  We study the electronic transport properties of two-dimensional (2D)
fully-hydrogenated borophene (namely, borophane), using the density functional
theory and non-equilibrium Green's function approaches. Borophane shows a
perfect electrical transport anisotropy and is promising for applications.
Along the peak- or equivalently the valley-parallel direction, the 2D borophane
exhibits a metallic characteristic and its current-voltage (I-V) curve shows a
linear behavior, corresponding to the ON state in borophane-based nano-switch.
In this case, electrons mainly propagate via the B-B bonds along the linear
boron chains. In contrast, the electron transmission is almost forbidden along
the perpendicular buckled direction (i.e., the OFF state), due to its
semi-conductor property. Our work demonstrates that 2D borophane could combine
the metal and semiconductor features and can be a promising candidate of
nano-switching materials with stable structure and high ON/OFF ratio.
