掺氮闭口碳化硅纳米管电子场发射的第一性原理研究

First-principles Study of the Electron Field Emission Properties of Nitrogen-doped Silicon Carbide Nanotubes

通过第一性原理的运用,对闭口碳化硅纳米管(SiCNT)顶层掺氮体系的电场发射性能进行研究,结果表明:掺氮的Si CNT的电子结构会发生非常明显的变化;通过外加电场,体系的态密度能够发生移动,移向低能端,赝能隙及最高占据分子轨道/最低未占据分子轨道能隙减小。态密度、最高占据分子轨道/最低未占据分子轨道能隙一致表明:各种体系中eqSiCNT的场发射性能最优。

The electron field emission performance of Si CNT capped and doped with one nitrogen atom is investigated through the first-principl calculations. The results show that the electronic structures of the systems change obviously. Under the applied electric field,N-doped changes the electronic structure of pristine silicon carbide nanotubes,and the Pseudo gap and the energy gap between the lowest unoccupied molecular orbital and the highest occupied molecular orbital decreases drastically. The investigations of the energy gap between the lowest unoccupied molecular orbital and the highest occupied molecular orbital analysis indicate that eq Si CNT system is more propitious to the electron＇s field emission than other systems. The doped systems are more excellent on field emission properties than the pristine silicon carbide nanotubes,especially the system in which Si is substituted by N.