Alloying and strain effect on the electron transport, mechanical, and optical properties of Ga2O3 monolayer: A first-principles investigation

In this work, we first investigate the effects of alloying on the transport properties of the ultra-wide bandgap semiconductor two-dimensional (2D) Ga2O3 using the special quasi-random structure approach and first-principles calculations. The primary change induced by alloying 2D Ga2O3 with Al2O3 and In2O3 is in electron mobility. Alloying with Al2O3 results in a decrease in electron mobility, while alloying with In2O3 leads to an increase, reaching a maximum of 1.430 × 104 cm2 V−1 s−1 in the (In0.75Ga0.25)2O3 alloy monolayer. Subsequently, we examine the effects of alloying on the mechanical and optical properties. The ductility of 2D Ga2O3 and its alloys is excellent, providing a solid foundation for strain engineering. Finally, we consider the impact of biaxial strain on the transport and optical properties of the Ga2O3 monolayer. The electron mobility of 2D Ga2O3 is significantly greater than that of hole mobility, and compressive strains in the a direction can further enhance it. In contrast, tensile strains can improve hole mobility in the b direction, facilitating bipolar transport. Both alloying and strain engineering can expand the optical absorption range of 2D Ga2O3 into the deep UV region, accompanied by high absorption coefficients.