▎ 摘　　要

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 degrees 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.