The growth of para-sexiphenyl (6P) thin films as a function of substrate temperature on Ir{111} supported graphene flakes has been studied in real-time with Low Energy Electron Microscopy (LEEM). Micro Low Energy Electron Diffraction (μLEED) has been used to determine the structure of the different 6P features formed on the surface. We observe the nucleation and growth of a wetting layer consisting of lying molecules in the initial stages of growth. Graphene defects – wrinkles – are found to be preferential sites for the nucleation of the wetting layer and of the 6P needles that grow on top of the wetting layer in the later stages of deposition. The molecular structure of the wetting layer and needles is found to be similar. As a result, only a limited number of growth directions are observed for the needles. In contrast, on the bare Ir{111} surface 6P molecules assume an upright orientation. The formation of ramified islands is observed on the bare Ir{111} surface at 320 K and 352 K, whereas at 405 K the formation of a continuous layer of upright standing molecules growing in a step flow like manner is observed.

中文翻译：

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LEEM研究衬底温度对Ir{111}负载石墨烯上对联苯薄膜生长的影响

已经使用低能电子显微镜 (LEEM) 实时研究了对联苯 (6P) 薄膜在 Ir{111} 支撑的石墨烯薄片上随基板温度的变化而生长。微低能量电子衍射 (μLEED) 已用于确定表面上形成的不同 6P 特征的结构。我们观察到由处于生长初始阶段的分子组成的润湿层的成核和生长。石墨烯缺陷——皱纹——被发现是润湿层和在沉积后期生长在润湿层顶部的 6P 针形核的优先位置。发现润湿层和针的分子结构相似。结果，仅观察到针的有限数量的生长方向。相比之下，在裸露的 Ir​​{111} 表面上，6P 分子呈直立取向。在 320 K 和 352 K 下，在裸露的 Ir​​{111} 表面上观察到分枝岛的形成，而在 405 K 下，观察到以阶梯流方式生长的连续直立分子层的形成。