A cerium hexaboride (CeB6) single crystal grown by the floating-zone method has a low work function of about 2.6 eV, and along with lanthanum hexaboride (LaB6), it is one of the most popular cathode materials. It has been widely used as the thermionic emitter of electron microscopes, such as SEMs and TEMs. However, cold-field emitters (CFEs) based on CeB6 and LaB6 have not been put to practical use due to their insufficient emission stability compared to that of conventional tungsten (W)-CFEs. In consideration of that background, in the present study, the stability of the emission current from a CeB6 single-crystal CFE was improved by using the (100) plane at the faceted tip of the single crystal. The CeB6⟨100⟩ single crystal was processed by electrochemical etching and successive high-temperature field evaporation and faceting under an appropriate electric field to make a (100) plane at the apex of the crystal. The improved CeB6(100)-CFE emitted a monochromatic electron beam, which has about three-quarters of the energy width of that of W(310)-CFEs. Emission current from the (100) plane maintained low emission noise, and emission decay in the electron-gun chamber of the SEM was suppressed. The resulting current noise is low enough to produce SEM images without image deterioration, and the relatively small decay makes it possible to use the CeB6(100) emitter for one flashing process per day.

中文翻译：

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使用刻面 (100) 平面稳定来自 CeB6 单晶发射器的冷场发射电流

通过浮区法生长的六硼化铈 (CeB6) 单晶具有约 2.6 eV 的低功函数，与六硼化镧 (LaB6) 一起是最受欢迎的正极材料之一。它已被广泛用作电子显微镜（如 SEM 和 TEM）的热离子发射器。然而，与传统的钨 (W)-CFE 相比，基于 CeB6 和 LaB6 的冷场发射器 (CFE) 尚未投入实际使用，因为它们的发射稳定性不足。考虑到这一背景，在本研究中，CeB6 单晶 CFE 的发射电流稳定性通过在单晶的刻面尖端使用 (100) 面来提高。CeB6⟨100⟩单晶在适当的电场下通过电化学蚀刻和连续的高温场蒸发和刻面加工，在晶体的顶点形成一个（100）面。改进的 CeB6(100)-CFE 发射单色电子束，其能量宽度约为 W(310)-CFE 的四分之三。(100)面的发射电流保持低发射噪声，SEM电子枪室的发射衰减得到抑制。由此产生的电流噪声足够低，可以在不损坏图像的情况下生成 SEM 图像，并且相对较小的衰减使得使用 CeB6(100) 发射器每天进行一次闪光过程成为可能。其能量宽度约为 W(310)-CFE 能量宽度的四分之三。(100)面的发射电流保持低发射噪声，SEM电子枪室的发射衰减得到抑制。由此产生的电流噪声足够低，可以在不损坏图像的情况下生成 SEM 图像，并且相对较小的衰减使得使用 CeB6(100) 发射器每天进行一次闪光过程成为可能。其能量宽度约为 W(310)-CFE 能量宽度的四分之三。(100)面的发射电流保持低发射噪声，SEM电子枪室的发射衰减得到抑制。由此产生的电流噪声足够低，可以在不损坏图像的情况下生成 SEM 图像，并且相对较小的衰减使得使用 CeB6(100) 发射器每天进行一次闪光过程成为可能。