This study focuses on charge transport in epoxy bulk, an insulating spacer material. We discuss the relationship between the space charge behavior and the external current determined by conduction and displacement currents. One-dimensional space charge behavior in epoxy is simulated using a bipolar charge transport model that considers charge trapping, de-trapping and recombination. The simulated results show that the charge accumulation in epoxy is successfully modeled by considering high-density deep traps at the epoxy/electrode interface and optimizing the parameters, whereas the simulated external current is inconsistent with the experimental results where the external current decreases in power-law behavior. In the simulation, the external current gradually increases and reaches a steady state as the charge accumulation gets saturated. Charge accumulation does not contribute to the decrease in the external current, which is contrary to the prediction based on the experimental results. We then show that the power-law decrease of the external current is due to the presence of bipolar initial charges before voltage application and multi-depth traps in epoxy. The results strongly indicate that multi-depth trapping/de-trapping, like hopping transfer, rather than single-depth trapping/de-trapping should be taken into account when modeling charge transport in epoxy.

中文翻译：

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DC-GIS 绝缘垫片环氧树脂中电荷传输的一维建模


本研究重点关注环氧树脂本体（一种绝缘隔离材料）中的电荷传输。我们讨论了空间电荷行为与由传导电流和位移电流确定的外部电流之间的关系。使用双极电荷传输模型模拟环氧树脂中的一维空间电荷行为，该模型考虑了电荷捕获、去捕获和复合。模拟结果表明，通过考虑环氧树脂/电极界面处的高密度深陷阱并优化参数，成功地模拟了环氧树脂中的电荷积累，但模拟的外部电流与实验结果不一致，外部电流随功率下降。法律行为。在仿真中，随着电荷积累饱和，外部电流逐渐增加并达到稳定状态。电荷积累不会导致外部电流的减小，这与基于实验结果的预测相反。然后我们表明，外部电流的幂律下降是由于在施加电压之前存在双极初始电荷和环氧树脂中的多深度陷阱所致。结果强烈表明，在对环氧树脂中的电荷传输进行建模时，应考虑多深度捕获/去捕获，例如跳跃转移，而不是单深度捕获/去捕获。