Monolayered Silicon and Germanium Monopnictide Semiconductors: Excellent Stability, High Absorbance, and Strain Engineering of Electronic Properties

Abstract

The discovery of stable two-dimensional (2D) semiconductors with exotic electronic properties is crucial to the future electronic technologies. Using the first-principles calculations, we predict the monolayered Silicon- and Germanium-monopnictides as a new class of semiconductors owning excellent dynamical and thermal stabilities, prominent anisotropy, and high possibility of experimental exfoliation. These semiconductors, including the monolayered SiP, SiAs, GeP, and GeAs, possess wide bandgaps of 2.08-2.64 eV obtained by hybrid functional calculation. Under small uniaxial strains (-2 to 3%), dramatic modulations of their band structures are observed, and furthermore, all the 2D monolayers (MLs) can be transformed between indirect and direct semiconductors. The monolayered GeAs and SiP exhibits extraordinary optical absorption in the range of visible and ultraviolet (UV) light spectra, respectively. The exfoliation energies of these monolayers are comparable to graphene, implying a strong probability of successful fabrication by mechanical exfoliation. These intriguing properties of the monolayered silicon- and germanium-monopnictides, combined with their highly stable structures, offer tremendous opportunities for electronic and optoelectronic devices working under UV-visible spectrum.

Chemical and Electrochemical Lithiation of van der Waals Tetrel‐Arsenides

“…Binary GeAs and SiAs compounds, which have been known for decades, have mostly been overlooked in terms of properties until recently . These isostructural compounds are built of covalently bonded Si‐As or Ge‐As layers held together by weak van der Waals interactions.…”

“…Layered compounds have garnered increasing attention in recent years after the discovery of graphene, a single layer of graphite . Layered tetrel‐pnictides are versatile materials, displaying several interesting properties, such as superconductivity at 1.3 K in NaSn 2 As 2 and ultra‐low thermal conductivity in metallic Li 1− x Sn 2+ x As 2 .…”

“…Layered tin phosphide, Sn 4 P 3 , has been studied for lithium‐ion and sodium‐ion battery applications and has been proven to be a promising material . Pnictides of lighter tetrels such as GeAs, SiAs, GeP, SiP, GeAs 2 , and SiAs 2 have been gaining interest in the field of thermoelectrics, photovoltaics, water splitting, and optics owing to their anisotropic nature, weak interlayer interactions, relatively small band gaps (<2 eV), and potential for tuning of properties through doping and strain …”

Magnetic 3d Transition Metal Atomic Chains Modulated by the Intrinsic Valley Structure in MX Monolayer

“…The optimized lattice parameters are a = 20. [18] As shown in Figure 1, the rippled MX monolayer unit cell contains an intrinsic valley along the y direction. [18] As shown in Figure 1, the rippled MX monolayer unit cell contains an intrinsic valley along the y direction.…”

Tunable Electronic Properties and Potential Applications of 2D GeP/Graphene van der Waals Heterostructure

“…More recently, the few‐layered and monolayered group IV‐V semiconductors have been fabricated and shown to possess excellent structural stability 6–12. Owing to their outstanding electrical and optical properties combined with suitable bandgaps (1.6–2.2 eV), the monolayered group IV‐V semiconductors are predicated to be promising candidates for electronic and optoelectronic applications 13–16. Recent experimental demonstrations have shown the achievement of few‐layered GeAs field effect transistors (FET) with p‐type behaviors at room temperature and an impressive hole carrier mobility of approaching 100 cm 2 V −1 s −1 17.…”