【Member News】To Characterize the Deformation and Fracture Behavior of Single Crystal β-Ga₂O₃ Based on Indentation Method and First-Principles Calculation

      Recently, Dalian University of Technology published an article titled Deformation and Fracture Behaviors of Monocrystalline β-Ga₂O₃ Characterized Using Indentation Method and First-Principles Calculations in the journal Materials Characterization.

Abstract

      β-Ga₂O₃ is an ultra-wide band gap semiconductor material, which has great development potential due to its excellent photoelectric properties and physicochemical stability. However, the deformation and fracture behavior are not well revealed, and few studies on the mechanical properties of different planes are reported, which hinders the development of ultra-precision machining. In this work, the surface deformation and fracture behavior of the single crystal β-Ga₂O₃ on (-201), (001), and (010) planes were systematically studied through nanoindentation test and micron indentation test.

      The results show that the (-201) plane has relatively large critical load of elastic-plastic transition, and the critical loads of (001) and (010) are close. Under the same pressure load, the (010)plane is more prone to fracture. The elastic modulus and hardness of different planes are obtained through the load-displacement curve, in which the elastic modulus is relatively close and the hardness shows obvious anisotropy. (010)plane has the lowest hardness. Through the first-principle calculation, it is discovered that chemical bonding composition and atomic stacking structure are the key factors affecting the mechanical properties. The deformation and fracture characteristics of different planes under micron indentation show great differences. Slip bands, cleavage cracks and slip cracks along multiple directions are found on (-201) and (001) planes. On (010) plane, no obvious slip phenomenon was observed. The deformation mode of the (010) plane is dominated by the cleavage crack induced by (100) and (001) . In addition, a phase transition from β-Ga₂O₃ to α-Ga₂O₃ are also found on the (-201) and (001) planes. This work systematically studies the deformation and fracture behavior of single crystal β-Ga₂O₃ on (-201), (001) and (010) planes under quasi-static indentation conditions, which is of great significance to realize the ultra-precision machining of single crystal β-Ga₂O₃.

Parts of datagrams of the thesis

Fig. Elastic modulus and hardness of (a), (d) (-201) plane, (b), (e) (001) plane and (c), (f) (001) plane plotted as a function of indentation load. The insets are SEM images of corresponding indentation load.

Fig. Spatial anisotropy of the (a) Young's modulus, (b) Shear modulus, and (c) Poisson's ratio of monocrystalline β-Ga₂O₃ using first-principles calculations and ELATE software for the elastic properties.

Fig. Schematic illustration of the deformation and fracture of monocrystalline β-Ga₂O₃ on (a) and (b) (-201), (c) and (d) (001), (e) and (f) (010) planes.

original link:https://www.sciencedirect.com/science/article/pii/S1044580323002784?via%3Dihub