高真空系统气体成分对GaAs光电阴极稳定性的影响

邬昊宇; 郭欣; 干林于; 陈鹏; 徐志锋; 刘晖; 焦岗成; 朱宇峰; 任雨田

高真空系统气体成分对GaAs光电阴极稳定性的影响

邬昊宇^{1, 2,},
郭欣^{1, 2},
干林于^{1, 2},
陈鹏^{1, 2},
徐志锋^{1, 2},
刘晖^{1, 2},
焦岗成^{1, 2},
朱宇峰^{1, 2},
任雨田^{1, 2}

1.
微光夜视技术重点实验室, 陕西西安 710065
2.
昆明物理研究所, 云南昆明 650223

详细信息

作者简介:
邬昊宇（1996-），男，山西忻州人，硕士，主要从事三代微光像增强器总装集成方面的研究工作。E-mail: 17636471316@163.com

中图分类号: TN233
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出版历程
- 收稿日期: 2021-11-03
- 修回日期: 2021-12-02
- 刊出日期: 2022-08-20

Influence of Chamber Gas Composition on the Stability of GaAs Photocathode

WU Haoyu^{1, 2
,},
GUO Xin^{1, 2},
GAN Linyu^{1, 2},
CHEN Peng^{1, 2},
XU Zhifeng^{1, 2},
LIU Hui^{1, 2},
JIAO Gangcheng^{1, 2},
ZHU Yufeng^{1, 2},
REN Yutian^{1, 2}

1.
Science and Technology on Low-Light-Level Night Vision Laboratory, Xi'an 710065, China
2.
Kunming Institute of Physics, Kunming 650223, China

摘要

摘要: GaAs光电阴极以其量子效率高、光谱可调等优点广泛应用于微光夜视领域，尤其以高积分灵敏度的特性区别于多碱光电阴极，而GaAs光电阴极负电子亲合势的特性是通过Cs，O激活实现的，但是激活结束后，负电子亲合势的维持受诸多因素影响，如激活源、激活方式、气体氛围等。为了探究超高真空系统中影响GaAs光电阴极稳定性的因素，开展了GaAs光电阴极的激活实验和稳定性实验，对激活光电流曲线与腔室气体成分进行了监测，实验结果表明，在真空度优于1×10⁻⁶ Pa的高真空系统中，影响其稳定性的是腔室中的气体成分，其中对稳定性影响最大的是H₂O，真空系统中H₂O分压的增加会导致GaAs光电阴极的Cs，O激活层迅速破坏，光电发射能力急剧下降。
- GaAs光电阴极 /
- 稳定性 /
- 气体成分 /
- Cs, O激活
Abstract: GaAs photocathodes are widely used in low-light night vision owing to their high quantum efficiency and adjustable spectra. In particular, they are distinguished from multi-alkali photocathodes based on their high integration sensitivity. The negative electron affinity of GaAs photocathodes is determined through Cs, and O activation is achieved. However, after activation, the maintenance of negative electron affinity is affected by many factors, such as the activation source, activation method, and gas atmosphere. To explore the factors that affect the stability of GaAs photocathodes in ultra-high vacuum systems, an activation and stability experiment was performed with a GaAs photocathode. The activation photocurrent curve and gas composition in a chamber were monitored. The experimental results show that in a high-vacuum system with vacuum degree less than 1×10⁻⁶ Pa, the stability of the GaAs photocathode was not directly affected by the degree of vacuum but by the gas composition in the chamber. Among these, H₂O had the greatest impact on stability. The increase in the H₂O partial pressure in the vacuum system rapidly destroyed the Cs and O activation layers of the GaAs photocathode and dramatically reduced the photoemission.
- GaAs photocathode /
- stability /
- gas composition /
- Cs, O activation

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图 1 透射式GaAs光电阴极激活与气体成分监测装置

Figure 1. Transmission type GaAs photocathode activation and gas composition monitoring device

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图 2 透射式GaAs光电阴极Cs, O激活机理图

Figure 2. Transmission type GaAs photocathode Cs, O activation mechanism diagram

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图 3 GaAs光电阴极Cs, O激活光电流曲线

Figure 3. GaAs photocathode Cs, O activated photocurrent curve

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图 4 四极质谱仪监测曲线与光电阴极光电流变化曲线：(a) H₂分压提升后四极质谱仪监测曲线；(b) H₂、N₂分压提升后四极质谱仪监测曲线；(c) H₂、N₂、H₂O分压提升后四极质谱仪监测曲线；(d) H₂分压提升后光电阴极光电流变化曲线；(e) H₂、N₂分压提升后光电阴极光电流变化曲线；(f) H₂、N₂、H₂O分压提升后光电阴极光电流变化曲线

Figure 4. Quadrupole mass spectrometer monitoring curve and photocathode photocurrent change curves: (a) The monitoring curve of quadrupole mass spectrometer after H₂ partial pressure is increased; (b) The monitoring curve of the quadrupole mass spectrometer after the partial pressure of H₂ and N₂ is increased; (c) The monitoring curve of the quadrupole mass spectrometer after the partial pressure of H₂, N₂, and H₂O is increased; (d) Change curve of photocathode photocurrent after H₂ partial pressure is increased; (e) Change curve of photocathode photocurrent after H₂ and N₂ partial pressure is increased; (f) The change curve of photocathode photocurrent after the partial pressure of H₂, N₂, and H₂O is increased

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图 5 光电流曲线稳定性对比

Figure 5. Comparison of the stability of the photocurrent curves

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