Graphene-templated directional growth of an inorganic nanowire

Inorganic nanowires composed of gold(I) cyanide can be grown directly on pristine graphene, aligning themselves with the zigzag lattice directions of the graphene, and then used as templates to create graphene nanoribbons with zigzag-edged directions. Assembling inorganic nanomaterials on graphene1,2,3 is of interest in the development of nanodevices and nanocomposite materials, and the ability to align such inorganic nanomaterials on the graphene surface is expected to lead to improved functionalities4, as has previously been demonstrated with organic nanomaterials epitaxially aligned on graphitic surfaces5,6,7,8,9,10. However, because graphene is chemically inert, it is difficult to precisely assemble inorganic nanomaterials on pristine graphene2,11,12,13,14,15,16. Previous techniques2,3 based on dangling bonds of damaged graphene11,17,18,19,20, intermediate seed materials11,15,16,21,22 and vapour-phase deposition at high temperature12,13,14,23,24,25 have only formed randomly oriented or poorly aligned inorganic nanostructures. Here, we show that inorganic nanowires of gold(I) cyanide can grow directly on pristine graphene, aligning themselves with the zigzag lattice directions of the graphene. The nanowires are synthesized through a self-organized growth process in aqueous solution at room temperature, which indicates that the inorganic material spontaneously binds to the pristine graphene surface. First-principles calculations suggest that this assembly originates from lattice matching and π interaction to gold atoms. Using the synthesized nanowires as templates, we also fabricate nanostructures with controlled crystal orientations such as graphene nanoribbons with zigzag-edged directions.