Terahertz detection in a slit-grating-gate field-effect-transistor structure

We have fabricated a grating-gate InGaAs/GaAs field-effect transistor structure with narrow slits between the grating gate fingers. The resonant photoconductive response of this structure has been measured in the sub-terahertz frequency range. The frequencies of the photoresponse peaks correspond to the excitation of the plasmon resonances in the structure channel. The obtained responsivity exceeds the responsivity reported previously for the grating-gate FET detector with wider slits of the grating-gate by two orders of magnitude due to enhanced coupling between incoming terahertz radiation and plasmon oscillations in the slit-grating-gate field-effect transistor structure.

► We fabricated a slit-grating-gate InGaAs/GaAs field-effect transistor structure. ► Terahertz photoconductive response of this structure has been measured. ► The photoresponse peaks correspond to the plasmon resonances in the structure. ► The slit-grating-gate terahertz detector demonstrates highly enhanced responsivity.