Observation at low voltage using scanning electron microscopes (SEMs) enables the characterization of surface details on specimens on a nanometer scale and is widely used in science and industry. However, the energy width of the electron source restricts the spatial resolution of SEMs at low voltage, but it can be narrowed by lowering the work function of the emitter material. Here, we developed a cold field emitter using a cerium hexaboride single crystal (CeB6-CFE) as a monochromatic electron source. The work function of the CeB6 (310) plane was estimated to be as low as 2.25 ± 0.17 eV, and the energy width ranged from 0.17 to 0.26 eV for angular current densities ranging from 0.10 to 80 μA/sr. This energy width was 20% to 30% narrower than that of conventional W(310)-CFEs. Using the CeB6-CFE, the spatial resolution of the SEM at an acceleration voltage of 0.5 kV was improved by 11% compared with that of an SEM using the W(310)-CFE.

中文翻译：

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CeB6 (310) 冷场发射器的单色电子发射

使用扫描电子显微镜 (SEM) 在低电压下观察可以在纳米尺度上表征样品的表面细节，并广泛用于科学和工业。然而，电子源的能量宽度限制了低电压下扫描电镜的空间分辨率，但可以通过降低发射体材料的功函数来缩小。在这里，我们开发了一种使用六硼化铈单晶 (CeB6-CFE) 作为单色电子源的冷场发射器。CeB6 (310) 平面的功函数估计低至 2.25 ± 0.17 eV，能量宽度范围为 0.17 至 0.26 eV，角电流密度范围为 0.10 至 80 μA/sr。该能量宽度比传统的 W(310)-CFE 窄 20% 至 30%。使用 CeB6-CFE，