  We propose the terahertz (THz) detectors based on field-effect transistors
(FETs) with the graphene channel (GC) and the black-Arsenic (b-As)
black-Phosphorus (b-P), or black-Arsenic-Phosphorus (b-As$_x$P$_{1-x}$) gate
barrier layer. The operation of the GC-FET detectors is associated with the
carrier heating in the GC by the THz electric field resonantly excited by
incoming radiation leading to an increase in the rectified current between the
channel and the gate over the b-As$_x$P$_{1-x}$ energy barrier layer (BLs). The
specific feature of the GC-FETs under consideration is relatively low energy
BLs and the possibility to optimize the device characteristics by choosing the
barriers containing a necessary number of the b-As$_x$P$_{1-x}$ atomic layers
and a proper gate voltage. The excitation of the plasma oscillations in the
GC-FETs leads to the resonant reinforcement of the carrier heating and the
enhancement of the detector responsivity. The room temperature responsivity can
exceed the values of $10^3$~A/W. The speed of the GC-FET detector's response to
the modulated THz radiation is determined by the processes of carrier heating.
As shown, the modulation frequency can be in the range of several GHz at room
temperatures.
