采用基于密度泛函理论的第一性原理计算方法,分别研究了N掺杂和N-M(Cd,Mg)共掺(9,0)型闭口氧化锌纳米管(ZnONT)的几何结构和场发射性能.结果表明:N原子能够提高体系帽端结构的稳定性;随外加电场增强,体系的态密度向低能方向移动,最高占据分子轨道(HOMO)-最低未占据分子轨道(LUMO)能隙及有效功函数变小,电荷向帽端聚集程度愈高.体系态密度/局域态密度,HOMO/LUMO,能隙及Mulliken电荷分析一致表明,N-Cd共掺可提高ZnONT的场发射性能,N-Mg共掺反而抑制其电子发射. The first principles calculations based on density functional theory (DFT) were used to investigate the geometries and field emission properties of N-doped and NM (Cd, Mg) co-doped (9,0) The results show that the N atom can improve the stability of the cap-head structure. With the increase of the applied electric field, the density of states shifts to the low energy direction, and the highest occupied molecular orbital (HOMO) -the lowest unoccupied molecular orbital (LUMO) The work function becomes smaller and the charge collects to the cap.The higher the density of states / the density of local states, the HOMO / LUMO, the energy gap and the Mulliken charge analysis show that N-Cd co-doping can improve the field emission performance of ZnONT, and N -Mg co-doped but inhibit its electron emission.