Unconventional thermal conductivity of suspended zigzag graphene nanomesh

Abstract Compared to the study of graphene itself, the study of nano-structured graphene is rather limited because it is difficult to prepare atomically ordered edges. In this study, we have fabricated a periodically patterned mesh structure of graphene with atomically precise zigzag edges (zGNM: zigzag graphene nanomesh) and studied its thermal conductivity ( κ ) by opto-thermal Raman measurement. Unintuitively, it is found that the κ of zGNM of 2 , 3 monolayers (MLs) thick is weakly inversely proportional to the nanoribbon width ( W ), while that of zGNM of 5∼10 MLs thick is independent of W down to 30 nm. In any case, their κ is not suppressed by nano-structuring. Since the κ of suspended zigzag graphene nanoribbons (zGNRs) is suppressed by decreasing W , this nonclassical behavior of zGNM is due to the mesh structure. In addition, zGNRs show a higher κ than GNRs with atomically rough edges. This is probably due to the atomically ordered zigzag edges.