Transition metal catalyzed chemical vapor deposition (CVD) is considered as the most promising approach to synthesize highquality graphene films, and low-temperature growth of defect-free graphene films is long-term c...Transition metal catalyzed chemical vapor deposition (CVD) is considered as the most promising approach to synthesize highquality graphene films, and low-temperature growth of defect-free graphene films is long-term challenged because of the high energy barrier for precursor dissociation and graphitization. Reducing the growth temperature can also bring advantages on wrinkle-free graphene films owing to the minimized thermal expansion coefficient mismatch. This work focuses on density functional theory (DFT) calculations of the carbon source precursor with hydroxyl group, especially CH_(3)OH, on low-temperature CVD growth of graphene on Cu and CuNi substrate. We calculated all the possible cleavage paths for CH_(3)OH on transition metal substrates. The results show that, firstly, the cleavage barriers of CH_(3)OH on transition metal substrates are slightly lower than those of CH_(4), and once CO appears, it is difficult to break the C-O bond. Secondly, the CO promotes a better formation and retention of perfect rings in the early stage of graphene nucleation and reduces the edge growth barriers. Thirdly, these deoxidation barriers of CO are reduced after CO participates in graphene edge growth. This paper provides a strategy for the lowtemperature growth of wrinkles-free graphene on transition metal substrates using CH_(3)OH.展开更多
基金supported by the National Natural Science Foundation of China(No.T2188101)Beijing National Laboratory for Molecular Science(No.BNLMS-CXTD-202001)National Key R&D Program of China(No.2018YFA0703502).
文摘Transition metal catalyzed chemical vapor deposition (CVD) is considered as the most promising approach to synthesize highquality graphene films, and low-temperature growth of defect-free graphene films is long-term challenged because of the high energy barrier for precursor dissociation and graphitization. Reducing the growth temperature can also bring advantages on wrinkle-free graphene films owing to the minimized thermal expansion coefficient mismatch. This work focuses on density functional theory (DFT) calculations of the carbon source precursor with hydroxyl group, especially CH_(3)OH, on low-temperature CVD growth of graphene on Cu and CuNi substrate. We calculated all the possible cleavage paths for CH_(3)OH on transition metal substrates. The results show that, firstly, the cleavage barriers of CH_(3)OH on transition metal substrates are slightly lower than those of CH_(4), and once CO appears, it is difficult to break the C-O bond. Secondly, the CO promotes a better formation and retention of perfect rings in the early stage of graphene nucleation and reduces the edge growth barriers. Thirdly, these deoxidation barriers of CO are reduced after CO participates in graphene edge growth. This paper provides a strategy for the lowtemperature growth of wrinkles-free graphene on transition metal substrates using CH_(3)OH.
