Hydrodynamic simulations of the subterahertz and terahertz response in a ratchet field-effect structure with several gate fingers reveal a significant responsivity enhancement compared to similar nonratchet structures. In high-mobility structures, the response exhibits a plasmonic peak with a half width determined by impurity and phonon scattering and by the viscosity of the electronic fluid. The device with a feature size of 100 nm exhibits a reasonable response up to 8 THz. At high frequencies, high mobilities, and short feature sizes (on the order of 50 nm), the viscosity of the 2D electronic fluid becomes a dominant attenuation mechanism. The finite ratchet structures also exhibit plasmonic peaks at lower plasmonic frequencies corresponding to the wavelengths determined by the overall lengths of the structures. These results are important for the modeling, design, and optimization of highly sensitive subterahertz and terahertz ratchet plasmonic devices.

• Received 18 January 2018

DOI:https://doi.org/10.1103/PhysRevApplied.9.064007