Nucleation layer microstructure, grain size, and electrical properties in GaN grown on a-plane sapphire

1999 ◽  
Vol 75 (5) ◽  
pp. 686-688 ◽  
Author(s):  
M. E. Twigg ◽  
R. L. Henry ◽  
A. E. Wickenden ◽  
D. D. Koleske ◽  
J. C. Culbertson
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Nucleation Layer

scholarly journals Structural and Electrical Studies on ZnO-Based Thin Films by Laser Irradiation

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Shanyue Zhao ◽  
Yinqun Hua ◽  
Ruifang Chen ◽  
Jian Zhang ◽  
Ping Ji
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Electrical Properties ◽  
Grain Boundaries ◽  
Laser Irradiation ◽  
Nonlinear Coefficient ◽  
Acceptor State ◽  
Xrd Pattern ◽  
Electrical Studies ◽  
Structural And Electrical Properties

The effects of laser irradiation on the structural and electrical properties of ZnO-based thin films were investigated. The XRD pattern shows that the thin films were highly textured along thec-axis and perpendicular to the surface of the substrate. Raman spectra reveal that Bi2O3segregates mainly at ZnO-ZnO grain boundaries. After laser irradiation processing, the grain size of the film was reduced significantly, and the intrinsic atomic defects of grain boundaries and Bi element segregated at the grain boundary were interacted frequently and formed the composite defects of acceptor state. The nonlinear coefficient increased to 24.31 and the breakdown voltage reduced to 5.34 V.

Effect of grain size on the electrical properties of strontium and magnesium doped lanthanum gallate electrolytes

2019 ◽  
Vol 777 ◽  
pp. 244-251 ◽  
Author(s):  
Shenglong Yu ◽  
Hailin Bi ◽  
Jialing Sun ◽  
Lili Zhu ◽  
Huamin Yu ◽  
...  
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Lanthanum Gallate

Thermal Diffusivity and Conductivity of La0.7Ca0.3-xSrxMnO3 (x=0 to 0.10)

2012 ◽  
Vol 501 ◽  
pp. 319-323
Author(s):  
Hasan A. Alwi ◽  
Lay S. Ewe ◽  
Zahari Ibrahim ◽  
Noor B. Ibrahim ◽  
Roslan Abd-Shukor
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Grain Size ◽  
Transition Temperature ◽  
Thermal Diffusivity ◽  
Electrical Properties ◽  
Room Temperature ◽  
Electronic Contribution ◽  
Insulator Metal Transition ◽  
Thermal And Electrical Properties

We report the room temperature thermal conductivity κ and thermal diffusivity α of polycrystalline La0.7Ca0.3-xSrxMnO3 for x = 0 to 0.1. The samples were prepared by heating at 1220 and 1320oC. The insulator-metal transition temperature, TIM and thermal diffusivity increased with Sr content. Phonon was the dominant contributor to thermal conductivity and the electronic contribution was less than 1%. Enhancement of electrical conductivity σ and thermal diffusivity for x ≥ 0.08 was observed in both series of samples. The grain size of the samples (28 to 46 µm) does not show any affect on the thermal and electrical properties.

Effect of WO3 Doping on Microstructural and Electrical Properties of ZnO-Pr6O11 Based Varistor Materials

2013 ◽  
Vol 591 ◽  
pp. 54-60
Author(s):  
Xiu Li Fu ◽  
Yan Xu Zang ◽  
Zhi Jian Peng
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Grain Growth ◽  
Doping Level ◽  
Nonlinear Coefficient ◽  
Current Voltage ◽  
Average Grain Size ◽  
Current Voltage Characteristics ◽  
Voltage Performance

The effect of WO3doping on microstructural and electrical properties of ZnO-Pr6O11based varistor materials was investigated. The doped WO3plays a role of inhibitor in ZnO grain growth, resulting in decreased average grain size from 2.68 to 1.68 μm with increasing doping level of WO3from 0 to 0.5 mol%. When the doping level of WO3was lower than 0.05 mol%, the nonlinear current-voltage characteristics of the obtained varistors could be improved significantly with increasing amount of WO3doped. But when the doping level of WO3became higher, their nonlinear current-voltage performance would be dramatically deteriorated when more WO3was doped. The optimum nonlinear coefficient, varistor voltage, and leakage current of the samples were about 13.71, 710 V/mm and 13 μA/cm2, respectively, when the doping level of WO3was in the range from 0.03 to 0.05 mol%.

Study on Microstructure and Properties of BTBY Piezoelectric Ceramics with High Curie Temperature

2010 ◽  
Vol 156-157 ◽  
pp. 1541-1544
Author(s):  
Bo Li ◽  
Feng Gao ◽  
Liang Liang Liu ◽  
Bei Xu
Keyword(s):  
Dielectric Constant ◽  
Grain Size ◽  
Electrical Properties ◽  
Dielectric Loss ◽  
Curie Temperature ◽  
Grain Morphology ◽  
High Curie Temperature ◽  
Microstructure And Properties ◽  
New Phase ◽  
Dielectric Relaxor

(1-x)(0.6BIT-0.4BT)-xBiYbO3(BTBY) ceramics with high Curie temperature were prepared by the conventional processing. The effect of BiYbO3 content on the microstructure and electrical properties was investigated. The results show that the main phase of BTBY ceramics is BIT-BT, and a new phase BaBi4Ti4O15 (BBT) appeared. The grain morphology of BTPY ceramics are platelike and the grain size was significantly increased with increasing content of BiYbO3 .Tc of all the BTBY samples are above 440 . The BTBY ceramics show obvious dielectric relaxor characteristic. The dispersion factor γ, the dielectric constant εr, and the dielectric loss tanδ decreased with increasing the content of BiYbO3. When the content of BiYbO3 is 0.06, the optimal properties of BTBY ceramics are obtained, Tc is 457 , εr is 165, tanδ is 0.0223 and d33 is 10 pC·N-1.

Microwave Sintering Technology for the Production of Metal Oxide Varistors

1990 ◽  
Vol 189 ◽  
Author(s):  
G. McMahon ◽  
A. Pant ◽  
R. Sood ◽  
A. Ahmas ◽  
R.T. Holt
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Metal Oxide ◽  
Leakage Current ◽  
Microwave Sintering ◽  
Identical Composition

ABSTRACTA microwave sintering technology has been developed for the production of metal oxide varistors. The electrical properties (leakage current and non-linearity coefficient) of the microwave sintered devices were found to be comparable to those obtained for conventionally sintered varistors of identical composition. Additionally, the reference voltages were greater (by a factor of two) and the biaxial moduli of rupture were higher for the microwave sintered specimens. These differences have been attributed to the smaller grain size associated with the microwave sintered specimens.

Synthesis of Nanocrystalline 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 Powder by a Citrate Method

2008 ◽  
Vol 368-372 ◽  
pp. 103-105
Author(s):  
Zhi Bin Tian ◽  
Xiao Hui Wang ◽  
Ji Li ◽  
Wei Zhao ◽  
Long Tu Li
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Traditional Method ◽  
Sintering Temperature ◽  
Ph Value ◽  
Precursor Solution ◽  
Milling Process ◽  
Citrate Method ◽  
Nano Powder ◽  
Average Grain Size

A citrate method to synthesize 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 nano-powder was studied. The stable gel was obtained by the control of the pH value and temperature of the precursor solution. The BNBT nano-powder was produced after calcining the xerogel at 600°C~800°C. The average grain size of the powder calcined at 700°C for 3 h is 50 nm, and the grain size of the ceramic sintered at 1080°C is 0.7 μm. The sintering temperature used is 100°C lower than the BNBT ceramic prepared by traditional method, but the electrical properties were comparable. In addition, it was found that the ball-milling process has important effect on the morphology of the ceramics and the orientation crystals were eliminated due to the disintegration of agglomerates during milling.

The Electrical Properties of BCZT Lead-Free Ceramics Induced by BaZrO3 Seeds

2016 ◽  
Vol 690 ◽  
pp. 114-119
Author(s):  
Piewpan Parjansri ◽  
Manlika Kamnoy ◽  
Uraiwan Intatha ◽  
Sukum Eitssayeam ◽  
Tawee Tunkasiri
Keyword(s):  
Grain Size ◽  
Electrical Properties ◽  
Perovskite Phase ◽  
Nano Particle ◽  
Sintered Ceramic ◽  
Voltage Coefficient ◽  
Lead Free Ceramics ◽  
Seed Content ◽  
Pure Perovskite Phase ◽  
Average Grain Size

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) ceramics were produced by using the seed-induced method. The nano-particle BZ (BaZrO3) seeds were mixed with BaCO3, CaCO3, ZrO2 and TiO2 powder for preparing by the mixed oxide method. The XRD results indicated that all powder and sintered ceramic samples showed a pure perovskite phase with coexistence between rhombohedral and tetragonal phase. As the BZ seed content increased, the density of ceramics tended to decrease from 5.61 g/cm3 to 5.37 g/cm3. The average grain size of the ceramics was in the range of 12.15 -13.50 mm. The dielectric loss (tand) was less than 0.03 for all samples at room temperature (at 1 kHz). Other electrical properties, including dielectric constant (εr), remnant polarization (Pr), and piezoelectric charge coefficient (d33) values decreased with increasing BZ seed doping with relates to the decreasing grain size and density of BCZT ceramics. However, the values of coercive field (Ec) decreased and piezoelectric voltage coefficient (g33) increased with BZ seed doping.

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