摘要
利用第一性原理密度泛函的方法对氢分子吸附开口碳纳米管的场发射性质进行了综合研究,建立了(5,5)开口碳纳米管吸附不同氢分子数量的吸附模型,并对加电场和未加电场下的模型进行了吸附能、最高占有分子轨道-最低未占分子轨道(HOMO-LUMO)帯隙及诱导偶极矩的计算和分析。计算结果表明吸附能随着电场的增加而变大,吸附稳定性增强。吸附氢分子的碳纳米管在施加外电场后,HOMO-LUMO帯隙明显减小,费米能级附近的局域态密度随着氢分子的吸附而增加。氢分子对碳纳米管的吸附可以在其尖端表面产生诱导偶极矩,导致电荷由碳纳米管向氢分子大量转移,从而驱使电子由碳纳米管尖端发射到真空中,提高了碳纳米管的场发射性能。
The field emission properties of hydrogen-adsorbed carbon nanotubes（CNTs） are studied using first-principles density functional theory.Open-ended（5,5） single-walled carbon nanotubes models with different numbers of hydrogen molecules adsorbed are built,and the adsorption energy,highest occupied molecular orbital-lowest unoccupied molecular orbital（HOMO-LUMO） band gap,the induced dipole moment of the model with and without applied electric field are calculated and analyzed.The calculation results reveal that the structure of carbon nanotubes with hydrogen molecules is stable under field-emission conditions,HOMO-LUMO band gap becomes narrower,the local density of states at the Fermi level increases with the adsorption of hydrogen molecules,and electrons emit more easily.
出处
《激光与光电子学进展》
CSCD
北大核心
2012年第9期168-171,共4页
Laser & Optoelectronics Progress
关键词
光电子学
场发射
碳纳米管
密度泛函
氢吸附
optoelectronics
carbon nanotube
density functional theory
field emission
hydrogen adsorption
