Abstract
This paper demonstrates the high yield and cost effectiveness of a simple and ecofriendly water-based solution processing, to produce Zinc-doped Zirconia (Zn-ZrO2) composite thin films, onto glass substrates, with excellent optical properties that make them of great interest for optical and microelectronics technologies. The effect of Zn variation (given as 10, 15, 20 at.%) on the crystallization, microstructure, and optical properties of ZrO2 film was examined. The addition of Zn did not restructure the ZrO2 lattice, as the results indicated by X-ray diffraction (XRD) and Raman spectroscopy revealed neither any mixed or individual phases; rather, all the films retained the amorphousness. Nonetheless, Zn did control the grain formation at the film surfaces, thereby changing the surface morphology. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) evidenced homogeneous, compact, crack-free, and dense films with surface roughness below 2 nm indicating smooth surfaces. The films were highly transparent (>80%) with tunable optical band gap Eg (5.21 to 4.66 eV) influenced by Zn dopant. Optical constants such as refractive index (n), extinction coefficient (k), and dielectric constant (ε) were obtained from spectroscopic ellipsometry (SE), and a correlation was established with respect to the doping level. A high value of n > 2 value indicated high packing density in these films, and it decreased slightly from 2.98 to 2.60 (at 632 nm); whereas, optical losses were brought down with increasing Zn indicated by decreasing k values. The photoluminescence (PL) spectra showed UV emissions more pronounced than the blue emissions indicating good structural quality of all the films. Nonetheless, added defects from Zn had suppressed the PL emission. The technique presented in this work, thus, manifests as high performance and robust and has the potential comparable to the sophisticated counter techniques. Furthermore, the Zn-ZrO2 films are promising for a low-cost solution to processed microelectronics and optical technologies after reaching high performance targets with regards to the electrical properties.
Highlights
The advent of modern transparent technology is owed to the development of metal oxide-based materials, especially semiconductors
We are not sure which of these reasons dominates over the other. These findings demonstrate that the optical properties of ZrO2 thin films are influenced by the doping level of the Zn, and these properties are no less in performance than those obtained through sophisticated deposition technique making water-based solution processing a reliable technique for future technologies
We observe that all the variations in the dopant concentration (0, 10, 15, and 20 at.%) bring no change to the structural phase of ZrO2 films; which retains the amorphous phase, whereas Zn plays an important role in changing the surface morphology and optical properties
Summary
The advent of modern transparent technology is owed to the development of metal oxide-based materials, especially semiconductors. The nano-sized grains in these films (confirmed from SEM) were found to be the likely cause in decreasing the resistance Most of these reports have focused mainly on sensing/catalytic applications of this material system fabricated by sol gel method using organic precursors. In this work, applying traditional spin coating of a simple and quickly made waterbased solution, we have fabricated Zn-doped ZrO2 films and have emphasized on the understanding of the effect of doping level on the films’ properties. The following precursors were used in this study, bought in analytical grade purity from Sigma Aldrich: Zirconium oxychloride octa hydrate (ZrOCl2·8H2O) and Zinc nitrate hexahydrate (Zn(NO3)2·6H2O) Both host (Zr-based) and doped (Zn-based) solutions (0.3 M concentration, each) were prepared separately using deionized (DI) water without any catalytic agents. The pristine and Zn (10, 15, and 20 at.%)-ZrO2 films are referred to as ZrO2, ZrZ10, ZrZ15, and ZrZ20, respectively
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
