Nanoscale Graphene-Based Ballistic Rectifiers for Detection of High Terahertz Frequency Optical Signals

Graphene exhibits the longest carrier mean free path of any known electronic material, yet only a few device concepts have successfully leveraged this exceptional property. Here, we present a ballistic graphene rectifier capable of operating at frequencies up to 3 THz, significantly extending the limits of direct current (DC) generation through rectification in two-dimensional materials. By engineering asymmetric nanojunction geometries in high-mobility monolayer graphene encapsulated in hBN, we harness ballistic transport over >100 nm length scales to achieve efficient rectification without relying on p-n junctions or Schottky barriers. The devices exhibit robust rectified signals, with voltage responsivities of 100 V/W, 20 pW/Hz^1/2 noise-equivalent powers at room temperature, and minimum detectable powers of 30 nW, outperforming conventional semiconductor-based rectifiers in the same frequency range. Our results establish a new pathway for passive THz detection and signal processing, highlighting the potential of graphene nanodevices for next-generation high-frequency technologies.