Effect of Layer Deposition and Thermal Treatment on the Structural, Optical, and Electrical Characteristics of Spin-Coated CaTiO3 Thin Films

This study investigates the effect of coating repetition and annealing temperature on the structural, optical, and electrical characteristics of calcium titanate (CaTiO3) thin films synthesized via a sol-gel spin coating method. The number of coatings (2, 4, 6, and 8 layers) and annealing temperatures (250 C, 350 C, and 450 C) were varied to optimize the characteristics. X-ray diffraction analysis indicated an improvement in crystallinity with increasing annealing temperature, as evident from the growing diffraction peaks. UV-Vis spectroscopy revealed a decrease in the optical band gap from 3.741 eV to 3.554 eV with increasing coating layers and thermal treatment, suggesting enhanced optical absorption. Current-voltage measurements using a two-point probe method generally showed linear conduction, indicative of ohmic behavior, with one sample exhibiting a mild nonlinear response at higher bias. The results confirm that process parameters significantly influence the functional properties of CaTiO3 thin films. This fundamental study provides a foundation for employing CaTiO3 as a functional layer in perovskite-based photovoltaic devices, paving the way for further device integration and optimization.