Structural, morphological, optical and magnetic properties of sprayed NiO thin films by perfume atomizer

Abstract

Nickel oxide (NiO) thin films were grown on glass substrates by a simplified spray pyrolysis technique using perfume atomizer at different substrate temperatures which is the novelty of this work. X-ray diffraction patterns reveal the cubic crystalline phase pure NiO film with preferential orientation along (2 0 0) plane. Thermal treatment of NiO thin films at 400 °C enables us to identify a suitable deposition temperature for obtaining good quality thin films. The average crystallite size calculated from Scherrer’s formula is found to be 28 nm. The closely packed and spherical shaped grains obtained were confirmed from field emission-scanning electron microscope (FE-SEM). From FE-SEM analysis, the smooth nature of NiO thin films deposited at 400 °C enables it to use for solar cell applications, whereas the porous nature of NiO thin films deposited at 300 °C enables it to use for gas sensing applications. The mean square roughness increased with substrate temperature is confirmed from atomic force microscope analysis. The average transmittance of 75–85% demonstrates the compactness of the film except for the film N400, which is attributed to the defects. The energy band gap (Eg) is found to be 2.93, 3.63, 3.72, and 3.67 eV, respectively, for NiO thin film deposited at substrate temperature 300 °C, 350 °C, 400 °C, and 450 °C. The Raman peak at 1573 cm−1 corresponds to 2 M band antiferromagnetic state. The presence of defect states is identified from PL and EPR spectra.