Electrical properties of spin coated Zn doped CuO films

Electrical properties of spin coated Zn²⁺ doped CuO films were investigated. The spin speed and deposition time period were varied to obtain uniform films with necessary thickness. Films were subsequently annealed in air to crystallize the phase of CuO. A liquid phase of Zn²⁺ and CuO was used as the initial solution in this sol-gel spin coating method. The doping concentration was varied up to 10%. Structural properties of thin films were investigated using XRD patterns. The dislocation density and strain were found to be 1.1 × 10¹³ lines/m² and 0.0012, respectively. Peaks of Zn²⁺ were not noticed in XRD patterns. Photocurrent and photovoltage of films were measured using Metrohm Autolab in the electrolyte of KI. Photovoltaic properties varied with doping concentration. Highest photocurrent was observed for the sample with lowest band gap. Although the highest photocurrent of 11.15 μA cm⁻² could be obtained at doping concentrations of 6% and 8%, the highest photovoltage of 0.12 V was observed at the doping concentration of 10%. Impedance was determined using Metrohm Autolab for illuminated and non-illuminated thin film samples. Three semicircles were observed in Nyquist plots indicating photoelectrochemical properties in the liquid junction photocell. Equivalent circuits found using Nyquist plots are consist of three RC parallel circuit elements. SEM was employed to find surface morphology and particles size of thin film samples. According to SEM micrographs, the average particle size of all the films is approximately 100 nm. (paper)