Optical, luminescence, photocurrent and structural properties of sol-gel ZnO fibrous structure thin films for optoelectronic applications: A combined experimental and DFT study

Abstract

Zinc oxide is an important oxide semiconductor, with excellent physical and chemical properties that are used in different applications fields. In this research paper, ZnO thin films were synthesized using different types of solvent by sol-gel spin coating technique. The effect of solvent on the structural, morphological, photocurrent and optical properties of the films has been studied. X-ray diffraction revealed the high crystallinity of films in the wurtzite structure with a c-axis preferred orientation. SEM micrographs revealed that all films exhibit a fibrous structure, where the more homogeneous and dense surfaces were observed for ZnO-2-PrOH and ZnO–EtOH films. The optical properties analysis shows that the films have high transparency. Different structural and optical parameters were influenced by the type of solvent, where ZnO-2-PrOH film displays an improvement in structural and optical properties. The photoluminescence PL spectrum revealed three emissions, two green emissions and a UV emission at 390 nm. ZnO-2-PrOH film exhibits a high intensity ratio of UV to visible (IUV/Ivis), a best UV response, and photocurrent properties. Finally, structural and optical parameters were also calculated by first-principles DFT calculations, discussed, and compared to those experimental.