Sol–gel production of ZnO:CO: Effect of post-annealing temperature on its optoelectronic properties

Thin films of ZnO:Co were prepared by a sol–gel process. The microstructure and optoelectronic properties as a function of sintering temperature were studied extensively by optoelectronic characterizations. It was observed from the scanning electron microscopy images that the introduction of Co eliminated the commonly observed wrinkle effect in sol-gel derived films. Structurally, XRD measurements revealed that the derived film were c-axis oriented that enhances as sintering temperature increases upto 500 °C. Electrical measurements confirm that the deposited ZnO:Co thin film is n-type with decreasing resistivity as sintering temperature increases. Optical measurements revealed that the derived films exhibit good transmittance ~82% with a wide band gap ~4.01 eV.