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叙述了Na2KSb(Cs)多碱光电阴极及其光致荧光的特点,测量了Na3Sb、K3Sb、Na>2K<1Sb和Na2KSb四种碱锑化合物膜层在785 nm波长激光激发条件下所发射荧光的峰值波长及所对应的峰值强度。Na3Sb、K3Sb、Na>2K<1Sb和Na2KSb四种碱锑化合物膜层荧光的峰值波长分别为876,877,886及899 nm。相比较而言,Na3Sb的荧光最弱,K3Sb的荧光次之,Na>2K<1Sb的荧光居中,Na2KSb的荧光最强。在Na2KSb膜层的生长过程中,当Na、K、Sb三种元素的化学计量比达到2∶1∶1时,其荧光最强,且峰值波长达到Na2KSb膜层的峰值波长;当Na2KSb膜层Na、K、Sb三种元素的化学计量比偏离2∶1∶1时,荧光峰值波长向短波方向移动,同时荧光减弱;当Na2KSb膜层在Na或K极度过量的条件下,膜层荧光的峰值波长接近Na3Sb或K3Sb的荧光峰值波长。因此在Na2KSb膜层的制作过程中,可以根据荧光的测量结果判断Na2KSb膜层Na、K、Sb三种元素的化学计量比是否达到2∶1∶1,从而可以指导制作工艺的改进,进一步提高多碱阴极的灵敏度。
The characteristics of Na2KSb (Cs) polybasic photocathode and its photoluminescence were described. The fluorescence of four alkaline antimony compound films of Na3Sb, K3Sb, Na> 2K <1Sb and Na2KSb were measured under 785 nm laser excitation Peak wavelength and corresponding peak intensity. The peak fluorescence wavelengths of Na3Sb, K3Sb, Na> 2K <1Sb and Na2KSb were 876, 877, 886 and 899 nm, respectively. In contrast, Na3Sb fluorescence was the weakest, K3Sb fluorescence followed, Na> 2K <1Sb fluorescence centered, Na2KSb the strongest fluorescence. In the process of Na2KSb film growth, when the stoichiometric ratio of Na, K and Sb reaches 2: 1: 1, the fluorescence peak is the strongest and the peak wavelength reaches the peak wavelength of Na2KSb film. When Na2KSb film When the stoichiometric ratio of Na, K and Sb deviates from 2: 1: 1, the peak wavelength of fluorescence shifts to the short wavelength and the fluorescence decreases. When Na2KSb film is in extremely excessive Na or K, the fluorescence The peak wavelength is close to the fluorescence peak wavelength of Na3Sb or K3Sb. Therefore, during the fabrication of Na2KSb film, it can be judged whether the stoichiometric ratio of Na, K, Sb of Na2KSb film reaches 2: 1: 1 according to the fluorescence measurement result, so as to guide the improvement of the manufacturing process and further improve Multi-alkali cathode sensitivity.