Negative electron affinity GaAs wire-array photocathodes.
Negative electron affinity GaAs wire-array photocathodes.
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DOI：
10.1364/oe.24.004632
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发表时间：
2016-03
期刊：
影响因子：
3.8
通讯作者：
J. Zou;Xiaowan Ge;Yijun Zhang;Wenjuan Deng;Zhifu Zhu;Weilu Wang;Xincun Peng;Zhaoping Chen;
中科院分区：
文献类型：
--
作者：
J. Zou;Xiaowan Ge;Yijun Zhang;Wenjuan Deng;Zhifu Zhu;Weilu Wang;Xincun Peng;Zhaoping Chen;
采用反应离子刻蚀和电感耦合等离子体刻蚀GaAs材料，并经Cs-O活化，制备了负电子亲和势GaAs线阵光电阴极。扫描电子显微镜显示，由此获得的高密度GaAs线阵列具有高周期性、大高度和良好的形貌。光致发光光谱表明，线阵列的结晶质量良好，没有任何明显的损伤。与原始GaAs晶片相比，线阵列的光致发光峰位置有所红移，这可能归因于温度效应和应变弛豫。与原始晶片相比，由于良好的光捕获效果，线阵列结构显示出显著降低的光反射。通过GaAs线阵的Cs-O激活实验，研究了入射角对量子效率的影响。结果表明，在30°附近，量子效率最大。鉴于这些独特的电学和光学特性，GaAs线阵光阴极是其平面结构对应物的有吸引力的替代品。
Negative electron affinity GaAs wire-array photocathodes have been fabricated by reactive ion etching and inductively coupled plasma etching of bulk GaAs material followed by Cs-O activation. Scanning electron microscope has revealed that the thus obtained high-density GaAs wire arrays had high periodicity, large height, and good morphology. Photoluminescence spectra indicated the wire arrays were of good crystalline quality and free from any obvious damage. Compared to the original GaAs wafer, the photoluminescence peak positions of the wire arrays were somewhat red-shifted, which may be attributed to the temperature effect and strain relaxation. The wire-array structures showed significantly reduced light reflection compared with the original wafer due to the excellent light-trapping effect. Cs-O activation experiments of the GaAs wire arrays have been performed to reveal the effect of incident angle on quantum efficiency. The results show that maximum quantum efficiency was obtained at about 30°. Given these unique electrical and optical properties, a GaAs wire-array photocathode is an attractive alternative to its planar-structured counterpart.