  In this work we develop a compact multi-orbital tight-binding model for
phosphorene that accurately describes states near the main band gap. The model
parameters are adjusted using as reference the band structure obtained by a
density-functional theory calculation with the hybrid HSE06 functional. We use
the optimized tight-binding model to study the effects of disorder on the
anisotropic transport properties of phosphorene. In particular, we evaluate how
the longitudinal resistivity depends on the lattice orientation for two typical
disorder models: dilute scatterers with high potential fluctuation amplitudes,
mimicking screened charges in the substrate, and dense scatterers with lower
amplitudes, simulating weakly bounded adsorbates. We show that the intrinsic
anisotropy associated to the band structure of this material, although
sensitive to the type and intensity of the disorder, is robust.
