Plasmon Mediated, Ingaas/Inp, Tunable Far-Ir Detector

Plasmon resonances in the two dimensional electron gas (2-deg) of a high electron mobility transistor (HEMT) can affect transport properties. The resonance frequency depends on the gate-tuned sheet charge density of the 2deg and on the characteristic length of the gate metallization by which free space THz radiation couples to the plasmon. Thus, this type of device can be used as a tunable detector. This work presents an experimental investigation of such a device fabricated from the InGaAs/InP material system. E-beam lithography was used to fabricate a gate in the form of a grating with submicron period. Sensitivity of the conductance to incident THz fields is reported. Direct absorption of THz, temperature effects, and the effects of source to drain current on system performance are also investigated. It is expected that this class of device will find use in space-borne remote sensing applications