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

Group-VA elemental monolayers, such as arsenene, antimonene, and bismuthene, are predicted to be wide band gap semiconductors, which are potential candidates for future nanodevices in spintronics and optoelectronics. We employ firstprinciples calculations to investigate the atomic structures and electronic properties of one-third-hydrogenated (OTH) group-VA elemental monolayers, that is, OTH-X (X = arsenene, antimonene, or bismuthene). Because of the hydrogenation, the threefold rotation symmetry of group-VA elemental monolayers is annihilated. This leads to the anisotropic electronic and optical properties, such as carrier (electron or hole) mobility and light absorbance. The band gaps of OTH-X are also tuned effectively compared to those of pristine group-VA elemental monolayers. Remarkably, OTH-bismuthene (OTH-Bi) shows an energy band gap inversion induced by external compression, implying a topological phase transition. Furthermore, the carrier mobilities of OTHBi for electron and hole along the zig-zag direction are on the order of 10(5) cm(2) V-1 s(-1), which is comparable to those of graphene. The hole mobilities of OTH-arsenene (OTH-As) and OTH-antimonene (OTH-Sb) along the zig-zag direction can reach as high as 3.8 X 10(4) and 3.0 X 10(3) cm(2) V-1 s(-1), respectively. Our results show that atomically precise functionalization of two-dimensional materials can effectively enhance the intrinsic electrical properties, which may have potential applications in future electronic and spintronic devices.