氮掺杂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 Fieldemission Properties of Nitrogen-Doped Silicon Carbide Nanotubes

运用第一性原理研究了氮掺杂对碳化硅纳米管场发射性能影响.计算结果表明,在外加电场作用下,体系的态密度均向低能端移动,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,且Mulliken电荷在帽端聚集程度增加.态密度、最高占据分子轨道/最低未占据分子轨道能隙及Mulliken电荷分析表明,氮掺杂改善了碳化硅纳米管的场发射性能,且N替代顶层五元环中Si原子体系场发射性能最优.

The first—principles were performed to calculate the electron field emission properties of N—doped capped single—walled silicon carbide nanotubes.The results show that under the applied electric field,N—doped changes the electronic structure of pristine silicon carbide nanotubes,the Pseudo gap and the energy gap between the lowest unoccupied molecular orbital and the highest occupied molecular orbital decreases drastically.Meanwhile the Mulliken electrons congregate to the capped side.The investigations of the energy gap between the lowest unoccupied molecular orbital and the highest occupied molecular orbital and Mulliken population analysis indicate that the doped systems are more excellent on field emission prop—erties than the pristine silicon carbide nanotubes,especially the system in which Si is substituted by N.