【作者】 蔡志鹏；

【导师】 侯洵；

【作者基本信息】 中国科学院研究生院（西安光学精密机械研究所） ， 光学， 2013， 博士

【摘要】 变像管分幅相机是研究物质超快过程的重要工具之一，在核聚变、高温高密度等离子体物理、非线性光学、光化学、光生物学等领域具有广泛的应用。变像管的光电阴极通常使用Ag-O-Cs阴极和多碱阴极。与Ag-O-Cs阴极和多碱阴极相比，以GaAs为代表的负电子亲和势（NEA）半导体光电阴极具有量子效率高、暗发射电流小、电子出射的平均能量和角分布小等优点，已在微光夜视、激光探测、辐射计量、自动控制等方面具有广泛的应用。如果这类光电阴极有足够的快速响应能力，这些优异的特点将使得GaAs类半导体光电阴极应用于超高速分幅相机成为可能。因此，研究并发展一种超快响应的光电阴极就是一个很值得探索的课题。本论文在理论上研究提高GaAs NEA阴极响应速度的方法，设计并理论分析了一种具有超快响应的NEA阴极新结构；在实验方面，在第三代像增强器的结构基础上，完成了使用GaAs NEA阴极的双微带选通型分幅管制作的整个工艺流程。首先，分别阐述了GaAs NEA阴极的特点和基于GaAs NEA阴极的分幅管的制作过程。简单描述了高速分幅相机的特点及发展状况。提出将半导体NEA阴极与分幅管结合发展，以进一步拓展变像管分幅相机的性能的实验构想；其次，提出了具有超快响应的大梯度指数掺杂NEA阴极结构，分别讨论了这种新结构的量子效率、空间分辨力和时间分辨力特性。在无偏压工作条件下，它的时间响应可以缩短到小于10ps，平均量子效率可以达到10～15％；首次提出了平均时间衰减常数的概念，有效地消除了以往计算中的缺陷。这为半导体NEA阴极在皮秒级分幅相机中的应用提供了必要的理论支持；然后，简单介绍了高分辨X射线衍射技术。设计并外协生长了用于GaAs阴极制作的四层结构的外延片，并利用高分辨X射线衍射仪测量了它的衍射曲线，使用非对称衍射测量技术分析了该结构的应变、Al组分含量和应力等结构特性。分析表明：外延片的Al组分和应力分布均匀性良好，同时高角度衍射测量获得的大面积外延片上应变曲率半径的分布优于低角度衍射，这可能表明高角度衍射更能够反映外延片的宏观应变；再次，进行了真空镀膜、光刻法制作网格电极、GaAs衬底化学刻蚀等工艺，构建了条形GaAs外延片与玻璃的真空热粘接设备，针对双条GaAs外延片与玻璃不易粘接的问题，设计并制作了真空粘接定位元件；探索利用金属网格电极代替常规Si3N4辅助粘接材料，实现了条形GaAs与玻璃的真空热粘接；粘接后的金属线的阻抗达到22-23欧姆，而分幅相机微带线的典型阻抗是1-25欧姆，因此新工艺的粘接效果能够满足分幅相机的要求；最后，进行了GaAs阴极激活和热铟封实验，完成了真空二极管的制作，为双条带及多条带阴极选通型GaAs分幅相机的制作提供了完整的工艺基础。本论文从理论上和工艺流程上探索了将GaAs光电阴极应用于双微带高速摄影分幅相机，为将来半导体NEA光电阴极应用于诸如多通道分幅相机和条纹相机等，提供了理论和实验的支持。更多还原

【Abstract】 High-speed framing cameras are one of the most important research tools of an physicalultrafast process, they have broad application in nuclear fusion, plasma physics with hightemperature and high density, nonlinear optics, photobiology and so on. With high quantumefficiency, low dark current, low energy distribution and low emittance, GaAs negative electronaffinity (NEA) photocathodes have the wide application in photomultipliers (PMT), laserdetection, radiation measurement, automatic control, low-light level image, spintronics andelectron-beam lithography. Because of these outstanding characteristics, it is possible that theGaAs NEA cathodes can be used in high-speed framing cameras if these NEA semiconductorphotocathodes have high-speed response behavior.In this paper, In theory, we design a new GaAs NEA cathode structure with ultrafast responseand theoretically analyse its response characteristics for improving the response speed; Inexperiment, based on the third generation image intensifier, this paper completes the wholetechnical processes of the third generation image intensifier uesd by double microstrip line GaAscathode gated framing camera.Firstly, we describe the characteristics of GaAs photocathodes and the manufacturingprocesses of the framing tube. The high-speed framing cameras are briefly described. Forimproving the further development of framing cameras, we bring forward the plan of combiningGaAs photocathodes with the application of the high-speed framing cameras.Secondly, a large exponential-doping transmission-mode GaAs photocathode is designed toimprove the response speed of GaAs NEA photocathodes to meet the application demands offraming cameras. The characteristics of the new photocathode——the quantum efficiency,spatial time resolution, is discussed in detail. Its response time is shorted to less than10ps, theaverage quantum efficiency can reach10-15%; a new concept——the average decay timeconstant is introduced firstly to the simulation and the defects in the previous calculation iseffectively eliminated. The results provide necessarily theoretical support for the application ofsemiconductor NEA cathodes to the picosecond framing cameras.Thirdly, the high resolution X ray diffraction technology is introduced briefly. we design andgrow the GaAs/GaAlAs epitaxial wafer for the GaAs photocathode fabrication. The diffraction curves are measured by the high resolution X-ray diffractometer. The structure characteristics oftrain Al component content and the stress is analyzed by the asymmetric diffraction measurementtechnique. The analysis results show that the GaAs/GaAlAs structure has good uniformitydistribution about Al component content and the stress. The strain curvature radius distribution ofthe epitaxial wafer obtained the high angle diffraction measurements is better than that of the lowangle diffraction measurements, which may indicate that the high angle diffraction can moremacroscopically reflect the structural stress condition.Fourth, the works as follows are made: the vacuum deposition, grid electrode fabrication byphotolithography, GaAs substrate corrosion; the new thermal bonding technique in vacuum ofstrip-type GaAs and K4glass is explored, in which Ni-Cr grid electrode instead by the auxiliarybonding material Si3N4; the positioning device is designed and fabricated for strip-type GaAs andK4glass positioning accurately in the vacuum heat bonding process.Finally, the vacuum diode is fabricated by the processes of the Cs: O activation of GaAsphotocathodes and the Indium seal experiment. Then, the whole technological processes of thenew framing camera are finished, which provide the necessarily experimental support.This thesis exploringly studies the fabrication processes of GaAs photocathode gated framingcamera, and study the ultrafast theory of the NEA photocathode. This work provides necessarilytheoretical and technological support, such as multi-channel framing camera and the developmentother ultrafast field.更多还原