Theoretical investigation of bottom-up synthesized graphene nanoribbon transistors

Bottom-up synthesized graphene nanoribbons (GNRs) have shown great promise in next generation electronic devices because of the perfect precision and wide diversity of their atomic structures and their intriguing transport properties. The armchair, semiconducting bottom-up GNRs are of particular interest in future ultimately scaled transistor technologies. Here we present a device model for bottom-up armchair GNR transistors based on the Landauer-Büttiker formalism. A systematic theoretical investigation of single-GNR transistors is carried on, with the consideration of intrinsic and extrinsic effects such as carrier scattering, scaling length, gating efficiency, thermionic field emission, short contact length, source-to-drain tunneling, charging of trap states, and GNR-GNR screening. To further analyze the electrical characterization of multiple-GNR transistors, a Monte Carlo simulation is performed to capture the length and spatial distributions of GNRs as well as the variance of the transport behavior in each GNR. The model shows good consistency with experimental results. This work establishes a solid foundation for in-depth studies of the unique mesoscopic transport properties of different types of GNRs, and for further optimizations of the transistor performance.