Optimization of β-Ga2O3 Device Performance through Rare Earth Doping: Analysis of Stability, Electronic Structure, and Optical Properties

β-Ga2O3 is a wide bandgap material with promising applications in high performance electronics. Dopants play a vital role in optimizing device performance. Here, we systematically discussed the stability, electronic structure, and optical properties of trivalent rare earth ion (RE) doped β-Ga2O3 using the general gradient approximation method and Hubbard term. The theoretical results show that the doping systems, β‑Ga2O3:RE (RE = La, Ce, Pr, Nd, Pm, Sm, and Eu), are all stable and easy to form. It is worth noting that the β-Ga2O3:RE system becomes more stable with the decrease of the radius of the doping ions. When RE are doped into β-Ga2O3, the band gap is reduced and spin asymmetry occurs. The Nd, Pm, Sm, and Eu doping introduces the spin-up impurity energy level, which consists mainly of RE-4f states orbitals. Simultaneously, RE-4f induces spin asymmetry, causing the system to develop some magnetism. It is interesting to note that as the atomic number increases, the energy levels of the impurities move sequentially towards the top of the valence band. The conductivity of the system increases after the rare earth is doped with β-Ga2O3. And the absorption spectra of β-Ga2O3 show a red shift, which indicates that the visible light absorption of β‑Ga2O3 is improved by doping with rare earth elements, especially Sm and Eu.