摘要
在飞速发展的纳米技术支撑下,近年来基于一维纳米材料的冷阴极场致电子发射研究和应用研发获得丰富的成果。相应的理论研究也不断深入,同时也发现一些新的理论问题亟待解决。简要回顾传统场致电子发射理论的主要内容之后本文将介绍一维纳米材料冷阴极场致电子发射理论研究的一些进展,重点在碳纳米管的尖端势垒和场发射图像,以及宽带隙纳米线场发射机制。关于宽带隙纳米线场发射,我们着重介绍了一个双电流模型。该模型假定纳米线表面存在定域态,在外电场下这些定域态能够把电子转移到纳米线尖端,在尖端形成积累层,场发射电流由表面定域态中的跳跃电流和导带上的电流共同维持。
Based on the rapid development of nano-technology,rich achievements have been accumulated in experiments of cold field electron emission of quasi one-dimensional nanomaterials and various applications have been pushed forward considerably in the last decade.Related theoretical studies are also in progress.In the same time,there are new theoretical problems emerged and appealed for solution.After a brief review of the conventional theory of field emission,some developments of theoretical studies will be introduced,emphasizing on the apex barrier,emission pattern of carbon nanotubes,and the field emission mechanism of nanowires of wide energy band gap materials.For the latter,we will introduce a double-current model which assumes that localized surface states play virtual role.In applied fields,electrons are transferred from the cathode to the apex through the localized surface states of the nanowire and form an accumulating layer in the apex.The emission current is sustained via the hopping current in the surface states and the conduction current in the conduction band.
出处
《真空电子技术》
2012年第6期15-22,共8页
Vacuum Electronics
基金
国家重点基础研究发展计划资助(2007CB935500)
关键词
场致电子发射
纳米材料
碳纳米管
宽带隙
Field electron emission,Nanomaterial,Carbon nanotube,Wide energy band gap
