Investigations on the grain and hetero interface growth of CuO/ZnO photo catalyst composite by thin film synthesis on fluorine doped tin oxide (FTO) glass substrates by sol-gel technique has been ventured. The coated substrates were annealed at three different temperatures; 300, 400 and 500°C. The grain size and compounds distribution were evaluated by SEM and EDS analysis. Structural properties were characterized by XRD analysis. Thin film synthesized with 500°C annealing temperature exhibits the best grain formation evaluated by the average size, uniformity of the grain grown and smooth interface buildup. Findings proposed that annealing temperature plays a significant role in tuning the end properties of the composite film. SEM observations found uniform grain growth in the 500°C composite film. The finding is further supported by EDS analysis showing the presence of oxygen in the film is low which is preferred, as high content of oxygen will deteriorate the end properties. XRD analysis reported that nanosized crystals were grown with the average size of 250 nm for CuO and 266 nm for ZnO. Low c/a ratio also suggested that the high temperature annealed sample has higher band gap, and this will boost the hetero interface between the two semiconductors. On the other hand, the band gap enhancement is measured on 400°C specimen with lowest c/a crystal structure ratio. The findings suggest that annealing temperature plays a vital role in determining the grain and hetero interface formation of the composite and the role of the yielded CuO monoclinic structure in bandgap tuning of the thin film.
Volume 11 | 12-Special Issue