Strain mediated ultra-high electron mobility in Ge-doped two-dimensional Ga2O3

Two-dimensional (2D) Ga2O3 has been of particular interest recently since it exhibits overwhelming superiority over bulk beta-Ga2O3; however, efforts to modify the carriers of 2D Ga2O3 are few both theoretically and experimentally. In this work, we study the biaxial strain mediated electronic structures and transport properties of Ge-doped 2D Ga2O3 using first-principles calculations with Perdew-Burke-Ernzerhof functional and Boltzmann transport theory. The Ge-doped Ga2O3 shows excellent structure stability as suggested by its low formation energy of -3.99 eV, as well as phonon dispersion analysis and ab initio molecular dynamic simulation. The bandgap values of Ge-doped 2D Ga2O3 are tunable from 2.37 to 1.30 eV using biaxial strain from -8% compressive to +8% tensile because of the changeable sigma* anti-bonding and pi bonding states in the conduction band minimum and valence band maximum, respectively, as well as the decreased quantum confinement effect. Importantly, an ultra-high electron mobility up to 6893.43 cm(2) V-1 s(-1) is predicated in Ge-doped 2D Ga2O3 as the biaxial tensile strain approaches 8%. Our work highlights the enormous potential of Ge-doped 2D Ga2O3 in nanoscale electronics and suggests that Ge is an excellent dopant candidate toward optoelectronic applications. (c) 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International (CC BY-NC-ND) license (https://creativecommons.org/licenses/by-nc-nd/4.0/).