Monochromatic Photocathodes from Graphene-Stabilized Diamondoids.-猫眼课题宝

DOI：

10.1021/acs.nanolett.7b04645

发表时间：

2018-01

期刊：

Nano letters

影响因子：

10.8

通讯作者：

中科院分区：

材料科学1区

文献类型：

作者：

Hao Yan;K. T. Narasimha;J. Denlinger;F. Li;S. Mo;J. Hohman;J. Dahl;R. Carlson;B. Tkachenko;A. Fokin;P. Schreiner;Z. Hussain;Z. Shen;N. Melosh

金刚石单层的单色光发射为制造低能量色散的电子源提供了一种新策略，并使具有高亮度和低光束发射度的小型电子枪能够用于无像差成像、光刻和加速器。然而，这些潜在的应用受到光子照射和电子轰击下金刚石单层降解的阻碍。在这里，我们报道了一种石墨烯保护的金刚石单层光电阴极，与裸金刚石相比，稳定性提高了4倍。单层石墨烯覆盖层保留了光电子的单色性，在动能半最大分布时显示12.5 meV的宽度。重要的是，石墨烯涂层有效地抑制了金刚石单层的脱附，使其热稳定性提高了至少100 K。此外，通过比较不同光子能量下的衰变速率，我们确定了电子轰击是石墨烯保护下金刚石类化合物的主要衰变途径。这为稳定光电阴极表面的挥发性物质提供了一种通用的方法，可以大大提高电子发射器的性能。

The monochromatic photoemission from diamondoid monolayers provides a new strategy to create electron sources with low energy dispersion and enables compact electron guns with high brightness and low beam emittance for aberration-free imaging, lithography, and accelerators. However, these potential applications are hindered by degradation of diamondoid monolayers under photon irradiation and electron bombardment. Here, we report a graphene-protected diamondoid monolayer photocathode with 4-fold enhancement of stability compared to the bare diamondoid counterpart. The single-layer graphene overcoating preserves the monochromaticity of the photoelectrons, showing 12.5 meV ful width at half-maximum distribution of kinetic energy. Importantly, the graphene coating effectively suppresses desorption of the diamondoid monolayer, enhancing its thermal stability by at least 100 K. Furthermore, by comparing the decay rate at different photon energies, we identify electron bombardment as the principle decay pathway for diamondoids under graphene protection. This provides a generic approach for stabilizing volatile species on photocathode surfaces, which could greatly improve performance of electron emitters.

Monochromatic Photocathodes from Graphene-Stabilized Diamondoids.

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