First-principles study on the electrical and thermal properties of the semiconducting Sc3(CN)F2 MXene

Abstract

The two-dimensional materials MXenes have recently attracted interest for their excellent performance from diverse perspectives indicated by experiments and theoretical calculations. For the application of MXenes in electronic devices, the exploration of semiconducting MXenes arouses particular interest. In this work, despite the metallic properties of Sc₃C₂F₂ and Sc₃N₂F₂, we find that Sc₃(CN)F₂ is a semiconductor with an indirect band gap of 1.18 eV, which is an expansion of the semiconducting family members of MXene. Using first-principles calculations, the electrical and thermal properties of the semiconducting Sc₃(CN)F₂ MXene are studied. The electron mobilities are determined to possess strong anisotropy, while the hole mobilities show isotropy, i.e. 1.348 × 10³ cm² V⁻¹ s⁻¹ along x, 0.319 × 10³ cm² V⁻¹ s⁻¹ along the y directions for electron mobilities, and 0.517 × 10³ cm² V⁻¹ s⁻¹ along x, 0.540 × 10³ cm² V⁻¹ s⁻¹ along the y directions for hole mobilities. The room-temperature thermal conductivity along the Γ → M direction is determined to be 123–283 W m⁻¹ K⁻¹ with a flake length of 1–100 μm. Besides, Sc₃(CN)F₂ presents a relatively high specific heat of 547 J kg⁻¹ K⁻¹ and a low thermal expansion coefficient of 8.703 × 10⁻⁶ K⁻¹. Our findings suggest that the Sc₃(CN)F₂ MXene might be a candidate material in the design and application of 2D nanoelectronic devices.