钨针尖放电处理后的场发射特性

在场发射显微镜（FEM）中使用1万伏以上的电压对钨针尖进行了放电处理。扫描电子显微镜（SEM）和透射电子显微镜（TEM）的观察表明在处理后形成了纳米尺寸的突起。从经过处理的钨针尖能够支取高达1.55mA的场发射电流。针尖的场发射像呈现四重对称，表明它来自单个突起。场发射电流与电压关系符合Fowler-Nordheim (F-N)理论。根据F-N理论算得的场发射面积与TEM下观察到的突起的面积在量级上一致。

Field Emission Properties of a Tungsten Tip after Discharge Treatment

A tungsten tip received discharge treatment under a high voltage over 10kV in a field-emission microscope (FEM). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observation showed that some nanometer-scale protrusions resulted from the discharge treatment. The post-treatment tungsten tip delivered a field emission current as high as 1.55mA. The FEM pattern of the tip demonstrated a four-fold symmetry and thus the field emission was attributed to a single protrusion. The dependence of the field emission current on the applied voltage approximately followed the Fowler-Nordheim (F-N) theory. The value of the emission area calculated by the F-N theory is in agreement with that obtained from the TEM observation in the order of magnitude.