Structural and Optical Characterization of ZnO and ZnO:Ag Films Produced by Sol–Gel Mechanism Combined with Screen-Printing

Abstract

Zinc oxide (ZnO) is a versatile and cost-effective semiconductor with an increased direct energy gap, making it suitable for various technological and scientific applications. In this study, we report the successful fabrication of ZnO and ZnO:Ag films on glass substrates using a combination of two solution-based techniques: the sol–gel method and screen printing. After sintering, the produced films were characterized using X-ray diffraction, optical transmission, and photoluminescence measurements. The X-ray diffraction analysis revealed a hexagonal (wurtzite) phase structure and polycrystalline nature, with a preferred orientation along the (101) plane. The crystallite size increased from 64 to 68 nm upon the substitution of silver (Ag) in the ZnO structure. Both optical transmission and photoluminescence characterizations confirmed a red shift in the ZnO:Ag films. The energy gap narrowed from 3.27 to 3.23 eV with the incorporation of Ag into ZnO. This observed increase in crystallite size and the reduction of the energy gap can be attributed to the successful substitution of Ag in the ZnO lattice.