Preparation and investigation of the screen-printed cobalt oxide (Co$_3$O$_4$) nanostructured thick film with annealing temperature

In this study, spinel type cobalt oxide (Co$_3$O$_4$) thick films are deposited on glass substrate by screen printing technique. All characterization was carried out for unannealed, annealed at 250 – 400$^\circ$C. The X-ray Diffraction (XRD) analysis indicates that prepared films have polycrystalline nature with cubic structure having preferential orientation through (311) plane. Crystallite size is found to be 18.52 nm. The lattice parameter found to be 8.036 – 8.138 $\mathring{\mathrm{A}}$ approaches to standard value ($a$ = 8.08 $\mathring{\mathrm{A}}$). Scanning Electron Microscopy (SEM) analysis of prepared films shows agglomeration of nanoparticles, occurrence of spherical-shaped grain aggregations. Spherical grain size increases from 47.66 to 77.33 nm with increase in annealing temperatures. A relation between structural and morphological properties is noted. The Energy Dispersive Analysis by X-Ray (EDAX) shows that all compositions have desired stoichiometric ratios. Besides electrical measurements, film D.C. resistance, resistivity was measured. It allows us to conclude that assured material has semiconducting nature. Specific surface area, Temperature Coefficient of Resistance (TCR), activation energy decreases with increase in annealing temperature were calculated. It was shown that structural, morphological and electrical properties of Co$_3$O$_4$ films were improved by increasing annealing temperature.