Researchers at the University of Illinois and the University of Nebraska-Lincoln have used graphene nanoribbons (GNRs) to create the electronic components used to carry out logic operations in computing. The team described this as "the first step toward integrating atomically precise graphene nanoribbons onto nonmetallic substrates".
The researchers explained that in most cases, GNRs are neither uniform nor narrow enough to exhibit the desired semiconductor properties. However, if the nanoribbons are made in a "bottom up” approach, it is possible to create atomically precise nanoribbons with highly uniform electronic properties.
Both solution-synthesized and surface-grown nanoribbons are exposed to chemicals during the transfer process that can affect the performance of graphene nanoribbons. However, scientists were able to use a dry transfer in an ultra-high vacuum environment. The team used a fiberglass applicator coated in graphene nanoribbon powder that was heated to remove contaminants and solvent residue. The substance pressed onto a freshly prepared hydrogen-passivated silicon surface.
Density functional theory calculations provided a deeper understanding of the electronic properties of the integrated system and the interactions between GNRs and the silicon substrate. The team stated that "It was exciting that the computational results could help explain and confirm the experimental results and provided a coherent story."