【International Papers】Chemical analysis of ion traces in the betta Ga₂O₃ structure and fundamentals of molecular dynamics of mobilization hydrogen and helium molecules

      Researchers from the L.N. Gumilyov Eurasian National University have published a dissertation titled "Chemical analysis of ion traces in the betta Ga₂O₃ structure and fundamentals of molecular dynamics of mobilization hydrogen and helium molecules" in Results in Materials.

Background

      Gallium oxide (Ga₂O₃), an ultra-wide-bandgap semiconductor (4.7–4.9 eV), has attracted significant attention due to its high melting point, high density, and stable electronic structure, enabling applications in high-temperature gas sensors, photodetectors, transistors, and optical and medical devices. Ga₂O₃ exists in five crystal phases—α, β, γ, δ, and ε—with the α and β phases being the most widely used. The monoclinic β-Ga₂O₃, with a wide bandgap and favorable conduction and valence band structures, is suitable for radiation detection, including neutron and high-energy particle detection, and exhibits long-term structural stability, making it a potential alternative to 4H-SiC detectors. In nuclear technology, the need for materials with high-temperature tolerance, low neutron absorption, and corrosion resistance has driven research into Zr-based alloys, Cr₂O₃/Al₂O₃/TiN-modified materials, nanoscale polycrystalline Mo, and GO/ZrO₂ composite coatings. Additionally, three-dimensional graphene, with its high Young’s modulus, chemical stability, hydrophobicity, and exceptional thermal conductivity, shows promise for electrical and thermal management in high-temperature corrosive environments. Moreover, molecular dynamics simulations of Cu surfaces implanted with high-energy clusters, combined with graphene layers, provide insights into material modification mechanisms and radiation response behaviors.

Abstract

      In the presented work, the molecular dynamics simulation and thermal conductivity mechanism of implantation of beta Ga₂O₃ structure with hydrogen and helium ions with energy 100 eV were analyzed. The mechanism of the initial formation stages of gas-atom-gas clustering in the β-Ga₂O₃ structure by proton and helium implantation was simulated using the LAMMPS package. The thermal conductivity is anisotropic in the crystal structure, and varies depending on the crystal orientation, with the highest conductivity observed along the k(001) direction.

Conclusion

      In this research, the dynamics of ion penetration depth in the crystal structure of β-Ga₂O₃ implanted with hydrogen and helium ions were simulated using the molecular dynamics method. Initial data on the kinetics of the transition from the ionic state to the molecular state, as well as changes in the structural, optical, and mechanical properties of the material, were obtained. The transition of ions to the molecular state in the material's structure was demonstrated after implantation times of 137.1 fs and 158.9 fs. The anisotropic properties of thermal conductivity in β-Ga₂O₃ were analyzed, revealing that the material exhibits the highest thermal conductivity in the k[001] direction. Future studies will focus on mechanisms for maintaining structural stability under various types of irradiation, as well as the formation of free volume and radicals. Additionally, research should aim to develop advanced composite structures and radiation-resistant materials that can operate under severe irradiation and implantation conditions, thereby expanding their potential applications.