Effect of copper substitution on the structural, optical, and magnetic properties of β-Ga₂O₃ powders

This study evaluates the structural, optical, and magnetic studies of copper-doped β-gallium oxide powders. A Hydrothermal method was employed to synthesize β-gallium oxide powder, in pure form and doped with copper at varying concentrations of Cu at 1, 2, 5, and 7 M%. Various characterization methods were employed to study the properties of the samples. Raman and XRD analyses confirmed that these powder samples exhibited a β-crystalline phase characterized by a monoclinic structure. XPS analysis verified the presence and oxidation states of Cu ions in the Cu-doped β-Ga₂O₃ samples. The powder samples’ surface morphology and elemental compositions underwent examination through SEM and EDAX analysis. The particle size distribution of the samples was studied using DLS analysis. Optical properties were studied using photoluminescence analysis and UV-vis diffuse reflectance spectroscopy. With the rise in Cu concentration, a decrease in the optical band gap was observed. UV, green, and blue emissions were observed from PL analysis. A vibrating sample magnetometer was utilized to investigate the magnetic characteristics of the samples at room temperature. The undoped sample exhibits diamagnetic behavior, while a shift towards ferromagnetism is observed as copper concentration increases. The diamagnetic characteristics of β-Ga₂O₃ limit its suitability for spintronic applications. From this work, the enhanced magnetism with Cu doping suggests that Cu-doped β-Ga₂O₃ can be useful for spintronic applications.