  Recent experiments demonstrate the synthesis of 2D black arsenic exhibits
excellent electronic and transport properties for nanoscale device
applications. Herein, we study by first principle calculations density
functional theory together with non equilibrium Greens function methods, the
structural, electronic, adsorption strength, charge transfer, and transport
properties of five gas molecules CO, CO2, NO, NO2, and NH3 on a monolayer of
black arsenic. Our findings suggest optimum sensing performance of black
arsenic that can even surpass that of other 2D material such as graphene.
Further, we note the optimum adsorption sites for all the five gas molecules on
the black arsenic and significant charge transfer between the gas molecules and
black arsenic are responsible for optimum adsorption strength. Particularly,
the significant charger transfer is a sign that the interaction between the
target gas molecule and nanoscale device is sufficient to yield noticeable
changes in the electronic transport properties. As a proof of principle, we
have examined the sensitivity of a modeled nano-scale device towards CO, CO2,
NO, NO2, and NH3 gas molecules, indicating that it is indeed possible to
reliably detect all the five gas molecules. Thus, based on all these findings,
such as sensitivity and selectivity to all the five gas molecules adsorption
make black arsenic a promising material as an optimum gas sensor nano-scale
device.
