Insights into the effect of gadolinium doping on the structural, magnetic, and optical properties of β-Ga2O3

To examine the effect of gadolinium (Gd) doping on the structural, magnetic, and optical characteristics of β-gallium oxide, Gd-doped β-Ga₂O₃ powder samples were prepared with Gd concentrations of 0, 1, 3, 5, and 7 M% using a reflux condensation method. Structural analysis via X-ray diffraction (XRD) and Rietveld refinement confirmed the formation of single-phase monoclinic β-Ga₂O₃ at Gd concentrations of 0, 1, and 3 M%. However, samples doped with 5 and 7 M% Gd exhibited minor phase contributions from cubic Gd₃Ga₅O₁₂ alongside β-Ga₂O₃ as the major phase. Analysis of the surface morphology revealed that both pure and Gd-doped samples retained an ellipsoidal morphology. Energy-dispersive X-ray spectroscopy (EDX) confirmed the purity of the prepared samples, identifying gallium, oxygen, and gadolinium as the sole elements present. Reflectance studies and Tauc plot analysis indicated a reduction in both reflectance and bandgap with increasing Gd doping. Photoluminescence studies in the UV–Vis region showed emission peaks in the UV, blue, and green regions. Magnetic studies conducted at room temperature demonstrated a transition in β-Ga₂O₃ from a diamagnetic to an antiferromagnetic state upon Gd doping. The modified magnetic properties, combined with the enhanced optical properties achieved through Gd doping, explore the efficacy of Gd-doped β-Ga₂O₃ as a multifunctional material, paving the way for its use in applications as a bifunctional semiconductor material.