We propose and analyze a detector of modulated terahertz (THz) radiation based on the graphene field-effect transistor with a mechanically floating gate also made of graphene. The THz component of incoming radiation induces resonant excitation of plasma oscillations in the graphene layers (GLs). The rectified component of the ponderomotive force between the GLs invokes resonant mechanical swinging of the top GL, resulting in drain current oscillations. To estimate the device responsivity, we solve the hydrodynamic equations for the electrons and holes in graphene which govern the plasma-wave response, and the equation describing the graphene membrane oscillations. The combined plasma-mechanical resonance raises the current amplitude by up to four orders of magnitude. The use of graphene for the elastic gate and conductive channel allows the voltage of both resonant frequencies to be tuned within a wide range.
- Field-effect transistors
- Nanoelectromechanical systems
- Plasma waves
- Terahertz radiation