Abstract The deposition of barium fluoride thin and ultra-thin films on gallium arsenide substrates was performed by electron beam evaporation for analyzing the influence of film thickness and chemical composition on the work function of the resulting heterostructure. X-ray photoemission spectroscopy combined with ultraviolet photoemission spectroscopy measurements reveals that films of 2 nm nominal thickness and Ba/F = 1.0 stoichiometry ratio induce the achievement of a significantly low work function of 2.1 eV to the BaFx/GaAs heterostructure. The significant reduction of the work function at least down to 3.0 eV is confirmed by a test thermionic converter operating at a cathode temperature of 1385 °C, where the heterostructure was applied as anode. The low work function, together with a negligible optical absorption, makes feasible the practical application of barium fluoride coatings on GaAs within hybrid thermionic-thermophotovoltaic devices.

中文翻译：

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用于热离子热光伏应用的低功函数氟化钡超薄膜

摘要 通过电子束蒸发在砷化镓衬底上沉积氟化钡薄膜和超薄膜，以分析薄膜厚度和化学成分对所得异质结构功函数的影响。X 射线光电子能谱结合紫外光电子能谱测量表明，2 nm 标称厚度和 Ba/F = 1.0 化学计量比的薄膜导致 BaFx/GaAs 异质结构的功函数显着降低，为 2.1 eV。在阴极温度为 1385°C 下运行的测试热离子转换器证实了功函数的显着降低至少低至 3.0 eV，其中异质结构用作阳极。低功函数，加上可忽略不计的光吸收，