Monolayer 2D semiconducting tellurides for high-mobility electronics

Abstract

Discovery and design of two-dimensional (2D) materials with suitable band gaps and high carrier mobility are of vital importance for the photonics, optoelectronics, and high-speed electronics. In this work, based on first principles calculations using density functional theory with Perdew-Burke-Ernzerhof and Heyd-Scuseria-Ernzerhoffunctionals, we introduce a family of monolayer isostructural semiconducting tellurides MN${\mathrm{Te}}_{4}$, with $M={\mathrm{Ti},\phantom{\rule{0.16em}{0ex}}\mathrm{Zr},\phantom{\rule{0.16em}{0ex}}\mathrm{Hf}}$ and $N={\mathrm{Si},\phantom{\rule{0.16em}{0ex}}\mathrm{Ge}}$. These compounds have been identified to possess direct band gaps from 1.0 to 1.31 eV, which are well suited for photonics and optoelectronics applications. Additionally, anisotropic in-plane transport behavior is observed, and small electron and hole $(0.11--0.15\phantom{\rule{0.16em}{0ex}}{m}_{e})$ effective masses are identified along the dominant transport direction. Ultrahigh carrier mobility is predicted for this family of 2D compounds, which host great promise for potential applications in high-speed electronic devices. Detailed analysis of electronic structures reveals the origins of the promising properties of this unique class of 2D telluride materials.