【摘要】 基于对长达 1μm的 (5 ,5 )碳纳米管的量子力学计算 ,作者发现使碳纳米管具有优异场致电子发射特性的因素除了人们预期的尖端场增强之外 ,电荷在纳米管尖端的积累造成有效功函数 (真空势垒 )的非线性下降也起了非常重要的作用 .对外加电场Vappl=10— 14V/ μm下的碳纳米管进行了计算 ,得到与实验结果相近的发射电流更多还原

【Abstract】 A quantum mechanical simulation is carried out to investigate the field emission mechanism of a 1μm long (5,5) single-walled carbon nanotube under realistic experimental conditions. Our simulation reveals that the mechanism of field emission is the combination of two effects: (1) shielding of the electric field along the tube away from the tube tip, which leads to the well-known field enhancement but only 1/4 of that expected from classical theory; (2) field penetration at the tip resulting in the lowering of the work function or potential barrier, which is recognized as another significant factor contributing to the strong electron emission. The combination of (1) and (2) gives an emission current that agrees with recent experiments.更多还原