Preparation of rod shaped nickel oxide thin films by a novel and cost effective nebulizer technique

• Published in: Materials science in semiconductor processing Vol. 27; pp. 1042 - 1049
• Main Authors: Gowthami, V., Meenakshi, M., Perumal, P., Sivakuma, R., Sanjeeviraja, C.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2014; Elsevier
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; EDAX; Exact sciences and technology; Nebulizer technique; NiO thin films; Optical constants: refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Photoluminescence; Physics; SEM; Solid surfaces and solid-solid interfaces; Structural, optical and electrical properties; Surface structure and topography; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Nebulizer technique; SEM; NiO thin films; Structural, optical and electrical properties; EDAX; Cubic lattices; Electrical conductivity; Profitability; Photoluminescence; Absorption coefficients; Optimization; Substrat temperature; Surface structure; Thin films; Energy gap; Aqueous solutions; Optical properties; Optical characteristic; Absorption spectra; Halide glass; Protective coatings; Optical absorption; Scanning electron microscopy; Surface morphology; Optical surface; Low intensity; Transmittance; Air flow; Ultraviolet radiation; Nickel; Nickel oxide
• ISSN: 1369-8001; 1873-4081
• DOI: 10.1016/j.mssp.2014.09.014

Nickel oxide thin films have been deposited from 0.3M aqueous solution of nickel chloride onto microscopic glass substrates, which were chemically and ultrasonically cleaned before coating. The film depositions are carried out with 1ml, 2ml, 5ml and 10ml. The substrate temperature, spray rate, distance between substrate and nozzle and air flow rate were fixed at 400°C, 0.5ml per min, ~7cm and 1.2kg/cm2 respectively after optimization of these deposition parameters. The effect of the volume of sprayed solution on structural, optical properties and surface morphology of the films was investigated using X-ray diffractrometer, UV–vis–NIR spectrometer, photoluminescence spectrometer, Raman spectrometer, scanning electron microscope and liner four probe resistivity set-up respectively. The diffraction peak along (111) plane at 2θ=37.2° for all the films was observed. Besides this other low intensity peaks were observed along (200) and (220) Miller planes. The peaks indicated that this corresponds to cubic structure of NiO thin films. Optical transmittance and absorption spectra are recorded using a UV–vis–NIR spectrometer. When the quantity of sprayed volume increased, the transmittance decreased, consequently the band-gap energy wanes from 3.64 to 3.21eV. From PL spectra, the samples show sharp and strong UV emission around 376nm corresponding to the near band-edge emission of NiO under excitation of 275nm. The surface morphology of the films was carried out using SEM to find the smooth, uniform and pin hole free surface. The composition of the films was estimated using EDAX spectrum of the films. The resistivity results show that the activation energy decreases with increase in the sprayed volume solution.