The optical, structural and morphological properties of ultrasonically sprayed ZnO:Mn films

Abstract

ZnO and ZnO:Mn (at Mn incorporation rates between 1 and 5%) films were obtained at a substrate temperature of 350 ± 5 °C by the ultrasonic spray pyrolysis technique. Optical, structural and morphological properties of ZnO films as a function of Mn amount were discussed. Transmittance spectra, x-ray diffraction (XRD) patterns, scanning electron microscopy (SEM) micrographs and energy dispersive x-ray spectroscopy (EDS) analyses were used to investigate the optical, structural and morphological properties and elemental analyses, respectively. All films have high transmittance, and the band gap changed with Mn incorporation from 3.32 to 3.18 eV. From Urbach tail analysis, the widths of localized states were calculated between 163 and 389 meV. XRD patterns indicated that all films have polycrystalline structures and the best effect on the structural properties of the films was obtained with 4% Mn incorporation. It was seen from SEM micrographs that all films have almost homogeneous surfaces. EDS analyses showed that the amount of Mn element in the solid film increased depending on the increasing Mn incorporation in the solution. As a result, Mn incorporation has a strong effect on the optical, structural and morphological properties of ZnO films and all films, especially the 4% Mn-incorporated one, can be used in optoelectronic industry or photovoltaic solar cells due to their suitable optical and structural properties.