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在一个商业超高真空装置中,对以玻璃为衬底并附有 Ga_xAl_1As 过渡层的半透明 GaAs 膜进行激活,获得了负电子亲和势(NEA)特性。在激活前后对光电阴极进行了定量表面分析,结果表明:Cs-O 表面层的化学计量是准确的 Cs_2O,其厚度约为1.3nm。通过测量阴极的光电子能带分布(EDC),首次证实了在负电子亲和势工作状态下,整个光电灵敏区域中热化电子的分布都很窄,并且几乎与波长无关。使用一架专用的超高真空可拆卸同步条纹相机测量了一些 NEA 阴极的响应时间,其典型值约8Ps。在中等瞬时分辩率的条纹相机中可考虑使用 GaAs NEA 光电阴极。这种相机工作于技术领域中重要的1.3～1.55μm 光谱波段。
In a commercial ultra-high vacuum device, a negative electron affinity (NEA) characteristic was obtained by activation of a translucent GaAs film that is glass-lined with a transition layer of Ga_xAl_1As. Quantitative surface analysis of the photocathode before and after activation shows that the stoichiometry of Cs-O surface layer is accurate Cs_2O with a thickness of about 1.3 nm. By measuring the photoelectron energy band-distribution (EDC) of the cathode, it was first demonstrated that the distribution of the heated electrons in the entire photo-sensitive region is very narrow and almost wavelength-independent in the case of negative-electron affinity working. The response time of some NEA cathodes was measured using a dedicated ultra-high vacuum detachable sync streak camera, which is typically around 8Ps. GaAs NEA photocathodes may be considered for use in streak cameras with medium instantaneous resolution. This camera works in the technical field of 1.3 ~ 1.55μm spectral band.