We present a study on the evolution of both transverse and longitudinal energy distributions due to oxygen-induced quantum efficiency degradation in the electrons emitted from a reflection-mode p-GaAs(Cs,O)-photocathode over an effective electron affinity range of χ ∗∼ -0.1 eV to χ ∗∼ +0.3 eV under illumination wavelengths λ = 808, 635 and 532 nm. For λ = 635 and 532 nm, we found that the mean transverse energy of electrons emitted as the photocathode effective electron affinity increased has a non-monotonic character. Our proposed fitting model links the measured response to changes in the relative number of thermalised and non-thermalised electrons in the total emitted photocurrent.
- electron source
- energy spread
- 2.05 MATERIALS ENGINEERING
- 1.03 PHYSICAL SCIENCES AND ASTRONOMY