Terahertz Detection by High Electron Mobility Transistor: Effect of Drain Current
Authors:
J.-Q. Lu, M.S. Shur
Abstract:
We report on a new regime of operation of High Electron Mobility Transistor (HEMT) terahertz detectors, in which we apply a constant (dc) drain bias. The measured responsivity increases with the drain current by more than an order of magnitude and saturates at the dc bias corresponding to the saturation of the dc drain current for given gate voltage. We link this increase in the detector responsivity to the drain bias dependence of the gate-to-source and gate-to-drain capacitances, which results in a much greater asymmetry in the boundary conditions for plasma waves. These results confirm our model linking the HEMT detector response to the propagation of overdamped plasma waves in the device channel.