Graphene Ballistic Rectifiers: Theory and Geometry Dependence

The graphene ballistic rectifier uses the ultra-high carrier mobility of graphene to rectify ballistic carriers in an asymmetric nanostructure, and has been previously shown to operate beyond 650 GHz. Unlike conventional diodes and transistors, it does not require a bandgap. Building on the previously developed extended Buttiker-Landauer formula for semiconductors, we derive an analytical theory suitable for coexistence of electrons and holes in semi-metal graphene. Four ballistic rectifier designs are fabricated and compared. The developed theory fits their characteristics well, with derived parameters showing good agreement with device geometries. We also predict achievable responsivities of at least 50,800 V/W and noise-equivalent powers of 0.51 pW/Hz1/2 using these designs, far better than has so far been achieved. Importantly, this theory predicts increased responsivities with a large difference in carrier mobilities. Using the theory presented here, other graphene based ballistic nanodevices may be designed and optimized.