碳纳米管场致电子发射新机制  

New mechanism for field emission from carbon nanotubes

作　　者：李志兵[1] 许宁生[1] 邓少芝[1] 郑晓[2] 陈冠华[2] 

机构地区：[1]中山大学物理科学与工程技术学院,广州510275 [2]香港大学化学系

出　　处：《物理》2004年第10期705-707,共3页Physics

基　　金：国家自然科学基金 (优秀创新群体基金 ;批准号 :90 10 3 0 2 8);中国教育部;高教局和广东省科技局;香港科技局 (RGC)资助项目

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 。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.

关 键 词：场致电子发射 量子力学计算 碳纳米管 电荷 势垒 功函数 外加电场 尖端 新机制 作者 

分 类 号：TB383[一般工业技术—材料科学与工程]