2020 Volume 63 Issue 9 Pages 492-497
In this review, we summarize recent progress achieved in on-surface bottom-up growth of graphene nanoribbons (GNRs) with well-defined edges. First, we show the simulation results suggesting that a GNR backward diode with GNR heterojunction can outperform the state-of-the-art diodes owing to their negligible junction capacitance. The major challenge required for achieving high-performance GNR diodes is low contact resistance and well-defined GNR heterojunction. The second part of this review is dedicated to our recent works on GNR heterojunctions by modifying electronic states by edge-functionalization. It was revealed that the important design policies for precursors are as follows : molecular design avoiding intramolecular steric hinderance upon polymerization, precursor design considering dehydrogenation path, and precursor design considering intramolecular side reaction. We also demonstrate our preliminary results of GNR-FET, which suggest that wider GNRs with narrower band gap is required for the electronic devices.