中文摘要：

对闭口碳纳米管（CNT）顶端分层掺氮及吸附不同数目水分子体系,运用第一性原理研究了有电场存在时的电子场发射性能.结果表明：掺氮并吸附水分子的CNT结构稳定;外电场愈强、水分子数愈多,体系态密度（DOS）向低能端移动幅度愈大且最高分子占据轨道（HOMO）/最低分子空轨道（LUMO）能隙愈小.吸附能,DOS/LDOS,HOMO/LUMO及其能隙分析一致表明,第三层氮掺杂CNT吸附不同数目水分子体系的场发射性能最佳.

英文摘要：

The electron field emission performance of CNT doped with one nitrogen atom in different atomic layers and adsorbed with H2O molecules of different numbers was investigated through the first-principles calculations. The results show that the structure of the systems investigated is stable. The margin of the density of states （DOS） shifting towards low energy position increases with the applied electric field and the number of water molecules, and the HOMO/LUMO gap decreases with these parameters. The analysis of adsorption energy, DOS/LDOS, HOMO/LUMO and their gap indicates that N3CNT＋βH2O system is more propitious to the electron′s field emission than other systems.