中文摘要：

采用第一性原理的密度泛函理论（DFT）研究了（5，5）碳纳米管（CNT）顶端硼（B）、氮（N）、硅（Si）等元素双掺杂体系的电子场发射性能。结果表明，在外电场下，各种双掺杂CNT帽端态密度（DOS）向价带移动，电子轨道分布变化显著，电荷分布明显局域化。根据电子态密度、差分电荷密度、最高分子占据轨道（HOMO）／最低分子非占据轨道（LUM0）分布等计算结果可预期Si双掺杂后更有利于场致电子发射。

英文摘要：

The electron field emission properties of （5,5） carbon nanotube （CNT） double doped with boron, nitrogen and silicon in the top layer respectively were investigated by the density functional theory （DFT）. The results indicate that the local density of states of each double doped CNT shifts towards to valance band, the e- lectronic orbital varies significantly and the charge distribution localizes obviously. It is expected that Si double doped CNT be more propitious to the electron field emission based on the calculations of DOS, deformation density of electron, highest occupied molecular orbital （HOMO） and lowest unoccupied molecular orbital （LUMO）.