We have developed a hybrid quantum Hall midinfrared (QHMIR)–quantum Hall far-infrared (QHFIR)
photodetector by the use of graphene-GaAs=ðAl; GaÞAs–layered composite material. Both MIR and FIR
photoresistance are observed in a single chip by utilizing cyclotron resonance in the quantum Hall regimes
of graphene and two-dimensional electron gas (2DEG) in GaAs=ðAl; GaÞAs heterostructure, respectively.
By cooperatively operating 2DEG as a back-gate electrode to change the carrier density of graphene or
graphene as a top-gate electrode to modulate the carrier density of 2DEG with an applied gate voltage less
than 1 V and applying the magnetic field to tune cyclotron resonance, we achieve a wide frequency
selectivity, covering 640–790 cm−1 for the graphene-QHMIR detector and 24–89 cm−1 for the 2DEGQHFIR
detector. Moreover, our design integrates a log-periodic antenna with the detector to minimize the
device size, while preserving high sensitivity. Our results pave the way for implementing a highly tunable
MIR-to-FIR photodetector and a dual-band (MIR-FIR) imaging array.
