Photoemission of reflection-mode InGaAs photocathodes after Cs,O activation and recaesiations

In order to study the photoemission performance of InGaAs photocathodes, experiments of Cs,O activation, multiple recaesiation, and degradation are performed on a reflection-mode InGaAs photocathode. The photocurrent curves during Cs,O activation, recaesiation, and degradation are measured and analyzed. Based on the quantum efficiency formula of InGaAs photocathodes, the critical performance parameters were obtained by fitting the experimental curves. Results show that Cs-only activation results in a positive electron affinity surface and Cs,O activation leads the surface to a negative electron affinity. Recaesiations can make the degraded InGaAs photocathode recover to a good level. Meanwhile, the spectral response and life time of InGaAs photocathode become smaller and smaller as the recaesiation times increase.