Gaas Material Photovoltage Spectrum Characteristic Analysis

Negative electron affinity gallium arsenide (GaAs) photocathode has many virtues, such as high quantum efficiency, low dark current, concentrated electrons energy distribution and angle distribution, great potential to extend the long-wave spectral response waveband and so on, and because of its super performance, during the past decades its development is very quickly, and therefore it is widely used in low-light-level night vision.At present, it is hard to test and research the parameters of GaAs before activation. The dissertation mainly introduces how to use the relatively simple equipment to test the parameters of semiconductor. This dissertation deeply explores the techniques of Surface Photovoltaic on GaAs photo-electric cathode. The important contents are summarized below:First, the dissertation introduces current development state and application of GaAs photocathode, analyze the feasibility and advantage of the techniques of Surface Photovoltaic on GaAs photo-electric cathode. The dissertation also introduces principle of the Surface Photovoltaic and Surface Photovoltaic Technique, discusses the method of test the diffusion length of GaAs photocathode.Second, the dissertation introduces the improvements of the hardware and the software, and mainly discusses the improvements of the Light Source, the signal collecting module and the software system. The dissertation also introduces the quartz fiber, automatic collecting data through serial port and the program of analyze and process the data.Finally, the dissertation introduces the testing of GaAs photocathode using the Surface Photovoltage Spectroscopy testing system. The dissertation also introduces the result of the testing the Surface Photovoltage Spectroscopy of GaAs photocathode and the result of calculating the diffusion length.