Structural, Morphological and Optical Properties of Spray Deposited Multi-doped (Ba, Sr, Mn, Fe and Ni) Compositionally Complex ZnO Thin Films

Abstract

Configurational disorder due to high level multi element doping has gained huge attention from research community because of its possibility of unique phase stability as well as unusual functional properties. Based on this context extensive researches performed in recent decades to establish a new horizon of materials i.e. high entropy alloy and ceramics. Of-late, compositionally complex ceramics (CCCs) has been released as an extended form of high entropy ceramics (HECs) where compositional space has been broadened by consideration of both non-equimolecular compositions and relatively low entropy regions. This report aims to stabilize ZnO wurtzite phase at room temperature replacing the Zn-site with five metallic elements i.e. Ba, Sr, Mn, Fe, Ni in equimolecular ratio to impose configurational disorder in the ZnO lattice. Therefore, (BaxSrxMnxFexNix) Zn1-5xO (where x=0, 0.01, 0.02 and 0.03; the films are denoted hereby as ZO, 5DZO, 10DZO and 15DZO respectively) thin films were deposited by low cost spray pyrolysis technique at 200°C. These high-level multi-element doping results in significant effects on the structural, morphological, optical properties of pure ZnO thin film. X-ray diffraction study demonstrated ZnO wurtzite phase stabilization for each deposited film. SEM micrographs revealed a noteworthy transition from original nanorod to well distributed homogeneous fine particles morphology. UV-vis spectroscopy disclosed a sharp rise in transparency (~98%) and band gap (4eV) doped films. At the end, correlations of structural and morphological parameters with tuned functional properties were demonstrated.