Anisotropic High Carrier Mobilities of One-Third-Hydrogenated Group V Elemental Monolayers*

Group-VA elemental monolayers, such as antimonene and bismuthene, are predicted to be wide band gap semiconductors. We employ first principles calculations to investigate the atomic structures and electronic properties of one-third-hydrogenated (OTH) group-VA elemental monolayers, that is, OTH-X (X = As, Sb, or Bi). OTH-X exhibit anisotropic electronic and optical properties, such as carrier mobility and light absorbance. Remarkably, OTH-Bi shows an energy band gap inversion induced by external compression, implying a topological phase transition. Furthermore, the carrier mobilities of OTH-Bi for electron and hole along the zigzag direction are on the order of 105 cm2*V−1*s-1 , which is comparable to those of graphene. Our results show that atomically precise functionalization of two-dimensional materials can effectively enhance the intrinsic electrical properties.