红外技术Issue(12)：1068-1073,6.
Cs2Te紫外光电阴极带外光谱响应研究
Study on Spectral Response beyond Cut off of Cs2Te Ultra Violet Photo Cathode
摘要
Abstract
With the strong light as the input, the spectral response beyond cut off of the Cs2Te ultraviolet photo cathode is measured. The results show that the spectral response of the Cs2Te cathode beyond cut off is lower, and is several orders of magnitude lower than that within the cutoff. The peak sensitivity of within cutoff can be greater than 40mA/W, but the spectral response beyond cut off can be as low as 10-3mA/W order of magnitude at 550nm wavelength. The divergence of spectral response beyond cut off of Cs2Te ultraviolet photo cathode made with the same process is large. According to the test of three different visible light photo cathode, namely Na2KSb (Cs), K2CsSb and GaAs (Cs-O), it is proved that these three kinds of visible light photo cathode also have certain spectral response. The test data show that the spectral response beyond cut off is related to the size of the work function (positive electron affinity cathode) or the band gap (negative electron affinity cathode). The smaller the work function or the band gap is, the greater the spectral response beyond cut off. The spectral response beyond cut off is a common phenomenon for photo cathode. The reason is that the effect of multiphoton absorption, i.e. multiphoton effect. Because Cs2Te photo cathodes are present spectral response beyond cut off, thus, when solar blind image intensifier adopting Cs2Te photo cathodes is used in the strong sun light or straight to the sun's light, detected signal would be disturbed by the light of the sun, or by the image of the sun like. Thus solar blind image intensifier does not have the sun blind characteristic. In order to make the solar blind ultraviolet image intensifier fully equipped with solar blind characteristic, solar blind filter is needed. Combining solar blind filter with spectral response of Cs2Te cathode beyond cut off, solar blind image intensifier can achieve complete solar blind. So in the practical application of ultra violet detecting, the solar blind filter is essential. One of the bases of the design of the solar blind filter is the response of the Cs2Te ultraviolet cathode to the solar radiation. The response of the Cs2Te ultraviolet cathode to the solar radiation is mainly concentrated in the 350-650nm, so the solar blind filter is mainly used to attenuate the visible light. Only with solar blind filter matching with spectral response of Cs2Te cathode, can solar blind ultraviolet image intensifier be made completely solar blind.关键词
Cs2Te紫外光电阴极/带外光谱响应/多光子吸收/紫外像增强器Key words
Cs2Te ultra violet photo cathode/spectral response beyond cut off/multi photon absorption/ultra violet image intensifier分类
数理科学引用本文复制引用
李晓峰,姜云龙,李靖雯,姬明,李金沙,张勤东..Cs2Te紫外光电阴极带外光谱响应研究[J].红外技术,2015,(12):1068-1073,6.基金项目
国家自然科学基金，编号11535014。 （）
