Surface activation behavior of negative-electron-affinity exponential-doping GaAs photocathodes
Surface activation behavior of negative-electron-affinity exponential-doping GaAs photocathodes
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DOI：
10.1016/j.optcom.2014.01.062
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发表时间：
2014-06
影响因子：
2.4
通讯作者：
Yijun Zhang;Jun Niu;J. Zou;Xinlong Chen;Yuan Xu;Benkang Chang;F. Shi
中科院分区：
文献类型：
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作者：
Yijun Zhang;Jun Niu;J. Zou;Xinlong Chen;Yuan Xu;Benkang Chang;F. Shi
考虑到掺杂结构对表面活化行为的影响，在相同的制备条件下，对指数掺杂和均匀掺杂的GaAs光电阴极进行了Cs-O活化实验。激活结果表明，与均匀掺杂光电阴极相比，指数掺杂光电阴极在初始Cs激活后光电流峰值较低，在Cs - o交替激活后光电流峰值较高。基于双偶极子模型，根据Cs - o活化后光电流峰值与Cs活化后光电流峰值的比值，计算出发射电子的纵向能量分布，得到表面势垒参数。在整个激活过程中光电流演变的差异与表面势垒分布的不同变化有关。
In view of the effect of doping structure on the surface activation behavior, the Cs–O activation experiments under the same preparation condition were performed on the exponential-doping and uniform-doping GaAs photocathodes. The activation results show that, compared with the uniform-doping photocathode, the exponential-doping photocathode presents a lower photocurrent peak after the initial Cs activation and a higher photocurrent peak after the Cs–O alternate activation. Based on the double dipole model, the parameters of surface potential barrier are obtained from the calculation of longitudinal energy distribution of emitted electrons according to the ratio of photocurrent peak after Cs–O activation to that after Cs activation. The discrepancy in the photocurrent evolution during the entire activation process is related to the different variations in surface potential barrier profile.