We describe the reversible intercalation of Na under graphene on Ir(111) by photo-dissociation of a previously adsorbed NaCl overlayer. After room temperature evaporation, NaCl adsorbs on top of graphene forming a bilayer. With a combination of electron diffraction and photoemission techniques we demonstrate that the NaCl overlayer dissociates upon a short exposure to an X-ray beam. As a result, chlorine desorbs while sodium intercalates under the graphene, inducing an electronic decoupling from the underlying metal. Low energy electron diffraction shows the disappearance of the moiré pattern when Na intercalates between graphene and iridium. Analysis of the Na 2p core-level by X-ray photoelectron spectroscopy shows a chemical change from NaCl to metallic buried Na at the graphene/Ir interface. The intercalation-decoupling process leads to a n-doped graphene due to the charge transfer from the Na, as revealed by constant energy angle resolved X-ray photoemission maps. Moreover, the process is reversible by a mild annealing of the samples without damaging the graphene.

中文翻译：

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通过 NaCl 光解耦合的可逆石墨烯。

我们通过光解先前吸附的 NaCl 覆盖层描述了 Na 在 Ir(111) 上石墨烯下的可逆插层。室温蒸发后，NaCl 吸附在石墨烯上形成双层。通过结合电子衍射和光电发射技术，我们证明 NaCl 覆盖层在短时间暴露于 X 射线束时会解离。结果，氯会解吸，而钠会嵌入石墨烯下方，从而引起与下方金属的电子去耦。当钠插入石墨烯和铱之间时，低能电子衍射显示莫尔图案消失。通过 X 射线光电子能谱分析 Na 2p 核心水平显示了在石墨烯/Ir 界面处从 NaCl 到金属掩埋 Na 的化学变化。正如恒定能量角分辨 X 射线光电发射图所揭示的那样，由于来自 Na 的电荷转移，嵌入-去耦过程导致了 n 型掺杂石墨烯。此外，通过对样品进行温和退火，该过程是可逆的，而不会损坏石墨烯。