Defect evolution in gallium oxide during stretching process: A molecular dynamics simulation

Abstract

Gallium oxide (Ga₂O₃) is a new generation ultra-wide bandgap semiconductor material with excellent properties such as high electron mobility, high-voltage electrical response speed, and radiation resistance. However, few reports currently exist on the nanomechanical properties of Ga₂O₃. In this study, a potential function of Ga₂O₃ can be used to describe α-, β- and ε-phases was developed through machine learning approach. Based on the developed potential function, the mechanical properties and defect evolution of Ga₂O₃ under different crystal structures, defects, and temperatures were thoroughly studied. The results indicate that the mechanical properties of Ga₂O₃ with different crystal phases exhibit significant anisotropy. Among them, the α phase Ga₂O₃ endures the largest deformation force, and the β phase undergoes the highest deformation. Upon loading α-Ga₂O₃, the slip phase transition occurs, whereas, for the β- and ε-Ga₂O₃, the amorphous phase transition occurs directly along the fracture interface without slip phase transition. Ga₂O₃ exhibits typical brittle fracture during tensile fracture. The adhesion degree of atoms at the fracture interface increases with the rise of temperature. The existence of defects in Ga₂O₃ changes the direction of phase transformation slip during the tensile fracture. The increased temperature leads to an increase in the proportion of amorphous phase transformation of Ga₂O₃ during stretching, but the proportion of bond breakage shows an overall downward trend.