Electrostatic force microscopy as a tool to estimate the number of active potential barriers in dense non-Ohmic polycrystalline SnO2 devices

Vasconcelos, J. S.; Vasconcelos, N. S. L. S.; Orlandi, Marcelo Ornaghi; Bueno, Paulo Roberto; Varela, José Arana; Longo, Elson; Barrado, Cristiano M.; Leite, E. R.

doi:10.1063/1.2354483

Cited by 35 publications

(23 citation statements)

References 15 publications

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“…Such approach was tested in a highly dense SnO 2 -based polycrystalline semiconductor. Therefore, the value of mean potential barrier height obtained was found to be about 1.4 V. 29 The comparison of this value obtained from EFM with that value obtained from a complex capacitance analysis according to the approach previously discussed is shown in Table 5. The other parameters of the system are still shown in this table, for instance, nonlinear coefficient value and electric breakdown field.…”

Section: Electrostatic Force Microscopy and Admittance Spectroscopymentioning

confidence: 69%

“…From the pattern of capacitive potential energy obtained from electrostatic force microscopy (EFM) technique as a function of the applied voltage, 29 it is possible to obtain the minimum voltage value corresponding to the mean value of potential barrier height for the active junctions. Such approach was tested in a highly dense SnO 2 -based polycrystalline semiconductor.…”

Section: Electrostatic Force Microscopy and Admittance Spectroscopymentioning

confidence: 99%

“…(6) with the complex capacitance analysis, respectively. 29 It is important to emphasize that, for the calculation of φ conv , the p parameter was corrected to consider the 85% of active potential barriers, i.e. p = 0.85L/d (L is the sample thickness and d the mean grain size).…”

Section: Electrostatic Force Microscopy and Admittance Spectroscopymentioning

confidence: 99%

See 2 more Smart Citations

Admittance and dielectric spectroscopy of polycrystalline semiconductors

Bueno

Varela

Longo

2007

Journal of the European Ceramic Society

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Section: Electrostatic Force Microscopy and Admittance Spectroscopymentioning

confidence: 69%

Section: Electrostatic Force Microscopy and Admittance Spectroscopymentioning

confidence: 99%

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Admittance and dielectric spectroscopy of polycrystalline semiconductors

Bueno

Varela

Longo

2007

Journal of the European Ceramic Society

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“…As the CuO concentration increases above 0.2 mol %, the nonlinear coefficient decreases. According to the previous work [22], the decreasing nonlinear coefficient might be associated to the reduction of the effective grain boundary. On the contrary, The leakage current density decreases firstly with the CuO concentration increasing from 0 to 0.2 mol %, and then increases gradually with the CuO concentration further increasing from 0.2 to 0.6 mol %.…”

mentioning

confidence: 74%

Effect of CuO addition on the microstructure and electrical properties of SnO2-based varistor

Zhu

Yang

et al. 2013

J Mater Sci: Mater Electron

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The effect of CuO addition on the properties of (Co, Nb, Cr)-doped SnO 2 varistors were investigated. The samples with different CuO concentrations were fabricated by the conventional ceramic method and sintered at 1,200, 1,250, 1,300 and 1,350°C for 2 h. It is found that the nonlinear coefficient presents a peak value at 0.2 mol % CuO addition. The leakage current density decreases with increasing CuO from 0 to 0.2 mol %, and then increases when the concentration of CuO is above 0.2 mol %. The breakdown electrical field decreases from 356 to 248 V/mm with increasing CuO from 0 to 0.6 mol %. The optimal samples obtained by doping CuO with 0.2 mol % and sintered at 1,300°C have the highest nonlinear coefficient value of 31 and the lowest leakage current density of 2 lA/cm 2 .

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“…based varistor the active potential barrier ranges from 15-35% [24][25] and SnO 2 -based varistor 85% of the grain-to-grain junctions were active potential barriers [26][27] . For the sample with x = 0.5, the increase in the capacitance with bias voltage can be related to degradation in the nonohmic properties involving a distortion of the Schottky barriers at intergrains.…”

Section: Resultsmentioning

confidence: 99%

Microstructural and nonohmic properties of ZnO.Pr6O11 CoO polycrystalline system

et al. 2010

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the effective cross-section area of the elements is increased 14 . Several studies describe the dependence of varistor properties on processing conditions of Pr-doped ZnO varistors, especially in the field of grain boundary formation [2][3][4] 13 . It is very important to understand the structure, composition and properties of the boundaries since they have a strong influence on electrical properties. Our purpose is to investigate the microstructure, the current density-electric field (J vs. E) characteristics, and the capacitance-voltage (C-V) characteristics of ZPC varistor systems. Experimental ProcedureThe varistor systems (95-x) mol% ZnO + x mol% Pr 6 O 11 + 5 mol% CoO (x = 0.1, 0.5 and 1.0) were prepared from the mixture of oxide precursors method, all of them being analytical grade oxides: ZnO (Aldrich-99.99%), Pr 6 O 11 (Aldrich-99.9%) and CoO (Riedel-99.9%). The starting materials were attrition-milled in water for 3 hours. Then the dry slurry was calcined at 750 °C in air for 2 hours. The calcined powders were pulverized using agate mortar and pestle and after 2 wt. (%) polyvinyl alcohol (PVA) binder addition, granulated by sieving 200-mesh screen to produce the starting powder. The powder was uniaxially pressed into discs of 12 mm diameter and 1 mm thickness at a pressure of 80 MPa. The pellets were sintered at 1300 and 1350 °C for 2 hours with a heating rate of 5 °C/min followed by furnace cooling. The samples were characterized by X-ray diffraction (XRD, Rigaku, 20-2000), 40 kV and 150 mA from 2θ (20 to 80°), ∆2θ = 0.02°, with Cukα wavelength monocromatized by a graphite crystal. To obtain the Scanning Electron Microscopy (SEM) micrographies (ZEISS ® DSM 940 A) the sintered samples were polished and thermally etched by heating at 100 °C below the IntroductionZnO varistor ceramics are resistor devices manufactured by sintering ZnO powder containing various minor additives 1 . It has been recognized that at least two different classes of additives must be added to the ceramic varistors in order to obtain good nonohmic characteristics 2 . The first class of such additives are varistor-forming oxides (VFO), such as Bi 2 O 3 , Pr 6 O 11 , La 2 O 3 , BaO, V 2 O 5 and glass frits. The second class of additives are 3d transition-metal oxides, which improve significantly the nonohmic characteristics 3 . Zinc oxide ceramics, containing Pr 6 O 11 and CoO, which exhibit current nonohmic characteristics, were first reported by Mukae et al. 4 . In fact, the history of Pr 6 O 11 -based ZnO varistors is similar to the Bi 2 O 3 -based ZnO varistors 5 , but they have not been adequately studied. However, the Pr 6 O 11 -based ZnO varistors don't have volatilization of components 3 and they own a simpler microstructure when compared with Bi 2 O 3 -based varistors, which is an important fact for the stability and degradation phenomena [6][7][8][9] . Most of commercial ZnO varistors are ZnO-Bi 2 O 3 -based varistor ceramics, possessing as major additive Bi 2 O 3 . Although they exhibit excellent varistor perform...

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Electrostatic force microscopy as a tool to estimate the number of active potential barriers in dense non-Ohmic polycrystalline SnO2 devices

Cited by 35 publications

References 15 publications

Admittance and dielectric spectroscopy of polycrystalline semiconductors

Admittance and dielectric spectroscopy of polycrystalline semiconductors

Effect of CuO addition on the microstructure and electrical properties of SnO2-based varistor

Microstructural and nonohmic properties of ZnO.Pr6O11 CoO polycrystalline system

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