Structural and electronic properties of graphene-like GeC3 under mechanical strain: a DFT study

Abstract

Owing to low carrier mobility and instability at low dimensions, traditional semiconductors, such as silicon, are becoming impractical for sharp-performance, minimal-power electronic applications. To address this challenge, we proposed the semi-metallic GeC₃ monolayer possessing a Dirac cone (DC), high carrier mobility, and robust stability, using first-principles calculations, as a favorable candidate for Dirac-source field effect transistors (DS-FETs). The two-dimensional (2D) GeC₃, derived from the transition metal tri-carbides group, offers fast switching, tunability, and durability. The phonon dispersion curve and ab initio molecular dynamics (AIMD) simulations suggest its dynamic and thermal stability. DC formation and semi-metallic nature ensure good electronic conductivity of both electrons and holes. The monolayer exhibits a bandgap of (0.0003/0.012) eV using (PBE+SOC/HSE06) functionals and maintains good electron and hole conductivity with a Fermi level lying at the middle of the gap. The application of strain affirms a shift in conductivity and bandgap tunability, offering a bandgap opening up to (0.01/0.14) eV along the (x/y) directions. Our findings suggest that the monolayer possesses excellent hole mobility, reaching 7000 cm² V⁻¹ s⁻¹. The semi-metallic nature, DC formation with bipolar conduction, low carrier effective mass, elevated charge carrier mobility, and bandgap tunability make it an excellent choice for ambipolar DS-FETs. These outcomes, thus, highlight the potential of GeC₃ for efficient nanoelectronics.