Predicted XN (X = C, Si, Ge, and Sn) Monolayers with Ultrahigh Carrier Mobility: Potential Photocatalysts for Water Splitting
Kai Ren, Huabing Shu, Lei Huang, Ke Wang, Yi Luo, Wenyi Huo, Changwei Bi, Yu Jing
Abstract
Using evolutionary search and first-principles methods, we predict new two-dimensional XN (X = C, Si, Ge, Sn) monolayers. They are confirmed to be indirect-gap semiconductors and are stable energetically and dynamically. In particular, the SiN monolayer shows a moderate gap of ∼2 eV and isotropic mechanical characteristics. The CN monolayer possesses a wide band gap of ∼6 eV, maximal Young’s modulus (∼550 N/m), and minimal Poisson’s ratio (∼0.12). The electron mobility of the SnN monolayer can be as large as ∼1.55 × 10 4 cm 2 ·V –1 ·s –1, exceeding that of previously reported black phosphorene (10 4 cm 2 ·V –1 ·s –1 ). Besides, the SnN and GeN monolayers also exhibit good light absorptions and excellent catalytic performances in terms of Gibbs free energies. These suggest that the XN (X = C, Si, Ge, or Sn) monolayers have potential applications in nanoelectronic and optoelectronic devices.