Bias electric field distribution analysis based on finite difference method with non-uniform grids for a non-contact tunneling current probe

Author(s):  
Xingyuan Bian ◽  
Junning Cui ◽  
Yesheng Lu ◽  
Jiubin Tan
Author(s):  
N. Rouger

Purpose – Scientists and engineers have been solving Poisson’s equation in PN junctions following two approaches: analytical solving or numerical methods. Although several efforts have been accomplished to offer accurate and fast analyses of the electric field distribution as a function of voltage bias and doping profiles, so far none achieved an analytic or semi-analytic solution to describe neither a double diffused PN junction nor a general case for any doping profile. The paper aims to discuss these issues. Design/methodology/approach – In this work, a double Gaussian doping distribution is first considered. However, such a doping profile leads to an implicit problem where Poisson’s equation cannot be solved analytically. A method is introduced and successfully applied, and compared to a finite element analysis. The approach is then generalized, where any doping profile can be considered. 2D and 3D extensions are also presented, when symmetries occur for the doping profile. Findings – These results and the approach here presented offer an efficient and accurate alternative to numerical methods for the modeling and simulation of mathematical equations arising in physics of semiconductor devices. Research limitations/implications – A general 3D extension in the case where no symmetry exists can be considered for further developments. Practical implications – The paper strongly simplify and ease the optimization and design of any PN junction. Originality/value – This paper provides a novel method for electric field distribution analysis.


2012 ◽  
Vol 229-231 ◽  
pp. 807-810
Author(s):  
Li Zhang ◽  
Qing Min Li ◽  
Li Na Zhang ◽  
Yu Di Cong

±1000kV DC wall bushing under planning is a complex insulation system which bears the effects imposed by different working conditions. The electric field distribution is concentrated at the bushing outlet terminal, which might result in breakdown discharge especially when short-time abrupt conditions such as polarity reversal occur. In this paper, the finite element method is utilized to analyze electric field distribution and potential distribution of wall bushing during polarity reversal. Electric field distribution and potential distribution at the moment of polarity reversal are obtained, which provides value reference for the study of polarity reversal process.


2016 ◽  
Vol 20 (5) ◽  
pp. 1359-1380 ◽  
Author(s):  
Peder Aursand ◽  
Gaetano Napoli ◽  
Johanna Ridder

AbstractWe propose an implicit finite-difference method to study the time evolution of the director field of a nematic liquid crystal under the influence of an electric field with weak anchoring at the boundary. The scheme allows us to study the dynamics of transitions between different director equilibrium states under varying electric field and anchoring strength. In particular, we are able to simulate the transition to excited states of odd parity, which have previously been observed in experiments, but so far only analyzed in the static case.


Author(s):  
Himadri Sekhar Basu ◽  
Supreet Singh Bahga ◽  
Sasidhar Kondaraju

Transient electrokinetic (EK) flows involve the transport of conductivity gradients developed as a result of mixing of ionic species in the fluid, which in turn is affected by the electric field applied across the channel. The presence of three different coupled equations with corresponding different time scales makes it difficult to model the problem using the lattice Boltzmann method (LBM). The present work aims to develop a hybrid LBM and finite difference method (FDM)-based model which can be used to study the electro-osmotic flows (EOFs) and the onset of EK instabilities using an Ohmic model, where fluid and conductivity transport are solved using LBM and the electric field is solved using FDM. The model developed will be used to simulate three different problems: (i) EOF with varying zeta-potential on the wall, (ii) similitude in EOF, and (iii) EK instabilities due to the presence of conductivity gradients. Problems (i) and (ii) will be compared with the analytical results and problem (iii) will be compared with the simulations of a spectral method-based numerical model. The results obtained from the present simulations will show that the developed model is capable of studying transient EK flows and of predicting the onset of instability.


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