Chemical bath deposition and characterisation of CdAl2S03 quaternary thin films
Date
2019-08
Authors
Journal Title
Journal ISSN
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Publisher
Federal University of Technology, Owerri
Abstract
Quaternary cadmium aluminiumsulphite (CdAl2SO3) thin film were synthesized via chemical bath deposition (CBD) technique using a reaction bath containing cadmium chloride, thiourea, and Aluminiumsulphateoctadecahydrate at room temperature. The thin films are white in colour and strongly adherent to the substrate. The materials were annealed at various temperatures of 150 °C, 200 °C and 250 °C before characterizing, using glancing incident X-Ray diffraction (GIXRD) and Raman spectroscopy for structural analysis, UV-Vis-NIR spectrophotometer for optical analysis, Energy Dispersive X-Ray(EDX) spectroscopy for compositional analysis, 3D thickness profiling for thickness of the films and Scanning electron microscopy (SEM) for morphological analysis. The XRD results showed that the CdAl2SO3thin films crystallize as binary-phase compounds of CdSO3 and Al2O3. The optical measurements show that the films have low transmittance in the photon wavelength of 300-900 nm explored. The films have very high absorbance across the wavelengths under study, with the highest absorbance of 99.5 % in the UV region of the solar spectrum. The CdAl2SO3 real dielectric constant value is of the range of 1.5 to 1.9, and the imaginary dielectric constant has the range of 1.5 to 2.28. The direct bandgap of the CdAl2SO3 thin films ranges from 3.75 eV to 4.10 eV. The thickness of the material ranges 207 nm to 879 nm. The SEM micrographs reveal homogenous and densely packed grains. The rough estimate of the grain size ranges from 15µm to 70µm. The EDX spectra reveal the presence of Cd, Al, S and O in the films investigated. The high absorption in the UV-Vis regions makes the material suitable for thin films absorber solar cells. The direct bandgap of the thin films makes them applicable in optical devices such as LEDs and semiconductor lasers.
Description
This thesis is for the award of Master of Science (MSc.) in Solar Energy Physics
Keywords
thin films, bandgap energy, Department of Physics, absorbance, CdAl2SO3
Citation
Ezihe, J. A. (2019). Chemical bath deposition and characterisation of CdAl2S03 quaternary thin films [Unpublished Master's Thesis]. Federal University of Technology, Owerri, Nigeria