Transistors based on graphene nanoribbon triple junctions

Bottom-up chemical self-assembly of graphene nanoribbons (GNRs) has opened the possibility for all-graphene integrated circuits of nanoscale dimensions. These versatile building blocks exhibiting a broad range of controllable electronic properties have been considered, for example, as potential interconnects or spin filters, but more complex components are not yet conceptualized. In this work, we envisage in-plane triple GNR junctions as potential next-generation transistors. Considering the three leads as either "source", "drain" or "gate", we investigate the transport properties of triple junctions with the help of tight-binding(TB) models, density-functional theory (DFT), and Green's function approach. Utilizing experimentally synthesized chevron-GNR triple junction as a basis, we introduce "bite" defects – the most common defect in chevron GNR synthesis – to enhance the transport between the source and drain leads, while suppressing the transmission to the gate lead. Next, we investigate the effects on the transmission by, first, a simple TB model, where a locally placed charge simulates the electric field and, second, by applying the gate voltage in DFT calculations.