Equipping a transmission electron microscope with a field emission electron gun.

我们研究了碳纳米管(CNT)在场发射电子枪中的应用。用精密金刚石切割机制备了碳化硅基尖，碳纳米管在(000-1)面上用表面分解法生长。具体工艺如下：1.用带特殊形状刀片的精密金刚石播种机切割出一根顶表面为0.5 mm×0.5 mm的碳化硅单晶棒材。2.通过化学腐蚀和化学清洗去除切割过程中引入的应变。3.采用聚焦离子束(FIB)工艺使棒材变薄。为了避免损坏顶面，在棒材上蒸发了SiO_2、Al或Won Al。4.去除SiO_2或Al层后，在1Pa1700℃真空度下热处理6h。为了使针尖具有较高的导电性，在1700μ的真空度为1×10^-2&gt；Pa10小时的真空度下进行了10小时的热处理，在低于1×10^-7&gt；pA的高真空室中测量了碳纳米管的场发射特性，并在荧光屏上观察到了发射图案。

We investigated to apply carbon nano-tubes (CNT) to field emission electron guns for transmission electron microscopes (TEM). Fundamental tips of SiC are prepared by a precision diamond cutter and CNTs are grown by surface decomposition on the top (000-1) surface. The detail of the process is shown hereafter:1.A rod of SiC single crystal along <0001> orientation having a top surface of 0.5mmx0.5mm is cut out by the precise diamond sow with a blade of a special figure. 2.The strain introduced in the cutting process is removed by chemical etching and chemical washing. 3.Focused Ion Beam (FIB) processing are introduced to make the rod thinner. To avoid damaging the top surface, SiO_2, Al or Won Al was evaporated on the rods. 4.Removed the layer of SiO_2 or Al, the rods were heat-treated in a vacuum of 1Pa at 1700℃ for 6hours. The growth of CNTs was confirmed even on the top surface of 0.2μmx0.3μm. 5.In order to give a high conductivity to the tip, graphite layers were grown on a (1210) surface by a heat-treatment in the vacuum of 1x10^<-2>Pa at 1700℃ for 10hours.Field emission characteristics were measured in a high vacuum chamber less than 1x10^<-7>Pa and emission patterns were observed on a fluorescent screen.