  The anisotropy in resonant tunneling transport through an electrostatic
barrier in mono layer black phosphorus either in presence or in absence of an
oscillating potential is studied. Non-perturbative Floquet theory is applied to
solve the time dependent problem and the results obtained are discussed
thoroughly. The resonance spectra in field free transmission are Lorentzian in
nature although the width of the resonance for the barrier along the zigzag
direction is too thinner than that for the armchair one. Resonant transmission
is suppressed for both the cases by the application of oscillating potential
that produces small oscillations in the transmission around the resonant energy
particularly at low frequency range. Sharp asymmetric Fano resonances are noted
in the transmission spectrum along the armchair direction while a distinct line
shape resonance is noted for the zigzag direction at higher frequency of the
oscillating potential. Even after the angular average, the conductance along
the armchair direction retains the characteristic Fano features that could be
observed experimentally. The present results are supposed to suggest that the
phosphorene electrostatic barrier could be used successfully as switching
devices and nano detectors.
