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用金属有机物化学气相沉积法外延制备了一个透射式蓝延伸GaAs光电阴极,积分灵敏度达到1980μA/lm,同时与美国ITT公司的一条蓝延伸阴极光谱响应曲线对比,分别对两者进行了光学结构拟合.结果表明,国内阴极在Ga_(1-x)Al_xAs层厚度、A1组分、电子扩散长度和后界面复合速率上与国外存在差距,这导致国内阴极的蓝延伸性能不及国外.国内蓝延伸阴极的表面电子逸出几率、发射层厚度与国外阴极拟合结果一致,这使得两者长波响应性能差别远小于短波部分的差别.另外响应波段全谱的吸收率小于国外阴极,导致国内透射式蓝延伸GaAs光电阴极光谱响应、积分灵敏度尚不及国外.
A transparent blue-extended GaAs photocathode was epitaxially grown by metal organic chemical vapor deposition. The integral sensitivity was up to 1980μA / lm. At the same time, a blue-extended cathode spectral response curve was compared with that of the ITT Company in the United States. The results show that there is a gap between the domestic cathode and the foreign countries in the Ga 1-x Al x As layer thickness, the Al composition, the electron diffusion length and the post-interface recombination rate, which leads to the domestic blue cathode extension performance less than abroad. Cathode surface electron escape probability, the thickness of the emissive layer consistent with the foreign cathode fitting results, which makes the two long-wave response performance difference is much smaller than the short-wave part of the difference.In addition the response band full-spectrum absorption rate is less than the foreign cathode, leading to the domestic transmission Blue extension GaAs photocathode spectral response, the integral sensitivity is not yet abroad.