碘化铯薄膜光阴极的研究进展

doi:10.15541/jim20140346

摘要/Abstract

摘要：

碘化铯(CsI)薄膜因对X射线及紫外光具有高的光电转换效率而倍受关注。在核物理、高能物理以及天体物理研究的推动下, 研制高量子效率(QE)、性能稳定的CsI薄膜光阴极成为了近年来研究的热点。然而, 目前人们对某些影响其性能的因素还不完全清楚或确定。本文综述了CsI薄膜光阴极的最新研究进展, 总结了影响QE的因素和光阴极的老化机理, 重点关注了一些存在争议的问题, 并对其研究发展方向进行了探讨。

关键词: CsI薄膜, 光阴极, 量子效率, 受潮老化, 辐照老化, 综述

Abstract:

Caesium iodide (CsI) thin films have attracted much attention due to good electron transport and emission properties in the soft X-ray and extreme ultraviolet range. With the rapid development of nuclear physics, high energy physics and astrophysics, the requirements for CsI film photocathodes become increasingly severe, and it is therefore of considerable interest to develop CsI photocathodes with high quantum efficiency (QE) and stable performance. However, the internal mechanisms of QE variation and photocathode aging are not entirely clear or certain up to date. In this paper, the recent progress on CsI film photocathodes is reviewed and some controversial issues are introduced. Several perspectives are also proposed in the end.

Key words: CsI film, photocathode, quantum efficiency, moisture aging, irradiation aging, review

中图分类号:

TQ174

樊龙, 黎宇坤, 陈韬, 李晋, 杨志文, 袁铮, 邓博, 曹柱荣, 胡昕. 碘化铯薄膜光阴极的研究进展[J]. 无机材料学报, 2015, 30(3): 225-232.

FAN Long, LI Yu-Kun, CHEN Tao, LI Jin, YANG Zhi-Wen, YUAN Zheng, DENG Bo, CAO Zhu-Rong, HU Xin. Recent Progress in Research on CsI Thin Film Photocathodes[J]. Journal of Inorganic Materials, 2015, 30(3): 225-232.

图/表 4

图1 (a) Parylene-N /Au /CsI透射式光阴极; (b) MCP表面反射式CsI光阴极

Fig. 1 (a) Parylene-N /Au /CsI semitransparence photocathode; (b) Refective CsI photocathode coated on the surface of microchannel plate (MCP)

图2 (a) CsI/ MgO/ MWCNTs/ Si结构光阴极的SEM照片[45]; (b)等离子体刻蚀过的Si基底的SEM照片; (c)Si基底上CsI薄膜暴露于空气前的AFM照片; (d) Si基底上CsI薄膜暴露于空气24 h的AFM照片[41]

Fig. 2 (a) SEM image of the CsI/ MgO/ MWCNTs/ Si photocathode[45]; (b) SEM image of the Si substrate patterned by colloidal lithography after lift-off process; (c)AFM image of the fresh CsI film evaporated on the Si patterned substrate; (d) AFM image of the CsI film on the Si patterned substrate exposed to ambient air for 24 h[41]

图3 (a)刚制备、(b)在空气中暴露后、(c)在极端潮湿环境中暴露后CsI薄膜的SEM照片[49]; (d)NIF采用的X射线条纹相机上200 nm厚的CsI透射式光阴极信号下降与空气暴露时间的关系[47]

Fig. 3 SEM images of as-deposited (a), aged in ambient air (b) and extreme moisture exposed CsI films (c)[49]; Percent degradation in the yield signal of streak camera used at NIF from a 200 nm thick CsI cathode as a function of air exposure time[47]

图4 (a)5 d UV辐照后CsI薄膜的AFM照片[11]; (b) 5 d UV辐照后的PEEM照片[11]; (c)UV辐照后的TEM照片[48]

Fig. 4 (a) AFM image of the 5 d UV-irradiated CsI photocathode[11]; (b) PEEM image of the 5 d UV-irradiated CsI photocathode[11]; (c) TEM image of the UV-irradiated CsI film[48]

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