A narrowband plasmonic terahertz detector with a monolithic hot electron bolometer

We have fabricated and characterized plasmonic terahertz detectors that integrate a voltage controlled planar barrier with a grating gated GaAs/AlGaAs high electron mobility transistor. These detectors exhibit a narrowband, tunable plasmonic response. Substantially increased responsivity is achieved by introducing an independently biased, narrow gate that produces a lateral potential barrier adjacent to the drain when biased to pinch-off. DC electrical characterization in conjunction with bias-dependent terahertz responsivity and time constant measurements indicate that a hot electron bolometric effect is the dominant response mechanism over a broad range of experimental conditions. The temperature dependence of the bolometric response is consistent with the energy relaxation time and absorption coefficient of a 2DEG. Rectification resulting from non-linear current-voltage characteristics also appears to contribute to the response. Additionally, we have begun investigating the operation of this device with the full grating gate biased to pinch-off to produce many detection elements in series.