多碱光电阴极光谱响应在线测试结果与分析

In-situ Spectral Response Measurement of the Multi-Alkali Photocathodes

介绍了多碱光电阴极制备过程中测试的光谱响应，并作了简单分析。研究结果表明，Sb，K交替决定双碱化合物Na_2KSb的导电类型，Cs处理降低Na_2KSb的电子亲和势，延伸长波阈；Sb，Cs交替形成锑铯偶极层，在Na_2KSb上吸附的铯原子数和感应的偶极层的偶极矩同时影响多碱光电阴极的灵敏度。

Multialkali photocathodes were prepaered in ultra high vacuum by alternating deposition of alkali metals on antimony substrates. The spectral response was measured in-situ for the first the. Our preliminary results indicated that alternating addition of Sb and K may determine whether Na_2KSb compound is the p-or n-conducting type and that Cs sensitization may reduce its electron affinity and extend the spectral response cut-off wavelength. After formation of Sb-Cs dipole layer through alternating depostion of Sb and Cs, the photosensitivity of the cathodes depends sensitively on both the number of absorbed Cs atoms and the dipole moment of Sb-Cs dipole layer formed on Na_2KSb surface.