Photoelectric Emission Properties of Photocathode Materials

In a bid to further improve the performance of photocathodes, and to identify excellent photocathodes, much research has been undertaken to understand the emission properties at a fundamental level. The quality of photocathode generated electron beam is fundamentally dependent upon the quality in both transverse and longitudinal (i.e., temporal) directions of the electron pulses produced by their front-end laser-driven electron gun. In the transverse spatial dimension, a high quality (high brightness) electron pulse requires a low normalized spatial transverse rms emittance. It is the aim of this thesis to facilitate and demonstrate a dramatic improvement in the performance of spatial-resolved research instruments by investi- gating selected robust photocathode materials exhibiting laser-driven emission with a low rms transverse momentum ∆pT . In this thesis, I present my contributions to this cutting-edge research field by investigating high-brightness photocathodes, which could generate bright electron beam (high quantum effi- ciency and low spatial emittance). The field of photocathode analysis connects the root mean square transverse momentum of electrons from solid-state photocathodes to their electronic band structures, which thereby provides the consistent theoretical groundwork geared towards selecting high brightness photocathode materials for electron pulse generation.