scholarly journals Electrical properties of mechanically activated zinc oxide

2006 ◽  
Vol 38 (2) ◽  
pp. 131-138 ◽  
Author(s):  
K. Vojisavljevic ◽  
M. Zunic ◽  
G. Brankovic ◽  
T. Sreckovic
Keyword(s):  
Zinc Oxide ◽  
Electrical Properties ◽  
Grain Boundaries ◽  
Arrhenius Equation ◽  
Electrical Response ◽  
High Energy ◽  
Microstructural Properties ◽  
Impedance Analyzer ◽  
Zinc Oxide Powder ◽  
Zno Ceramics

Microstructural properties of a commercial zinc oxide powder were modified by mechanical activation in a high-energy vibro-mill. The obtained powders were dry pressed and sintered at 1100?C for 2 h. The electrical properties of grain boundaries of obtained ZnO ceramics were studied using an ac impedance analyzer. For that purpose, the ac electrical response was measured in the temperature range from 23 to 240?C in order to determine the resistance and capacitance of grain boundaries. The activation energies of conduction were obtained using an Arrhenius equation. Donor densities were calculated from Mott-Schottky measurements. The influence of microstructure, types and concentrations of defects on electrical properties was discussed.

Electrical properties of zinc oxide thin films deposited using high-energy H2O generated from a catalytic reaction on platinum nanoparticles

2013 ◽  
Vol 1494 ◽  
pp. 127-132
Author(s):  
Kanji Yasui ◽  
Naoya Yamaguchi ◽  
Eichi Nagatomi ◽  
Souichi Satomoto ◽  
Takahiro Kato
Keyword(s):  
Zinc Oxide ◽  
Electrical Properties ◽  
Film Thickness ◽  
Electron Mobility ◽  
Lattice Mismatch ◽  
Defect Density ◽  
Chemical Vapor ◽  
High Energy ◽  
Chemical Vapor Deposition Method ◽  
Zno Films

ABSTRACTZinc oxide (ZnO) with excellent crystallinity and large electron mobility was grown on aplane (11-20) sapphire (a-Al2O3) substrates by a new chemical vapor deposition method via the reaction between dimethylzinc (DMZn) and high-energy H2O produced by a Pt-catalyzed H2-O2 reaction. The electron mobility at room temperature increased from 30 cm2/Vs to 189 cm2/Vs with increasing film thickness from 0.1 μm to approximately 3 μm. Electron mobility increased significantly with decreasing temperature to approximately 110 – 150 K, but decreased at temperatures less than 100 K for films greater than 500 nm in thickness. On the other hand, the mobility hardly changed with temperature for films lesser than 500 nm in thickness. Based on the dependence of the electrical properties on the film thickness, the ZnO films grown on a-Al2O3 substrates are considered to consist of an interfacial layer with a high defect density (degenerate layer) generated due to a large lattice mismatch between ZnO and Al2O3 substrates and an upper layer with a low defect density.

The Influence of Ion Beam Implantation on Electrical Properties of Polycrystalline MnNiCuFeO

1992 ◽  
Vol 279 ◽  
Author(s):  
Li Binbin ◽  
Tan Hui ◽  
Han Ying ◽  
Tao Wei ◽  
Lin Chenglu
Keyword(s):  
Electrical Properties ◽  
Grain Boundaries ◽  
Boundary Effect ◽  
Ion Beam ◽  
Low Frequency ◽  
Bulk Properties ◽  
Spreading Resistance ◽  
Impedance Analyzer ◽  
Ion Beam Implantation ◽  
Grain Boundary Effect

ABSTRACTPolycrystalline MnNiCuFeO was implanted by B+, P+ and Si+ ion beams and thermally annealed. The structure and electrical properties of the sample were measured using SEM, Microprobe (MP), Low Frequency Impedance Analyzer (LFIA) and Spreading Resistance Probe (SRP). The results show that the resistance of grain boundaries is much higher than that of grains. The spreading resistance of the implanted samples is lower by factor of 2 than that of the unimplanted ones. The ratio of the real part Rs (grain effect) to imaginary part Xs (grain boundary effect) decreases with ion beam implantation. From these results, we came to the conclusion that the behavior of the grain boundaries is important to the bulk properties of polycrystalline MnNiCuFeO.

Grain Boundary Dopant and Heat Treatment Effects on the Electrical Properties of Polycrystalline ZnO

1995 ◽  
Vol 411 ◽  
Author(s):  
T. D. Chen ◽  
J.-R. Lee ◽  
H. L. Tuller ◽  
Y.-M. Chiang
Keyword(s):  
Heat Treatment ◽  
Zinc Oxide ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Deep Level Transient Spectroscopy ◽  
Deep Level ◽  
Low Leakage ◽  
Current Voltage ◽  
Transient Spectroscopy

ABSTRACTSimplified varistor systems of bismuth- and cobalt-doped zinc oxide are studied. A prior study has shown that the distributions of bismuth segregation at the grain boundaries in such samples can be controlled by varying microstructure and heat treatment. Current-voltage and deep level transient spectroscopy measurements were done to evaluate the corresponding electrical properties. Low leakage and α values of ˜30 were attained, despite the nominal, twocomponent doping of these simplified varistors. Moreover, these samples show the signature defects that are found in many multi-dopant, commercial devices: two shallow bulk traps at ˜0.14 eV and ˜0.24 eV and one prominent interfacial trap at ˜1 eV.

Microstructural and Electrical Properties of ZnO Ceramics with ZnO-Na2O-P2O5 Glass Oxide Additions

2014 ◽  
Vol 912-914 ◽  
pp. 231-234
Author(s):  
Wen Shiush Chen ◽  
Cheng Hsing Hsu ◽  
Chang Yi Peng ◽  
Ming Lang Hung ◽  
Ching Fang Tseng ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Electrical Properties ◽  
Electronic Device ◽  
Oxide Ceramics ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Suitable Candidate ◽  
X Ray ◽  
Device Applications ◽  
Zno Ceramics

The compositions, electrical properties and microstructures of zinc oxide ceramics with various 46.6ZnO-20Na2O-33.4P2O5glass oxide additions prepared by solid-state method have been investigated. The structure of the materials is studied using X-Ray diffraction, and the microstructure is analyzed using scanning electron microscopy. The results indicated that the electrical properties were associated with the amount of 46.6ZnO-20Na2O-33.4P2O5glass oxide additions and the sintering temperatures. The correlation between the microstructures, oxide additions and the sintering temperature was also discussed. From the results of electrical properties measurements, zinc oxide ceramics with various 46.6ZnO-20Na2O-33.4P2O5glass oxide additions exhibits a good electrical behavior, which can be a suitable candidate material for electronic device applications.

Electrical and Microstructural Properties of Varistors Based on Nanostructured Tetra-Needle Like Zinc Oxide Powders

2012 ◽  
Vol 727-728 ◽  
pp. 533-538
Author(s):  
Felipe Antonio Lucca Sánchez ◽  
Diego Pereira Tarragó ◽  
A.S. Takimi ◽  
V.C. Sousa ◽  
Carlos Pérez Bergmann
Keyword(s):  
Zinc Oxide ◽  
Surface Area ◽  
Electrical Characterization ◽  
Oxide Powder ◽  
Microstructural Properties ◽  
Powder Morphology ◽  
Oxide Powders ◽  
Nanostructured Zinc Oxide ◽  
Transmission Electron ◽  
Zinc Oxide Powder

t is well known that nanostructured materials have relevant influences in properties behavior that can be achieved when compared with conventional materials. In this study is proposed an investigation of the electrical and microstructural properties of zinc oxide based varistors prepared with nanostructured zinc oxide powder obtained by a thermal evaporation process. Zinc oxide powder morphology was investigated by scanning and transmission electron microscopy (SEM and TEM, respectively) and the specific surface area evaluated by adsorption of N2. The varistors were prepared by the mixture of typical dopants with zinc oxide powders in a ball mill. The surface area of zinc oxide powder used was 17.4 m2/g with tetra-needle like morphology. After powder mixture process it was observed by TEM micrographs that most of the tetrapod shaped zinc oxide broke into needles well mixed with dopant particles. The compressed powders were sintering at 1050, 1150 and 1250°C for 1.5 h and densification over 94% were achieved in all tested temperatures. Preliminary electrical characterization reveals that nanostructured zinc oxide compositions have interesting varistor properties.

Characterization of Extended Defects Observed in Cadmium Zinc Telluride (CZT) Crystal

2015 ◽  
Vol 1792 ◽  
Author(s):  
Samuel Uba ◽  
Stephen Babalola ◽  
Anwar Hossain ◽  
Ralph James
Keyword(s):  
Electrical Properties ◽  
Grain Boundaries ◽  
Cadmium Zinc Telluride ◽  
Zinc Telluride ◽  
High Energy ◽  
Extended Defects ◽  
Detector Performance ◽  
Te Inclusions ◽  
Czt Detectors ◽  
Cadmium Zinc

ABSTRACTCadmium Zinc Telluride (CZT) semiconductor crystal properties have been studied extensively with a focus on correlations to their radiation detector performance. The need for defect-free CZT crystal is imperative for optimal detector performance. Extended defects like Tellurium (Te) inclusions, twins, sub-grain boundaries, and dislocations are common defects found in CZT crystals; they alter the electrical properties and, therefore, the crystal's response to high energy radiation. In this research we studied the extended defects in CZT crystals from two separate ingots grown using the low-pressure Bridgman technique. We fabricated several detectors cut from wafers of two separate ingots by dicing, lapping, polishing, etching and applying gold metal contacts on the main surfaces of the crystals. Using infrared (IR) transmission microscope we analyzed the defects observed in the CZT detectors, showing three dimensional scans and plot size distributions of Te inclusions, twins and sub-grain boundaries observed in particular regions of the CZT detectors. We characterized electrical properties of the detectors by measuring bulk resistivity and detector response to gamma radiation. We observed that CZT detectors with more extended defects showed poor opto-electrical properties compared to detectors with fewer defects.

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