scholarly journals A temperature dependent measurement of the carrier velocity vs. electric field characteristic for as-grown and H-intercalated epitaxial graphene on SiC

2013 ◽  
Vol 113 (19) ◽  
pp. 193708 ◽  
Author(s):  
M. Winters ◽  
J. Hassan ◽  
H. Zirath ◽  
E. Janzén ◽  
N. Rorsman
Keyword(s):  
Electric Field ◽  
Epitaxial Graphene ◽  
Temperature Dependent ◽  
Field Characteristic ◽  
Dependent Measurement ◽  
Carrier Velocity

Carrier Mobility as a Function of Temperature in as-Grown and H-Intercalated Epitaxial Graphenes on 4H-SiC

2014 ◽  
Vol 778-780 ◽  
pp. 1146-1149 ◽  
Author(s):  
Michael Winters ◽  
E.B. Thorsteinsson ◽  
Einar Ö. Sveinbjörnsson ◽  
H.P. Gislason ◽  
Jawad Hassan ◽  
...  
Keyword(s):  
Electric Field ◽  
Acoustic Phonon ◽  
Carrier Mobility ◽  
Phonon Scattering ◽  
Impurity Scattering ◽  
Temperature Dependent ◽  
Low Field ◽  
Carrier Scattering ◽  
Carrier Velocity ◽  
Two Temperature

The carrier velocity is measured as a function of electric field in as-grown and H-intercalaed epitaxial graphene grown on semi-insulating 4H-SiC in order to estimate the low field carrier mobility as a function of temperature. The mobility is also measured on the same samples as a function of temperature in a liquid Helium (He) cooled cryostat. The two temperature dependent measurements are compared in order to deduce the dominant carrier scattering mechanisms in both materials. In as-grown material, acoustic phonon scattering and impurity scattering both contribute, while impurity scattering dominates in H-intercalated material.

scholarly journals Effects of Frequency and Temperature on Electric Field Mitigation Method via Protruding Substrate Combined with Applying Nonlinear FDC Layer in Wide Bandgap Power Modules

Energies ◽  
2020 ◽  
Vol 13 (8) ◽  
pp. 2022 ◽  
Author(s):  
Maryam Mesgarpour Tousi ◽  
Mona Ghassemi
Keyword(s):  
Electrical Conductivity ◽  
Electric Field ◽  
Metal Layer ◽  
Wide Bandgap ◽  
High Density ◽  
Field Calculation ◽  
Power Module ◽  
Temperature Dependent ◽  
Ac Electrical Conductivity ◽  
Power Modules

Our previous studies showed that geometrical techniques including (1) metal layer offset, (2) stacked substrate design and (3) protruding substrate, either individually or combined, cannot solve high electric field issues in high voltage high-density wide bandgap (WBG) power modules. Then, for the first time, we showed that a combination of the aforementioned geometrical methods and the application of a nonlinear field-dependent conductivity (FDC) layer could address the issue. Simulations were done under a 50 Hz sinusoidal AC voltage per IEC 61287-1. However, in practice, the insulation materials of the envisaged WBG power modules will be under square wave voltage pulses with a frequency of up to a few tens of kHz and temperatures up to a few hundred degrees. The relative permittivity and electrical conductivity of aluminum nitride (AlN) ceramic, silicone gel, and nonlinear FDC materials that were assumed to be constant in our previous studies, may be frequency- and temperature-dependent, and their dependency should be considered in the model. This is the case for other papers dealing with electric field calculation within power electronics modules, where the permittivity and AC electrical conductivity of the encapsulant and ceramic substrate materials are assumed at room temperature and for a 50 or 60 Hz AC sinusoidal voltage. Thus, the big question that remains unanswered is whether or not electric field simulations are valid for high temperature and high-frequency conditions. In this paper, this technical gap is addressed where a frequency- and temperature-dependent finite element method (FEM) model of the insulation system envisaged for a 6.5 kV high-density WBG power module will be developed in COMSOL Multiphysics, where a protruding substrate combined with the application of a nonlinear FDC layer is considered to address the high field issue. By using this model, the influence of frequency and temperature on the effectiveness of the proposed electric field reduction method is studied.

Temperature dependent domain-wall moving dynamics of lithium niobate during high electric field periodic poling

2020 ◽  
Vol 128 (22) ◽  
pp. 224101
Author(s):  
Qilu Liu ◽  
Fulei Wang ◽  
Dongzhou Wang ◽  
Dehui Sun ◽  
Yuanhua Sang ◽  
...  
Keyword(s):  
Domain Wall ◽  
Lithium Niobate ◽  
Electric Field ◽  
High Electric Field ◽  
Temperature Dependent ◽  
Dependent Domain

Study on the Influence of Electrode Collocation to Electric Field Characteristic of ESP

2014 ◽  
Vol 875-877 ◽  
pp. 1683-1686
Author(s):  
Cheng Liang Jia ◽  
You Shan Sun ◽  
Chao Huang ◽  
Wan Peng Zhang ◽  
Fang Chen
Keyword(s):  
Electric Field ◽  
Current Density ◽  
Surface Current ◽  
Electrode Configuration ◽  
Electrode Gap ◽  
Average Current Density ◽  
Surface Current Density ◽  
Discharge Electrode ◽  
Field Characteristic ◽  
Average Current

A laboratory-scale ESP with new electrode configuration was established to investigate the electric field characteristic. Eight teeth prick line and prick plate with the length of 20mm were employed as discharge electrodes, respectively. The effects of discharge electrode type and electrode gap on V-I characteristic and surface current density were studied. The results showed that the optimum electrode gaps were 350-400mm for eight teeth line and 300-350mm for prick plate, which could obtained higher average current density and lower variance.

Temperature Dependent Measurement And Simulation Of Fresnel Lenses For Concentrating Photovoltaics

2010 ◽  
Author(s):  
Thorsten Hornung ◽  
Andreas Bachmaier ◽  
Peter Nitz ◽  
Andreas Gombert ◽  
Andreas W. Bett ◽  
...  
Keyword(s):  
Temperature Dependent ◽  
Dependent Measurement ◽  
Fresnel Lenses

Temperature and electric field induced phase transition in [110]C-oriented 0.63Pb(Mg1/3Nb2/3)O3–0.37PbTiO3 single crystals

CrystEngComm ◽  
2015 ◽  
Vol 17 (45) ◽  
pp. 8664-8670 ◽  
Author(s):  
Wenhui He ◽  
Qiang Li ◽  
Nengneng Luo ◽  
Yiling Zhang ◽  
Qingfeng Yan
Keyword(s):  
Phase Transition ◽  
Electric Field ◽  
Light Microscopy ◽  
Single Crystals ◽  
Polarized Light ◽  
Polarized Light Microscopy ◽  
Temperature Dependent ◽  
Dependent Domain

Temperature-dependent domain configurations were studied for both unpoled and poled [110]C-oriented 0.63Pb(Mg1/3Nb2/3)O3–0.37PbTiO3 (PMN–0.37PT) single crystals by polarized light microscopy (PLM).

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