Synthesis of Cadmium doped CuO thin films via spray pyrolysis and optimization of the optical band gap using Taguchi approach

This study focuses on the synthesis of CuO (Copper Oxide) thin films via the spray pyrolysis method, along with the optimization of parameters affecting the experimental process. Using the Taguchi design with an L9(33) orthogonal array, we systematically investigated the influence of three critical controllable parameters on the deposition process. These parameters included the cadmium doping percentage, the substrate temperature, and the precursor molar concentration. The Taguchi method was chosen for its efficiency in experimental design, allowing us to study the effects of multiple variables simultaneously with a reduced number of experiments. For each factor, three levels were predefined to represent distinct conditions, ensuring a comprehensive exploration of their individual and interactive impacts on the process. The signal-to-noise (S/N) ratio is used to minimize variation and identify the optimal parameter combination that ensures the desired optical band gap is achieved. The obtained deposited thin film under optimal conditions exhibit a uniform and pure CuO monoclinic structure. Raman spectroscopy unveiled distinct modes characteristic of affirming the composition of CuO. Additionally, the CuO film showed an optical bandgap value of 1.53 eV.