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

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.