Abstract Combining the scanning tunneling microscopy (STM) and density functional theory (DFT) calculation, the growth mechanism of Graphene based on self-assembly of 1,3,5-Benzenetribenzoic acid (BTB) on Ru(0001) has been investigated. Upon deposition, the BTB molecule deprotonates at the carboxylic acid ends (-COOH), and two adsorption configurations without ordered packing structure for the adsorbates are observed in STM images. The calculated adsorption energies of the two adsorption configurations for the intact (deprotonated) BTB molecules are about 8.77 eV (16.39 eV) and 9.09 eV (17.69 eV), denoting strong interaction between the adsorbates and substrate. After the annealing of sample to 450°C, the coexistence of the deprotonated BTB molecules and graphene flakes converted from the molecules is observed, implying the onset of graphene growth. Meanwhile, an H-bonding stabilized structure between the deprotonated BTB molecules and the truncated deprotonated benzoic acid groups (− C6H4COO) could be observed at this stage. Corresponding potential barrier analysis based on the nudged elastic band (NEB) calculation provides a plausible growth mechanism.

中文翻译：

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基于1,3,5-苯三苯甲酸在Ru(0001)上自组装石墨烯的生长机理

摘要 结合扫描隧道显微镜 (STM) 和密度泛函理论 (DFT) 计算，研究了基于 1,3,5-苯三苯甲酸 (BTB) 在 Ru(0001) 上自组装的石墨烯生长机制。沉积后，BTB 分子在羧酸末端 (-COOH) 去质子化，并且在 STM 图像中观察到两种吸附结构没有吸附物的有序堆积结构。完整（去质子化）BTB 分子的两种吸附构型的计算吸附能约为 8.77 eV（16.39 eV）和 9.09 eV（17.69 eV），表明吸附物和底物之间的相互作用很强。样品退火至 450°C 后，观察到去质子化的 BTB 分子和由分子转化的石墨烯薄片共存，意味着石墨烯生长的开始。同时，在这个阶段可以观察到去质子化的 BTB 分子和截断的去质子化苯甲酸基团 (- C6H4COO) 之间的氢键稳定结构。基于轻推弹力带 (NEB) 计算的相应势垒分析提供了一种合理的增长机制。