Impact of Si4+ substitution on structural and dielectric properties of Si-mixed Ga2O3 compounds

In this study, the impact of Si⁴⁺ substitution on the structural and dielectric properties of Ga₂O₃ powder was investigated in detail. High-temperature solid-state chemical reaction method was employed to prepare pure and Si-mixed Ga₂O₃ compounds. The formation of the monoclinic structure of Ga₂O₃ was confirmed through X-ray diffraction pattern. Field emission scanning electron microscopy micrographs revealed agglomerated particles. All prepared samples consisted of particles with sizes in the range of 0.191 to 0.202 µm. The X-ray photoelectron spectroscopy (XPS) analysis of Ga 2p reveals a positive shift as compared to metallic Ga due to the interaction between the electron cloud of adjacent ions. XPS analyses, which considered the Ga 2p doublet (Ga 2p_3/2 and Ga 2p_1/2 peaks), also indicate that Ga exists in its highest chemical valence state (Ga³⁺) in the sample. The frequency dependence of the dielectric constant, ac conductivity and dielectric loss of the synthesized samples was investigated at room temperature (RT). The dielectric constant increases with an increase in Si concentration at RT.