Comparison of photoemission behavior between negative electron affinity GaAs and GaN photocathodes

In view of the important application of GaAs and GaN photocathodes in electron sources [1,2], the difference in the photoemission behavior, namely the activation process and quantum yield decay, between the two typical types of III-V compound photocathodes has been investigated using the multi-information measurement system. The reflection-mode GaAs and GaN photocathode samples both were grown by metal organic chemical vapor deposition, wherein the former is a substrate/AlGaAs/GaAs structure and the latter is a sapphire/AlN/GaN structure. The active layer in both structures was uniformly doped with p-type zinc and magnesium respectively.