基于单极性输运模型的聚乙烯空间电荷输运特性研究

Space Charge Transport Properties of Polyethylene Thin Films Based on Unipolar Transport Model

采用单极性载流子输运模型仿真了聚乙烯短路后的空间电荷的输运特性,比较了不同对流项离散格式数值解的准确性,并研究了放电电流的影响因素。研究结果表明,电子连续性方程为对流占优的对流扩散方程,应采用三阶迎风格式离散对流项。采用欧姆电极时,空间电荷消散所引起的放电电流衰减比阻塞电极快。随着电子迁移率和初始电荷密度的增加,相同时刻的放电电流密度越大。随着温度的增加,放电电流密度减小。该结果可为深刻认识等温松弛电流法和热刺激电流法实验结果提供理论基础。

The paper gives a simulation of its properties based on unipolar carrier transport model,makes a comparison of the accuracy of numerical results when different schemes are adopted for discrete convective term,and analyzes the influence factors of discharge current.The results show that:(1)three order upwind scheme is most suitable for electron continuity equation,which is a convectiondiffusion equation with dominant convection;(2)The discharge current originated from space charge dissipation under the condition of ohmic electrodes decreases more rapidly than that under the condition of blocking electrodes;(3)as the increase of electron mobility and initial charge density,discharge current at the same moment also becomes more bigger;and(4)the discharge current decreases with the increase of temperature.The results provided the theoretical basis for isothermal relaxation current method and thermally stimulated current method.