Silicon carbide (SiC) nanostructures were synthesized on a silicon (Si) substrate that served as a thermionic cathode. Nanosheets, nanograins, and high-aspect-ratio nanostructures formed on the thermionic cathodes, depending on the synthesis parameters. The calculated work functions of thermionic cathodes ranged from 4.48 eV to 4.83 eV. It can be observed that the work function is attributed to the geometrical characteristics, such as the aspect ratios and the surface-area-to-volume ratios of SiC nanostructures. Among the nanostructures, using SiC nanowire structures (M200SC3) resulted in the greatest reduction in the thermionic cathode’s work function, which was 0.36 eV. This reduction is attributed to the sharp-tip structures having high aspect ratios, which is a strong field enhancement factor to the electron emission. This study suggests that the presence of SiC nanostructures on a thermionic cathode can potentially enhance electron emission in a thermionic energy converter (TEC) system.

中文翻译：

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生长在Si衬底上作为热离子阴极的SiC纳米结构及其功函数降低效应的研究

在用作热离子阴极的硅 (Si) 衬底上合成碳化硅 (SiC) 纳米结构。根据合成参数，在热离子阴极上形成纳米片、纳米颗粒和高纵横比纳米结构。热离子阴极的计算功函数范围从 4.48 eV 到 4.83 eV。可以观察到，功函数归因于几何特征，例如 SiC 纳米结构的纵横比和表面积与体积比。在纳米结构中，使用 SiC 纳米线结构 (M200SC3) 导致热离子阴极的功函数降低最大，为 0.36 eV。这种减少归因于具有高纵横比的尖端结构，这是电子发射的强场增强因子。