Towards the assembly of structurally precise graphene nanoribbons for electronic applications

Graphene's lack of band gap has been a bottleneck that limits its use in transistors. One promising approach to open up a gap in its band structure is to narrow the width of graphene, i.e., make ``nanoribbons.'' Bottom-up synthesis is a most promising method to produce structurally precise nanoribbons. But the assembly and patterning of these nanoribbons remains a challenge. In this study, we demonstrate a method for the assembly of structurally precise graphene nanoribbons. We observe preferential adsorption of nanoribbons on gold surfaces as opposed to silicon dioxide surfaces with aerosol-assisted chemical vapor deposition. Importantly, we can tune the coverage of graphene nanoribbons through appropriate surface treatments. Graphene nanoribbon adsorption on a gold surface that had been modified with pentafluorobenzenethiol, for example, is higher than that on ozone-cleaned gold, as evidenced by higher D and G band intensities in its Raman spectra. The ability to tune the surface coverage through surface treatment provides a unique opportunity to assemble and pattern graphene nanoribbons for electronic applications.