Tuning the electronic transport anisotropy in α-phase phosphorene through superlattice design

Rational tuning the anisotropic electronic properties of monolayer phosphorene is essential to their applications in electronic and optoelectronic devices. By combining the density functional theory and the nonequilibrium Green's function method, we developed a strategy to tune the anisotropic transport properties of phosphorene by designing stable arsenic-phosphorene ($\mathrm{A}{\mathrm{s}}_{x}{\mathrm{P}}_{1\ensuremath{-}x}$) superlattice (SL). It was found that, with a careful design of As:P ratio and atomic arrangement, the anisotropic transport properties could be tuned in a wide range. The transport current along the zigzag direction, which is very low in pristine phosphorene, was gradually enhanced by increasing the As:P ratio, and even became larger than that along armchair direction when the As:P ratio achieved 1:1 under a given arrangement of As atoms in $\mathrm{A}{\mathrm{s}}_{x}{\mathrm{P}}_{1\ensuremath{-}x}$ SL. The tunable anisotropic transport properties of $\mathrm{A}{\mathrm{s}}_{x}{\mathrm{P}}_{1\ensuremath{-}x}$ SL are attributed to the interplay between the different scattering rates related to the number and orientation of As-P interfaces. This finding demonstrates that the $\mathrm{A}{\mathrm{s}}_{x}{\mathrm{P}}_{1\ensuremath{-}x}$ SL design could be an effective approach to tune the anisotropic electronic properties of monolayer phosphorene, which is important for the development of high-performance electronic and optoelectronic devices based on phosphorene.