Effect of solvent on the structure and optical properties of c-axis oriented ZnO thin films

The ZnO films were prepared using ethanol,ethylene glycol ether or glycol ether/ethanol mixture(1∶1) as a solvent system by sol-gel methods.The composition,structure and optical properties were studied by means of scanning electron microscopy(SEM),X-ray diffraction(XRD),and spectral shape.The results showed that the films prepared using three solvent systems are all hexagonal wurtzite structure with c-axis oriented.The surface of ZnO films,which prepared using glycol ether/ethanol mixture(1∶1) as solvent is smooth and densification.In the visible region,the light transmittance of the ZnO thin films is about 90%,and the band gap is about 3.25eV,which can meet the material requirements for photoelectric devices such as photovoltaic solar cell.