  We propose to use 2D monolayers possessing optical gaps and high exciton
oscillator strength as an element of one-dimensional resonant photonic
crystals. We demonstrate that such systems are promising for the creation of
effective and compact delay units. In the transition-metal-dichalcogenide-based
structures where the frequencies of Bragg and exciton resonances are close, a
propagating short pulse can be slowed down by few picoseconds while the pulse
intensity decreases only 2 - 5 times. This is realized at the frequency of the
"slow" mode situated within the stopband. The pulse retardation and attenuation
can be controlled by detuning the Bragg frequency from the exciton resonance
frequency.
