Thermal, Structural, Spectroscopic, and Optical Properties of Zn0.95Ca0.05O Nanoparticles Synthesized by Co-Precipitation Method

Zinc oxide (ZnO) has drawn significant attention in recent nanomaterial applications. The co-precipitation method was used to prepare the pure ZnO and Zn0.95Ca0.05O nanoparticles. Thermal analysis of Ca-doped ZnO was performed by thermogravimetric (TG) and differential thermal analysis (DTA) techniques. TG results show that there is significant weight loss of nanoparticles due to the decomposition of crystallized water and OH in Zn(OH)2 composition. DTA curve has a large exothermic peak at 580 ℃; this is attributed to the formation of the ZnO phase. XRD technique was used to understand structural properties of the prepared nanomaterials. XRD analysis reveals the hexagonal wurtzite structure of ZnO. The Scherrer equation was used to estimate crystallite size. The lattice parameters were deduced from the Rietveld refinement. The doping effect on the bond length of ZnO is analyzed. The characteristic absorption peaks of pure and Ca-doped ZnO nanoparticles were identified using Fourier transform infrared spectroscopy (FTIR) spectrum. The observed absorption peaks of the samples were found at 519 cm−1 for ZnO and 480 cm−1 for Ca-doped ZnO. The SEM–EDS characterization shows the morphology and the presence of the chemical elements present in the samples. UV–VIS spectroscopy shows the presence of an optical band gap. The optical band gap was estimated from the Tauc plot, and it is found to be 3.20 eV (ZnO) and 3.15 eV (Ca-ZnO), respectively.