摘要
本文研究了碱锑型光电阴极的光学过程.利用反荧石结构和其结构的相似性,确定了Na2KSb、Cs3Sb和K2CsSb阴极在光谱结构上对应布里渊区中发生的光学跃迁,发现多碱阴极的跃迁更接近晶态,而Cs3Sb和K2CsSb阴极和非晶态的非常类似,在Na2KSb中出现的来自Δ、Σ方向跃迁形成的极大峰并不出现在Cs3Sb和K2CsSb.基于碱锑光电阴极间有序度的不同,解释了碱锑型光电阴极的光学跃迁类型及其变化的原因,得出由于无序引起的非直接跃迁类型仍然可以出现在一定无序度的多晶薄膜上的结论,还解释了多碱效应.
The optical processes of alkali antimonide photocathodes are investigated. Based on the similarity of structure between the antifluoride and alkali antimonide, the possible transitions taking place in the Brillouin zone corresponding to the structure in the optical spectra are identified for Na_2KSb(Cs),Css_3Sb and K_2CsSb cathode. It is found that the optical transition of Na_2KSb(Cs) is similar to that of crystalline film and Cs_3Sb and K_2CsSb are similar to amorphous film. The peak arising from the contribution of Δ and Σ direction in Na_2KSb(Cs) isn't observed in Cs_3Sb and K_2CsSb. We explain the transformation from nondirect transition to direct transition which takes place in alkali antimonides and draw a conclusion that nondirect transition in which momentum K conservation doesn't play an important rule in optical transition due to disorder remains in the polycrystalline film with some degree of disorder. The multialkali effect is also explained.
出处
《电子学报》
EI
CAS
CSCD
北大核心
1996年第8期44-49,共6页
Acta Electronica Sinica
关键词
碱锑型
光电阴极
类非晶模型
非直接跃迁
Amorphouslike model
Alkali antimonide photocathodes
Multialkali effect
Nondirect transition