Influence of pH value of precursor on growth, structural, and optical properties of Cu 2 O thin films grown in Mist-CVD

The Cu 2 O thin films were prepared from copper (II) acetylacetonate (Cu(acac) 2 ) by the mist chemical vapor deposition (mist-CVD) method, depending on the pH value of the prepared solution. It was confirmed that the well-oriented Cu 2 O thin films were grown at a dominant (111) peak according to X-ray diffraction (XRD) measurement using an alkaline precursor solution. The pH of the prepared solution drastically affected the surface morphology of the Cu 2 O thin films, and the lowest Root Means Square (RMS) was found for pH -10 of the precursor solution. The confocal Raman spectrum confirmed the formation of the cubic Cu 2 O crystal structures for each pH value of the precursor solution. The very transparent Cu 2 O thin films that were grown. The highest transmittance, 70%, was obtained at 1100 nm from the absorption spectrum for Sample B. The optical energy band gaps of Cu 2 O thin films were determined using Tauc ' s method and found to vary within a range of 2.53 to 2.49 eV, indicating a change in the material ' s electronic structure. The study demonstrated the crucial role of the pH level of the prepared solution in the growth of the Cu 2 O thin film. Specifically, it was found that a higher pH level resulted in a greater concentration of hydroxide ions (OH - ), which was a crucial factor in the growth process. These findings can be significant in using p -type Cu 2 O thin films prepared based on mist-CVD for optoelectronic applications.