Investigation of Multi-Phase Structure and Optoelectronic Performance of Bi-Doped (Cu−Zn) Oxide Composite Thin Films

In this research, thin film composite structures were used to prepare optoelectronic devices from bare and Bi-substituted p-CuO/n-ZnO systems. The p-CuO/n-ZnO composite thin film structures were prepared by the SILAR technique, and the influences of two different Bi contents on the structure and main physical performances of the samples were investigated. The X-ray diffraction (XRD) technique showed that the composited thin film materials were multiphased in rutile hexagonal (wurtzite) phase (ZnO) and monoclinic tenorite phase (CuO) type crystal structure. The obtained surface morphological results presented that the structure exhibits an almost homogeneous, plate-like surface distribution, and depending on the increase of Bi concentration, the plate-like sheet area widens from ~2.5 μm to 10 μm and the layer boundaries decrease. FT-IR and Raman spectroscopy were used to investigate the various vibration and Raman active phonon modes of Bi:p-CuO/n-ZnO nanostructured heterostructures. For a comprehensive analysis of the optical bandgap of the fabricated composite samples, the estimated values were obtained from the Tauc plot. Produced samples exhibited an Ohmic behavior and dc resistivity values of films can be determined via Ohm′s Law. The adjusted sheet resistance value of 11.51 MΩ/sq when the content of Bi 3.0 % in the growth bath.