We report on characteristics of the photocathode using cesium telluride thin film for an electron gun in this paper. The quantum efficiency of a cesium telluride photocathode changes in accordance to deposition conditions of cesium telluride.
Conditions here include: the thickness of tellurium, the quantity of deposited cesium, passage of time from production of thin film, and a substrate condition to deposition. We show the results of measurement of a thickness dependence of the quantum efficiency. It is observed that the quantum efficiency has a peak at thickness of tellurium about 10 nm.
We conceived a model for a photoemission from cesium telluride thin film on metal substrate. This model can explain the results of this experiment qualitatively. This model has parameters of dependence on reflections of thin film and metal substrate, and dependence on thickness of thin film. It can explain that quantum efficiency has its peak under thickness of 10 nm, and it can estimate that unknown optical constants of cesium telluride.
