中文摘要：

对闭口硼氮纳米管（BNNT）顶层掺碳体系，运用第一性原理研究了电子场发射性能．结果表明，掺碳的BNNT体系电子结构变化显著；外电场愈强，体系态密度向低能端移动幅度愈大，且最高占据分子轨道（HOMO）／最低未占据分子轨道（LUMO）能隙愈小．体系态密度和局域态密度，HOMO和LUMO及其能隙分析一致表明，各种碳掺杂体系中CeqBNNT的场发射性能最佳．

英文摘要：

The electron field emission performances of BN nano tube （BNNT） capped and doped with one carbon atom are investigated through the first principles calculations. The results show that the electronic structures of the systems change obviously. The shift of margin of the density of states （DOS） towards low energy position increases as the applied electric field and the highest occupied molecular orbital （HOMO）-lowest unoccupied molecular orbital （LUMO） gap decrease. The analyses of DOS, local DOS,HOMO, LUMO and their gap consistently indicate that CeqBNNT system is more propitious to the electron field emission than other systems.