The Effects of Cu Dopant on the Microstructure and Non-Ohmic Electrical Properties of ZnO Varistors

2011 ◽  
Vol 343-344 ◽  
pp. 160-165 ◽  
Author(s):  
Ji Wei Fan ◽  
Xiao Peng Li ◽  
Zhen Guo Zhang ◽  
Zhi Qiang Jiao ◽  
Xiang Yang Liu ◽  
...  
Keyword(s):  
Electrical Property ◽  
Electrical Properties ◽  
Grain Boundary ◽  
Grain Growth ◽  
Electrical Characteristics ◽  
Doping Effects ◽  
Zno Varistors ◽  
Doped Zno ◽  
Cu Dopant ◽  
Good Agreement

The doping effects of Cu on the microstructure and non-ohmic electrical properties of ZnO varistors were studied. Addition of Cu2O can enhance the ZnO grain growth during sintering. The SEM and EDS results revealed that the added Cu mainly distributed in the grain boundary and spinel phases of ZnO varistors. The Cu2O addition increased the both of grain and grain boundary resistances. However it decreased the non-ohmic electrical characteristics of ZnO varistors, which is a good agreement with similar findings on Ag2O additions, but contrasts to the reports of good non-ohmic electrical property which found on binary Cu doped ZnO varistors.

Analysis of Grain-Boundary in SrCoO3–Doped ZnO Varistors and its Electrical Characteristics

2013 ◽  
Vol 582 ◽  
pp. 181-184 ◽  
Author(s):  
Eiichi Koga ◽  
Masayuki Hogiri ◽  
Yoshiko Higashi
Keyword(s):  
Grain Boundary ◽  
Schottky Barrier ◽  
Boundary Region ◽  
Electrical Characteristics ◽  
Electrical Behavior ◽  
Hetero Structure ◽  
Characteristic Behavior ◽  
Zno Varistors ◽  
Doped Zno ◽  
Barrier Model

The grain-boundary and its electrical characteristics in SrCoO3doped ZnO varistors were studied. The grain-boundary around ZnO-grain is probably composed of SrCoO3, and its electrical behavior is clearly different from two conventional types of Bi-and Pr-based ZnO varitors. The non-linearity and characteristic behavior could be explained by considering the n-p-n hetero-structure at the grain boundary. SrCoO3 in the grain-boundary region should play crucial roles of not only the appearance of non-liner property but also the formation of different hetero-structure from double Schottky-barrier model on conventional varistors.

The Electrical Properties and Impedance Analysis of ZnO Varistors Doped with Different Cu2O Contents

2014 ◽  
Vol 681 ◽  
pp. 173-176
Author(s):  
Ji Wei Fan ◽  
Hui Jun Zhao ◽  
Xiao Li Zhang
Keyword(s):  
Electrical Properties ◽  
Grain Boundary ◽  
Leakage Current ◽  
Impedance Analysis ◽  
Boundary Resistance ◽  
Zno Varistors ◽  
Good Agreement

The Cu2O addition deteriorates the electrical properties of ZnO varistors, which is a good agreement with similar findings on Ag2O additions. The best fitted impedance analysis reveals that the Cu2O addition increases grain resistance and lowers the grain boundary resistance, results in low nonlinearity and higher leakage current of ZnO varistors.

Effect of Si and Ba Addition on ZnO Grain Growth and Electrical Characteristics of Bi-Based ZnO Varistors

2013 ◽  
Vol 566 ◽  
pp. 219-222 ◽  
Author(s):  
Atsuko Kubota ◽  
Ai Fukumori ◽  
Yuuki Sato ◽  
Shinzo Yoshikado
Keyword(s):  
Grain Boundary ◽  
Grain Growth ◽  
Electrical Characteristics ◽  
Electrical Degradation ◽  
Zno Varistors

With the goal of fabricating varistors with low varistor voltages, we investigated the effects of adding Ba and Si to BiCoMn-added ZnO varistors on the varistor voltage and the resistance to electrical degradation. Ba2Mn3O8, which reduces the resistance to electrical degradation, was not formed at the grain boundary when Si was added. The resistance to electrical degradation was considerably improved by adding 0.10.15 mol% Si relative to samples to which small amounts of Sb had been added. The varistor voltage increased monotonically with increasing amount of added Si; it was approximately 36 V/mm for 0.1 mol% Si.

scholarly journals Microstructure and Electrical Properties of Low-Voltage Barium Titanate Doped Zinc Oxide Varistor Ceramics

2019 ◽  
Vol 8 (4) ◽  
pp. 2713-2718
Keyword(s):  
Zinc Oxide ◽  
Electrical Properties ◽  
Barium Titanate ◽  
Grain Boundary ◽  
Barrier Height ◽  
Current Density ◽  
Low Voltage ◽  
X Ray ◽  
Highly Nonlinear ◽  
Zno Varistors

In the present, varistor ceramics through the combination of zinc oxide (ZnO) with a perovskite material have become widespread because of their unique properties for a wide range of applications in electronic protection devices. Low-voltage zinc oxide (ZnO) varistors with fast response and highly nonlinear electrical properties for overvoltage protection in an integrated circuit are increasingly significant in the application of low-voltage electronics. The present study highlights the interaction between barium titanate (BaTiO3 ) and ZnO varistors through the employment of solid-state reaction method in the production of low-voltage varistors. The effects of BaTiO3 on the microstructure of ZnO varistors were analyzed through scanning electron microscopy (SEM), energy dispersive X-ray analysis spectroscopy (EDS) and X-ray diffraction (XRD). The EDS analysis and XRD measurements suggest the presence of ZnO and BaTiO3 phases. The electrical properties of BaTiO3 -doped ZnO varistors were examined based on the current density-electric field (J-E) characteristics measurement. The varistor properties showed the nonlinear coefficient (α) from 1.8 to 4.8 with the barrier height (φB) ranged from 0.70 to 0.88 eV. The used of BaTiO3 additive in ZnO varistors produced varistor voltages of 4.7 to 14.1 V/mm with the voltage per grain boundary (Vgb) was measured in the ranges 0.03 to 0.05 V. The lowest leakage current density was 348 µA/cm2 , obtained at the samples containing 12 wt.% BaTiO3 with high barrier height. The reduction in barrier height with increasing BaTiO3 content was associated with the excessive amount of BaTiO3 phase, hence cause the deterioration of active grain boundary due to the variation of oxygen (O) vacancies in the grain boundary.

scholarly journals Ion Beam Enhanced Grain Growth in Thin Films

1986 ◽  
Vol 74 ◽  
Author(s):  
Harry A. Atwater ◽  
Carl V. Tiiompson ◽  
Henry I. Smith
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Grain Boundary ◽  
Grain Growth ◽  
Thermal Equilibrium ◽  
Ion Beam ◽  
Defect Concentration ◽  
Growth Enhancement ◽  
Frenkel Defect ◽  
Good Agreement

AbstractIon beam enhanced grain growth has been investigated in thin films of Ge. Grain boundary mobilities are greatly enhanced over their thermal equilibrium values and exhibit a very weak temperature dependence. We propose that defects which are generated by the ion beam at or near the grain boundary are responsible for the boundary mobility enhancement. Films of Ge deposited under different conditions, either unsupported or on thermally oxidized Si, exhibit similar normal grain growth enhancement when implanted with 50 keV Ge+. Beam-enhanced grain growth in Ge was also demonstrated using Xe+, Kr+, and Ar+ ions. The variation in growth enhancement with projectile ion mass is in good agreement with the enhanced Frenkel defect population calculated using a modified Kinchin-Pease formula and Monte Carlo simulation of ion transport in thin films. Calculations based on experiments suggest that there is approximately one atomic jump across the grain boundary per defect generated. Also, the grain growth rate for a given beam-generated defect concentration near the boundary is approximately equal to the expected growth rate for the same defect concentration if thermally generated.

Effects of cobalt doping on the electrical characteristics of Al-doped ZnO varistors

2010 ◽  
Vol 64 (9) ◽  
pp. 1081-1084 ◽  
Author(s):  
Wangcheng Long ◽  
Jun Hu ◽  
Jun Liu ◽  
Jinliang He
Keyword(s):  
Electrical Characteristics ◽  
Cobalt Doping ◽  
Zno Varistors ◽  
Doped Zno

Effect of Ba Addition on Grain Growth of ZnO and Electrical Characteristics of Bi-based ZnO Varistors

2011 ◽  
Vol 131 (3) ◽  
pp. 211-218
Author(s):  
Ai Fukumori ◽  
Takayuki Watanabe ◽  
Yuuki Sato ◽  
Shinzo Yoshikado
Keyword(s):  
Grain Growth ◽  
Electrical Characteristics ◽  
Zno Varistors
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