Theoretical study on strain-controllable gradient Schottky barrier of dumbbell-shape graphene nanoribbon for highly sensitive strain sensors

The strain-induced change of electronic conduction properties in the dumbbell-shape graphene nanoribbon structure and the electronic band structure around the jointed interface between the metallic GNR (Graphene NanoRibbon) and the semiconductive GNR in the proposed dumbbell-shape structure were analyzed by using first-principles calculations in this study. The dumbbell-shape GNR exhibited a complicated current-voltage characteristics under the application of uniaxial strain. The main reason for the complicated behavior was attributed to the existence of the strain-induced change of gradient Schottky barrier around the newly formed atomic seamless interface between the metallic GNR and semiconductive GNR under the application of uniaxial tensile strain. The band diagram of the newly formed gradient Schottky barrier around atomic seamless interface was completely different with that of the conventional step-like metal-semiconductor interface. This energy height of gradient Schottky barrier can be modulated by applying an appropriate range of tensile strain. This strain-induced change of the electronic band structure of dumbbell-shape GNR showed a great potential for developing a highly sensitive strain sensor with stable electronic performance.