Influence of cathode module technology on photoemission of transmission-mode GaAs photocathode materials

In order to research the influence of cathode module technology on photoemission of transmission-mode GaAs photocathode materials, high resolution X-ray diffraction (HRXRD) instrument was adopted to measure the HRXRD curves of transmission-mode GaAs materials and modules respectively. By comparison of the structures of reflection-mode and transmission-mode GaAs epilayers, both the cathode materials with the same uniform-doping or exponential-doping active layers were grown by molecular beam epitaxy. After the high-low temperature activation, the reflection-mode photocathodes were tested directly by on-line spectral response measurement system, while the transmission-mode photocathodes were maken into cathode modules for testing performance. The comparison results indicate that the electron diffusion length decreases by 10% approximately in the case of uniform doping after cathode module technology, while it decreases by 5% for exponential doping. It shows that the active layer with exponential doping can affect smaller on GaAs photocathode materials during cathode module technology.