Record-level quantum efficiency from a high polarization strained GaAs/GaAsP superlattice photocathode with distributed Bragg reflector
Record-level quantum efficiency from a high polarization strained GaAs/GaAsP superlattice photocathode with distributed Bragg reflector
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DOI：
10.1063/1.4972180
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发表时间：
2016-12
影响因子：
4
通讯作者：
W. Liu;Yiqiao Chen;Wentao Lu;A. Moy;M. Poelker;M. Stutzman;S. Zhang
中科院分区：
文献类型：
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作者：
W. Liu;Yiqiao Chen;Wentao Lu;A. Moy;M. Poelker;M. Stutzman;S. Zhang
提供高电子自旋极化（ESP）和高量子效率（QE）的光电阴极可以显著增强电子加速器的物理性能。本文报道了用分布布拉格反射器（DBR）制作的高极化应变GaAs/GaAsP超晶格光电阴极的量子效率。DBR光阴极技术增强入射激光的吸收，从而增强QE，但如文献所示，优化与由许多不同层组成的复杂光阴极结构的制造相关的所有参数是非常具有挑战性的。DBR光电阴极的过去报告描述了高偏振，但通常QE仅为100%，这与没有DBR结构生长的高偏振光电阴极的QE相当。本文报道了一种应变GaAs/GaAsP超晶格DBR光电阴极，其极化率高达84%，量子效率显著提高，达6.4%。
Photocathodes that provide high electron-spin polarization (ESP) and high quantum efficiency (QE) can significantly enhance the physics capabilities of electron accelerators. We report record-level QE from a high-polarization strained GaAs/GaAsP superlattice photocathode fabricated with a Distributed Bragg Reflector (DBR). The DBR photocathode technique enhances the absorption of incident laser light thereby enhancing QE, but as literature suggests, it is very challenging to optimize all of the parameters associated with the fabrication of complicated photocathode structures composed of many distinct layers. Past reports of DBR photocathodes describe high polarization but typically QE of only ∼1%, which is comparable to QE of high polarization photocathodes grown without a DBR structure. This work describes a strained GaAs/GaAsP superlattice DBR photocathode exhibiting a high polarization of 84% and significantly enhanced QE of 6.4%.