Plasma wave electronics: terahertz detectors and sources using two dimensional electronic fluid in high electron mobility transistors

We discuss applications of plasma waves in high electron mobility transistors for detectors and sources operating in millimeter and submillimeter range. A short channel high electron mobility transistor (HEMT) has a resonance response to electromagnetic radiation at the plasma oscillation frequencies of the two dimensional electrons in the device. The devices, which use this resonance response should operate at much higher frequencies than conventional, transit-time limited devices since the plasma waves propagate much faster than electrons. The responsivities of such devices may greatly exceed the responsivities of Schottky diodes currently used as detectors and mixers in the terahertz range. A long channel HEMT has a nonresonant response to electromagnetic radiation and can be used as a broad band detector for frequencies up to several tens of terahertz. Recently, a prototype nonresonant detector (operating in the microwave range) was fabricated using an AlGaAs/GaAs 0.15 micron gate HEMT. The measured dependencies of the detector responsivity on the gate bias and frequency are in good agreement with our theory.