 176 ?g/ml ZnO NPs induced decreases in mitochondrial activity and increases in lactate dehydrogenase release, permeability to fluorescein sulfonic acid, increased intracellular ROS, and translocation of ZnO NPs from apical to basolateral fluid (most likely across injured cells and/or damaged paracellular pathways). Conclusions: ZnO NPs cause severe injury to RAECMs in a dose- and time-dependent manner, mediated, at least in part, by free Zn released from ZnO NPs, mitochondrial dysfunction, and increased intracellular ROS. PMID:20639441

Kim, Yong Ho; Fazlollahi, Farnoosh; Kennedy, Ian M.; Yacobi, Nazanin R.; Hamm-Alvarez, Sarah F.; Borok, Zea; Kim, Kwang-Jin; Crandall, Edward D.

2010-01-01

218

Feeding Low or Pharmacological Concentrations of Zinc Oxide Changes the Hepatic Proteome Profiles in Weaned Piglets  

PubMed Central

Pharmacological levels of zinc oxide can promote growth and health of weaning piglets, but the underlying molecular mechanisms are yet not fully understood. The aim of this study was to determine changes in the global hepatic protein expression in response to dietary zinc oxide in weaned piglets. Nine half-sib piglets were allocated to three dietary zinc treatment groups (50, 150, 2500 mg/kg dry matter). After 14 d, pigs were euthanized and liver samples taken. The increase in hepatic zinc concentration following dietary supplementation of zinc was accompanied by up-regulation of metallothionein mRNA and protein expression. Global hepatic protein profiles were obtained by two-dimensional difference gel electrophoresis following matrix-assisted laser desorption ionization/time-of-flight mass spectrometry. A total of 15 proteins were differentially (P<0.05) expressed between groups receiving control (150 mg/kg) or pharmacological levels of zinc (2500 mg/kg) with 7 down- (e.g. arginase1, thiosulfate sulfurtransferase, HSP70) and 8 up-regulated (e.g. apolipoprotein AI, transferrin, C1-tetrahydrofolate synthase) proteins. Additionally, three proteins were differentially expressed with low zinc supply (50 mg/kg Zn) in comparison to the control diet. The identified proteins were mainly associated with functions related to cellular stress, transport, metabolism, and signal transduction. The differential regulation was evaluated at the mRNA level and a subset of three proteins of different functional groups was selected for confirmation by western blotting. The results of this proteomic study suggest that zinc affects important liver functions such as blood protein secretion, protein metabolism, detoxification and redox homeostasis, thus supporting the hypothesis of intermediary effects of pharmacological levels of zinc oxide fed to pigs. PMID:24282572

Bondzio, Angelika; Pieper, Robert; Gabler, Christoph; Weise, Christoph; Schulze, Petra; Zentek, Juergen; Einspanier, Ralf

2013-01-01

219

Desulfurization behavior of zinc oxide based sorbent modified by the combination of Al 2O 3 and K 2CO 3  

Microsoft Academic Search

In order to reduce the unfavorable effect of carbon oxide on desulfurization efficiency for zinc oxide based sorbent and decrease the concentration of carbonyl sulfide in effluent gas during desulfurization process, the modification of zinc oxide based sorbent is necessary in the preparation of zinc oxide based desulfurization sorbent. In this paper, the modified ZnO based desulfurization sorbents were obtained

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

220

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

221

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

222

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

223

Anticancer activity of fungal L-asparaginase conjugated with zinc oxide nanoparticles.  

PubMed

Demand for developing novel delivery system for cancer treatment has increased due to the side effects present in intravenous injection of L-asparaginase. Nanoparticles are used for delivering the drugs to its destination in cancer cure. Nanobiocomposite of zinc oxide nanoparticles conjugated with L-asparaginase was produced by Aspergillus terreus and was confirmed using maximum UV-Vis absorption at 340 nm in the present work. The presence of functional groups like OH, C-H, -C=N and C=O on the surface of nanobiocomposite was found from Fourier transform infrared spectrum analysis. Size of the produced nanocomposite was found in the range of 28-63 nm using scanning electron microscope. The crystalline nature of the synthesized nanobiocomposites was confirmed by X-ray diffraction analysis. The presence of zinc oxide on synthesized nanobiocomposite was confirmed by energy dispersive spectrum analysis. The anti-cancerous nature of the synthesized zinc oxide conjugated L-asparaginase nanobiocomposite on MCF-7 cell line was studied using MTT assay. The viability of the MCF-7 cells was decreased to 35.02 % when it was treated with L-asparaginase conjugated zinc oxide nanobiocomposite. Hence it is proved that the synthesized nanobiocomposites of zinc oxide conjugated L-asparaginase has good anti-cancerous activity. PMID:25589205

Baskar, G; Chandhuru, J; Sheraz Fahad, K; Praveen, A S; Chamundeeswari, M; Muthukumar, T

2015-01-01

224

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; Oberdörster, Günter

2005-01-01

225

Zinc Oxide Nanostructures and High Electron Mobility Nanocomposite Thin Film Transistors  

Microsoft Academic Search

This paper reports on the synthesis of zinc oxide (ZnO) nanostructures and examines the performance of nanocomposite thin-film transistors (TFTs) fabricated using ZnO dispersed in both n- and p-type polymer host matrices. The ZnO nanostructures considered here comprise nanowires and tetrapods and were synthesized using vapor phase deposition techniques involving the carbothermal reduction of solid-phase zinc-containing compounds. Measurement results of

Flora M. Li; Gen-Wen Hsieh; Sharvari Dalal; Marcus C. Newton; James E. Stott; Pritesh Hiralal; Arokia Nathan; Paul A. Warburton; Husnu Emrah Unalan; Paul Beecher; Andrew J. Flewitt; Ian Robinson; Gehan Amaratunga; William I. Milne

2008-01-01

226

[Efficacy of using zinc oxide nanoparticles in nutrition. Experiments on the laboratory animal].  

PubMed

In experiments on rats there was researched bioavailability of zinc oxide (ZnO) nanoparticles. There were determined the content of Zn in blood serum and tibia, intestinal uptake of macromolecules of egg albumin, some hematological, biochemical and immune indices, liver cells apoptosis. The results obtained show that the uptake of nanoparticles of ZnO enables restoration of this microelement status damaged by zinc deficit diet. PMID:22238947

Raspopov, R V; Trushina, E N; Mustafina, O K; Tananova, O N; Gmoshinski?, I V; Khotimchenko, S A

2011-01-01

227

Zinc oxide films prepared by sol-gel spin-coating  

Microsoft Academic Search

The d.c. electrical conductivity and optical properties of undoped zinc oxide films prepared by the sol-gel process using a spin-coating technique were investigated. The ZnO films were obtained by 10 cycle spin-coated and dried zinc acetate films followed by annealing in air at 500–575°C. The films deposited on the Pyrex glass substrate were polycrystalline and c-axis oriented. A minimum film

Y. Natsume; H Sakata

2000-01-01

228

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 2013-07-01 false Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...substance identified generically as lithium salt of sulfophenyl azo phenyl azo...

2013-07-01

229

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

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...substance identified generically as lithium salt of sulfophenyl azo phenyl azo...

2010-07-01

230

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

Code of Federal Regulations, 2014 CFR

...2014-07-01 2014-07-01 false Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...substance identified generically as lithium salt of sulfophenyl azo phenyl azo...

2014-07-01

231

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...Chemical Substances § 721.9538 Lithium salt of sulfophenyl azo phenyl azo disulfostilbene...substance identified generically as lithium salt of sulfophenyl azo phenyl azo...

2012-07-01

232

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

2014-11-01

233

Atmospheric pressure chemical vapor deposition of gallium doped zinc oxide thin films from diethyl zinc, water, and triethyl gallium  

NASA Astrophysics Data System (ADS)

Gallium doped zinc oxide films have been deposited in the temperature range 150 to 470 C from 0.05 percent diethyl zinc, 0.8 percent water, and various triethyl gallium concentrations. The films are polycrystalline with crystallite sizes varying between 275 and 500 A for undoped films and between 125 and 400 A for doped films. Only those films deposited above 430 C are highly oriented and have their c axes perpendicular to the substrate plane. The electron density, conductivity, and mobility always increase with temperature. Thicker films have higher conductivity and mobility than thinner films. The refractive index is reduced from 1.96 to 1.73 when the electron density is increased from zero to 3.7 x 10 exp 20/cu cm.

Hu, Jianhua; Gordon, Roy G.

1992-12-01

234

Biocidal effects of silver and zinc oxide nanoparticles on the bioluminescent bacteria  

NASA Astrophysics Data System (ADS)

The effect of silver and zinc oxide nanoparticles in combination with alginate on bioluminescent Photobacterium leiognathi Sh1 bacteria was investigated. Silver nanoparticles were found to be more toxic than zinc oxide nanoparticles on bioluminescent bacteria. The nanoparticles and their ions released results in the same effect, however, it was absent in combination with alginate. The effective inhibiting concentration (EC50) for silver nanoparticles was found about 0.3 - 0.4 ?g mL-1, which was up to two times larger then for zinc oxide nanoparticles. The absence of sodium chloride in the tested media prevented the formation of colloidal particles of larger size and the effective inhibition concentrations of metal derivatives were lower than in the presence of sodium chloride.

Taran, M. V.; Starodub, N. F.; Katsev, A. M.; Guidotti, M.; Khranovskyy, V. D.; Babanin, A. A.; Melnychuk, M. D.

2013-11-01

235

EXAMINATION OF THE OXIDATION PROTECTION OF ZINC COATINGS FORMED ON COPPER ALLOYS AND STEEL SUBSTRATES  

SciTech Connect

The exposure of metallic components at aggressive high temperature environments, usually limit their usage at similar application because they suffer from severe oxidation attack. Copper alloys are used in a wide range of high-quality indoor and outdoor applications, statue parts, art hardware, high strength and high thermal conductivity applications. On the other hand, steel is commonly used as mechanical part of industrial set outs or in the construction sector due to its high mechanical properties. The aim of the present work is the examination of the oxidation resistance of pack cementation zinc coatings deposited on copper, leaded brass and steel substrates at elevated temperature conditions. Furthermore, an effort made to make a long-term evaluation of the coated samples durability. The oxidation results showed that bare substrates appear to have undergone severe damage comparing with the coated ones. Furthermore, the mass gain of the uncoated samples was higher than this of the zinc covered ones. Particularly zinc coated brass was found to be more resistant to oxidation conditions in which it was exposed as it has the lower mass gain as compared to the bare substrates and zinc coated copper. Zinc coated steel was also proved to be more resistive than the uncoated steel.

Papazoglou, M.; Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Stergioudis, G. [Department of Physics, Aristotle University of Thessaloniki, 541 24 Thessaloniki (Greece); Skolianos, S. [Physical Metallurgy Laboratory, Department of Mechanical Engineering, Aristotle University of Thessaloniki, 541 24, Thessaloniki (Greece)

2010-01-21

236

Electrical and optical properties of zinc oxide for scintillator applications  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a wide-band-gap semiconductor suitable for many optical and optoelectronic applications. Among these is to use single crystal, powder, or ceramic forms of ZnO as a fast UV scintillator. In this work, the electrical and optical properties of ZnO were studied using photoluminescence, X-ray-induced luminescence, optical absorption, and Hall Effect techniques. This study included single crystal ZnO and ZnO:Ga samples grown from high-pressure-melt (HPM), seeded chemical-vapor-transport (SCVT), and hydrothermal (HYD) techniques; powder samples synthesized using both solution and solid-state processes, and purchased from different commercial sources; and ceramic samples prepared by hot-uni-axial-pressing and spark-plasma-sintering methods. Temperature-dependent PL and Hall measurements were combined to establish the luminescence origins in the n-type ZnO and ZnO:Ga single crystals. Based on a PL line-shape analysis, including band-gap renormalization, the direct (e,h) transition is the main luminescent channel in highly n-type ZnO:Ga, while FX and FX-LO recombinations are responsible for the UV PL from as-grown ZnO. An intrinsic mobility limit for n-type ZnO was established by including three major phonon-scattering mechanisms. Analysis of Hall data from single-crystal samples including both neutral- and ionized-impurity scatterings provided donor and acceptor concentrations and energy levels. High n-type single-crystal ZnO samples prepared either by Ga doping and co-doping, or by after-growth treatments, were also studied. Absorption and reflectance data were used to obtain free carrier concentrations from the Ga-doped and co-doped crystals, and it was found that several samples with n ˜ high-1018 to low-1019 cm -3 had optimum UV luminescence. Anneal treatments in reducing atmospheres increased free carrier concentrations in HPM and HYD samples, but an induced absorption band due to oxygen vacancies limited the UV emission from these samples. PL and X-ray-induced luminescence studies on powder ZnO:Ga samples demonstrated that high Ga-doping levels and H-anneal treatments can improve UV emission, while impurities such as Cu and Li enhance the lower energy visible emissions and affect the UV output. For ceramic forms of ZnO, reduction of scattering losses remains as the main challenge for improved scintillation.

Yang, Xiaocheng

237

Effect of thermal treatment in oxygen, nitrogen, and air atmospheres on the electrical transport properties of zinc oxide thin films  

Microsoft Academic Search

The effects of thermal treatment in oxygen, air, and nitrogen gas atmospheres, at temperatures ranging from 573 to 1173 K, on the electrical transport properties of thin films of zinc oxide, prepared by sputtering deposition, have been investigated. These experiments have been carried out in preparation for future ion implantation doping studies in zinc oxide. As-prepared samples were slightly oxygen-deficient

Omima Hamad; Gabriel Braunstein; Harshad Patil; Neelkanth Dhere

2005-01-01

238

Controlled Growth of one-dimensional zinc oxide nanostructures in the pulsed electrodeposition mode  

SciTech Connect

Zinc oxide nanostructures are objects of study in the field of optoelectronics, solar power engineering, nanosensorics, and catalysis. For the purpose of the controlled growth of one-dimensional submicrometer zinc oxide structures in the pulsed electrodeposition mode, the effect of the pulse electrolysis parameters on the morphology of ZnO layers, their optical properties, and structural and substructural characteristics is determined using X-ray diffraction, optical spectrophotometry, and atomic-force microscopy. The possibility of fabricating arrays of ZnO nanowires with different geometrical shapes, perpendicular to the substrate surface, by varying the frequency of cathode-substrate potential pulses is shown.

Klochko, N. P., E-mail: klochko_np@mail.ru; Khrypunov, G. S. [National Technical University 'Kharkiv Polytechnical Institute' (Ukraine); Myagchenko, Yu. O.; Melnychuk, E. E. [Taras Shevchenko National University of Kyiv (Ukraine); Kopach, V. R.; Klepikova, E. S.; Lyubov, V. M. [National Technical University 'Kharkiv Polytechnical Institute' (Ukraine); Kopach, A. V.

2012-06-15

239

Using C??? Sputtering to Improve Detection Limit of Nitrogen in Zinc Oxide  

SciTech Connect

C??? sputtering was firstly used to determine depth profile of nitrogen in zinc oxide materials by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Compared to traditional Cs+ sputtering depth profiling, the C??? sputtering provides over 200 times of effective signal intensity and the detection limit is about 10 times better. In addition, our X-ray photoelectron spectroscopy (XPS) results show that sputtering zinc oxide materials by 10 keV C??? leads to very weak carbon deposition at bottom of the sputter crater.

Zhu, Zihua; Shutthanandan, V.; Nachimuthu, Ponnusamy

2010-05-11

240

Zinc regulates iNOS-derived nitric oxide formation in endothelial cells.  

PubMed

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; Opländer, Christian; Kolb-Bachofen, Victoria; Kröncke, Klaus-D; Suschek, Christoph V

2014-01-01

241

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; Opländer, Christian; Kolb-Bachofen, Victoria; Kröncke, Klaus-D.; Suschek, Christoph V.

2014-01-01

242

Growth of high-quality, uniform c-axis-oriented zinc oxide nano-wires on a-plane sapphire substrate with zinc oxide templates  

Microsoft Academic Search

High-quality, vertically aligned zinc oxide (ZnO) nano-wires were grown by the vapour-transport method on (112¯0) (a-plane) sapphire substrate covered by a uniform ZnO nano-crystalline seed layer which was deposited in a preceding growth step via simple chemical vapour deposition. A thin layer of close-packed nano-seeds with an average size of 12nm was formed rapidly on the substrate by sublimation and

A. Reiser; V. Raeesi; G. M. Prinz; M. Schirra; M. Feneberg; U. Röder; R. Sauer; K. Thonke

2009-01-01

243

Heat-sterilized silver oxide-zinc cells: Cycle life studies  

NASA Technical Reports Server (NTRS)

A JPL study was conducted to evaluate the cell design parameters that contribute to the cycle life of sealed, heat-sterilized silver oxide-zinc cells. Test cells having a rated capacity of 4.2 A-h were fabricated using zinc oxide electrodes prepared by the sintered Teflon process. Two separator variations were evaluated, one having acrylic acid and the other methacrylic acid grafted to irradiated polyethylene film. Significant results of this study include the following: (1) cycle life in excess of 300 cycles was attained; (2) a zinc oxide/silver stoichiometric ratio of 1.5 resulted in greater cycle life than a ratio of 1.1, and similar cycle life to cells having a ratio of 2; (3) cells having methacrylic acid grafted separators suffered somewhat less in capacity loss due to zinc electrode shape change than cells having acrylic acid type; (4) use of acrylic acid grafted separators was slightly superior to the methacrylic acid type in respect to silver penetration; and (5) the inclusion of a layer of potassium titanate paper adjacent to the zinc electrodes resulted in cells that achieved higher cycle life before any of the group failed than that reached by cells of any other construction.

Arms, J. T.

1973-01-01

244

Supercritical antisolvent precipitation of nanoparticles of a zinc oxide precursor  

Microsoft Academic Search

Supercritical antisolvent (SAS) precipitation has been applied to the production of zinc acetate with the aim of evaluating the applicability of this new process to the production of controlled size nanoparticles of catalyst precursors. SAS process is based on the large volumetric expansion of the liquid solvent induced by the fast diffusion of the antisolvent inside the liquid phase. The

E Reverchon; G Della Porta; D Sannino; P Ciambelli

1999-01-01

245

Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics  

Microsoft Academic Search

Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction, energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens are studied. The synthesis conditions, under which specimens with the

L. N. Demyanets; L. E. Li; A. S. Lavrikov; S. V. Nikitin

2010-01-01

246

Corrosion electrochemical behavior of epoxy anticorrosive paints based on zinc molybdenum phosphate and zinc oxide  

Microsoft Academic Search

Electrochemical impedance spectroscopy (EIS) was applied as a principal tool to describe the efficiency of anticorrosive epoxy paints (primers) based on zinc molybdenum phosphate (ZMP) pigment. Steel-coated samples were exposed to a 0.5M NaCl solution. During the study the corrosion potential (Eoc) and Rp values also were monitored every 24h. It is discussed the incorporation of micronized ZnO (1?m) pigment

L. Veleva; J. Chin; B. del Amo

1999-01-01

247

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

248

Hydrothermal synthesis of iron and zinc double vanadium oxides using the tetramethyl ammonium ion  

SciTech Connect

There has been much effort recently to find more cost-effective oxide cathodes for advanced lithium batteries, to replace the technically excellent but expensive lithium cobalt oxide. The authors have studied the hydrothermal synthesis of tetramethyl ammonium vanadium oxides that contain an additional transition metal, such as iron or zinc, in order to stabilize the layered structure of vanadium oxide for electrochemical redox reactions with lithium. Addition of the lower cost iron and zinc is also beneficial for commercial application. Several new layered structures which contain double sheets of V{sub 2}O{sub 5} have been formed and characterized. The iron compound contains the TMA ion. Their structures and electrochemical behavior are reported.

Fan Zhang; Zavalij, P.Y.; Whittingham, M.S. [State Univ. of New York, Binghamton, NY (United States)] [State Univ. of New York, Binghamton, NY (United States)

1997-06-01

249

Direct electrical junction formation of highly vertical aligned zinc oxide nanorods.  

PubMed

A two dimensionally assembled monolayer of hexagonal convexo-convex ?-cobalt hydroxide nanoplates as a self-disposable sacrificial epi-template leads to a highly vertical alignment of zinc oxide nanorods array having a good electrical contact with metal or semiconductor layer on a substrate in a hydrothermal process. PMID:22048309

Lee, Tae Il; Jang, Woo Soon; Park, Ji Hyeon; Kang, Youn Hee; Lee, Sang Hoon; Hwang, Sung Hwan; Baik, Hong Koo; Myoung, Jae Min

2011-12-28

250

Formation and crystallization in the yttrium aluminosilicate glasses containing zinc oxide  

SciTech Connect

Formation of yttrium aluminosilicate glasses containing zinc oxide from batches melted at 1550/sup 0/c was investigated. Densities, thermal expansion coefficients, and Vickers hardnesses were measured for some glasses. In a specific compositional region, crystals with a convex and pyramidal habit were observed on the glass surface.

Makishima, A.; Kubo, H.; Kotani, K.; Tsutsumi, M.; Asami, M.

1986-12-01

251

Processing and Characterization of P-Type Doped Zinc Oxide Thin Films  

E-print Network

Applications of zinc oxide (ZnO) for optoelectronic devices, including light emitting diodes, semiconductor lasers, and solar cells have not yet been realized due to the lack of high-quality p-type ZnO. In the research presented herein, pulsed laser...

Myers, Michelle Anne

2013-03-18

252

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

253

Biosynthesis of silver and zinc oxide nanoparticles using Pichia fermentans JA2 and their antimicrobial property  

NASA Astrophysics Data System (ADS)

The development of eco-friendly alternative to chemical synthesis of metal nanoparticles is of great challenge among researchers. The present study aimed to investigate the biological synthesis, characterization, antimicrobial study and synergistic effect of silver and zinc oxide nanoparticles against clinical pathogens using Pichia fermentans JA2. The extracellular biosynthesis of silver and zinc oxide nanoparticles was investigated using Pichia fermentans JA2 isolated from spoiled fruit pulp bought in Vellore local market. The crystalline and stable metallic nanoparticles were characterized evolving several analytical techniques including UV-visible spectrophotometer, X-ray diffraction pattern analysis and FE-scanning electron microscope with EDX-analysis. The biosynthesized metallic nanoparticles were tested for their antimicrobial property against medically important Gram positive, Gram negative and fungal pathogenic microorganisms. Furthermore, the biosynthesized nanoparticles were also evaluated for their increased antimicrobial activities with various commercially available antibiotics against clinical pathogens. The biosynthesized silver nanoparticles inhibited most of the Gram negative clinical pathogens, whereas zinc oxide nanoparticles were able to inhibit only Pseudomonas aeruginosa. The combined effect of standard antibiotic disc and biosynthesized metallic nanoparticles enhanced the inhibitory effect against clinical pathogens. The biological synthesis of silver and zinc oxide nanoparticles is a novel and cost-effective approach over harmful chemical synthesis techniques. The metallic nanoparticles synthesized using Pichia fermentans JA2 possess potent inhibitory effect that offers valuable contribution to pharmaceutical associations.

Chauhan, Ritika; Reddy, Arpita; Abraham, Jayanthi

2015-01-01

254

Influence of DC magnetron sputtering parameters on the properties of amorphous indium zinc oxide thin film  

Microsoft Academic Search

Amorphous or crystalline indium zinc oxide (IZO) thin films, which are highly transparent and conducting, were deposited by DC magnetron sputtering. X-Ray diffraction technique was used for analyzing microstructures of the films, and also differential thermal analysis was performed for observing their crystallization behavior. The IZO thin films prepared were crystallized at much higher temperature than ITO films were. The

Yeon Sik Jung; Ji Yoon Seo; Dong Wook Lee; Duk Young Jeon

2003-01-01

255

Room temperature fast synthesis of zinc oxide nanowires by inductive heating  

E-print Network

Room temperature fast synthesis of zinc oxide nanowires by inductive heating Lei Luo,a Brian D; published online 26 February 2007 ZnO nanowires have been rapidly synthesized using inductive heating the inductive heating assisted fast synthesis of ZnO nanowires using ZnO/graphite solid source powder in a room

Lin, Liwei

256

Optical properties of epitaxially grown zinc oxide films on sapphire by pulsed laser deposition  

E-print Network

Optical properties of epitaxially grown zinc oxide films on sapphire by pulsed laser deposition X 18 August 1998; accepted for publication 23 March 1999 ZnO thin films were epitaxially grown on c-sapphire and unavailable in large wafers for the time being, ZnO thin film, especially on sapphire, is a relatively good

Kwok, Hoi S.

257

Electrical effect of titanium diffusion on amorphous indium gallium zinc oxide  

NASA Astrophysics Data System (ADS)

In this work, thermal diffusion phenomenon of Ti into amorphous indium gallium zinc oxide (?-IGZO) was carefully investigated with secondary ion mass spectroscopy, I-V, and Rs 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 ?-IGZO during the oxidation of Ti, the number of oxygen vacancies working as electron-donating sites in ?-IGZO was dramatically increased, contributing to the decrease of resistivity (?) from 1.96 ? cm (as-deposited ?-IGZO) to 1.33 × 10-3 ? cm (350 °C annealed ?-IGZO).

Choi, Seung-Ha; Jung, Woo-Shik; Park, Jin-Hong

2012-11-01

258

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

259

Synthesis and optical properties of tetrapod-like zinc oxide nanorods  

Microsoft Academic Search

Uniform tetrapod-like zinc oxide (T-ZnO) nanorods were produced in bulk quantity by oxidation of Zn powders. Field-emission scanning electron microscope and transmission electron microscopy investigations showed that T-ZnO nanorods were high-quality nanocrystals. The length of legs of T-ZnO nanorods was 2–3?m and the edge size of centering nucleus was 70–150 nm. The growth of T-ZnO nanorods was controlled by a

Y. Dai; Y. Zhang; Q. K. Li; C. W. Nan

2002-01-01

260

Growth of zinc oxide by chemical vapor transport  

NASA Astrophysics Data System (ADS)

ZnO crystal growth by chemical vapor transport (CVT) is carried out using carbon as a transport agent. Under the optimum ?T and growth temperature, a single crystal was grown. The carbon contamination is not detected by SIMS measurements and all the crystals are orange-red colored. It is claimed that the orange-red color is attributed to the shift of stoichiometry to zinc rich atmosphere.

Mikami, Makoto; Eto, Toshiaki; Wang, JiFeng; Masa, Yoshihiko; Isshiki, Minoru

2005-04-01

261

Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics  

NASA Astrophysics Data System (ADS)

Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction, energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens are studied. The synthesis conditions, under which specimens with the crystallite morphology optimal for a low-threshold lasing are obtained, are found.

Demyanets, L. N.; Li, L. E.; Lavrikov, A. S.; Nikitin, S. V.

2010-01-01

262

Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics  

Microsoft Academic Search

Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of\\u000a a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction,\\u000a energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens\\u000a are studied. The synthesis conditions, under which specimens with the

L. N. Demyanets; L. E. Li; A. S. Lavrikov; S. V. Nikitin

2010-01-01

263

Nanocrystalline zinc oxide: Pyrolytic synthesis and spectroscopic characteristics  

SciTech Connect

Nanocrystalline and microcrystalline ZnO powders are synthesized by the pyrolysis of organic zinc salts in the presence of a reducing catalyst represented by a porous cellulose carrier. The specimens obtained are characterized by X-ray powder diffraction, energy dispersive analysis, scanning electron microscopy, and pulse cathodoluminescence. Lasing characteristics of the specimens are studied. The synthesis conditions, under which specimens with the crystallite morphology optimal for a low-threshold lasing are obtained, are found.

Demyanets, L. N., E-mail: demianets@ns.crys.ras.ru; Li, L. E.; Lavrikov, A. S.; Nikitin, S. V. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)

2010-01-15

264

Optical and electronic properties of native zinc oxide films on polycrystalline Zn.  

PubMed

The oxide layer spontaneously formed on zinc and an "electrochemically reduced" oxide has been characterised by a combination of X-ray photoelectron spectroscopy (XPS) and spectroscopic ellipsometry (SE). The onset of the main electronic absorption, which is directly related to the bandgap, is extracted from the SE measurements. The SE results are compared with simulations on the basis of zinc and bulk zinc oxide optical constant data. Measurements in the ultraviolet and visible (UV-vis) spectral range show the presence of an absorption at ?1.8 eV (680 nm) which is unaccounted for from the bulk data, and is likely to originate from intragap energy levels, implicating the presence of surface defects in the layers. Analysis of the Zn LMM Auger peaks in XPS data show the presence of Zn different from bulk zinc and bulk ZnO, attributed to excess Zn in the oxide films. Mid-infrared (IR) ellipsometry shows two peaks around 0.12 and 0.15 eV (1000 and 1200 cm(-1)), which strengthen the assumption of the presence of a locally distorted structure in the oxide layers. Electrochemically reduced samples show a much thinner oxide layer and higher Zn-doping concentration films than samples purely dipped in NaOH solution. Using a self-contained multiple sample SE analysis, estimates of the refractive index and absorption coefficient (i.e., the optical constants) of the oxide films are presented from 1.5-4.4 eV (280 to 810 nm). PMID:20676459

Zuo, Juan; Erbe, Andreas

2010-10-01

265

Radiation Stability of Zinc Oxide Pigment Modified by Zirconium Oxide and Aluminum Oxide Nanopowders  

SciTech Connect

The effect on the reflective spectra of heat treatment and modification of ZnO pigments by 1-30 wt.%ZrO{sub 2} and Al{sub 2}O{sub 3} nanoparticles has been investigated before and after irradiation by 100 keV protons with a fluence of 5x10{sup 15} cm{sup -2}. It is established that with the optimum concentration of 5 wt.% nanoparticles and the temperature of 800 deg. C a 20% increase in the radiation stability is observed for the modified ZnO pigment in comparison with the not modified pigment. The decrease of absorption in the modified pigments is determined by the decrease of the intensity of the absorption bands of the zinc vacancies (V{sub zn}{sup -}), oxygen vacancies (V{sub o}{sup +}) and donor-acceptor couples (V{sub zn}-{sup -}Zn{sub i}{sup 0})

Mikhailov, M. M. [Tomsk State University of Control Systems and Radioelectronics, 40 Lenina Prospect, Tomsk, Russia 634050 (Russian Federation); Harbin Institute of Technology, Harbin (China); Neshchimenko, V. V. [Amur State University, Ignatyevskoye Shosse 21, Blagoveshchensk, Amur region, 675027 (Russian Federation); Li Chundong [Harbin Institute of Technology, Harbin (China)

2009-01-05

266

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

267

High quality ZnO:Al transparent conducting oxide films synthesized by pulsed filtered cathodic arc deposition  

SciTech Connect

Aluminum-doped zinc oxide, ZnO:Al or AZO, is a well-known n-type transparent conducting oxide with great potential in a number of applications currently dominated by indium tin oxide (ITO). In this study, the optical and electrical properties of AZO thin films deposited on glass and silicon by pulsed filtered cathodic arc deposition are systematically studied. In contrast to magnetron sputtering, this technique does not produce energetic negative ions, and therefore ion damage can be minimized. The quality of the AZO films strongly depends on the growth temperature while only marginal improvements are obtained with post-deposition annealing. The best films, grown at a temperature of about 200?C, have resistivities in the low to mid 10-4 Omega cm range with a transmittance better than 85percent in the visible part of the spectrum. It is remarkable that relatively good films of small thickness (60 nm) can be fabricated using this method.

Anders, Andre; Lim, Sunnie H.N.; Yu, Kin Man; Andersson, Joakim; Rosen, Johanna; McFarland, Mike; Brown, Jeff

2009-04-24

268

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

269

Electrical and optical properties of doped tin and zinc oxide thin films by atmospheric pressure chemical vapor deposition  

NASA Astrophysics Data System (ADS)

Zinc oxide and tin oxide films have been deposited by atmospheric pressure chemical vapor deposition. Zinc oxide films doped with fluorine have higher mobility and higher visible transmission than those doped with the Group III elements (B, Al, Ga). A ZnO:F film with a sheet resistance of 5 ?/square has an average visible absorption of about 3%. Various doped zinc oxide films were compared with each other and with SnO2:F films through their Figure of Merit, which is defined as the ratio of the conductivity over the visible absorption coefficient. Zinc oxide films doped with fluorine have the highest Figure of Merit and are very promising as transparent electrodes for solar cells with high cell efficiency.

Hu, Jianhua; Gordon, Roy G.

1992-12-01

270

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

271

Effects of Li and Cu dopants on structural properties of zinc oxide nanorods  

NASA Astrophysics Data System (ADS)

We fabricated undoped zinc oxide (ZnO), Li-doped zinc oxide (LZO), and Cu-doped zinc oxide (CZO) nanorods (NRs) on fluorine-doped tin oxide (FTO)-coated glass substrates using chemical solution deposition and investigated their structural properties. With the incorporation of the Li dopant, the length and crystallinity of LZO NRs increased and improved, respectively, compared to that of the ZnO NRs. The average optical transmittance of LZO NRs was slightly lower than that of the ZnO NRs, but otherwise very similar over the visible wavelength region. With the incorporation of the Cu dopant, however, the morphology of the CZO sample was remarkably different from that of the pure ZnO NRs. Rods with a length of ?12 ?m and a diameter of 0.5-1.2 ?m were randomly oriented on the substrate, and copper oxide (CuO) nanocrystals were uniformly grown on the surface of substrate. This paper presents a simple way to tune the growth behaviors of the ZnO NRs by adding dopants.

Kim, Kyung Ho; Jin, Zhuguang; Abe, Yoshio; Kawamura, Midori

2015-01-01

272

Differential impact of zinc deficiency on phagocytosis, oxidative burst, and production of pro-inflammatory cytokines by human monocytes.  

PubMed

Zinc deficiency has a fundamental influence on the immune defense, with multiple effects on different immune cells, resulting in a major impairment of human health. Monocytes and macrophages are among the immune cells that are most fundamentally affected by zinc, but the impact of zinc on these cells is still far from being completely understood. Therefore, this study investigates the influence of zinc deficiency on monocytes of healthy human donors. Peripheral blood mononuclear cells, which include monocytes, were cultured under zinc deficient conditions for 3 days. This was achieved by two different methods: by application of the membrane permeable chelator N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) or by removal of zinc from the culture medium using a CHELEX 100 resin. Subsequently, monocyte functions were analyzed in response to Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae. Zinc depletion had differential effects. On the one hand, elimination of bacterial pathogens by phagocytosis and oxidative burst was elevated. On the other hand, the production of the inflammatory cytokines tumor necrosis factor (TNF)-? and interleukin (IL)-6 was reduced. This suggests that monocytes shift from intercellular communication to basic innate defensive functions in response to zinc deficiency. These results were obtained regardless of the method by which zinc deficiency was achieved. However, CHELEX-treated medium strongly augmented cytokine production, independently from its capability for zinc removal. This side-effect severely limits the use of CHELEX for investigating the effects of zinc deficiency on innate immunity. PMID:24823619

Mayer, Lena S; Uciechowski, Peter; Meyer, Sören; Schwerdtle, Tanja; Rink, Lothar; Haase, Hajo

2014-07-01

273

Evaluation of growth and biochemical indicators of Salvinia natans exposed to zinc oxide nanoparticles and zinc accumulation in plants.  

PubMed

The adverse effects of zinc oxide nanoparticles (ZnO NPs) with an average diameter of 25 nm on the aquatic plant Salvinia natans (L.) All. were determined. Growth, superoxide dismutase (SOD) activity, catalase (CAT) activity, peroxidase activity, and chlorophyll content of the plants were measured after 7 days of exposure to different concentrations of ZnO NPs (1 to 50 mg L(-1)). The particle distribution in the culture medium (without plants) during the first 24 h was determined using a Nanotrac 250 particle analyzer. We also investigated the zinc accumulation in leaves and roots of the plant after 7 days of exposure. Exposure to 50 mg L(-1) ZnO NPs significantly increased SOD and CAT activities (P??0.05). NPs completely precipitated at the bottom of the container at 8 h except for the portions of dissolution and aggregation on the roots. ZnO NPs at a concentration of 50 mg L(-1) can adversely affect S. natans, and their stress is affected by their aggregation and dissolution. PMID:23860598

Hu, Changwei; Liu, Xu; Li, Xiuling; Zhao, Yongjun

2014-01-01

274

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

275

40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...  

Code of Federal Regulations, 2014 CFR

...methoxy-sulfophenyl)azo], metal salt (generic). 721.10107 Section 721...methoxy-sulfophenyl)azo], metal salt (generic). (a) Chemical substance...methoxy-sulfophenyl)azo], metal salt (PMN P-04-495) is subject to...

2014-07-01

276

40 CFR 721.2577 - Copper complex of (substituted sulfonaphthyl azo substituted phenyl) disulfonaphthyl azo, amine...  

Code of Federal Regulations, 2014 CFR

...substituted phenyl) disulfonaphthyl azo, amine salt (generic). 721.2577 Section 721...substituted phenyl) disulfonaphthyl azo, amine salt (generic). Link to an amendment published...substituted phenyl) disulfonaphthyl azo, amine salt (PMNs P-00-0364 and...

2014-07-01

277

40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...  

Code of Federal Regulations, 2012 CFR

...methoxy-sulfophenyl)azo], metal salt (generic). 721.10107 Section 721...methoxy-sulfophenyl)azo], metal salt (generic). (a) Chemical substance...methoxy-sulfophenyl)azo], metal salt (PMN P-04-495) is subject to...

2012-07-01

278

Power dissipation characteristics of zinc-oxide arresters for HVDC systems  

SciTech Connect

Zinc-oxide arresters without series gaps have been used for HVDC systems. The voltage wave shapes applied to HVDC arresters are not a simple sinusoidal shape, so that the leakage current contains high frequency components. The power dissipation characteristics of a thyristor valve arrester were measured using a 1/25 prorated arrester section with a 5kV/500kW thyristor bridge. High frequency power dissipation characteristics of zinc-oxide elements were measured and it was shown that the high frequency power dissipation of the thyristor valve arrester was larger than that of an AC system arrester. Consideration of the equivalent continuous operating voltage for the performance test of an HVDC arrester are presented.

Horiuchi, S.; Ichikawa, F. (Tokyo Electric Power Co., Inc., Tokyo (JP)); Mizukoshi, A. (Hitachi Research Lab., Hitachi Ltd. (JP)); Kurita, K.; Shirakawa, S. (Kokubu Works Hitachi Ltd., Ibaraki (JP))

1988-10-01

279

Enhancement in Conductivity and Transmittance of Zinc Oxide Prepared by Chemical Bath Deposition  

NASA Astrophysics Data System (ADS)

Highly conductive and transparent zinc oxide thin films were prepared on cleaned Corning Eagle2000 glass substrates by chemical bath deposition (CBD) using Zn(NO3)2 and (CH3)2NHBH3; the effects of annealing on the structural, electrical and optical properties were investigated. The electrical properties of the film were greatly affected by annealing. Structural characterization was performed by x-ray diffraction and field emission scanning electron micro- scopy. The thin film had a low resistivity of 2.9 × 10-2 ? cm, an average transmittance of 81.2%, and a bandgap of 3.23 eV (which is in the visible range) when the film was annealed at 600°C in Ar + H2. The results demonstrated that a low-resistivity and high-transmittance zinc oxide film can be prepared by CBD, which makes the process readily applicable for a roll-to-roll process.

Luo, Wei-Hsiang; Tsai, Ting-Kan; Yang, Jen-Chieh; Hsieh, Wei-Ming; Hsu, Chia-His; Fang, Jau-Shiung

2009-11-01

280

The electronic structure of co-sputtered zinc indium tin oxide thin films  

SciTech Connect

Zinc indium tin oxide (ZITO) transparent conductive oxide layers were deposited via radio frequency (RF) magnetron co-sputtering at room temperature. A series of samples with gradually varying zinc content was investigated. The samples were characterized with x-ray and ultraviolet photoemission spectroscopy (XPS, UPS) to determine the electronic structure of the surface. Valence and conduction bands maxima (VBM, CBM), and work function were determined. The experiments indicate that increasing Zn content results in films with a higher defect rate at the surface leading to the formation of a degenerately doped surface layer if the Zn content surpasses {approx}50%. Furthermore, the experiments demonstrate that ZITO is susceptible to ultraviolet light induced work function reduction, similar to what was earlier observed on ITO and TiO{sub 2} films.

Carreras, Paz; Antony, Aldrin; Bertomeu, Joan [Departament de Fisica Aplicada i Optica, Universitat de Barcelona, 08028 Barcelona (Spain); Gutmann, Sebastian [Department of Chemistry, University of South Florida, Tampa, Florida 33620 (United States); Schlaf, Rudy [Department of Electrical Engineering, University of South Florida, Tampa, Florida 33620 (United States)

2011-10-01

281

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

282

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

283

J. Phys.: Condens. Matter 11 (1999) 36353644. Printed in the UK PII: S0953-8984(99)98511-9 Electronic structure of spinel oxides: zinc aluminate and  

E-print Network

-8984(99)98511-9 Electronic structure of spinel oxides: zinc aluminate and zinc gallate Suresh K Sampath, D G Kanhere with the atomic sphere approximation. The calculated results predict these zinc-based spinel oxides to be direct and ZnGa2O4 with that of MgAl2O4 clearly shows the bonding to be less ionic in the zinc-based spinel

Pandey, Ravi

284

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

285

Amorphous indium zinc oxide thin film transistors with poly-4-vinylphenol gate dielectric layers  

Microsoft Academic Search

Thin film transistors (TFTs) with amorphous indium zinc oxide (a-IZO) as channel layers and poly-4-vinylphenol as dielectric layers were fabricated. Transmission curves show that the double-layer structure of the a-IZO layer and the poly-4-vinylphenol layer exhibits the antireflection effect. It was found that post heat-treatment at relatively low temperature will improve the electrical performance of the transistors. TFT devices with

Haifeng Pu; Guifeng Li; Jiahan Feng; Baoying Liu; Qun Zhang

2011-01-01

286

Factors influencing the cytotoxicity of zinc oxide nanoparticles: particle size and surface charge  

Microsoft Academic Search

Zinc oxide (ZnO) nanoparticle is one of the most important materials in diverse applications, since it has UV light absorption, antimicrobial, catalytic, semi-conducting, and magnetic properties. However, there is little information about the toxicological effects of ZnO nanoparticles with respect to physicochemical properties. The aim of this study was, therefore, to evaluate the relationships between cytotoxicity and physicochemical properties of

M. Baek; M. K. Kim; H. J. Cho; J. A. Lee; J. Yu; H. E. Chung; S. J. Choi

2011-01-01

287

Power dissipation characteristics of zinc-oxide arresters for HVDC systems  

Microsoft Academic Search

Zinc-oxide arresters without series gaps have been used for HVDC systems. The voltage wave shapes applied to HVDC arresters are not a simple sinusoidal shape, so that the leakage current contains high frequency components. The power dissipation characteristics of a thyristor valve arrester were measured using a 1\\/25 prorated arrester section with a 5kV\\/500kW thyristor bridge. High frequency power dissipation

S. Horiuchi; F. Ichikawa; A. Mizukoshi; K. Kurita; S. Shirakawa

1988-01-01

288

Zinc oxide nanoparticles cause nephrotoxicity and kidney metabolism alterations in rats  

Microsoft Academic Search

Although zinc oxide nanoparticles (ZnO NPs) have been widely used, their potential hazards on mammalian and human remain largely unknown. In this study, the biochemical compositions of urine and kidney from the rats treated with ZnO NPs (100, 300 and 1000 mg\\/kg, respectively) were investigated using H nuclear magnetic resonance (NMR) technique with the pattern recognition of partial least squares-discriminant analysis.

Guangyan Yan; Yina Huang; Qian Bu; Lei Lv; Pengchi Deng; Jiaqing Zhou; Yanli Wang; Yanzhu Yang; Qiangqiang Liu; Xiaobo Cen; Yinglan Zhao

2012-01-01

289

Effects of an Electrically Conducting Layer at the Zinc Oxide Surface  

Microsoft Academic Search

Measurements of the electrical properties of high-resistivity zinc oxide (ZnO) are strongly influenced by the sample ambient. Temperature-dependent Hall-effect measurements were performed on Li- and Cu-doped bulk crystals in both air and vacuum. Repeating the measurements under a given test ambient produced stable results. Changing the ambient systematically changed the measured results. We explain this behavior in terms of a

Oliver Schmidt; Peter Kiesel; Chris G. Van de Walle; Noble M. Johnson; Jeff Nause; Gottfried H. Döhler

2005-01-01

290

Analysis of a conducting channel at the native zinc oxide surface  

Microsoft Academic Search

The electrical properties of high-resistivity zinc oxide (ZnO) bulk and epi-samples are strongly influenced by the sample ambient. Bulk samples that are highly resistive in ambient air can be reversibly transformed into a high conducting state under vacuum. As an explanation we suggest a conducting electron channel at the ZnO surface. Under vacuum this channel appears upon annealing. Exposure to

Oliver Schmidt; Arnd Geis; Peter Kiesel; Chris. G. Van de Walle; Noble M. Johnson; Andrey Bakin; Andreas Waag; Gottfried H. Döhler

2006-01-01

291

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

E-print Network

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, Fabio Antonio; Belardini, Alessandro; Sibilia, Concita

2009-01-01

292

Low temperature growth and photoluminescence of well-aligned zinc oxide nanowires  

Microsoft Academic Search

Well-aligned single-crystalline zinc oxide (ZnO) nanowires with high density were successfully synthesized on nickel monoxide (NiO) catalyzed alumina substrate through a simple metal–vapor deposition method at an extremely low temperature (450 °C). The single-crystalline ZnO nanowires had a hexagonal wurzite structure and diameters of about 55 nm, and lengths up to 2.6 ?m. The photoluminescence spectra under excitation 325 nm

Seung Chul Lyu; Ye Zhang; Hyun Ruh; Hwack-Joo Lee; Hyun-Wook Shim; Eun-Kyung Suh; Cheol Jin Lee

2002-01-01

293

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

294

Transparent and conductive aluminum doped zinc oxide films prepared by mid-frequency reactive magnetron sputtering  

Microsoft Academic Search

In this study, aluminum doped zinc oxide films were prepared by reactive mid-frequency (MF) magnetron sputtering (Leybold TwinMagTM) at deposition rate of approx. 9 nm\\/s and substrate temperature of 100 to 300°C. Process stabilization in the metallic mode was performed by the control of plasma impedance due to adjustment of oxygen flow. Metallic Zn:Al targets with different aluminum content were

B. Szyszka

1999-01-01

295

Zinc protects HepG2 cells against the oxidative damage and DNA damage induced by ochratoxin A.  

PubMed

Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (??m). Meanwhile, the addition of the zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2'-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds. PMID:23391613

Zheng, Juanjuan; Zhang, Yu; Xu, Wentao; Luo, YunBo; Hao, Junran; Shen, Xiao Li; Yang, Xuan; Li, Xiaohong; Huang, Kunlun

2013-04-15

296

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

297

PEGylated silver doped zinc oxide nanoparticles as novel photosensitizers for photodynamic therapy against Leishmania.  

PubMed

We describe daylight responsive silver (Ag) doped semiconductor nanoparticles of zinc oxide (DSNs) for photodynamic therapy (PDT) against Leishmania. The developed materials were characterized by X-ray diffraction analysis (XRD), Rutherford backscattering (RBS), diffused reflectance spectroscopy (DRS), and band-gap analysis. The Ag doped semiconductor nanoparticles of zinc oxide were PEGylated to enhance their biocompatibility. The DSNs demonstrated effective daylight response in the PDT of Leishmania protozoans, through the generation of reactive oxygen species (ROS) with a quantum yield of 0.13 by nondoped zinc oxide nanoparticles (NDSN) whereas 0.28 by DSNs. None of the nanoparticles have shown any antileishmanial activity in dark, confirming that only ROS produced in the daylight were involved in the killing of leishmanial cells. Furthermore, the synthesized nanoparticles were found biocompatible. Using reactive oxygen species scavengers, cell death was attributable mainly to 77-83% singlet oxygen and 18-27% hydroxyl radical. The nanoparticles caused permeability of the cell membrane, leading to the death of parasites. Further, the uptake of nanoparticles by Leishmania cells was confirmed by inductively coupled plasma atomic emission spectroscopy (ICP-AES). We believe that these DSNs are widely applicable for the PDT of leishmaniasis, cancers, and other infections due to daylight response. PMID:25266330

Nadhman, Akhtar; Nazir, Samina; Ihsanullah Khan, Malik; Arooj, Syeda; Bakhtiar, Muhammad; Shahnaz, Gul; Yasinzai, Masoom

2014-12-01

298

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

299

Analysis of copper incorporation into zinc oxide nanowires.  

PubMed

ZnO nanowires (NWs) are grown on a bulk copper half-transmission electron microscopy grid by chemical vapor deposition in a high temperature tube furnace. Photoluminescence (PL) microscopy revealed band gap emission at 380 nm and a more intense visible emission around 520 nm due to defect states in these NWs. High-resolution transmission electron microscopy shows that the ZnO NWs are single crystalline with hexagonal structure. Auger electron spectroscopy (AES) and energy dispersive X-ray spectroscopy reveal that copper atoms are present along the length of the NW. AES also found that the surface of the NWs is oxygen rich. The surface concentration of zinc increases moving from the tip toward the base of the NW while the concentration of oxygen decreases. The copper in this system not only remains at the tip of the growing NW but also acts as a dopant along the length of the NW, leading to a decrease in the intensity of the band gap PL of these NWs. PMID:19206639

Eustis, Susie; Meier, Douglas C; Beversluis, Michael R; Nikoobakht, Babak

2008-02-01

300

Response of bioluminescent bacteria to sixteen azo dyes  

Microsoft Academic Search

Recombinant bioluminescent bacteria were used to monitor and classify the toxicity of azo dyes. Two constitutive bioluminescent\\u000a bacteria,Photobacterium phosphoreum andEscherichia coli, E. coli GC2 (lac::luxCDABE), were used to detect the cellular toxicity of the azo dyes. In addition, four stress-inducible bioluminescentE. coli, DPD2794 (recA::luxCDABE), a DNA damage sensitive strain; DPD2540 (fabA::luxCDABE), a membrane damage sensitive strain; DPD2511 (katG::luxCDABE), an oxidative

Hwa Young Lee; Sue Hyung Choi; Man Bock Gu

2003-01-01

301

Zinc Oxide Surge Arresters and HVDC 125kV-upgrade 500kV Converter Stations  

NASA Astrophysics Data System (ADS)

Gapless Metal (Zinc) Oxide Surge Arresters for a.c. systems contribute to the insulation co-ordination based on the suppression of lightning surges and switching surges. These gapless metal oxide surge arresters using ZnO elements are effective to HVDC systems. This paper describes basic characteristics of ZnO (zinc oxide) elements for d.c. systems and applications of gapless surge arresters to HVDC 125kV frequency converters, HVDC 250kV, upgrade HVDC 500kV converter stations, and HVDC 500kV cables of Japan through the experience of developments and applications of gapless metal oxide surge arresters.

Shirakawa, Shingo; Kobayashi, Takayuki; Matsushita, Yoshinao; Sakai, Takehisa; Suzuki, Hironori; Ozaki, Yuzo

302

Growth of Zinc Oxide Single Crystals by Vapor Phase Reaction  

Microsoft Academic Search

ZnO single crystals are grown by vapor phase reaction with ZnI2 source. When the growth region is maintained between 1150°C and 1200°C, crystals grow by oxidation, and between 970°C and 1020°C, by hydrolysis. Crystals are mainly needles 15 mm in length or plates 8 mm2 in area. Patterns suggesting their growth mechanisms are observed in their microphotographs. The present experiments

Masami Hirose

1971-01-01

303

Hydrogen as a Cause of Doping in Zinc Oxide  

Microsoft Academic Search

the prevailing conductivity of the material. This ampho- teric behavior precludes hydrogen from acting as a dopant, i.e., from being a source of conductivity. In ZnO, however, we find that hydrogen occurs exclusively in the positive charge state; i.e., it always acts as a donor. This opens up prospects for similar behavior in other oxides, in which hydrogen may be

Chris G. Van de Walle

2000-01-01

304

Routes to Novel Azo compounds   

E-print Network

Routes to novel heterocyclic azo compounds and components of use as potential inkjet dyes were investigated. A new route to fluorenones from biphenyl acid chlorides using FVP (Flash Vacuum Pyrolysis) has been discovered. ...

Iannarelli, Paul M.

305

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

306

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

307

High stability mechanisms of quinary indium gallium zinc aluminum oxide multicomponent oxide films and thin film transistors  

NASA Astrophysics Data System (ADS)

Quinary indium gallium zinc aluminum oxide (IGZAO) multicomponent oxide films were deposited using indium gallium zinc oxide (IGZO) target and Al target by radio frequency magnetron cosputtering system. An extra carrier transport pathway could be provided by the 3 s orbitals of Al cations to improve the electrical properties of the IGZO films, and the oxygen instability could be stabilized by the strong Al-O bonds in the IGZAO films. The electron concentration change and the electron mobility change of the IGZAO films for aging time of 10 days under an air environment at 40 °C and 75% humidity were 20.1% and 2.4%, respectively. The experimental results verified the performance stability of the IGZAO films. Compared with the thin film transistors (TFTs) using conventional IGZO channel layer, in conducting the stability of TFTs with IGZAO channel layer, the transconductance gm change, threshold voltage VT change, and the subthreshold swing S value change under the same aging condition were improved to 7.9%, 10.5%, and 14.8%, respectively. Furthermore, the stable performances of the IGZAO TFTs were also verified by the positive gate bias stress. In this research, the quinary IGZAO multicomponent oxide films and that applied in TFTs were the first studied in the literature.

Lee, Ching-Ting; Lin, Yung-Hao; Lin, Jhong-Ham

2015-01-01

308

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

309

Proteus mirabilis alleviates zinc toxicity by preventing oxidative stress in maize (Zea mays) plants.  

PubMed

Plant-associated bacteria can have beneficial effects on the growth and health of their host. However, the role of plant growth promoting bacteria (PGPR), under metal stress, has not been widely investigated. The present study investigated the possible mandatory role of plant growth promoting rhizobacteria in protecting plants from zinc (Zn) toxicity. The exposure of maize plants to 50µM zinc inhibited biomass production, decreased chlorophyll, total soluble protein and strongly increased accumulation of Zn in both root and shoot. Similarly, Zn enhanced hydrogen peroxide, electrolyte leakage and lipid peroxidation as indicated by malondaldehyde accumulation. Pre-soaking with novel Zn tolerant bacterial strain Proteus mirabilis (ZK1) isolated zinc (Zn) contaminated soil, alleviated the negative effect of Zn on growth and led to a decrease in oxidative injuries caused by Zn. Furthermore, strain ZK1 significantly enhanced the activities of catalase, guaiacol peroxidase, superoxide dismutase and ascorbic acid but lowered the Proline accumulation in Zn stressed plants. The results suggested that the inoculation of Zea mays plants with P. mirabilis during an earlier growth period could be related to its plant growth promoting activities and avoidance of cumulative damage upon exposure to Zn, thus reducing the negative consequences of oxidative stress caused by heavy metal toxicity. PMID:25240234

Islam, Faisal; Yasmeen, Tahira; Riaz, Muhammad; Arif, Muhammad Saleem; Ali, Shafaqat; Raza, Syed Hammad

2014-12-01

310

Pencil-like zinc oxide micro/nano-scale structures: Hydrothermal synthesis, optical and photocatalytic properties  

SciTech Connect

Graphical abstract: - Highlights: • Zinc oxide micro/nanopencils have been synthesized hydrothermally. • Photocatalytic activity has been evaluated by the degradation of methylene blue under UV light irradiation. • ZnO nanopencils exhibit much higher photocatalytic activity than the commercial ZnO. - Abstract: Zinc oxide micro/nanopencils have been successfully synthesized by hydrothermal process using zinc acetate and diamines as structure-directing agents. The morphology, the structure, the crystallinity and the composition of the materials were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The optical properties of synthesized ZnO were investigated by UV–vis spectroscopy. The photocatalytic activity of the material has been evaluated by the degradation of methylene blue under UV irradiation. As a result, after the lapse of 150 min, around 82% bleaching was observed, with ZnO nanopencils yielding more photodegradation compared to that of commercial ZnO (61%)

Moulahi, A. [Laboratoire de Chimie de la Matière Condensée, IPEIT, Université de Tunis, 2 rue Jawaher Lel Nehru 1008, B. P. 229 Montfleury (Tunisia); Sediri, F., E-mail: faouzi.sediri@ipeit.rnu.tn [Laboratoire de Chimie de la Matière Condensée, IPEIT, Université de Tunis, 2 rue Jawaher Lel Nehru 1008, B. P. 229 Montfleury (Tunisia); Faculté des Sciences de Tunis, Université de Tunis El Manar, 2092 El Manar (Tunisia)

2013-10-15

311

Effects of hydrogen adsorption on mechanical properties of chiral single-walled zinc oxide nanotubes  

NASA Astrophysics Data System (ADS)

Size- and chirality-dependent mechanical properties of single-walled zinc oxide nanotubes (ZnONTs) under four different states of hydrogen adsorption have been investigated in this paper. A molecular mechanics model is developed to derive analytical expressions for surface Young's modulus and Poisson's ratio of chiral hydrogenated ZnONTs (H-ZnONTs). On the basis of quantum mechanics, density functional theory (DFT) is utilized to obtain the force constants of molecular mechanics theory. Also, the values of surface Young's modulus, bending stiffness, Poisson's ratio, and atomic structure of a hydrogenated zinc oxide (H-ZnO) sheet associated with the four positions of adsorption are determined via the DFT calculations. The related results indicate that the bending stiffness of a H-ZnO sheet is chirality-independent. The present analysis provides the possibility of considering nanotubes with different types of chirality. It is indicated that, for all positions of hydrogen adsorption, the values of surface Young's modulus for armchair H-ZnONTs are higher than those of zigzag H-ZnONTs and the results of chiral H-ZnONTs are between the results of armchair and zigzag nanotubes. Also, the maximum stability happens when the hydrogen atoms are adsorbed on zinc and oxygen atoms at the two opposite sides of a ZnO sheet.

Mirnezhad, M.; Ansari, R.; Rouhi, H.

2012-01-01

312

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

PubMed Central

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

313

40 CFR 721.5930 - Phenylenebis[imino (chlorotriazinyl)imino(substituted naphthyl)azo(substituted phenyl)azo, sodium...  

Code of Federal Regulations, 2011 CFR

...azo(substituted phenyl)azo, sodium salt (generic name). 721.5930 Section...azo(substituted phenyl)azo, sodium salt (generic name). (a) Chemical substance...azo (substituted phenyl) azo, sodium salt (PMN P-95-274) is subject to...

2011-07-01

314

40 CFR 721.5930 - Phenylenebis[imino (chlorotriazinyl)imino(substituted naphthyl)azo(substituted phenyl)azo, sodium...  

Code of Federal Regulations, 2013 CFR

...azo(substituted phenyl)azo, sodium salt (generic name). 721.5930 Section...azo(substituted phenyl)azo, sodium salt (generic name). (a) Chemical substance...azo (substituted phenyl) azo, sodium salt (PMN P-95-274) is subject to...

2013-07-01

315

40 CFR 721.5930 - Phenylenebis[imino (chlorotriazinyl)imino(substituted naphthyl)azo(substituted phenyl)azo, sodium...  

Code of Federal Regulations, 2010 CFR

...azo(substituted phenyl)azo, sodium salt (generic name). 721.5930 Section...azo(substituted phenyl)azo, sodium salt (generic name). (a) Chemical substance...azo (substituted phenyl) azo, sodium salt (PMN P-95-274) is subject to...

2010-07-01

316

Fabrication of a TiO2-BDD heterojunction and its application as a photocatalyst for the simultaneous oxidation of an azo dye and reduction of Cr(VI).  

PubMed

A TiO2-boron doped diamond (TiO2-BDD) heterojunction was employed as a photocatalyst to simultaneously oxidize an azo dye C.I. reactive yellow 15 (RY15) and reduce hexavalent chromium (Cr(VI)). This heterojunction was fabricated first by depositing a BDD film on a Ti sheet in a hot filament chemical vapor deposition reactor, followed by covering a layer of TiO2 in a metal-organic chemical vapor deposition system. The morphology of this heterojunction was characterized by using a scanning electron microscope (SEM). X-ray diffraction (XRD), Raman spectroscopy, and current-voltage (I-V) measurement were used to characterize its structures. Additionally, the characterization of surface photovoltage showed that the TiO2-BDD heterojunction exhibited a higher photovoltage response and a better ability for charge separation than the photocatalyst of TiO2 directly deposited on a Ti sheet (TiO2-Ti). The photocatalytic experiments revealed that the kinetic constants for the oxidation of RY15 and the reduction of Cr(VI) were, respectively, increased by 85 and 71% when the photocatalyst of TiO2-Ti was replaced by the TiO2-BDD heterojunction. Meanwhile, a significant synergy was confirmed in the simultaneous oxidation of RY15 and reduction of Cr(VI). The enhanced photocatalytic ability of the TiO2-BDD composite could be attributed to the heterojunction. The possible photocatalytic mechanism was also discussed. PMID:18546724

Yu, Hongbin; Chen, Shuo; Quan, Xie; Zhao, Huimin; Zhang, Yaobin

2008-05-15

317

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

PubMed

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. PMID:23686093

Rajiv, P; Rajeshwari, Sivaraj; Venckatesh, Rajendran

2013-08-01

318

Cathodoluminescence of yttrium oxide and yttrium and zinc silicate films  

NASA Astrophysics Data System (ADS)

We have studied the cathodoluminescent properties of Y2SiO5:Ce, Zn2SiO4:Ti, Zn2SiO4:Mn, Y2O3:Eu thin films obtained by high-frequency magnetron sputtering. Based on measurements of the luminescence spectra, we have shown that the films can be used as luminophores with blue emission (Y2SiO5:Ce, Zn2SiO4:Ti), green emission (Zn2SiO4:Mn), and red emission (Y2O3:Eu). We have studied the dependences of the luminescence intensity on the energy of the exciting electrons, the electron beam current density, and the exposure time. We hypothesize that the decrease in the luminescence intensity during electron bombardment is connected with formation of new oxide layers as a result of an electron-stimulated surface chemical reaction.

Bordun, O. M.; Dovga, E. V.; Kukharskii, I. I.

2011-09-01

319

Morphological impact of zinc oxide layers on the device performance in thin-film transistors.  

PubMed

Zinc oxide thin-films are prepared either by spin coating of an ethanolic dispersion of nanoparticles (NP, diameter 5 nm) or by spray pyrolysis of a zinc acetate dihydrate precursor. High-resolution electron microscopy studies reveal a monolayer of particles for the low temperature spin coating approach and larger crystalline domains of more than 30 nm for the spray pyrolysis technique. Thin-film transistor devices (TFTs) based on spray pyrolysis films exhibit higher electron mobilities of up to 24 cm2 V(-1) s(-1) compared to 0.6 cm2 V(-1) s(-1) for NP based TFTs. These observations were dedicated to a reduced number of grain boundaries within the transistor channel. PMID:21116548

Faber, Hendrik; Klaumünzer, Martin; Voigt, Michael; Galli, Diana; Vieweg, Benito F; Peukert, Wolfgang; Spiecker, Erdmann; Halik, Marcus

2011-03-01

320

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

321

Gas evolution in a flow-assisted zinc-nickel oxide battery  

NASA Astrophysics Data System (ADS)

An experimental study on hydrogen and oxygen evolution was carried out in a sealed zinc-nickel oxide battery. The effects of flowing electrolyte on gas evolution were quantitatively evaluated. The results show that both the hydrogen and oxygen evolution are suppressed by making the electrolyte flow on a regular cycle. This is due to increased cell polarization in the non-flowing case attributed to the concentration boundary layer of zinc (zincate) ion near the anode surfaces. Though the Coulombic efficiency in the flowing case was higher than that in the non-flowing case, the fraction of gas evolution against Coulombic loss was the same for both the cases. When deeply discharging the cell, more hydrogen is evolved in the flowing case than in the non-flowing case.

Ito, Yasumasa; Nyce, Michael; Plivelich, Robert; Klein, Martin; Banerjee, Sanjoy

2011-08-01

322

Solvothermal synthesis of gallium-doped zinc oxide nanoparticles with tunable infrared absorption  

NASA Astrophysics Data System (ADS)

The doping of ZnO nanoparticles (NPs) has been attracting a lot of attention both for fundamental studies and potential applications. In this manuscript, we report the preparation of gallium doped zinc oxide (GZO) NPs through the solvothermal method. In order to obtain the effective Ga doping in the ZnO crystalline lattice, we identified the optimal reaction conditions in terms of different Zn precursors, temperature, and heating rate. The results show that GZO NPs with tunable infrared absorption can be received using different molar ratios of Ga(NO3)3 and zinc stearate (Zn[CH3(CH2)16COO]2, ZnSt2) kept in the sealed autoclaves at 160 °C for 8 h. Furthermore, the growth of the GZO NPs was investigated by monitoring the optical absorption spectral and the corresponding chemical composition of aliquots extracted at different reaction time intervals.

Zhou, Haifeng; Wang, Hua; Tian, Xingyou; Zheng, Kang; Xu, Fei; Su, Zheng; Tian, Konghu; li, Qiulong; Fang, Fei

2014-12-01

323

Effect of Supersaturation on the Growth of Zinc Oxide Nanostructured Films by Electrochemical Deposition  

SciTech Connect

The changes in crystal growth habit of electrodeposited zinc oxide with zinc nitrate concentration are explained by changes in the levels of saturation at the electrode. Three growth regimes are found between 0.5 and 50 mM. For concentrations less than 2 mM, the growth is one-dimensional. Nanorods grow by screw dislocations from the outside inward, no coalescence is observed, and their surface shows pyramid-like features. For concentrations above 20 mM, the growth is two-dimensional. Large levels of supersaturation favor the nucleation on the low indexes faces and large sheets are observed. In the intermediate regime of growth, the growth is pseudo three-dimensional. Nanorods with a conical ends grow initially before coalescing and forming dense films.

Illy, B.; Ingham, B; Ryan, M

2010-01-01

324

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

325

Description of industrial technology for production of active zinc oxide for production of sulfur purification catalysts  

SciTech Connect

Physicochemical and technological tests have shown that by means of sufficiently thorough chemical processing of various inactive feedstocks using ammonia-carbonate solutions (ACS's) it is possible to produce a finely divided zinc oxide with dispersity d/sub ZnO/ = 200 to 350 A and capacity of 30 to 32%. For example, muffle-furnace zinc oxide with d/sub ZnO/ = 1300 A and sulfur capacity of 2 to 3% can be used as such an inactive feedstock. A merit of this process is the possibility of setting up large-tonnage production with a closed cycle with regard to ammonia and practically without waste effluent or gaseous discharges. The process of production of active ZnO using ACS's consists of the following consecutive steps: chemical reaction of ACS components at 40 to 50/sup 0/C with the feedstock (ZnO, Zn(OH)/sub 2/), which is in the general case accompanied by partial dissolution of the feedstock with formation of Zn-ACS and partial reaction of ACS with the solid phase with separation of the corresponding salts; driving NH/sub 3/ and excess CO/sub 2/ and H/sub 2/O off at 80 to 100/sup 0/C with simultaneous precipitation of zinc salts from the Zn-ACS; thermal decomposition of the zinc salts at 320 to 400/sup 0/C. The process regimes in all steps must be such that at the end of the reactions finely divided salts have been produced, which makes it possible to produce finely divided ZnO upon thermal decomposition.

Dantsig, M.L.; Turcheninova, E.V.; Dantsig, G.A.; Sobolevsky, V.S.; Men'shov, V.N.; Zhavoronkov, V.V.; Kondrashchenko, T.A.; Ermina, Z.E.

1980-08-01

326

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

327

Inkjet printed ambipolar transistors and inverters based on carbon nanotube/zinc tin oxide heterostructures  

SciTech Connect

We report ambipolar field-effect transistors (FETs) consisting of inkjet printed semiconductor bilayer heterostructures utilizing semiconducting single-walled carbon nanotubes (SWCNTs) and amorphous zinc tin oxide (ZTO). The bilayer structure allows for electron transport to occur principally in the amorphous oxide layer and hole transport to occur exclusively in the SWCNT layer. This results in balanced electron and hole mobilities exceeding 2 cm{sup 2} V{sup ?1} s{sup ?1} at low operating voltages (<5?V) in air. We further show that the SWCNT-ZTO hybrid ambipolar FETs can be integrated into functional inverter circuits that display high peak gain (>10). This work provides a pathway for realizing solution processable, inkjet printable, large area electronic devices, and systems based on SWCNT-amorphous oxide heterostructures.

Kim, Bongjun; Jang, Seonpil; Dodabalapur, Ananth, E-mail: ananth.dodabalapur@engr.utexas.edu [Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758 (United States); Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Geier, Michael L.; Prabhumirashi, Pradyumna L. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Hersam, Mark C. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Department of Medicine, Northwestern University, Evanston, Illinois 60208 (United States)

2014-02-10

328

Molybdenum as a contact material in zinc tin oxide thin film transistors  

SciTech Connect

Amorphous oxide semiconductors are of increasing interest for a variety of thin film electronics applications. Here, the contact properties of different source/drain electrode materials to solution-processed amorphous zinc tin oxide (ZTO) thin-film transistors are studied using the transmission line method. The width-normalized contact resistance between ZTO and sputtered molybdenum is measured to be 8.7 ?-cm, which is 10, 20, and 600 times smaller than that of gold/titanium, indium tin oxide, and evaporated molybdenum electrodes, respectively. The superior contact formed using sputtered molybdenum is due to a favorable work function lineup, an insulator-free interface, bombardment of ZTO during molybdenum sputtering, and trap-assisted tunneling. The transfer length of the sputtered molybdenum/ZTO contact is 0.34??m, opening the door to future radio-frequency sub-micron molybdenum/ZTO thin film transistors.

Hu, W.; Peterson, R. L., E-mail: blpeters@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122 (United States)

2014-05-12

329

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

NASA Astrophysics Data System (ADS)

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.

Kim, Baek Hyun; Kwon, Jae W.

2014-03-01

330

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

331

Toxic effects of high concentrations of zinc oxide in the diet of the chick and laying hen  

Microsoft Academic Search

1. The effects of high dietary concentrations of zinc oxide on chicks and hens were studied in four experiments.2. Chicks given 2 000, 4 000 or 6 000 mg zinc\\/kg diet from 2 to 6 weeks of age grew poorly, many showing gizzard erosion and lesions of the exo?crine pancreas. Dissecting aneurysms occurred in a few birds receiving 6 000

W. A. Dewar; P. A. L. Wight; R. Anne Pearson; M. J. Gentle

1983-01-01

332

Zinc Deficiency Causes Oxidative Damage to Proteins Lipids and DNA in Rat Testes1'2'3  

Microsoft Academic Search

ABSTRACT To investigate the effects of zinc defi ciency on oxidative damage to testes proteins, lipids and DNA, weanling male rats were allowed free access to low (0.5 fzinc diets for 14 d. A third group was,restricted intake of the adequate Zn diet to the amount,consumed,by the low Zn diet-fed group. Compared with ad

Patricia L Oteiza; Katherine L Olin; Cesar G. Fraga

333

Low intracellular zinc induces oxidative DNA damage, disrupts p53, NFB, and AP1 DNA binding, and affects DNA repair in a rat glioma cell line  

Microsoft Academic Search

Approximately 10% of the U.S. population ingests <50% of the current recommended daily allowance for zinc. We investigate the effect of zinc deficiency on DNA damage, expression of DNA-repair enzymes, and downstream signaling events in a cell-culture model. Low zinc inhibited cell growth of rat glioma C6 cells and increased oxidative stress. Low intracellular zinc increased DNA single-strand breaks (comet

Emily Ho; Bruce N. Ames

2002-01-01

334

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

335

In-vitro antibacterial study of zinc oxide nanostructures on Streptococcus sobrinus  

NASA Astrophysics Data System (ADS)

Zinc oxide nanostructures were prepared using a pilot plant of zinc oxide boiling furnace. Generally, it produced two types of nanostructures different in morphology; one is rod-like shaped (ZnO-1) and a plate-like shape (ZnO-2). The properties of ZnO were studied by structural, optical and morphological using XRD, PL and FESEM respectively. The XRD patterns confirmed the wurtzite structures of ZnO with the calculated crystallite size of 41 nm (ZnO-1) and 42 nm (ZnO-2) using Scherrer formula. The NBE peaks were determined by photoluminescence spectra which reveal peak at 3.25 eV and 3.23 eV for ZnO-1 and ZnO-2 respectively. Prior to that, the morphologies for both ZnO-1 and ZnO-2 were demonstrated from FESEM micrographs. Subsequently the antibacterial study was conducted using in-vitro broth dilution technique towards a gram positive bacterium Streptococcus sobrinus (ATCC 33478) to investigate the level of antibacterial effect of zinc oxide nanostructures as antibacterial agent. Gradual increment of ZnO concentrations from 10-20 mM affected the inhibition level after twenty four hours of incubation. In conjunction with concentration increment of ZnO, the percentage inhibition towards Streptococcus sobrinus was also increased accordingly. The highest inhibition occurred at 20 mM of ZnO-1 and ZnO-2 for 98% and 77% respectively. It showed that ZnO has good properties as antibacterial agent and relevancy with data presented by XRD, PL and FESEM were determined.

Bakhori, Siti Khadijah Mohd; Mahmud, Shahrom; Ann, Ling Chuo; Sirelkhatim, Amna; Hasan, Habsah; Mohamad, Dasmawati; Masudi, Sam'an Malik; Seeni, Azman; Rahman, Rosliza Abd

2014-10-01

336

Evaluation of zinc oxide nanoparticles toxicity on marine algae chlorella vulgaris through flow cytometric, cytotoxicity and oxidative stress analysis.  

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 (ZnO NPs) was investigated in Marine algae Chlorella vulgaris (C. vulgaris). High zinc dissociation from ZnONPs, releasing ionic zinc in seawater, is a potential route for zinc assimilation and ZnONPs toxicity. To examine the mechanism of toxicity, C. vulgaris were treated with 50mg/L, 100mg/L, 200mg/L and 300mg/L ZnO NPs for 24h and 72h. The detailed cytotoxicity assay showed a substantial reduction in the viability dependent on dose and exposure. Further, flow cytometry revealed the significant reduction in C. vulgaris viable cells to higher ZnO NPs. Significant reductions in LDH level were noted for ZnO NPs at 300mg/L concentration. The activity of antioxidant enzyme superoxide dismutase (SOD) significantly increased in the C. vulgaris exposed to 200mg/L and 300mg/L ZnO NPs. The content of non-enzymatic antioxidant glutathione (GSH) significantly decreased in the groups with a ZnO NPs concentration of higher than 100mg/L. The level of lipid peroxidation (LPO) was found to increase as the ZnO NPs dose increased. The FT-IR analyses suggested surface chemical interaction between nanoparticles and algal cells. The substantial morphological changes and cell wall damage were confirmed through microscopic analyses (FESEM and CM). PMID:25483368

Suman, T Y; Radhika Rajasree, S R; Kirubagaran, R

2015-03-01

337

Sensor photoresponse of thin-film oxides of zinc and titanium to oxygen gas  

SciTech Connect

Response of steady-state photoconductivity to changes in oxygen partial pressure (10{sup {minus}3} to 1 atm) has been quantitatively studied in thin-film polycrystalline TiO{sub 2}:Nb and ZnO at 80--120 C. The magnitude of photoconductivity varied as a square root of illumination intensity regardless of oxygen pressure. Both materials showed fast response to oxygen, although in different pressure ranges. Zinc oxide was more sensitive to lower oxygen pressures while titanium dioxide worked better at pressures close to 1 atm.

Golego, N.; Studenikin, S.A.; Cocivera, M.

2000-04-01

338

Amorphous indium zinc oxide thin film transistors with poly-4-vinylphenol gate dielectric layers  

NASA Astrophysics Data System (ADS)

Thin film transistors (TFTs) with amorphous indium zinc oxide (a-IZO) as channel layers and poly-4-vinylphenol as dielectric layers were fabricated. Transmission curves show that the double-layer structure of the a-IZO layer and the poly-4-vinylphenol layer exhibits the antireflection effect. It was found that post heat-treatment at relatively low temperature will improve the electrical performance of the transistors. TFT devices with saturation mobility of 25.4 cm2 V-1 s-1, threshold voltage of 4.0 V, subthreshold swing value of 0.88 V/decade and current on/off ratio of 106 were obtained.

Pu, Haifeng; Li, Guifeng; Feng, Jiahan; Liu, Baoying; Zhang, Qun

2011-09-01

339

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

340

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

341

Gelatin-assisted hydrothermal synthesis of single crystalline zinc oxide nanostars and their photocatalytic properties.  

PubMed

Biotemplate-assisted approach is simple and friendly to the environment. With the assistance of gelatin as a soft biotemplate and a structure-directing agent, star-like zinc oxide (ZnO) nanostructures have been prepared by assembly of well-defined nanorods under hydrothermal conditions. Their morphology and structures were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The growth mechanism of the ZnO nanostars is also investigated. The as-prepared ZnO nanostars display high photocatalytic activity toward the degradation of methyl orange (MO) under ultraviolet (UV) irradiation. PMID:23664389

Fang, Ke-Ming; Wang, Zhen-Zhen; Zhang, Ming; Wang, Ai-Jun; Meng, Zi-Yan; Feng, Jiu-Ju

2013-07-15

342

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

343

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

344

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

345

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

346

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

347

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

348

Surface nanostructuring by ion-induced localized plasma expansion in zinc oxide  

SciTech Connect

Creation of hillock-like nanostructures on the surface of zinc oxide single crystals by irradiation with slow highly charged ions is reported. At constant kinetic energy, the nanostructures were only observed after irradiation with ions of potential energies above a threshold between 19.1?keV and 23.3?keV. The size of the nanostructures increases as a function of potential energy. A plasma expansion approach is used to explain the nanostructures creation. The calculations showed that the surface nanostructures became taller with the increase of ionic temperature. The influence of charged cluster formation and the relevance of their polarity are discussed.

El-Said, A. S., E-mail: elsaid@kfupm.edu.sa, E-mail: a.s.el-said@hzdr.de [Physics Department, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia); Institute of Ion Beam Physics and Materials Research, Helmholtz-Zentrum Dresden-Rossendorf (HZDR), 01328 Dresden (Germany); Physics Department, Faculty of Science, Mansoura University, 35516 Mansoura (Egypt); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Centre for Theoretical Physics, British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt); Djebli, M. [Theoretical Physics Laboratory, Faculty of Physics USTHB, B.P. 32 Bab Ezzour, 16079 Algiers (Algeria)

2014-06-09

349

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

350

Improvement by Laser Annealing for Transparent Conducting Zinc Oxide Films Deposited on Plastic Substrate  

NASA Astrophysics Data System (ADS)

Gallium-doped zinc oxide (GZO) thin films have been deposited on Cyclo-Olefin Polymer (COP) substrates at room temperature by pulsed laser deposition (PLD) using FHG of Nd: YAG laser (?=266 nm, 1.6 mJ/cm2) and then, thin films were annealed by pulsed laser with FHG of Nd: YAG laser (?=266 nm, 8~20 mJ/cm2) at room temperature. As a result, the resistivity was improved from 6.61×10-4 ?·cm to 5.94×10-4 ?·cm for films annealed at a laser energy density of 12 mJ/cm2.

Kaminishi, Toshimichi; Aoki, Takanori; Matsushita, Tatsuhiko; Suzuki, Akio; Okuda, Masahiro

351

Fabrication of inverted zinc oxide photonic crystal using sol–gel solution by spin coating method  

PubMed Central

Inverted zinc oxide photonic crystal structures were fabricated from polystyrene sphere (PSS) template using the sol–gel solution of ZnO by spin-coating method. It is easily able to control and fabricate the photonic crystal structures using the self-organized PSS with a size of 193 nm. The inverted ZnO photonic crystal structures observed show the (111) tendency of the hexagonal compact arrangement formation. The resulting structures possess the photonic band gaps in the near-ultraviolet range and exhibit an enhanced photoluminescence spectrum. The technology can effectively increase the light output intensity or efficiency for the applications of optoelectronic devices. PMID:23819709

2013-01-01

352

Novel diluted magnetic semiconductor materials based on zinc oxide  

NASA Astrophysics Data System (ADS)

The primary aim of this work was to develop a ZnO based diluted magnetic semiconductor (DMS) materials system which displays ferromagnetism above room temperature and to understand the origin of long-range ferromagnetic ordering in these systems. Recent developments in the field of spintronics (spin based electronics) have led to an extensive search for materials in which semiconducting properties can be integrated with magnetic properties to realize the objective of successful fabrication of spin-based devices. For these devices we require a high efficiency of spin current injection at room temperature. Diluted magnetic semiconductors (DMS) can serve this role, but they should not only display room temperature ferromagnetism (RTFM) but also be capable of generating spin polarized carriers. Transition metal doped ZnO has proved to be a potential candidate as a DMS showing RTFM. The origin of ferromagnetic ordering in ZnO is still under debate. However, the presence of magnetic secondary phases, composition fluctuations and nanoclusters could also explain the observation of ferromagnetism in the DMS samples. This encouraged us to investigate Cu-doped(+ spin in the 2+ valence state) ZnO system as a probable candidate exhibiting RTFM because neither metallic Cu nor its oxides (Cu2O or CuO) are ferromagnetic. The role of defects and free carriers on the ferromagnetic ordering of Cu-doped ZnO thin films was studied to ascertain the origin of ferromagnetism in this system. A novel non-equilibrium Pulsed Laser Deposition technique has been used to grow high quality epitaxial thin films of Cu:ZnO and (Co,Cu):ZnO on c-plane Sapphire by domain matching epitxay. Both the systems showed ferromagnetic ordering above 300K but Cu ions showed a much stronger ferromagnetic ordering than Co, especially at low concentrations (1-2%) of Cu where we realized near 100% polarization. But, the incorporation of Cu resulted in a 2-order of magnitude rise in the resistivity from 10-1 to 101 Ohm cm which can prove to be detrimental to the injection of polarized electrons. In order to decrease the resistivity and to understand the role of free carriers in mediating the ferromagnetic ordering, the Cu-doped ZnO films were co-doped with an n-type dopant like Al which increased the free carriers concentration by 3 orders of magnitude from 1017 to 1020 cm -3 without significantly altering the near 100% spin polarization in the Cu:ZnO system. This lack of correlation between free carrier concentration and the magnetic moment implied that a free carrier mediated exchange does not stabilize the long range ferromagnetic ordering. A reduction in the number of oxygen vacancies brought about by high temperature oxygen annealing had a large degrading effect on the ferromagnetism by reducing the total saturation magnetization by almost an order of magnitude. This strong dependence of magnetization on vacancy concentration and the corresponding weak relationship with free carriers pointed towards a defect mediated mechanism, such as a bound magnetic polaron mediated exchange as being responsible for stabilizing the ferromagnetic ordering in these systems. However, a BMP mechanism would not guarantee a strong coupling between the free carriers and the localized spins to produce spin-polarized current. To investigate this we have fabricated spin valve type device structures where a nonmagnetic ZnO layer was sandwiched between two ferromagnetic (Cu,Al):ZnO layers allowing us to study spin polarized carrier injection across the nonmagnetic semiconductor gap. Initial results have shown evidence of spin polarized carrier injection across the nonmagnetic semiconductor layer even at 300K. Hence, this work demonstrates that the (Cu,Al):ZnO system may become a viable solution for spin injection into spintronic devices.

Chakraborti, Deepayan

353

Deposition of boron doped zinc oxide films and their electrical and optical properties  

NASA Astrophysics Data System (ADS)

Boron doped zinc oxide films were deposited by atmospheric-pressure CVD in a laminar flow reactor from diethyl zinc, tert-butanol, and diborane in the temperature range from 300 to 420 C. When the deposition temperature was above 320 C, both doped and undoped films have highly oriented crystallites with their c-axes perpendicular to the substrate plane. Films deposited from 0.07 percent diethyl zinc and 2.4 percent tert-butanol have electron densities from 3.5 to 5.5 x 10 exp 20/cu cm, conductivities from 250 to 2500/ohm per cm, and mobilities from 2.5 to 35.0 sq cm/V-s, depending on dopant concentration, film thickness, and deposition temperature. Optical measurements show that the maximum infrared reflectance of the doped films is close to 90 percent, compared to about 20 percent for undoped films. Visible absorption and conductivity were found to increase with thickness. The ratio of conductivity to visible absorption coefficient for doped films was from 0.1 to 1.1/ohm. The bandgap of the film changes from 3.3 to 3.7 eV when the film is doped with 0.012-percent diborane.

Hu, Jianhua; Gordon, Roy G.

1992-07-01

354

Analysis of indium zinc oxide thin films by laser-induced breakdown spectroscopy  

SciTech Connect

We have performed spectroscopic analysis of the plasma generated by Nd:YAG ({lambda} = 266 nm) laser irradiation of thin indium zinc oxide films with variable In content deposited by combinatorial pulsed laser deposition on glass substrates. The samples were irradiated in 5 x 10{sup 4} Pa argon using laser pulses of 5 ns duration and 10 mJ energy. The plasma emission spectra were recorded with an Echelle spectrometer coupled to a gated detector with different delays with respect to the laser pulse. The relative concentrations of indium and zinc were evaluated by comparing the measured spectra to the spectral radiance computed for a plasma in local thermal equilibrium. Plasma temperature and electron density were deduced from the relative intensities and Stark broadening of spectral lines of atomic zinc. Analyses at different locations on the deposited thin films revealed that the In/(In + Zn) concentration ratio significantly varies over the sample surface, from 0.4 at the borders to about 0.5 in the center of the film. The results demonstrate that laser-induced breakdown spectroscopy allows for precise and fast characterization of thin films with variable composition.

Popescu, A. C. [LP3, CNRS - Universite Aix-Marseille, 163 Ave. de Luminy, Marseille 13288 (France); National Institute for Lasers, Plasma and Radiation Physics, Magurele, Ilfov 077125 (Romania); Beldjilali, S. [LP3, CNRS - Universite Aix-Marseille, 163 Ave. de Luminy, Marseille 13288 (France); LPPMCA, Universite des Sciences et de la Technologie d'Oran, BP 1505 El Mnaouer, Oran (Algeria); Socol, G.; Mihailescu, I. N. [National Institute for Lasers, Plasma and Radiation Physics, Magurele, Ilfov 077125 (Romania); Craciun, V. [National Institute for Lasers, Plasma and Radiation Physics, Magurele, Ilfov 077125 (Romania); MAIC, University of Florida, Gainesville, FL 32611 (United States); Hermann, J. [LP3, CNRS - Universite Aix-Marseille, 163 Ave. de Luminy, Marseille 13288 (France)

2011-10-15

355

Sensing behaviour of nanosized zinc-tin composite oxide towards liquefied petroleum gas and ethanol  

SciTech Connect

A chemical route has been used to synthesize composite oxides of zinc and tin. An ammonia solution was added to equal amounts of zinc and tin chloride solutions of same molarities to obtain precipitates. Three portions of these precipitates were annealed at 400, 600 and 800 {sup o}C, respectively. Results of X-ray diffraction and transmission electron microscopy clearly depicted coexistence of phases of nano-sized SnO{sub 2}, ZnO, Zn{sub 2}SnO{sub 4} and ZnSnO{sub 3}. The effect of annealing on structure, morphology and sensing has been observed as well. It has been observed that annealing promoted growth of Zn{sub 2}SnO{sub 4} and ZnSnO{sub 3} at the expense of zinc. The sensing response of fabricated sensors from these materials to 250 ppm LPG and ethanol has been investigated. The sensor fabricated from powder annealed at 400 {sup o}C responded better to LPG than ethanol.

Singh, Ravi Chand, E-mail: ravichand.singh@gmail.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005, Punjab (India); Singh, Onkar, E-mail: garhikang@gmail.com [Department of Physics, Guru Nanak Dev University, Amritsar 143005, Punjab (India)] [Department of Physics, Guru Nanak Dev University, Amritsar 143005, Punjab (India); Singh, Manmeet Pal [Khalsa College of Engineering and Technology, Amritsar 143001, Punjab (India)] [Khalsa College of Engineering and Technology, Amritsar 143001, Punjab (India); Chandi, Paramdeep Singh [Indian Institute of Science Education and Research, Mohali, Chandigarh 160019 (India)] [Indian Institute of Science Education and Research, Mohali, Chandigarh 160019 (India); Thangaraj, R. [Department of Applied Physics, Guru Nanak Dev University, Amritsar 143005, Punjab (India)] [Department of Applied Physics, Guru Nanak Dev University, Amritsar 143005, Punjab (India)

2010-09-15

356

Role of quercetin and arginine in ameliorating nano zinc oxide-induced nephrotoxicity in rats  

PubMed Central

Background Nanoparticles are small-scale substances (<100?nm) with unique properties. Therefore, nanoparticles pose complex health risk implications. The objective of this study was to detect whether treatment with quercetin (Qur) and/or arginine (Arg) ameliorated nephrotoxicity induced by two different doses of nano zinc oxide (n-ZnO) particles. Method ZnO nanoparticles were administered orally in two doses (either 600?mg or 1?g/Kg body weight/day for 5 conscutive days) to Wister albino rats. In order to detect the protective effects of the studied antioxidants against n-ZnO induced nepherotoxicity, different biochemical parameters were investigated. Moreover, histopathological examination of kidney tissue was performed. Results Nano zinc oxide-induced nephrotoxicity was confirmed by the elevation in serum inflammatory markers including: tumor necrosis factor alpha (TNF-?), interleukin-6 (IL-6); and C-reactive protein (CRP). Moreover, immunoglobulin (IGg), vascular endothelium growth factor (VEGF), and nitric oxide (NO) were significantly increased in rat serum. Serum urea and creatinine levels were also significantly increased in rats intoxicated with n-ZnO particles compared with the control group. Additionally, a significant decrease in the non-enzymatic antioxidant reduced glutathione (GSH) was shown in kidney tissues and serum glucose levels were increased. These biochemical findings were supported by a histopathological examination of kidney tissues, which showed that in the animals that received a high dose of n-ZnO, numerous kidney glomeruli underwent atrophy and fragmentation. Moreover, the renal tubules showed epithelial desquamation, degeneration and necrosis. Some renal tubules showed casts in their lumina. Severe congestion was also observed in renal interstitium. These effects were dose dependent. Cotreatment of rats with Qur and/or Arg along with n-ZnO significantly improved most of the deviated tested parameters. Conclusions The data show that Qur has a beneficial effect against n-ZnO oxidative stress and related vascular complications. Also, its combination with Arg proved to be even more effective in ameliorating nano zinc oxide nephrotoxicity. PMID:22551254

2012-01-01

357

Dual operation characteristics of resistance random access memory in indium-gallium-zinc-oxide thin film transistors  

SciTech Connect

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; Chen, Yu-Ting; Chu, Ann-Kuo [Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Chang, Ting-Chang, E-mail: tcchang@mail.phys.nsysu.edu.tw [Department of Photonics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Advanced Optoelectronics Technology Center, National Cheng Kung University, Taiwan (China); Huang, Jheng-Jie; Chen, Yu-Chun; Tseng, Hsueh-Chih [Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Sze, Simon M. [Department of Physics, National Sun Yat-Sen University, Kaohsiung, Taiwan (China); Department of Electronics Engineering, National Chiao Tung University, Hsinchu, Taiwan (China)

2014-04-14

358

Origin of deep subgap states in amorphous indium gallium zinc oxide: Chemically disordered coordination of oxygen  

NASA Astrophysics Data System (ADS)

The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

Sallis, S.; Butler, K. T.; Quackenbush, N. F.; Williams, D. S.; Junda, M.; Fischer, D. A.; Woicik, J. C.; Podraza, N. J.; White, B. E.; Walsh, A.; Piper, L. F. J.

2014-06-01

359

Hydrogen plasma treatment for improved conductivity in amorphous aluminum doped zinc tin oxide thin films  

SciTech Connect

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 (H{sub 2})-plasma post-deposition treatment improves the conductivity of amorphous aluminum-doped zinc tin oxide while retaining its low optical absorption. We found that the H{sub 2}-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., E-mail: monica.moralesmasis@epfl.ch; Ding, L.; Dauzou, F. [Photovoltaics and Thin-Film Electronics Laboratory (PVLab), Institute of Microengineering (IMT), Ecole Polytechnique Fédérale de Lausanne - EPFL, Rue de la Maladière 71b, CH-2002 Neuchatel (Switzerland); Jeangros, Q. [Interdisciplinary Centre for Electron Microscopy, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne (Switzerland); Hessler-Wyser, A. [Photovoltaics and Thin-Film Electronics Laboratory (PVLab), Institute of Microengineering (IMT), Ecole Polytechnique Fédérale de Lausanne - EPFL, Rue de la Maladière 71b, CH-2002 Neuchatel (Switzerland); Interdisciplinary Centre for Electron Microscopy, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne (Switzerland); Nicolay, S. [Centre Suisse d’Electronique et de Microtechnique (CSEM) SA, Rue Jaquet-Droz 1, CH-2002 Neuchatel (Switzerland); Ballif, C. [Photovoltaics and Thin-Film Electronics Laboratory (PVLab), Institute of Microengineering (IMT), Ecole Polytechnique Fédérale de Lausanne - EPFL, Rue de la Maladière 71b, CH-2002 Neuchatel (Switzerland); Centre Suisse d’Electronique et de Microtechnique (CSEM) SA, Rue Jaquet-Droz 1, CH-2002 Neuchatel (Switzerland)

2014-09-01

360

Inkjet-printed zinc-tin-oxide TFTs with a solution-processed hybrid dielectric layer  

NASA Astrophysics Data System (ADS)

Sol-gel TiO2 was synthesized and used as a gate dielectric for oxide thin-film transistors (TFTs). A hybrid gate insulator composed of sol-gel TiO2/thermally-grown SiO2 was applied to the inkjet-printed zinc-tin oxide (ZTO) TFTs for the first time. The electrical properties of an inkjet-printed ZTO TFT with a hybrid gate insulator show a mobility of 0.17 cm2/Vs, an on-to-off current ratio of 5 × 104, a subthreshold slope of 0.8 V/dec, and a threshold voltage of 0.6 V. The hybrid gate insulator for the inkjet-printed ZTO TFT shows a much improved operating voltage and subthreshold slope and a lower mobility compared to the SiO2 gate insulator.

Jang, Hye-Ryun; Kwack, Young-Jin; Choi, Woon-Seop

2014-11-01

361

Origin of deep subgap states in amorphous indium gallium zinc oxide: Chemically disordered coordination of oxygen  

SciTech Connect

The origin of the deep subgap states in amorphous indium gallium zinc oxide (a-IGZO), whether intrinsic to the amorphous structure or not, has serious implications for the development of p-type transparent amorphous oxide semiconductors. We report that the deep subgap feature in a-IGZO originates from local variations in the oxygen coordination and not from oxygen vacancies. This is shown by the positive correlation between oxygen composition and subgap intensity as observed with X-ray photoelectron spectroscopy. We also demonstrate that the subgap feature is not intrinsic to the amorphous phase because the deep subgap feature can be removed by low-temperature annealing in a reducing environment. Atomistic calculations of a-IGZO reveal that the subgap state originates from certain oxygen environments associated with the disorder. Specifically, the subgap states originate from oxygen environments with a lower coordination number and/or a larger metal-oxygen separation.

Sallis, S.; Williams, D. S. [Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States); Butler, K. T.; Walsh, A. [Center for Sustainable Technologies and Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Quackenbush, N. F. [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Junda, M.; Podraza, N. J. [Department of Physics and Astronomy, University of Toledo, Toledo, Ohio 43606 (United States); Fischer, D. A.; Woicik, J. C. [Materials Science and Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); White, B. E.; Piper, L. F. J., E-mail: lpiper@binghamton.edu [Department of Physics, Applied Physics, and Astronomy, Binghamton University, Binghamton, New York 13902 (United States); Materials Science and Engineering, Binghamton University, Binghamton, New York 13902 (United States)

2014-06-09

362

Synchrotron Speciation of Silver and Zinc Oxide Nanoparticles Aged in a Kaolin Suspension  

SciTech Connect

Assessments of the environmental fate and mobility of nanoparticles must consider the behavior of nanoparticles in relevant environmental systems that may result in speciation changes over time. Environmental conditions may act on nanoparticles to change their size, shape, and surface chemistry. Changing these basic characteristics of nanoparticles may result in a final reaction product that is significantly different than the initial nanomaterial. As such, basing long-term risk and toxicity on the initial properties of a nanomaterial may lead to erroneous conclusions if nanoparticles change upon release to the environment. The influence of aging on the speciation and chemical stability of silver and zinc oxide nanoparticles in kaolin suspensions was examined in batch reactors for up to 18 months. Silver nanoparticles remained unchanged in sodium nitrate suspensions; however, silver chloride was identified with the metallic silver nanoparticles in sodium chloride suspensions and may be attributed to an in situ silver chloride surface coating. Zinc oxide nanoparticles were rapidly converted via destabilization/dissolution mechanisms to Zn{sup 2+} inner-sphere sorption complexes within 1 day of reaction and these sorption complexes were maintained through the 12 month aging processes. Chemical and physical alteration of nanomaterials in the environment must be examined to understand fate, mobility, and toxicology.

Scheckel, Kirk G.; Luxton, Todd P.; El Badawy, Amro M.; Impellitteri, Christopher A.; Tolaymat, Thabet M. (EPA); (UCIN)

2010-07-23

363

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

364

Solvothermal synthesis of gallium-indium-zinc-oxide nanoparticles for electrolyte-gated transistors.  

PubMed

Solution-processed field-effect transistors are strategic building blocks when considering low-cost sustainable flexible electronics. Nevertheless, some challenges (e.g., processing temperature, reliability, reproducibility in large areas, and cost effectiveness) are requirements that must be surpassed in order to achieve high-performance transistors. The present work reports electrolyte-gated transistors using as channel layer gallium-indium-zinc-oxide nanoparticles produced by solvothermal synthesis combined with a solid-state electrolyte based on aqueous dispersions of vinyl acetate stabilized with cellulose derivatives, acrylic acid ester in styrene and lithium perchlorate. The devices fabricated using this approach display a ION/IOFF up to 1 × 10(6), threshold voltage (VTh) of 0.3-1.9 V, and mobility up to 1 cm(2)/(V s), as a function of gallium-indium-zinc-oxide ink formulation and two different annealing temperatures. These results validates the usage of electrolyte-gated transistors as a viable and promising alternative for nanoparticle based semiconductor devices as the electrolyte improves the interface and promotes a more efficient step coverage of the channel layer, reducing the operating voltage when compared with conventional dielectrics gating. Moreover, it is shown that by controlling the applied gate potential, the operation mechanism of the electrolyte-gated transistors can be modified from electric double layer to electrochemical doping. PMID:25517251

Santos, Lídia; Nunes, Daniela; Calmeiro, Tomás; Branquinho, Rita; Salgueiro, Daniela; Barquinha, Pedro; Pereira, Luís; Martins, Rodrigo; Fortunato, Elvira

2015-01-14

365

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

366

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

367

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, Jürgen

2014-01-01

368

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

369

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

370

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

371

Properties of Transparent Conductive Zinc Oxide Films Deposited on COP Substrates by PLD Method  

NASA Astrophysics Data System (ADS)

The Al-doped ZnO (AZO) films and ZnO buffer layer were deposited on cyclo-olefin polymer (COP) substrates by pulsed laser deposition (PLD) method using ArF excimer laser (? = 193 nm) with an energy densities of 1.0 ? 2.5 J/cm2. Film structure was composed of a 150 nm-thick AZO film, a 100 nm-thick ZnO buffer layer, and a 188 ?m-thick COP substrate. As a result, in the range of 1.0 ? 2.5 J/cm2, Hall mobility and carrier concentration were found to decrease linerly. Therefore, the lowest resistivity of 2.77×10-4 ?-cm was obtained at laser energy density of 1.0 J/cm2. By the results of FE-SEM photograph and AFM image of a AZO / ZnO / COP structure deposited at a laser energy density of 1.0 J/cm2, it was found that smooth-surface-films with average roughness of 4.26 nm and AZO / ZnO films of good quality without cracked or flaked conditions were obtained. This will enables us to realize low-cost, lightweight, and flexible devices.

Ueno, Yuki; Aoki, Takanori; Suzuki, Akio; Matsushita, Tatsuhiko; Okuda, Masahiro

372

Sol-Gel Zinc Oxide Humidity Sensors Integrated with a Ring Oscillator Circuit On-a-Chip  

PubMed Central

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

373

Antimicrobial Efficacy of Zinc Oxide Quantum Dots Against Listeria Monocytogenes, Salmonella Enteritidis and Escherichia coli O157:H7  

Technology Transfer Automated Retrieval System (TEKTRAN)

Zinc oxide quantum dots (ZnO QDs) in a powder form, a ZnO-polystyrene (PS) film form and a polyvinylprolidone capped ZnO (ZnO-PVP) gel form were prepared and their antibacterial activities against foodborne pathogenic Listeria monocytogenes, Salmonella Enteritidis and Escherichia coli O157:H7 in cul...

374

Human Skin Penetration of Sunscreen Nanoparticles: In-vitro Assessment of a Novel Micronized Zinc Oxide Formulation  

Microsoft Academic Search

The extent to which topically applied solid nanoparticles can penetrate the stratum corneum and access the underlying viable epidermis and the rest of the body is a great potential safety concern. Therefore, human epidermal penetration of a novel, transparent, nanoparticulate zinc oxide sunscreen formulation was determined using Franz-type diffusion cells, 24-hour exposure and an electron microscopy to verify the location

Sheree E. Cross; Brian Innes; Michael S. Roberts; Takuya Tsuzuki; Terry A. Robertson; Paul McCormick

2007-01-01

375

Preparation of magnetic and bioactive calcium zinc iron silicon oxide composite for hyperthermia treatment of bone cancer  

E-print Network

Preparation of magnetic and bioactive calcium zinc iron silicon oxide composite for hyperthermia]. Therefore hyperthermia at between 43 and 45°C is expected to be one of the most useful treatments of bone, the hyperthermia treatment can be classified as microwave thermotherapy, RF thermotherapy, ultrasonic thermotherapy

Qin, Qinghua

376

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

377

Influence of the semiconductor thickness on the electrical properties of transparent TFTs based on indium zinc oxide  

Microsoft Academic Search

Multicomponent amorphous oxides are starting to emerge as a class of appealing semiconductor materials for application in transparent electronics. In this work, a high performance bottom-gate n-type transparent thin-film transistors are reported, being the discussion primarily focused on the influence of the indium zinc oxide active layer thickness on the properties of the devices. For this purpose, transparent transistors with

P. Barquinha; A. Pimentel; A. Marques; L. Pereira; R. Martins; E. Fortunato

2006-01-01

378

Characterization of precursors of methanol synthesis catalysts, copper\\/zinc\\/aluminum oxides, precipitated at different pHs and temperatures  

Microsoft Academic Search

Catalyst precursors for copper\\/zinc aluminum mixed oxide catalysts with an atomic ratio of 6\\/3\\/1 were prepared by co-current precipitation at different pH levels and different temperatures. The precursors, catalysts and reduced catalysts were characterized by means of infrared spectroscopy, X-ray diffraction, thermal analysis, temperature-programmed oxidation and BET surface measurements. The catalysts were also tested for methanol synthesis activity in a

J.-L. Li; T. Inui

1996-01-01

379

Structural, optical and electrical properties of zinc oxide thin films deposited by a spray pyrolysis technique  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin films were deposited on glass substrates by spray pyrolysis technique decomposition of zinc acetate dihydrate in an ethanol solution with 30 mL of deposition rate, the ZnO thin films were deposited at two different temperatures: 300 and 350 °C. The substrates were heated using the solar cells method. The substrate was R217102 glass, whose size was 30 × 17.5 × 1 mm3. The films exhibit a hexagonal wurtzite structure with a strong (002) preferred orientation. The higher value of crystallite size is attained for sprayed films at 350 °C, which is probably due to an improvement of the crystallinity of the films at this point. The average transmittance of obtain films is about 90%–95%, as measured by a UV—vis analyzer. The band gap energy varies from 3.265 to 3.294 eV for the deposited ZnO thin film at 300 and 350 °C, respectively. The electrical resistivity measured of our films are in the order 0.36 ?·cm.

Aoun, Yacine; Benhaoua, Boubaker; Gasmi, Brahim; Benramache, Said

2015-01-01

380

Zinc(II) oxide solubility and phase behavior in aqueous sodium phosphate solutions at elevated temperatures  

SciTech Connect

A platinum-lined, flowing autoclave facility is used to investigate the solubility/phase behavior of zinc(II) oxide in aqueous sodium phosphate solutions at temperatures between 290 and 560 K. ZnO solubilities are observed to increase continuously with temperature and phosphate concentration. At higher phosphate concentrations, a solid phase transformation to NaZnPO{sub 4} is observed. NaZnPO{sub 4} solubilities are retrograde with temperature. The measured solubility behavior is examined via a Zn(II) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reaction equilibria are obtained from a least-squares analysis of the data. The existence of two new zinc(II) ion complexes is reported for the first time: Zn(OH){sub 2}(HPO{sub 4}){sup 2{minus}} and Zn(OH){sub 3}(H{sub 2}PO{sub 4}){sup 2{minus}}. A summary of thermochemical properties for species in the systems ZnO-H{sub 2}O and ZnO-Na{sub 2}O-P{sub 2}O{sub 5}-H{sub 2}O is also provided. 21 refs., 10 figs., 7 tabs.

Ziemniak, S.E.; Jones, M.E.; Combs, K.E.S.

1990-02-01

381

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

382

Structure-property-composition relationships in doped zinc oxides: enhanced photocatalytic activity with rare Earth dopants.  

PubMed

In this paper, we demonstrate the use of continuous hydrothermal flow synthesis (CHFS) technology to rapidly produce a library of 56 crystalline (doped) zinc oxide nanopowders and two undoped samples, each with different particle properties. Each sample was produced in series from the mixing of an aqueous stream of basic zinc nitrate (and dopant ion or modifier) solution with a flow of superheated water (at 450 °C and 24.1 MPa), whereupon a crystalline nanoparticle slurry was rapidly formed. Each composition was collected in series, cleaned, freeze-dried, and then characterized using analytical methods, including powder X-ray diffraction, transmission electron microscopy, Brunauer-Emmett-Teller surface area measurement, X-ray photoelectron spectroscopy, and UV-vis spectrophotometry. Photocatalytic activity of the samples toward the decolorization of methylene blue dye was assessed, and the results revealed that transition metal dopants tended to reduce the photoactivity while rare earth ions, in general, increased the photocatalytic activity. In general, low dopant concentrations were more beneficial to having greater photodecolorization in all cases. PMID:25602735

Goodall, Josephine B M; Illsley, Derek; Lines, Robert; Makwana, Neel M; Darr, Jawwad A

2015-02-01

383

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

384

Face-selective electrostatic control of hydrothermal zinc oxide nanowire synthesis  

NASA Astrophysics Data System (ADS)

Rational control over the morphology and the functional properties of inorganic nanostructures has been a long-standing goal in the development of bottom-up device fabrication processes. We report that the geometry of hydrothermally grown zinc oxide nanowires can be tuned from platelets to needles, covering more than three orders of magnitude in aspect ratio (~0.1-100). We introduce a classical thermodynamics-based model to explain the underlying growth inhibition mechanism by means of the competitive and face-selective electrostatic adsorption of non-zinc complex ions at alkaline conditions. The performance of these nanowires rivals that of vapour-phase-grown nanostructures, and their low-temperature synthesis (<60?°C) is favourable to the integration and in situ fabrication of complex and polymer-supported devices. We illustrate this capability by fabricating an all-inorganic light-emitting diode in a polymeric microfluidic manifold. Our findings indicate that electrostatic interactions in aqueous crystal growth may be systematically manipulated to synthesize nanostructures and devices with enhanced structural control.

Joo, Jaebum; Chow, Brian Y.; Prakash, Manu; Boyden, Edward S.; Jacobson, Joseph M.

2011-08-01

385

Face-selective electrostatic control of hydrothermal zinc oxide nanowire synthesis.  

PubMed

Rational control over the morphology and the functional properties of inorganic nanostructures has been a long-standing goal in the development of bottom-up device fabrication processes. We report that the geometry of hydrothermally grown zinc oxide nanowires can be tuned from platelets to needles, covering more than three orders of magnitude in aspect ratio (~0.1-100). We introduce a classical thermodynamics-based model to explain the underlying growth inhibition mechanism by means of the competitive and face-selective electrostatic adsorption of non-zinc complex ions at alkaline conditions. The performance of these nanowires rivals that of vapour-phase-grown nanostructures, and their low-temperature synthesis (<60 °C) is favourable to the integration and in situ fabrication of complex and polymer-supported devices. We illustrate this capability by fabricating an all-inorganic light-emitting diode in a polymeric microfluidic manifold. Our findings indicate that electrostatic interactions in aqueous crystal growth may be systematically manipulated to synthesize nanostructures and devices with enhanced structural control. PMID:21743451

Joo, Jaebum; Chow, Brian Y; Prakash, Manu; Boyden, Edward S; Jacobson, Joseph M

2011-08-01

386

Structural and photoluminescence properties of terbium-doped zinc oxide nanoparticles  

NASA Astrophysics Data System (ADS)

We present in this paper a study of the structural and photoluminescence (PL) properties of terbium (Tb) doped zinc oxide (ZnO) nanoparticles synthesized by a simple low temperature chemical precipitation method, using zinc acetate and terbium nitrate in an isopropanol medium with diethanolamine (DEA) as the capping agent at 60 °C. The as-prepared samples were heat treated and the PL of the annealed samples were studied. The prepared nanoparticles were characterized with X-ray diffraction (XRD). The XRD patterns show the pattern of typical ZnO nanoparticles and correspond with the standard XRD pattern given by JCPDS card No. 36-1451, showing the hexagonal phase structure. The PL intensity was enhanced due to Tb3+ doping, and it decreased at higher concentrations of Tb3+ doping after reaching a certain optimum concentration. The PL spectra of Tb3+ doped samples exhibited blue, bluish green, and green emissions at 460 nm (5D3 - 7F3), 484 nm (5D4 - 7F6), and 530 nm (5D4 - 7F5), respectively, which were more intense than the emissions for the undoped ZnO sample. Based on the results, an energy level schematic diagram was proposed to explain the possible electron transition processes.

Ningthoujam Surajkumar, Singh; Shougaijam Dorendrajit, Singh; Sanoujam Dhiren, Meetei

2014-05-01

387

Functional finishing of cotton fabrics using zinc oxide soluble starch nanocomposites  

NASA Astrophysics Data System (ADS)

Zinc oxide-soluble starch nanocomposites (nano-ZnO) synthesized using water as a solvent and soluble starch as a stabilizer is impregnated onto cotton fabrics to impart antibacterial and UV-protection functions. Nano-ZnO synthesized by reacting zinc nitrate with sodium hydroxide in the presence of soluble starch absorbed strongly at 361 nm due to the quantum confinement effect. The average size of ZnO nanoparticles is estimated to be 38 ± 3 nm using a transmission electron microscope (TEM); this was confirmed by x-ray diffraction analysis and the effective mass approximation method. The starch content in synthesized nano-ZnO was estimated to be 37.57% using thermo-gravimetric analysis. The nano-ZnO impregnated cotton fabrics showed excellent antibacterial activity against two representative bacteria, Staphylococcus aureus (Gram positive) and Klebsiella pneumoniae (Gram negative). Also, nano-ZnO impregnation enhanced the protection of cotton fabrics against UV radiation in comparison with the untreated cotton fabrics.

Vigneshwaran, Nadanathangam; Kumar, Sampath; Kathe, A. A.; Varadarajan, P. V.; Prasad, Virendra

2006-10-01

388

Nano-encapuslated of zinc sulfide:silver with indium tin oxide and aluminum doped zinc oxide for flat panel display applications  

NASA Astrophysics Data System (ADS)

Reduction in cathodoluminescent degradation through the application of nanometer thick films of indium tin oxide (ITO) and aluminum doped zinc oxide (ZAO) has been investigated using x-ray photoelectron spectroscopy (XPS), cathodoluminescent degradation, scanning electron microscopy, transmission electron spectroscopy, and optical spectrometry. The partial pressure of water and the oxygen deposition pressure used during the coating process were controlled as parameters critical to degradation. The cathodoluminescent measurements were performed at vacuum levels between 1 · 10-7 to 5 · 10-5 Torr as measured by residual gas analysis. The primary electron beam used in the degradation experiments varied from 5--15 keV and the electron current density varied between two conditions: 10 muA/cm2 and 0.10 muA/cm2. The ITO coatings were deposited at 1 · 10-5 Torr while the ZAO films were deposited at 100 mTorr, 0.6 mTorr, and 0.14 mTorr using a modified pulsed laser ablation technique. For the ITO coated ZnS:Ag phosphors, the amount of water vapor pressure present during cathodoluminescent degradation had a dramatic effect on the brightness lifetime. The higher the partial pressure of water, the faster the degradation rate of the phosphor. The ITO coating on the ZnS:Ag phosphor reduced the rate of cathodoluminescent degradation at both partial pressures of water that were studied. XPS showed that the coatings provided sufficient protection against the adverse affects from the water vapor. For the ZAO coated ZnS:Ag phosphors, it was shown that the partial pressure used during the coating process effected the cathodoluminescent degradation lifetimes. The coating performed at the lowest vacuum level of oxygen provided the longest brightness lifetime. This increased phosphor lifetime was attributed to the highly deficient nature of the ZAO coating at this vacuum pressure and the continuous nature of the coating. XPS showed that the ZAO deposited at lower oxygen pressures showed a higher degree of oxidation than the other two cases. Indicating that the ZAO coating was able to behave as a sacrificial layer, which was attacked by the reactive atomic oxygen, created from the electron beam stimulated surface chemical reactions. The TEM results showed that the lower the deposition pressure, the better the coverage of the coatings. The improved conformal coverage provides better protection of the phosphor surface from the harmful residual gases, which led to improved CL degradation lifetimes.

Ollinger, Michael

2002-09-01

389

40 CFR 721.10108 - Naphthalenedisulfonic acid, hydrozy-[[[(hydroxyl-disulfo-naphthaleneyl)azo]-alkyl(C=1-5...  

Code of Federal Regulations, 2011 CFR

...cyclic]azo]-substituted azo-, metal salt (generic). 721.10108 Section 721...cyclic]azo]-substituted azo-, metal salt (generic). (a) Chemical substance...cyclic]azo]-substituted azo-, metal salt (PMN P-04-498) is subject to...

2011-07-01

390

40 CFR 721.10108 - Naphthalenedisulfonic acid, hydrozy-[[[(hydroxyl-disulfo-naphthaleneyl)azo]-alkyl(C=1-5...  

Code of Federal Regulations, 2013 CFR

...cyclic]azo]-substituted azo-, metal salt (generic). 721.10108 Section 721...cyclic]azo]-substituted azo-, metal salt (generic). (a) Chemical substance...cyclic]azo]-substituted azo-, metal salt (PMN P-04-498) is subject to...

2013-07-01

391

40 CFR 721.10108 - Naphthalenedisulfonic acid, hydrozy-[[[(hydroxyl-disulfo-naphthaleneyl)azo]-alkyl(C=1-5...  

Code of Federal Regulations, 2012 CFR

...cyclic]azo]-substituted azo-, metal salt (generic). 721.10108 Section 721...cyclic]azo]-substituted azo-, metal salt (generic). (a) Chemical substance...cyclic]azo]-substituted azo-, metal salt (PMN P-04-498) is subject to...

2012-07-01

392

Optical Kerr phase shift in a nanostructured nickel-doped zinc oxide thin solid film.  

PubMed

The optical Kerr effect exhibited by a nickel doped zinc oxide thin solid film was explored with femto- and pico-second pulses using the z-scan method. The samples were prepared by the ultrasonic spray pyrolysis technique. Opposite signs for the value of the nonlinear refractive index were observed in the two experiments. Self-defocusing together with a two-photon absorption process was observed with 120 ps pulses at 1064 nm, while a dominantly self-focusing effect accompanied by saturated absorption was found for 80 fs pulses at 825 nm. Regarding the nanostructured morphology of the resulting film, we attribute the difference in the two ultrafast optical responses to the different physical mechanism responsible of energy transfer generated by multiphoton processes under electronic and thermal effects. PMID:24104010

Torres-Torres, C; Can-Uc, B A; Rangel-Rojo, R; Castañeda, L; Torres-Martínez, R; García-Gil, C I; Khomenko, A V

2013-09-01

393

Zinc oxide nanowire-poly(methyl methacrylate) dielectric layers for polymer capacitive pressure sensors.  

PubMed

Polymer capacitive pressure sensors based on a dielectric composite layer of zinc oxide nanowire and poly(methyl methacrylate) show pressure sensitivity in the range of 2.63 × 10(-3) to 9.95 × 10(-3) cm(2) gf(-1). This represents an increase of capacitance change by as much as a factor of 23 over pristine polymer devices. An ultralight load of only 10 mg (corresponding to an applied pressure of ?0.01 gf cm(-2)) can be clearly recognized, demonstrating remarkable characteristics of these nanowire-polymer capacitive pressure sensors. In addition, optical transmittance of the dielectric composite layer is approximately 90% in the visible wavelength region. Their low processing temperature, transparency, and flexible dielectric film makes them a highly promising means for flexible touching and pressure-sensing applications. PMID:25494204

Chen, Yan-Sheng; Hsieh, Gen-Wen; Chen, Shih-Ping; Tseng, Pin-Yen; Wang, Cheng-Wei

2015-01-14

394

Superhydrophobic surfaces using selected zinc oxide microrod growth on ink-jetted patterns.  

PubMed

The synthesis and properties of superhydrophobic surfaces based on binary surface topography made of zinc oxide (ZnO) microrod-decorated micropatterns are reported. ZnO is intrinsically hydrophilic but can be utilized to create hydrophobic surfaces by creating artificial roughness via microstructuring. Micron scale patterns consisting of nanocrystalline ZnO seed particles were applied to glass substrates with a modified ink-jet printer. Microrods were then grown on the patterns by a hydrothermal process without any further chemical modification. Water contact angle (WCA)(1) up to 153° was achieved. Different micro array patterned surfaces with varying response of static contact angle or sessile droplet analysis are reported. PMID:21109250

Myint, Myo Tay Zar; Kitsomboonloha, Rungrot; Baruah, Sunandan; Dutta, Joydeep

2011-02-15

395

In situ analyses on negative ions in the indium-gallium-zinc oxide sputtering process  

NASA Astrophysics Data System (ADS)

The origin of negative ions in the dc magnetron sputtering process using a ceramic indium-gallium-zinc oxide target has been investigated by in situ analyses. The observed negative ions are mainly O- with energies corresponding to the target voltage, which originates from the target and barely from the reactive gas (O2). Dissociation of ZnO-, GaO-, ZnO2-, and GaO2- radicals also contributes to the total negative ion flux. Furthermore, we find that some sputtering parameters, such as the type of sputtering gas (Ar or Kr), sputtering power, total gas pressure, and magnetic field strength at the target surface, can be used to control the energy distribution of the O- ion flux.

Jia, Junjun; Torigoshi, Yoshifumi; Shigesato, Yuzo

2013-07-01

396

Electroluminescence from isolated defects in zinc oxide, towards electrically triggered single photon sources at room temperature  

E-print Network

Single photon sources are required for a wide range of applications in quantum information science, quantum cryptography and quantum communications. However, so far majority of room temperature emitters are only excited optically, which limits their proper integration into scalable devices. In this work, we overcome this limitation and present room temperature electrically triggered light emission from localized defects in zinc oxide (ZnO) nanoparticles and thin films. The devices emit at the red spectral range and show excellent rectifying behavior. The emission is stable over an extensive period of time, providing an important prerequisite for practical devices. Our results open up possibilities to build new ZnO based quantum integrated devices that incorporate solid-state single photon sources for quantum information technologies.

Choi, Sumin; Gentle, Angus; Ton-That, Cuong; Phillips, Matthew R; Aharonovich, Igor

2015-01-01

397

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

398

Enhanced boundary-scattering of electrons and phonons in nanograined zinc oxide  

NASA Astrophysics Data System (ADS)

Nanoscale constituents in bulk materials can promote enhanced boundary-scattering in the transport of phonons as well as electrons, which is considered a key design factor for enhancing thermoelectric properties. Here, we demonstrate a method for synthesizing zinc oxide bulk materials from nanoparticles without significant grain growth by means of pressure-induced deformation at 200 °C. This allows us to comprehensively analyze the grain size dependence of thermoelectric properties in the nanoscale range above 30 nm, the size of a nanoparticle. Grain size was found to largely influence thermal conductivity as well as electrical conductivity. The observed thermal conductivity agreed with the Callaway model, indicating that enhanced phonon boundary-scattering was responsible for the variation. On the contrary, Seebeck coefficient was mostly governed by effective mass and carrier concentration, and was independent of the grain size. The dimensionless figure of merit systematically increased with grain size, which challenged the effect of nanograin on this system.

Kinemuchi, Yoshiaki; Nakano, Hiromi; Mikami, Masashi; Kobayashi, Keizo; Watari, Koji; Hotta, Yuji

2010-09-01

399

Amorphous Indium Gallium Zinc Oxide Thin-Film Transistors Fabricated by Direct Transfer Printing  

NASA Astrophysics Data System (ADS)

This letter describes the fabrication of amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) by direct transfer printing. An a-IGZO layer and a silicon dioxide (SiO2) layer were sequentially sputtered on a poly(dimethylsiloxane) (PDMS) stamp; the stamp was then pressed onto a glass substrate on which a gate metal had been previously deposited. Then, a-IGZO/SiO2 layers were successfully transferred by simply releasing the stamp from the substrate; a bottom-gate TFT was finally constructed. The measured current-voltage characteristics exhibited good field-effect mobility exceeding 10 cm2 V-1 s-1. The on/off current ratio and subthreshold slope were 4×105 and 0.86 V/decade, respectively.

Adachi, Susumu; Okamura, Shoichi

2010-10-01

400

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

401

Red fluorescent zinc oxide nanoparticle: a novel platform for cancer targeting.  

PubMed

Multifunctional zinc oxide (ZnO) nanoparticles (NPs) with well-integrated multimodality imaging capacities have generated increasing research interest in the past decade. However, limited progress has been made in developing ZnO NP-based multimodality tumor-imaging agents. Here we developed novel red fluorescent ZnO NPs and described the successful conjugation of (64)Cu (t1/2 = 12.7 h) and TRC105, a chimeric monoclonal antibody against CD105, to these ZnO NPs via well-developed surface engineering procedures. The produced dual-modality ZnO NPs were readily applicable for positron emission tomography (PET) imaging and fluorescence imaging of the tumor vasculature. Their pharmacokinetics and tumor-targeting efficacy/specificity in mice bearing murine breast 4T1 tumor were thoroughly investigated. ZnO NPs with dual-modality imaging properties can serve as an attractive candidate for future cancer theranostics. PMID:25607242

Hong, Hao; Wang, Fei; Zhang, Yin; Graves, Stephen A; Eddine, Savo Bou Zein; Yang, Yunan; Theuer, Charles P; Nickles, Robert J; Wang, Xudong; Cai, Weibo

2015-02-11

402

Self-aligned coplanar amorphous indium zinc oxide thin-film transistors with high performance  

NASA Astrophysics Data System (ADS)

Self-aligned coplanar amorphous indium zinc oxide thin-film transistors (a-IZO TFTs) were fabricated. The a-IZO TFTs had a field-effect mobility of ?FE = 24.4 cm2 V-1 s-1, a subthreshold slope of 180 mV/dec, and an on/off ratio of 109. As the channel length decreased, the threshold voltage VTH shifted to more negative voltages, and ?FE increased due to the diffused carriers from the contact regions. The intrinsic field-effect mobility was estimated to be 15.05 cm2 V-1 s-1 in the linear mode and 13.28 cm2 V-1 s-1 in saturation mode. Under positive/negative bias-temperature-illumination stress, the shift in VTH was less than ±0.7 V after 11,000 s.

Park, Jae Chul; Lee, Ho-Nyeon

2015-01-01

403

In situ analyses on negative ions in the indium-gallium-zinc oxide sputtering process  

SciTech Connect

The origin of negative ions in the dc magnetron sputtering process using a ceramic indium-gallium-zinc oxide target has been investigated by in situ analyses. The observed negative ions are mainly O{sup -} with energies corresponding to the target voltage, which originates from the target and barely from the reactive gas (O{sub 2}). Dissociation of ZnO{sup -}, GaO{sup -}, ZnO{sub 2}{sup -}, and GaO{sub 2}{sup -} radicals also contributes to the total negative ion flux. Furthermore, we find that some sputtering parameters, such as the type of sputtering gas (Ar or Kr), sputtering power, total gas pressure, and magnetic field strength at the target surface, can be used to control the energy distribution of the O{sup -} ion flux.

Jia, Junjun; Torigoshi, Yoshifumi; Shigesato, Yuzo [Graduate School of Science and Engineering, Aoyama Gakuin University, 5-10-1 Fuchinobe, Chuo, Sagamihara, Kanagawa 252-5258 (Japan)

2013-07-01

404

The E3 center in zinc oxide: Evidence for involvement of hydrogen  

SciTech Connect

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 6×10{sup 10}?cm{sup ?2} to 4.3×10{sup 12}?cm{sup ?2} were implanted into hydrothermally grown ZnO samples with original concentrations of E3 below 5×10{sup 14}?cm{sup ?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. [Physics Department/Center for Materials Science and Nanotechnology, University of Oslo, P.O. Box 1048 Blindern, Oslo N-0316 (Norway)

2014-03-03

405

Electrohydrodynamic jet-printed zinc-tin oxide TFTs and their bias stability.  

PubMed

Zinc-tin oxide (ZTO) thin-film transistors (TFTs) were fabricated using an electrohydrodynamic-jet (EHD-jet) printing technique at annealing temperatures ranging from 300 to 500 °C. An EHD-jet-printed ZTO active layer was patterned with a 60 ?m width using a 100 ?m inner diameter metal nozzle. The electrical properties of an EHD-jet-printed ZTO TFT showed a mobility of 9.82 cm(2)/(V s), an on-off current ratio of 3.7 × 10(6), a threshold voltage of 2.36 V, and a subthreshold slope of 0.73 V/dec at 500 °C. Significantly improved properties were obtained compared to the spin-coated and inkjet-printed ones. Better hysteresis behavior and positive bias stability of the ZTO TFTs were also achieved using EHD-jet printing technology. PMID:25000343

Lee, Yong Gu; Choi, Woon-Seop

2014-07-23

406

Thermal Conductivity of Amorphous Indium-Gallium-Zinc Oxide Thin Films  

NASA Astrophysics Data System (ADS)

We investigated the thermal conductivity of 200-nm-thick amorphous indium-gallium-zinc-oxide (a-IGZO) films. Films with a chemical composition of In:Ga:Zn= 1:1:0.6 were prepared by dc magnetron sputtering using an IGZO ceramic target and an Ar-O2 sputtering gas. The carrier density of the films was systematically controlled from 1014 to >1019 cm-3 by varying the O2 flow ratio. Their Hall mobility was slightly higher than 10 cm2·V-1·s-1. Those films were sandwiched between 100-nm-thick Mo layers; their thermal diffusivity, measured by a pulsed light heating thermoreflectance technique, was ˜5.4×10-7 m2·s-1 and was almost independent of the carrier density. The average thermal conductivity was 1.4 W·m-1·K-1.

Yoshikawa, Toru; Yagi, Takashi; Oka, Nobuto; Jia, Junjun; Yamashita, Yuichiro; Hattori, Koichiro; Seino, Yutaka; Taketoshi, Naoyuki; Baba, Tetsuya; Shigesato, Yuzo

2013-02-01

407

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

408

Biokinetics of zinc oxide nanoparticles: toxicokinetics, biological fates, and protein interaction  

PubMed Central

Biokinetic studies of zinc oxide (ZnO) nanoparticles involve systematic and quantitative analyses of absorption, distribution, metabolism, and excretion in plasma and tissues of whole animals after exposure. A full understanding of the biokinetics provides basic information about nanoparticle entry into systemic circulation, target organs of accumulation and toxicity, and elimination time, which is important for predicting the long-term toxic potential of nanoparticles. Biokinetic behaviors can be dependent on physicochemical properties, dissolution property in biological fluids, and nanoparticle–protein interaction. Moreover, the determination of biological fates of ZnO nanoparticles in the systemic circulation and tissues is critical in interpreting biokinetic behaviors and predicting toxicity potential as well as mechanism. This review focuses on physicochemical factors affecting the biokinetics of ZnO nanoparticles, in concert with understanding bioavailable fates and their interaction with proteins. PMID:25565844

Choi, Soo-Jin; Choy, Jin-Ho

2014-01-01

409

Temperature dependent current-voltage characteristics of zinc oxide nanowire/polypyrrole nanocomposite  

NASA Astrophysics Data System (ADS)

Temperature dependent current-voltage (I-V) measurements of electrochemically prepared zinc oxide nanowire/polypyrrole (ZnONW/PPy) nanocomposite yielded non-linear I-V characteristics at temperatures between 300 and 4.5 K. The low-field conductance (G) of the ZnONW/PPy film exhibits pronounced temperature dependence with room temperature conductance (G300K) ˜ 10-3 S and a conductance ratio (G300K/G4.5K) of ˜104, indicating dominance of significant temperature dependent charge transport processes. The conduction mechanism of the film is satisfactorily understood by extended fluctuation induced tunneling (FIT) model as the non-linear I-V characteristics fit fairly well to the extended FIT model. Further, the temperature dependence of G? obtained from fitting followed Sheng's model also.

Sameera, I.; Bhatia, Ravi; Prasad, V.; Menon, Reghu

2014-12-01

410

Synthesis of zinc oxide films in glow discharge of various configurations  

NASA Astrophysics Data System (ADS)

The structure of zinc oxide (ZnO) films deposited on silicon substrates using dc glow discharge in oxygen have been studied for two electrode configurations—with tubular (hollow) and planar cathodes. At a substrate temperature of 670 K and oxygen pressure of 0.5 Torr, ZnO films synthesized in the hollow cathode geometry possess a columnar structure, while those obtained in the planar geometry are continuous. A decrease in the oxygen pressure from 0.5 to 0.2 Torr in discharge with the hollow cathode geometry leads to a change from a columnar to continuous film structure, while the morphology of films obtained in the planar geometry remains unchanged. The synthesized films exhibit a high degree of crystallographic orientation [001]ZnO ? [001]Si with complete azimuthal disorientation in the plane of film conjugation with the substrate.

Zinchenko, S. P.; Lyanguzov, N. V.; Zakharchenko, I. N.; Ratushnyi, V. I.; Shirokov, V. B.

2014-11-01

411

Bidirectional reflectance measurement of zinc oxide in 0.25 to 2.5 microns spectrum  

NASA Technical Reports Server (NTRS)

An experimental apparatus was designed and used to measure the bidirectional reflectance of zinc oxide in the spectrum 0.25 to 2.5 microns. The nonspecular reflectance is essentially Lambert for wavelengths above 0.40 microns with the most deviation occuring for large source zenith angles. Below 0.400 microns the nonspecular reflectance is greater than Lambert in all directions and is greatest in the forward and backscatter directions. The ratio of the specular component to the nonspecular component at a zenith of 0 degrees was found to increase with source zenith and wavelength for wavelengths above 0.400 microns. Below 0.400 microns this ratio increases as wavelengths decrease. The variation of bidirectional reflectance with wavelength was found to have the characteristics absorption for Zn0 for wavelength below 0.400 microns.

Scott, R. L., Jr.

1974-01-01

412

4D electron diffraction reveals correlated unidirectional behavior in zinc oxide nanowires.  

PubMed

The confined electronic structure of nanoscale materials has increasingly been shown to induce behavior quite distinct from that of bulk analogs. Direct atomic-scale visualization of nanowires of zinc oxide was achieved through their unique pancake-type diffraction by using four-dimensional (4D) ultrafast electron crystallography. After electronic excitation of this wide-gap photonic material, the wires were found to exhibit colossal expansions, two orders of magnitude higher than that expected at thermal equilibrium; the expansion is highly anisotropic, a quasi-one-dimensional behavior, and is facilitated by the induced antibonding character. By reducing the density of nanowires, the expansions reach even larger values and occur at shorter times, suggesting a decrease of the structural constraint in transient atomic motions. This unanticipated ultrafast carrier-driven expansion highlights the optoelectronic consequences of nanoscale morphologies. PMID:18801993

Yang, Ding-Shyue; Lao, Changshi; Zewail, Ahmed H

2008-09-19

413

Influence of substrate temperature on the performance of zinc oxide thin film transistor  

NASA Astrophysics Data System (ADS)

Top-contact thin film transistors (TFTs) using radio frequency (RF) magnetron sputtering zinc oxide (ZnO) and silicon dioxide (SiO2) films as the active channel layer and gate insulator layer, respectively, were fabricated. The performances of ZnO TFTs with different ZnO film deposition temperatures (room temperature, 100 °C and 200 °C) were investigated. Compared with the transistor with room-temperature deposited ZnO films, the mobility of the device fabricated at 200 °C is improved by 94% and the threshold voltage shift is reduced from 18 to 3 V (after 1 h positive gate voltage stress). Experimental results indicate that substrate temperature plays an important role in enhancing the field effect mobility, sharping the subthreshold swing and improving the bias stability of the devices. Atomic force microscopy was used to investigate the ZnO film properties. The reasons for the device performance improvement are discussed.

Junwei, Ma; Feng, Ran; Meihua, Xu; Huijied, Ji

2011-04-01

414

High-speed, inkjet-printed carbon nanotube/zinc tin oxide hybrid complementary ring oscillators.  

PubMed

The materials combination of inkjet-printed single-walled carbon nanotubes (SWCNTs) and zinc tin oxide (ZTO) is very promising for large-area thin-film electronics. We compare the characteristics of conventional complementary inverters and ring oscillators measured in air (with SWCNT p-channel field effect transistors (FETs) and ZTO n-channel FETs) with those of ambipolar inverters and ring oscillators comprised of bilayer SWCNT/ZTO FETs. This is the first such comparison between the performance characteristics of ambipolar and conventional inverters and ring oscillators. The measured signal delay per stage of 140 ns for complementary ring oscillators is the fastest for any ring oscillator circuit with printed semiconductors to date. PMID:24849313

Kim, Bongjun; Jang, Seonpil; Geier, Michael L; Prabhumirashi, Pradyumna L; Hersam, Mark C; Dodabalapur, Ananth

2014-06-11

415

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

416

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

417

Crystal plane-dependent gas-sensing properties of zinc oxide nanostructures: experimental and theoretical studies.  

PubMed

The sensitivity of a metal oxide gas sensor is strongly dependent on the nature of the crystal surface exposed to the gas species. In this study, two types of zinc oxide (ZnO) nanostructures: nanoplates and nanorods with exposed (0001) and (10?10) crystal surfaces, respectively, were synthesized through facile solvothermal methods. The gas-sensing results show that sensitivity of the ZnO nanoplates toward ethanol is two times higher than that of the ZnO nanorods, at an optimum operating temperature of 300 °C. This could be attributed to the higher surface area and the exposed (0001) crystal surfaces. DFT (Density Functional Theory) simulations were carried out to study the adsorption of ethanol on the ZnO crystal planes such as (0001), (10?10), and (11?20) with adsorbed O(-) ions. The results reveal that the exposed (0001) planes of the ZnO nanoplates promote better ethanol adsorption by interacting with the surface oxygen p (O2p) orbitals and stretching the O-H bond to lower the adsorption energy, leading to the sensitivity enhancement of the nanoplates. These findings will be useful for the fabrication of metal oxide nanostructures with specifically exposed crystal surfaces for improved gas-sensing and/or catalytic performance. PMID:24801357

Kaneti, Yusuf V; Zhang, Zhengjie; Yue, Jeffrey; Zakaria, Quadir M D; Chen, Chuyang; Jiang, Xuchuan; Yu, Aibing

2014-06-21

418

Surfactant-mediated growth of nanostructured zinc oxide thin films via electrodeposition and their photoelectrochemical performance  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin films were electrodeposited from an aqueous zinc acetate solution onto fluorine-doped thin oxide (FTO) coated conducting glass substrates. The effect of organic surfactants like polyvinyl pyrrolidone (PVP), sodium dodecyl sulfate (SDS), polyethylene glycol (PEG), ethylene glycol (EG) and polyvinyl alcohol (PVA) on their structural, morphological, optical and photoelectrochemical properties was studied. The x-ray diffraction patterns revealed the formation of phase-pure ZnO thin films. The films deposited using organic surfactants exhibit different surface morphologies. It was observed that the organic surfactants play important roles in modifying the surface morphology and size of the crystallites. A compact granular morphology was observed for the ZnO samples grown without organic surfactants. The films exhibit nanoparticles of size 100-150 nm for PVP, EG and PVA mediated growth. The vertically aligned thin and compact hexagonal crystallites stem from the SDS, whereas microporous corrugated morphology is observed for PEG-mediated growth. All the samples exhibit room temperature photoluminescence (PL). Oxygen vacancies contribute to the active luminescent centers for the emission of green light in ZnO thin films. PL gets quenched for the SDS surfactant. All the samples were post-treated with ethanol to remove stray surfactant molecules. FTIR study was used to confirm the removal of adsorbed surfactant molecules from the samples. Moreover the samples are photoelectrochemically (PEC) active and exhibit the highest photocurrent of 231 µA, a photovoltage of 492 mV and 0.42 fill factor for the ZnO:SDS films.

Inamdar, A. I.; Mujawar, S. H.; Ganesan, V.; Patil, P. S.

2008-08-01

419

Zinc oxide nano-particles as sealer in endodontics and its sealing ability  

PubMed Central

Aims: The aim of this study was to evaluate the sealing ability of new experimental nano-ZOE-based sealer. Settings and Design: Three types of nano-ZOE-based sealer (calcined at different temperatures of 500, 600 and 700°C) with two other commercially available sealers (AH26 and micro-sized zinc oxide eugenol sealer) were used. Materials and Methods: Zinc oxide nano-particles were synthesized by a modified sol-gel method. The structure and morphology of the prepared powders were characterized using x-ray diffraction (XRD) and transmission electron microscopy (TEM) techniques. The instrumented canals of 60 single-rooted teeth were divided into five groups (n = 10), with the remaining ten used as controls. The canals were filled with gutta-percha using one of the materials mentioned above as sealer. After 3, 45 and 90 days, the samples were connected to a fluid filtration system. Statistical Analysis Used: The data were analyzed using Student's t-test. Results: The XRD patterns and TEM images revealed that all the synthesized powders had hexagonal wurtzite structures with an average particle size of about 30-60 nm at different calcination temperatures. Microleakage in AH26 groups was significantly more than that in three groups of ZnO nano-particles at all the three evaluation intervals. Apical microleakage of ZnO micro-powders was significantly more than that of all the materials, but the sealing ability of ZnO nano-powder sealers did not differ significantly. Conclusion: The results of this study showed that the synthesized ZnO nano-powder sealers are suitable for use as a nano-sealer in root canal therapy to prevent leakage; however, further studies should be carried out to verify their safety. PMID:24808690

Javidi, Maryam; Zarei, Mina; Naghavi, Neda; Mortazavi, Majed; Nejat, Amir Hosein

2014-01-01

420

Tribological behavior of alumina doped zinc oxide films grown by pulsed laser deposition  

NASA Astrophysics Data System (ADS)

Zinc oxide, a well-known piezoelectric material, has become the subject of tribological investigations. This research describes the synthesis and tribological evaluation of alumina doped zinc oxide ZnO(Al2O3) films grown in vacuum by a pulsed laser deposition (PLD) technique using hot pressed ZnO-5 wt % Al2O3 targets. For comparison, pure ZnO films were grown under identical PLD conditions. The films were characterized by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, and x-ray photoelectron spectroscopy. Friction measurements were made using a ball-on-disk tribometer. Nanotribological studies were conducted on wear scars of ZnO and ZnO(Al2O3) films by atomic and lateral force microscopy. Both ZnO and ZnO(Al2O3) films were crystalline, with a strong (002) texture. The friction coefficient of the ZnO(Al2O3) film (mu=0.15) was considerably less than that of the pure ZnO film (mu=0.34). Wear scars on doped ZnO films were relatively smooth and, unlike in the case of pure ZnO films, no cracks were observed. Lateral force microscopy images of wear scars on ZnO(Al2O3) films showed dark contrast regions indicating the presence of a slippery phase. No such phase contrast was observed in the case of pure PLD ZnO film grown in vacuum. copyright 2002 American Vacuum Society.

Prasad, S. V.; Nainaparampil, J. J.; Zabinski, J. S.

2002-09-01

421

Influence of heat treatment in an oxidizing medium on the properties of copper-zinc-chromium-aluminum oxide catalyst for dehydrogenation of cyclohexanol  

Microsoft Academic Search

The authors report the results of a study of changes in the structure and catalytic properties of a copper-zinc-chromium-aluminum (CuZnCrAl) oxide catalyst, used for dehydrogenation of cyclohexanol, under the influence of heat treatment in an oxidizing medium. A catalyst of the composition (mass %): CuO 54.0, ZnO 12.0, CrâOâ 11.0, AlâOâ 20.0, the rest being graphite, was prepared by the

F. Kh. Sapozhnikova; V. Z. Fridman; I. Ya. Petrov; T. S. Polovkina; E. A. Kriventsova

1988-01-01

422

On the possibility to grow zinc oxide-based transparent conducting oxide films by hot-wire chemical vapor deposition  

SciTech Connect

Hot-wire chemical vapor deposition (HW-CVD) was applied to grow zinc oxide (ZnO)-based transparent conducting oxide (TCO) films. Indium (In)-doped ZnO films were deposited using a cold wall pulsed liquid injection CVD system with three nichrome wires installed at a distance of 2?cm from the substrate holder. The wires were heated by an AC current in the range of 0–10 A. Zn and In 2,2,6,6-tetramethyl-3,5-heptanedionates dissolved in 1,2-dimethoxyethane were used as precursors. The hot wires had a marked effect on the growth rates of ZnO, In-doped ZnO, and In{sub 2}O{sub 3} films; at a current of 6–10 A, growth rates were increased by a factor of ?10–20 compared with those of traditional CVD at the same substrate temperature (400?°C). In-doped ZnO films with thickness of ?150?nm deposited on sapphire-R grown at a wire current of 9?A exhibited a resistivity of ?2?×?10{sup ?3} ?cm and transparency of >90% in the visible spectral range. These initial results reveal the potential of HW-CVD for the growth of TCOs.

Abrutis, Adulfas, E-mail: adulfas.abrutis@chf.vu.lt; Silimavicus, Laimis; Kubilius, Virgaudas; Murauskas, Tomas; Saltyte, Zita; Kuprenaite, Sabina; Plausinaitiene, Valentina [Faculty of Chemistry, Vilnius University, Naugarduko 24, LT-03225 Vilnius (Lithuania)

2014-03-15

423

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

424

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

425

Recovery of manganese oxides from spent alkaline and zinc–carbon batteries. An application as catalysts for VOCs elimination  

SciTech Connect

Highlights: • Manganese oxides were synthesized using spent batteries as raw materials. • Spent alkaline and zinc–carbon size AA batteries were used. • A biohydrometallurgical process was employed to bio-lixiviate batteries. • Manganese oxides were active in the oxidation of VOCs (ethanol and heptane). - Abstract: 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 KMnO{sub 4} solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnO{sub x} synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn{sub 2}O{sub 3} in the EMO and the CMO samples, together with some Mn{sup 4+} cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn{sub 3}O{sub 4}. 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 CO{sub 2}. 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.

Gallegos, María V., E-mail: plapimu@yahoo.com.ar [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina); Falco, Lorena R., E-mail: mlfalco@quimica.unlp.edu.ar [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina); Peluso, Miguel A., E-mail: apelu@quimica.unlp.edu.ar [Centro de Investigación y Desarrollo en Ciencias Aplicadas, “Dr. J. Ronco” CINDECA (CONICET CCT La Plata), 47 N°257, La Plata, Buenos Aires (Argentina); Sambeth, Jorge E., E-mail: sambeth@quimica.unlp.edu.ar [Centro de Investigación y Desarrollo en Ciencias Aplicadas, “Dr. J. Ronco” CINDECA (CONICET CCT La Plata), 47 N°257, La Plata, Buenos Aires (Argentina); Thomas, Horacio J. [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina)

2013-06-15

426

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

E-print Network

and chemical stability in reducing ambient over ITO. In this report, AZO was grown by sputtering Al target and ZnO target simultaneously, and the Al dopant concentration can be easily tuned by adjusting.8%. The transmittance of AZO is even better than commercial ITO glass. OLED devices based on TPD-Alq3 were fabricated

427

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

428

The effect of zinc and copper oxides and other zinc compounds as fillers on the tribological behavior of thermosetting polyester  

Microsoft Academic Search

The tribological behavior of thermosetting polyester filled with CuO, ZnO, ZnF2, and Zn(C18H35O2)2 fillers was studied. Sliding was performed in ambient atmosphere at 1.0 m s?1 between a polyester pin and a hardened tool steel disk in a pin-on-disk machine. The worn and the unworn specimen pin surfaces, zinc stearate powder, and the transfer films formed during sliding were studied

S. Bahadur; L. Zhang; J. W. Anderegg

1997-01-01

429

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

430

Influence of surface properties of zinc oxide nanoparticles on their cytotoxicity.  

PubMed

The toxicity of nanoparticles (NPs) depends on several factors including size, shape, surface properties and chemical nature of the NPs. The release of toxic ions due to the dissolution of NPs is another important factor. In addition, impurities or reaction products from synthesis procedures on the NP surfaces may contribute to the toxicity. Zinc oxide nanoparticles (ZnO NPs) are one of the unique NPs showing toxicity through all of these mentioned factors. In this study, we demonstrate that the treatment of the ZnO NPs with hydrogen peroxide (H2O2) alters the surface properties of the ZnO NPs by decomposing organic impurities remained from synthesis procedures. The changes on the surface chemistry and properties of the ZnO NPs influence their behavior in cell culture media and the NPs-cell interactions. Finally, a decrease in the cytotoxicity of H2O2 treated ZnO NPs is observed on HDF and A549 cells through the decrease of the membrane damage and oxidative stress. PMID:25042418

Altunbek, Mine; Baysal, Asl?; Çulha, Mustafa

2014-09-01

431

Zinc oxide nanoparticles cause inhibition of microbial denitrification by affecting transcriptional regulation and enzyme activity.  

PubMed

Over the past few decades, human activities have accelerated the rates and extents of water eutrophication and global warming through increasing delivery of biologically available nitrogen such as nitrate and large emissions of anthropogenic greenhouse gases. In particular, nitrous oxide (N2O) is one of the most important greenhouse gases, because it has a 300-fold higher global warming potential than carbon dioxide. Microbial denitrification is a major pathway responsible for nitrate removal, and also a dominant source of N2O emissions from terrestrial or aquatic environments. However, whether the release of zinc oxide nanoparticles (ZnO NPs) into the environment affects microbial denitrification is largely unknown. Here we show that the presence of ZnO NPs lead to great increases in nitrate delivery (9.8-fold higher) and N2O emissions (350- and 174-fold higher in the gas and liquid phases, respectively). Our data further reveal that ZnO NPs significantly change the transcriptional regulations of glycolysis and polyhydroxybutyrate synthesis, which causes the decrease in reducing powers available for the reduction of nitrate and N2O. Moreover, ZnO NPs substantially inhibit the gene expressions and catalytic activities of key denitrifying enzymes. These negative effects of ZnO NPs on microbial denitrification finally cause lower nitrate removal and higher N2O emissions, which is likely to exacerbate water eutrophication and global warming. PMID:25384038

Zheng, Xiong; Su, Yinglong; Chen, Yinguang; Wan, Rui; Liu, Kun; Li, Mu; Yin, Daqiang

2014-12-01

432

High-performance ge quantum dot decorated graphene/zinc-oxide heterostructure infrared photodetector.  

PubMed

A novel size-controllable germanium quantum dot (Ge QD) is synthesized and decorated onto reduced graphene oxide (RGO) fragments to overcome the low infrared (IR) photoresponses (?0.1 A/W)13,14 of pristine graphene. With the integration of flexible substrate, monolayer graphene (MLG) electrode and n-type zinc oxide (ZnO), a high-performance QD-decorated-RGO/ZnO heterostructure infrared photodetector is reported in this study. The Ge QD-decorated-RGO hybrid photosensitive composite improves the responsivity (?9.7 A/W, 1400 nm) in IR waveband without sacrificing the response speed (?40 ?s rise time and 90 ?s recovery time). In addition, the effective barrier formed between graphene and ZnO interface restricts the dark current (?1.4 nA, -3 V) to guarantee the relatively excellent rectifying behavior and high on/off ratio (?10(3)) for this IR photodetector. With these superior inherent properties and micron-sized sensing active area, this photodetector manifests great potential in the future application of graphene-based IR photodetector. PMID:25561422

Liu, Xiang; Ji, Xiangbing; Liu, Mingju; Liu, Nianze; Tao, Zhi; Dai, Qing; Wei, Lei; Li, Chi; Zhang, Xiaobing; Wang, Baoping

2015-02-01

433

Oxidative stress may modify zinc protoporphyrin/heme ratio in hematofluorometry.  

PubMed

Washed red blood cells (RBCs), supplemented or non-supplemented with sodium azide (to inhibit catalase activity), were exposed to different concentrations of hydrogen peroxide as well as ascorbic acid. Strikingly, catalase within RBCs protected the cells against exogenic hydrogen peroxide even at millimolar concentrations. However, the activity of the erythrocytic catalase failed to protect the RBCs when they were exposed to an oxidative burst of stimulated polymorphonuclear cells (PMNCs) in the presence of several reactive species in addition to peroxide. Oxyhemoglobin, with an excess of hydrogen peroxide, formed oxidized hemoglobin species and caused protein denaturation as well as the rise of heme degradation products which was suspected to falsify zinc protoporphyrin/heme (ZPP/heme) ratio as assessed by hematofluorometry. Our experiments may thus imply that the non-fluorescent hemoglobin background can be modified by reactive oxygen species (ROS) and this can lead to a spurious ZPP/heme ratio. We discuss this phenomenon with respect to ZPP quantification in clinical practice. PMID:19055648

Janousek, S J; Rosa, L; Janousek, S; Jirova, D; Kejlova, K

2010-02-01

434

Does zinc in livestock wastewater reduce nitrous oxide (N2O) emissions from mangrove soils?  

PubMed

Zinc (Zn) affects nitrogen cycling but the effect of Zn in wastewater on the emission of nitrous oxide (N2O) from the soil has not been reported. This study compared N2O emissions from mangrove soil receiving livestock wastewater containing various Zn(2+) concentrations and evaluated how long the effects of Zn would last in these soil-wastewater microcosms. Significant increases in N2O flux were observed soon after the discharge of wastewater with a low Zn content. On the other hand, the flux was reduced significantly in the wastewater with high Zn levels but such inhibitory effect was not observed after tidal flushing. Continuous monitoring of the N2O fluxes also confirmed that the inhibitory effect of Zn was confined within a few hours and the fluxes recovered in 6-9 h after the wastewater was completely drained away. These results indicated that the inhibitory effect of Zn on N2O fluxes occurred immediately after wastewater discharge and disappeared gradually. In the surface soil, nitrate levels increased with the addition of wastewater but there was no significant accumulation of NH4(+)-N, irrespective of the Zn content in the wastewater. The study also showed that nitrification potential and immediate N2O emissions were inhibited by high Zn levels in the soil, but the total oxidation of ammonium to nitrate was not affected. PMID:25171729

Chen, Guang C; Tam, Nora F Y; Ye, Yong

2014-11-15

435

Endoplasmic reticulum stress induced by zinc oxide nanoparticles is an earlier biomarker for nanotoxicological evaluation.  

PubMed

Zinc oxide nanoparticles (ZnO NPs) have been widely used in cosmetics and sunscreens, advanced textiles, self-charging and electronic devices; the potential for human exposure and the health impact at each stage of their manufacture and use are attracting great concerns. In addition to pulmonary damage, nanoparticle exposure is also strongly correlated with the increase in incidences of cardiovascular diseases; however, their toxic potential remains largely unclear. Herein, we investigated the cellular responses and endoplasmatic reticulum (ER) stress induced by ZnO NPs in human umbilical vein endothelial cells (HUVECs) in comparison with the Zn2+ ions and CeO2 NPs. We found that the dissolved zinc ion was the most significant factor for cytotoxicity in HUVECs. More importantly, ZnO NPs at noncytotoxic concentration, but not CeO2 NPs, can induce significant cellular ER stress response with higher expression of spliced xbp-1, chop, and caspase-12 at the mRNA level, and associated ER marker proteins including BiP, Chop, GADD34, p-PERK, p-eIF2?, and cleaved Caspase-12 at the protein levels. Moreover, ER stress was widely activated after treatment with ZnO NPs, while six of 84 marker genes significantly increased. ER stress response is a sensitive marker for checking the interruption of ER homeostasis by ZnO NPs. Furthermore, higher dosage of ZnO NPs (240 ?M) quickly rendered ER stress response before inducing apoptosis. These results demonstrate that ZnO NPs activate ER stress-responsive pathway and the ER stress response might be used as an earlier and sensitive end point for nanotoxicological study. PMID:24490819

Chen, Rui; Huo, Lingling; Shi, Xiaofei; Bai, Ru; Zhang, Zhenjiang; Zhao, Yuliang; Chang, Yanzhong; Chen, Chunying

2014-03-25

436

Synthesis of ALD zinc oxide and thin film materials optimization for UV photodetector applications  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) is a direct, wide bandgap semiconductor material. It is thermodynamically stable in the wurtzite structure at ambient temperature conditions. ZnO has very interesting optical and electrical properties and is a suitable candidate for numerous optoelectronic applications such as solar cells, LEDs and UV-photodetectors. ZnO is a naturally n-type semiconductor. Due to the lack of reproducible p-type ZnO, achieving good homojunction ZnO-based photodiodes such as UV-photodetectors remains a challenge. Meanwhile, heterojunction structures of ZnO with p-type substrates such as SiC, GaN, NiO, AlGaN, Si etc. are used; however, those heterojunction diodes suffer from low efficiencies. ZnO is an n-type material with numerous intrinsic defect levels responsible for the electrical and optical behaviors. Presently, there is no clear consensus about the origin of those defects. In this work, ZnO was synthesized by atomic layer deposition (ALD). ALD is a novel deposition technique suitable for nanotechnology engineering that provides unique features such as precise control of ZnO thin film with atomic resolution, high uniformity, good conformity and high aspect ratio. Using this novel deposition technique, the ALD ZnO deposition process was developed and optimized using diethyl zinc as the precursor for zinc and water vapor as the oxygen source. In order to optimize the film quality for use in electronic applications, the physical, mechanical and electrical properties were investigated. The structural and mechanical properties of the ALD ZnO thin films were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), spectroscopic Ellipsometry, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-VIS absorption and nanoindentation. The electrical characterizations were performed using C-V, I-V, DLTS, Hall Effect, and four-point probe. The intrinsic defects responsible for the electrical and optical properties of the ALD ZnO films were analyzed and identified. ALD ZnO based electronic devices were fabricated, optimized and their electrical characteristics measured. The photocurrent characteristics of ALD ZnO were also optimized, and high efficiency UV-photodetectors were achieved.

Tapily, Kandabara Nouhoum

437

A thermalization energy analysis of the threshold voltage shift in amorphous indium gallium zinc oxide thin film transistors under simultaneous negative gate bias and illumination  

E-print Network

It has been previously observed that thin film transistors (TFTs) utilizing an amorphous indium gallium zinc oxide (a-IGZO) semiconducting channel suffer from a threshold voltage shift when subjected to a negative gate bias and light illumination...

Flewitt, Andrew J.; Powell, M.J.

2014-01-01

438

Antibacterial activity and mechanism of action of zinc oxide nanoparticles against Campylobacter jejuni.  

PubMed

The antibacterial effect of zinc oxide (ZnO) nanoparticles on Campylobacter jejuni was investigated for inhibition and inactivation of cell growth. The results showed that C. jejuni was extremely sensitive to treatment with ZnO nanoparticles. The MIC of ZnO nanoparticles for C. jejuni was determined to be 0.05 to 0.025 mg/ml, which is 8- to 16-fold lower than that for Salmonella enterica serovar Enteritidis and Escherichia coli O157:H7 (0.4 mg/ml). The action of ZnO nanoparticles against C. jejuni was determined to be bactericidal, not bacteriostatic. Scanning electron microscopy examination revealed that the majority of the cells transformed from spiral shapes into coccoid forms after exposure to 0.5 mg/ml of ZnO nanoparticles for 16 h, which is consistent with the morphological changes of C. jejuni under other stress conditions. These coccoid cells were found by ethidium monoazide-quantitative PCR (EMA-qPCR) to have a certain level of membrane leakage. To address the molecular basis of ZnO nanoparticle action, a large set of genes involved in cell stress response, motility, pathogenesis, and toxin production were selected for a gene expression study. Reverse transcription-quantitative PCR (RT-qPCR) showed that in response to treatment with ZnO nanoparticles, the expression levels of two oxidative stress genes (katA and ahpC) and a general stress response gene (dnaK) were increased 52-, 7-, and 17-fold, respectively. These results suggest that the antibacterial mechanism of ZnO nanoparticles is most likely due to disruption of the cell membrane and oxidative stress in Campylobacter. PMID:21296935

Xie, Yanping; He, Yiping; Irwin, Peter L; Jin, Tony; Shi, Xianming

2011-04-01

439

Toll-like receptor 6 mediated inflammatory and functional responses of zinc oxide nanoparticles primed macrophages.  

PubMed

Macrophages are among the most sensitive immune cells because of their phagocytic activity and are prone to become dysfunctional or not able to perform properly if nanoparticle load increases. We have previously reported that zinc oxide nanoparticles (ZNPs) induce inflammatory responses in macrophages that contribute to their death. Recognition of ZNPs by pattern recognition receptors such as toll-like receptors (TLRs) might be a factor in the initiation of these responses in macrophages. Therefore, in this study we explored the role played by TLR6 and mitogen-activated protein kinase (MAPKs) pathways in the inflammatory responses of macrophages during ZNPs exposure. ZNPs-activated macrophages showed enhanced expression of activation and maturation markers (CD1d, MHC-II, CD86 and CD71). Among various TLRs screened, TLR6 emerged as the most potent activator for ZNPs-induced inflammatory responses. Downstream signalling proteins myeloid differentiation 88, interleukin-1 receptor associated kinase and tumour necrosis factor receptor-associated factor were also enhanced. On inhibiting MAPKs pathways individually, the inflammatory responses such as interleukin-1?, interleukin-6, tumour necrosis factor-?, cyclooxygenase-2 and inducible nitric oxide synthase were suppressed. TLR6 silencing significantly inhibited the pro-inflammatory cytokine levels, reactive nitrogen species generation and inducible nitric oxide synthase expression. Also, inhibition of MAPKs in the absence of TLR6 signalling validated the link between TLR6 and MAPKs in ZNPs-induced inflammatory responses. TLR6 was found to be co-localized with autophagosomes. Macrophages lacking TLR6 inhibited the autophagosome marker protein-microtubule-associated protein1 light chain 3-isoform II formation and phagocytosis. These results demonstrate that inflammatory responses caused by ZNPs-activated macrophages strongly depend on TLR6-mediated MAPK signalling. PMID:24593842

Roy, Ruchi; Singh, Sunil K; Das, Mukul; Tripathi, Anurag; Dwivedi, Premendra D

2014-07-01

440

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

441

Defect Analysis and Optimization of the Indium Oxide (Zinc Oxide) System for Energy Applications  

NASA Astrophysics Data System (ADS)

The defect chemistry of compounds in the In2O3(ZnO) k system (k = 3, 5, 7, and 9) was investigated via analysis of the dependence of conductivity on oxygen partial pressure at high temperature (750°C). Defect mechanisms were proposed based on the resulting Brouwer slopes, and the presence of two defect regimes was attributed to competition between In 2O3--like (k = 3) and ZnO--like behavior (k = 5, 7, 9). The donor in both cases is proposed to be the In antisite defect ( In•Zn ). To support the validity of the proposed models, density functional theory was used to calculate the formation energies of the proposed defects. X-ray and ultraviolet photoelectron spectroscopy studies were performed on the surfaces of thin film (k = 2) and bulk specimens (k = 3, 5, 7, and 9) to investigate their work functions, Fermi levels, and ionization potentials. The work functions and Fermi levels for all samples fell on a line of constant ionization potential (˜7.7--7.8 eV), which was independent of composition and unchanged by oxidation and reduction treatments. This ionization potential was very close to those of oxidized In2O3 and ZnO surfaces. The work functions of each sample were similar when measured under vacuum or ambient conditions (4.7--4.9 eV). The high-temperature (750°C) electrical conductivity and thermopower of bulk samples of In2O3(ZnO)k were analyzed to assess their potential for use in thermoelectric power applications. The density of states-mobility products were determined by Jonker analysis (thermopower vs. ln conductivity) of the measured electrical properties. Ioffe analysis (log-log plots of maximum power factor vs. density of states-mobility product) was employed to predict the maximum thermoelectric power factor that could be achieved for each compound with an optimized carrier concentration, which agreed well with the best performances reported in the literature. The maximum predicted power factors were similar for the k = 1--7 phases, between 2 and 15x10-4 W/mK2, and were comparable to those of other n-type thermoelectric oxides. The predicted power factors were much lower for the k = 9 phase.

Hopper, E. Mitchell

442

Oxidation of ultrathin copper layers on zinc oxide polar surfaces: unoccupied electronic states  

NASA Astrophysics Data System (ADS)

Total current spectroscopy (TCS) was used to study an evolution of unoccupied states through the process of thin-layer copper deposition and its oxidation on polar ZnO(0001) and 0953-8984/9/35/005/img9 surfaces. Zn-derived and O-derived unoccupied bands were identified in the TC spectrum at 7.7 and 9.8 eV, respectively, from the clean and well ordered polar ZnO faces, while the spectra from a thin CuO layer reveal an intensive fine structure in the 6 - 25 eV energy range above the Fermi level, which is discussed in comparison with previously reported results of experimental and theoretical investigations. The obtained data provide additional information on the energy location of the edges of unoccupied bands in CuO in the 6 - 25 eV range relative to 0953-8984/9/35/005/img10.

Komolov, S. A.; Lazneva, E. F.; Egebjerg, T.; Møller, P. J.

1997-09-01

443

Solar thermal decomposition of zinc oxide in aerosol flow for renewable hydrogen production  

NASA Astrophysics Data System (ADS)

Hydrogen could be a clean replacement for fossil fuels. The Zn/ZnO solar thermochemical water-splitting cycle provides a renewable path to this fuel. Thermodynamic simulations showed that the Zn/ZnO cycle has the lowest temperature of all two-step metal oxide cycles, and the prediction of relatively high efficiency based on its lower temperature and number of steps led to its selection for further study. A rapid aerosol configuration for ZnO decomposition was chosen based on expectation of high reaction rates and small product particle production, and proof-of-concept experiments confirmed this assumption. Thermogravimetric studies of the thermal decomposition kinetics of ZnO showed that the rate followed a 2/3 order L'vov kinetic expression. The activation energy was found to be 353 +/- 25.9 kJ/mol, and a simple electrostatic model was used to describe the reaction mechanism. The pre-exponential factor was found, as expected, to vary inversely with the distance to a product concentration sink. Investigation of the aerosol decomposition of ZnO showed high forward conversion (˜60%) but low net yield (18%) of zinc due to recombination of product oxygen with nucleated zinc particles. Products that were initially converted had high surface area (15.5 +/- 0.13 g/m2), small particle size (5-70 nm), and relatively spherical morphology, properties desirable when considering the hydrolysis step of the water-splitting cycle. Rates in the aerosol reactor were found to be three orders of magnitude greater than those in a stationary configuration. Computational fluid dynamics (CFD) simulations of the aerosol reaction showed rapid particle heating and high forward conversion (>90%) in short residence times (<1.5s). Results could be used to scale a commercial size reactor, and the recommended particle size based on conversion and handling considerations was 1 mum. Reactor materials sensitive to oxidation were shown to be inappropriate for application due to high corrosion rates. Experiments showed poor stability of the protective SiO2 film in the presence of ZnO, consistent with thermodynamic simulation. CFD simulation of a fluid-wall reactor predicted that such a strategy would be effective at preventing particle-wall contact, but would fare poorly at preventing gas-wall corrosion reactions, a conclusion verified experimentally in a solar reactor.

Perkins, Christopher Michael

444

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

445

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, Inès; Trabelsi, Hamdi; Hanini, Amel; Ferchichi, Soumaya; Tebourbi, Olfa; Sakly, Mohsen; Abdelmelek, Hafedh

2014-01-01

446

Anomalous Threshold Voltage Shift and Surface Passivation of Transparent Indium–Zinc–Oxide Electric-Double-Layer TFTs  

Microsoft Academic Search

Threshold voltage (Vth) instability and surface passivation effect of transparent indium-zinc-oxide electric- double-layer thin-film transistors (TFTs) are investigated. Unpas- sivated devices show a large negative threshold voltage shift of 0.68 V in the beginning of light-illuminated negative gate bias stress. Under longer time stress, anomalous positive Vth shifts are observed for both unpassivated and passivated TFTs, which is due to

Jia Sun; Jie Jiang; Wei Dou; Bin Zhou; Qing Wan

2011-01-01

447

Low-voltage indium-zinc-oxide thin film transistors gated by solution-processed chitosan-based proton conductors  

Microsoft Academic Search

We fabricated indium-zinc-oxide (IZO) thin film transistors (TFT) gated by chitosan (CS) on ITO\\/glass substrate. Chitosan is demonstrated to be a new kind of solution-processed organic polymer electrolyte, which has nice film-forming characteristic. The chitosan thin film shows a large specific gate capacitance of 8.06 (µF\\/cm2 due to the mobile-ions induced electric-double-layer effect. These devices exhibited a good performance with

Xiao Han; Jie Jiang; Bin Zhou; Jia Sun; Wei Dou; Huixuan Liu; Qing Wan

2011-01-01