Charging dynamics of a polymer due to electron irradiation： A simultaneous scattering-transport model and preliminary results

• Published in: Chinese physics B Vol. 21; no. 12; pp. 487 - 493
• Main Author: 曹猛 王芳 刘婧 张海波
• Format: Journal Article
• Language: English
• Published: 01.12.2012
• Subjects: Charge; Charging; Computer simulation; Dynamics; Electric charge; Electric fields; Electron irradiation; Electron scattering; Mathematical models; 传输模型; 充电过程; 数值模拟; 电子散射; 电子束照射; 电子辐照; 空间电荷分布; 聚合物
• ISSN: 1674-1056; 2058-3834; 1741-4199
• DOI: 10.1088/1674-1056/21/12/127901

We present a novel numerical model and simulate preliminarily the charging process of a polymer subjected to electron irradiation of several 10 keV. The model includes the simultaneous processes of electron scattering and ambipolar transport and the influence of a self-consistent electric field on the scattering distribution of electrons. The dynamic spatial distribution of charges is obtained and validated by existing experimental data. Our simulations show that excess negative charges are concentrated near the edge of the electron range. However, the formed region of high charge density may extend to the surface and bottom of a kapton sample, due to the effects of the electric field on electron scattering and charge transport, respectively. Charge trapping is then demonstrated to significantly influence the charge motion. The charge distribution can be extended to the bottom as the trap density decreases. Charge accumulation is therefore balanced by the appearance and increase of leakage current. Accordingly, our model and numerical simulation provide a comprehensive insight into the charging dynamics of a polymer irradiated by electrons in the complex space environment.