摘要
本文计算了在透射式GaAs光电阴极的窗玻璃和GaAlAs缓冲层之间引入Si_3N_4或SiO_2膜使光电阴极的入射光反射率所产生的变化,并测量了Si_3N_4膜、SiO_2膜和SiO_2/Si_3N_4复合膜对阴极反射率的影响。理论计算和测量表明,Si_3N_4膜和SiO_2/Si_3N_4复合膜可有效地降低光电阴极对入射光的反射率。当Si_3N_4膜的厚度约为100nm时,可使光电阴极的反射率降低近60％。本文结果为科学地选择透射式GaAs光电阴极所需的的抗光反射膜提供了依据。
The change of the reflectivity of transmission mode GaAs photocathodes has been calculated, which is caused by introducing Si3 N4 or SiO2 film between the input window glass and the GaAlAs buffer layer of the photocathodes. The effects of Si3 N4 .SiO2 and SiO2 /Si3N4 films on the reflectivity have also been measured. The results of the calculation and the measurements show that the Si3N4 film and the SiO2/Si3N4 multifilms can reduce the reflectivity efficiently. The reflectivity can be lowered 60%as the thinkness of Si3N4 is 100nm. Those results provide the basis to scientifically select the antireflection film for GaAs photocathodes.
关键词
GAAS
光电阴极
抗光
反射膜
反射率
Transmission mode GaAs photocathode
Anti-reflection film
Reflectivity
