Analyses the Character of GaAs Photocathode by Diffraction Curve from Spectrophotometer

Abstract

Transmissivity and reflectivity of GaAs photocathode get from spectrophotometer are measured and analyzed according to various wave bands, so that the corresponding optics parameter is obtained. The typical optics parameter of various GaAs photocathode has been summarized. For blue-light extension photocathode, the diffraction peak will be close to ultraviolet wave band from the reflection curve. The thickness of Active layer film and optimal Si3N4 film on the GaAlAs layer have been acquired. The experimental and analyzed results have shown that the Si3N4 film on the GaAlAs layer should be about 1000A when the the GaAs photocathode got the optimum performance.The thickness of Active layer film should not be too thick to escape of electron and too thin to transfer of photon-electron. The experiment shows that the spectrophotometer can analyze epitaxial material and assist the manufacture of GaAs photocathode.