Correlation between transitional alumina phase evolution and the structural- optical development of ZnAl2O4 spinel and Al2O3/ZnO nanocomposites

This study investigates the relationship between the structural and optical advancement of ZnAl 2 O 4 spinel and the phase evolution of transitional alumina in Al 2 O 3 /ZnO nanocomposites synthesized by Solution Combustion Synthesis (SCS) and annealed at temperatures between 500℃,700℃,900℃ and 1200℃. XRD and SEM analysis revealed a progressive phase change of alumina with increasing temperature, accompanied by the gradual formation of the cubic ZnAl 2 O 4 spinel phase (Fd-3m). Spinel lattice creation was confirmed by FTIR spectra, which showed distinctive Zn-O and Al-O vibrational bands in the 400–700 cm − 1 area. PL spectra showed visible emissions at 410–650 nm and significant near band edge emission around 390 nm, which were attributed to defect related conversions and excitonic recombination. Overall, the study established a direct correlation between the γ → δ → α phase transformation of alumina and the structural, morphological and optical evolution of ZnAl 2 O 4 spinel nanocomposites.