Gaas Photocathode Defect Characterization Studies

GaAs substrate is the main material to produce photocathode of the third generation low-light-level image intensifier, its quality has important influence to the key parameters of optoelectronic materials, such as quantum efficiency and resolution. GaAs photocathode pinhole defect is the most intuitive performance of the quality which has major impact on the quality of GaAs photocathode, and it has complicated causes. Therefore, high-quality GaAs epitaxial material is prerequisite for activation of the high sensitivity of the cathode, it is the basis to improve yield of image intensifier device. The topic of this paper is theoretical research for the GaAs photocathode defects, we use the database for the analysis of the GaAs surface defects and reveal its intrinsic link, in order to improve the process and produce more reliable product.This paper describes the preparation and development of GaAs photocathode and derivate the quantum efficiency formula of reflective and transmission photocathode combined with photoemission theory. We analyze the key parameters which affect the quantum efficiency combined with the formula; combined the defect levels, we analyze the recombination centers, the trap effect and impact recombination centers on the electronic life; we theoretically analyze the impact of the capture cross sections for the electron diffusion length and the quantum efficiency, which temperature is the key factor of the impact of the capture cross section. Using surface structure model, we analyze the defects impact on the electron affinity, Cs/O activation model and obtain the impact on GaAs Electronics overflow probability and quantum efficiency. Using database system, we effectively analyze the distribution of the GaAs substrate and the photocathode defects, and summarize the law.Finally, we summarize the subject of work and analyze the lack of research. We prospected in-depth study.