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基于密度泛函理论的第一性原理,研究了(5,5)型封闭碳纳米管(CNT)帽端掺杂钛原子对其场发射性能的影响。结果表明:钛原子掺杂CNT体系的几何结构更加稳定;施加电场后,掺杂CNT的态密度在费米能级处明显增加,赝能隙显著减小,电子的活跃度明显提高;钛原子掺杂不仅引起了CNT最低未占有轨道与最高占有轨道的能量差值和有效功函数的减小,而且使电子向掺杂CNT帽端聚集。说明钛原子掺杂可以显著提高CNT的场发射性能。
Based on the first principle of density functional theory (DFT), the influence of titanium atoms on the field emission properties of (5,5) capped carbon nanotubes (CNTs) was investigated. The results show that the lattice structure of CNT doped with titanium atoms is more stable. The state density of doped CNTs increases remarkably at Fermi level and the pseudogap gap decreases significantly with the increase of electric field. The activity of titanium increases obviously. Doping not only causes the energy difference between the lowest unoccupied or highest occupied molecular orbital of CNTs and the decrease of effective work function, but also causes electrons to aggregate toward the doping CNT cap. Titanium doping can significantly improve the CNT field emission properties.