二维、三维模型碳纳米管场发射场强计算的比较研究

Comparison of 2D and 3D Model for Calculations of Electric-field Intensity

在计算碳纳米管场发射显示器中电场强度时,为了提高计算效率,许多资料将三维空间的场发射简化为二维模型进行计算,为了比较分析使用二维模型和三维模型计算结果的差异,建立了二维模型单根碳纳米管、三维模型单根碳纳米管和单碳纳米墙3个模型,应用AnsoftMaxwell有限元数值仿真软件进行了仿真,计算结果表明:二维碳纳米管场发射模型的仿真结果代表的三维空间实际情况为碳纳米墙场发射,而不是真正的三维空间碳纳米管场发射。对于单根碳纳米管,用二维模型计算的碳纳米管尖端电场强度仅为三维空间碳纳米管尖端电场强度的1/4。

The electron emission of a carbon nanotube-field emission display mainly depends on the electric field intensity of carbon nanotubes tip.So the accurate calculation of the electric field intensity of carbon nanotubes tip is very important for the development of carbon nanotube-field emission display.In calculating the electric field intensity in a carbon nanotube-field emission display,the field emission model of carbon nanotubes cathode have been simplified as 2D model in many reports for increasing the computation efficiency.To compare and analyze the differences between the calculated results obtained by using 2D and 3D models,single carbon nanotube 2D model,single carbon nanotube and single carbon nano-wall 3D models are constructed respectively,and the finite element simulation software Ansoft Maxwell is used.The calculated results indicate that 2D model field emission of carbon nanotubes cathode expresses the actual field emission of carbon nano-wall cathode,not the actual field emission of carbon nanotubes cathode.The electric field intensity of single carbon nanotube tip calculated by 2D model is only about 1/4 of actual electric field intensity of 3D carbon nanotube tip.