Paper Title:
Electric Field Strength Dependent Electric Conductivity in Highly Insulating Materials
  Abstract

The electric conductivity σ in highly insulating materials is determined by the equilibrium thermally generated carriers and by the injected carriers. The injected excess electrons will dominate the thermally generated electrons when the total number of injected electrons substantially exceeds the total number of initially empty electron traps existing in the material. Under these circumstances the electrical charge transport mechanism is no longer ohmic. In order to analyze the dependence of σ upon injected/trapped charge, isothermal and non-isothermal currents in Teflon FEP have been investigated at various temperatures, field strengths, in a vacuum or in ambient air conditions. At temperatures below 413 K, for charging times longer than about 10 s but shorter than about 600 s, the electric conductivity is almost electrical field strengths independent proving that the injected charge plays a minor role. For these conditions the charge is mostly trapped in superficial traps. At higher temperatures σ is field dependent. The final thermally stimulate discharge current has a peak around 500 K with a mean apparent activation energy around 1.35 eV. For a well conditioned sample the peak current is strongly dependent on the charging electric field and on the mean trapping depth of the injected charge. The relaxation time of the trapped charge is around 106 s at 523 K, proving that the injected charge is very stable, a fact of significant importance for applications.

  Info
Periodical
Materials Science Forum (Volumes 514-516)
Edited by
Paula Maria Vilarinho
Pages
920-924
DOI
10.4028/www.scientific.net/MSF.514-516.920
Citation
E. R. Neagu, J. N. Marat-Mendes, "Electric Field Strength Dependent Electric Conductivity in Highly Insulating Materials", Materials Science Forum, Vols. 514-516, pp. 920-924, 2006
Online since
May 2006
Export
Price
$32.00
Share

In order to see related information, you need to Login.

In order to see related information, you need to Login.

Authors: Xiao Ya Li, Yun Yu, Dong Li Wang, Li Dong Chen
Abstract:[Ca2(Co0.65Cu0.35)2O4]0.624CoO2 polycrystalline samples were prepared using sol-gel method followed by spark plasma sintering....
805
Authors: M. Gustavsson, Hideaki Nagai, Takeshi Okutani
Abstract:In modern thermal analysis and design involving thermal transport in solid components it is necessary to apply different modeling of the...
1641
Authors: Zhi Wen Wu, Shu Shu, Da Ren Yu, Xiang Yang Liu, Ning Fei Wang
Abstract:The wall material plays an important role for the electron current due to near wall conductivity in Hall Thrusters. A Monte Carlo method...
519
Authors: Min Zhang, Jian Hua Chen, Zhen Hua Che, Hui Zhong Zhao, Jian Hua Lu
Abstract:Based on idealized non-steady state transient heat conduction model, the thermal conductivities of apple samples were determined at various...
556
Authors: Li Min Zhao, Wei Fen Jiang, Hao Shan Hao
Abstract:Bi2Sr2Co2-xCuxOy (x=0.0, 0.2, 0.4) samples were prepared by solid-state reaction method and the effect of Cu substitution on the...
656