Variation of spectral response for exponential-doped transmission-mode GaAs photocathodes in the preparation process.
Variation of spectral response for exponential-doped transmission-mode GaAs photocathodes in the preparation process.
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DOI：
10.1364/ao.49.003935
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发表时间：
2010-07
期刊：
影响因子：
1.9
通讯作者：
Yijun Zhang;Jun Niu;J. Zou;Benkang Chang;Y. Xiong
中科院分区：
文献类型：
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作者：
Yijun Zhang;Jun Niu;J. Zou;Benkang Chang;Y. Xiong
为了证实指数掺杂结构对阴极性能的实际影响，将指数掺杂结构应用于透射式GaAs光电阴极的制备，并利用光谱响应在线测量系统分别测量了高温激活、低温激活和铟封层工艺后的光谱响应曲线。结果表明，与均匀掺杂的光阴极相比，指数掺杂的光阴极由于内建电场的作用，可以获得更高的阴极性能和光电发射能力。然而，封接过程中铯的脱附和气体的杂质会导致整个响应波段的光谱响应退化，特别是在长波长区域，表面电子逃逸几率降低，表面势垒分布发生不利演化。
To confirm the actual effect of an exponential-doped structure on cathode performance, an exponential-doped structure was applied to the preparation of a transmission-mode GaAs photocathode, and spectral response curves after high-temperature activation, low-temperature activation, and the indium sealing process were separately measured by use of the on-line spectral response measurement system. The results show that, compared to the previously uniform-doped photocathode, the exponential-doped photocathode can obtain higher cathode performance and photoemission capability because of the built-in electric field. Nevertheless, cesium desorption and impurity of gas during the sealing process can cause the degeneration of spectral response in the entire response waveband, especially in the long-wavelength region, with the decrease in surface electron escape probability related to the adverse evolution of the surface potential barrier profile.