摘要
Bottom-up synthesis of graphene nanoribbons (GNRs) by surface-assisted polymerization and cyclodehydrogenation of specifically designed precursor monomers has been shown to yield precise edges and doping.Here we use a precursor monomer containing sulfur atoms to fabricate nanostructures on a Au(111) surface at different annealing temperatures.The nanostructures have distinct configurations,varying from sulfur-doped polymers to sulfur-doped chevron-type GNRs (CGNRs) and,finally,pristine graphene nanoribbons with specific edges of periodic five-member carbon rings.Non-contact atomic force microscopy provides clear evidence for the cleavage of C-S bonds and formation of pristine CGNRs at elevated annealing temperatures.First-principles calculations show that the CGNRs exhibit negative differential resistance.
基金
the National Key Research and Development Projects of China (No.2016YFA0202300)
the National Basic Research Program of China (No.2013CBA01600)
the National Natural Science Foundation of China (Nos.61390501, 51572290,61306015,61471337,51325204,and 11604373)
the Chinese Academy of Sciences (Nos.1731300500015 and XDB07030100).