Field electron emission from frozen lithium cones on a tungsten tip

For a lithium deposited W〈1 1 0〉 field emitter tip, the freezing of liquid-lithium cones formed on the tip apex was attempted in order to prolong the lifetime of cones. The cones were successfully frozen by quenching a tip with liquid-nitrogen. However, the electron emission current from the frozen cones was one order of magnitude smaller than that for liquid cones and the current as well as the emission pattern varied largely with time. Further, the evaporation of lithium atoms was not suppressed and the lifetime was short. Therefore, the freezing of the lithium cones is not a useful method to prolong the lifetime.