Role of Ir incorporation on structural, surface, optical, and electrical properties of ultrasonically produced ZnO films

Abstract

Pure and doped ZnO films are among the promising materials in technological applications, which is constantly developing and seeking innovations. In this study, the effect of Ir element on the structural, optical, electrical, and surface properties of ZnO films produced by ultrasonic spray pyrolysis at different Ir incorporation rates (4% and 8%) was investigated. XRD patterns show that the 4% Ir-doped ZnO film have the best crystallization level. The thickness and band gap values of pure, 4%, and 8% Ir-doped ZnO films were determined as 269 nm, 278 nm, 267 nm, and 3.20 eV, respectively, by using spectroscopic ellipsometry and optical method. Surface properties were analyzed by field emission scanning electron microscopy, and elemental analyses were performed by energy dispersive X-ray spectroscopy. Electrical resistivity values of ZnO:Ir films calculated by the two-point technique were determined to vary between 8.26 x 10(0) and 6.29 x 10(2) omega cm. Besides, the activation and trap energy values of the films from temperature-dependent resistivity measurements were calculated as 1.358-3.977 meV and 18.019-28.307 meV, respectively. It was concluded from all analyses that Ir element has a strong effect on the structural, surface, and electrical properties of ZnO films and Ir-incorporated ZnO films having suitable structural and surface properties can be used as photocatalysts in photocatalytic applications. Moreover, we suggest that p-type ZnO films can be produced using different Ir incorporation rates.