Behavior of photocathodes on superficial modification by electrical breakdown

In this work, we present the experimental study and a theoretical approach of the photoemission of rough and smooth photocathodes. The cathode was made of pure yttrium while its surface was morphologically modified. The cathode surface was irradiated by a KrF excimer at normal incidence. The measurements were performed after electric breakdowns between anode and cathode. For the rough cathode the maximum output current was 10.5 A, with a maximum quantum efficiency value of 1.3 × 10−4. Instead, the smooth cathode provided an output current of 8.4 A with a maximum quantum efficiency value of 7.0 × 10−5. In this process, the plasma production and the Schottky effect play a fundamental role.