New high brightness and stability point electron source

The report presents physical technology and field emission properties of nanoheterostructures formed by a thin (~5-10 nm) dielectric (ZrO₂) layer at the surface of needle-shaped W and Mo microcrystals. The field emission properties of the ZrO₂/W<;100> nanoheterostructure were defined as a function of the ZrO₂ epitaxial layer thickness and nanoheterostructured material temperature. It has been found that at a ZrO₂ layer thickness of _~ 5-10nm and nanoheterostructured material temperature _~ 1900K the nanoheterostructure exhibits an abnormally high normalized brightness β (up to ~10¹⁰ A/m srV) and high stability of field emission properties. Under these conditions the dependence of the total electron emission current from the nanoheterostructured surface vs the field strength at the ZrO₂ surface is described by a power function.