Borazine is a well-established precursor molecule for the growth of hexagonal boron nitride (h-BN) via chemical vapor deposition on metal substrates. To understand the formation of the h-BN/Rh(111) moiré from borazine on a molecular level, we investigated the low-temperature adsorption and thermally induced on-surface reaction of borazine on Rh(111) in situ using synchrotron radiation-based high-resolution x-ray photoelectron spectroscopy (XPS), temperature-programmed XPS, and near-edge x-ray absorption fine structure measurements. We find that borazine adsorbs mainly as an intact molecule and have identified a flat-lying adsorption geometry. Borazine multilayers are observed to desorb below 200 K. Starting at about 300 K, dehydrogenation of the remaining borazine and borazine fragments takes place, and disordered boron nitride starts to grow. Above 600 K, the formation of the h-BN sets in. Finally, at 1100 K, the conversion to h-BN is complete. The h-BN formed by deposition and post-annealing was compared to the h-BN grown by an established procedure, proving the successful preparation of the desired two-dimensional material.

中文翻译：

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制造中的 h-BN：Rh(111) 上环硼氮烷的表面化学

环硼嗪是一种成熟的前体分子，用于通过化学气相沉积在金属基材上生长六方氮化硼 (h-BN)。为了在分子水平上了解环硼氮烷 h-BN/Rh(111) 莫尔条纹的形成，我们使用基于同步辐射的方法原位研究了环硼氮烷在 Rh(111) 上的低温吸附和热诱导表面反应。高分辨率 X 射线光电子能谱 (XPS)、程序升温 XPS 和近边缘 X 射线吸收精细结构测量。我们发现环硼嗪主要作为完整分子进行吸附，并确定了平躺的吸附几何形状。观察到环硼氮烷多层在低于 200 K 的温度下解吸。从大约 300 K 开始，剩余的环硼氮烷和环硼氮烷片段发生脱氢，并且无序氮化硼开始生长。温度高于 600 K 时，h-BN 开始形成。最后，在 1100 K 时，h-BN 的转化完成。将通过沉积和后退火形成的 h-BN 与通过既定程序生长的 h-BN 进行比较，证明成功制备了所需的二维材料。