【Member Papers】 Xi'an Jiaotong University —— Alloying and strain effect on the electron transport, mechanical, and optical properties of Ga₂O₃ monolayer: A first-principles investigation

      Researchers from the Xi'an Jiaotong University have published a dissertation titled "Alloying and strain effect on the electron transport, mechanical, and optical properties of Ga₂O₃ monolayer: A first-principles investigation" in Journal of Applied Physics.

Program Support

      The authors gratefully acknowledge the financial support of the National Natural Science Foundation of China (Nos. 12374074 and 11874294) and the Youth Innovation Team of Shaanxi Universities. The authors would also like to acknowledge the high-performance computing support of Xi'an Jiaotong University HPC platform.

Background

      Recently, there has been a significant amount of interest in two-dimensional (2D) materials (such as graphene, transition-metal dichalcogenides, and black phosphorus), which are known as semiconductors and may facilitate the continuation of Moore's law. 2D materials are expected to be formally commercialized by 2034 according to the latest roadmap of the International Roadmap for Semiconductor Devices and Systems (IRDS). Due to their thickness at the atomic level, 2D materials exhibit a range of novel quantum properties. This motivates researchers to seek out non-layered materials with the least thickness possible to match the properties of 2D materials and explore their unique optoelectronic properties.

Abstract

      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 (In_0.75Ga_0.25)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.

Experimental Diagram