Towards chirality control of graphene nanoribbons embedded in hexagonal boron nitride

Oriented trenches are created in h-BN using different catalysts, and used as templates to grow seamlessly integrated armchair and zigzag graphene nanoribbons with chirality-dependent electrical and magnetic conductance properties. The integrated in-plane growth of graphene nanoribbons (GNRs) and hexagonal boron nitride (h-BN) could provide a promising route to achieve integrated circuitry of atomic thickness. However, fabrication of edge-specific GNRs in the lattice of h-BN still remains a significant challenge. Here we developed a two-step growth method and successfully achieved sub-5-nm-wide zigzag and armchair GNRs embedded in h-BN. Further transport measurements reveal that the sub-7-nm-wide zigzag GNRs exhibit openings of the bandgap inversely proportional to their width, while narrow armchair GNRs exhibit some fluctuation in the bandgap-width relationship. An obvious conductance peak is observed in the transfer curves of 8- to 10-nm-wide zigzag GNRs, while it is absent in most armchair GNRs. Zigzag GNRs exhibit a small magnetic conductance, while armchair GNRs have much higher magnetic conductance values. This integrated lateral growth of edge-specific GNRs in h-BN provides a promising route to achieve intricate nanoscale circuits.

Automated summary

Utilizing oriented trenches in h-BN as templates, armchair and zigzag graphene nanoribbons with chirality-dependent electrical and magnetic conductance properties were successfully grown, offering a promising route for integrated circuitry of atomic thickness. Fabricating edge-specific GNRs in the lattice of h-BN remains a significant challenge despite the developed two-step growth method for achieving sub-5-nm-wide zigzag and armchair GNRs. Conductance measurements show that different widths of zigzag GNRs exhibit openings of the bandgap inversely proportional to their width, while armchair GNRs display fluctuation in this relationship.