Cesiated thin‐film field‐emission microcathode arrays

The effect of adsorbed cesium on the performance of thin‐film field‐emission microcathode arrays with molybdenum tips is discussed. A reduction in the voltage required to extract an average of 1 nA per tip from 50 to 15 V is reported. Cesiated arrays have exhibited stable performance when operated continuously for up to 650 h at array current densities up to 100 A/cm2, with minimal leakage current. Using the Fowler–Nordheim theory, analysis of current‐voltage characteristics of a heavily cesiated emitter array gives values for the emitting area, work function, and geometrical factor.