Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim

The structural and optical properties of ZnO can be modified by doping. The most important issue in this research is band gap. This is because band gaps of materials can be the criteria for its usage in various device applications. The motivation for this research is to obtain substitutionally doped...

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Main Author:	Kasim, Muhd Firdaus
Format:	Thesis
Language:	English
Published:	2015
Subjects:	Nanostructures Nanocomposites
Online Access:	https://ir.uitm.edu.my/id/eprint/15791/2/15791.pdf
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id	my-uitm-ir.15791
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spelling	my-uitm-ir.157912022-11-24T03:49:00Z Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim 2015 Kasim, Muhd Firdaus Nanostructures Nanocomposites The structural and optical properties of ZnO can be modified by doping. The most important issue in this research is band gap. This is because band gaps of materials can be the criteria for its usage in various device applications. The motivation for this research is to obtain substitutionally doped ZnO with various band gap values. This will enhance the light absorption properties of the modified materials. Modified ZnO materials can be used in future applications such as solar cells, gas sensors,optoelectronic devices and etc with improved performance. In this work, Copper (Cu) and Manganese (Mn) will be used as dopant in ZnO nanostructures. Fundamental studies of ZnO and Cu and Mn doped ZnO were studied. Synthesis and characterization of ZnO and (TM=Cu, Mn) doped ZnO nanostructures are analysed and the relationship with their band gaps were investigated. The nanostructures were successfully synthesized via a simple sol-gel method without using any chelating agents. The fundamental properties such as thermal behaviour, crystal structure, size, morphology, electronic configuration, oxidation states, valence band, chemical environment and band gap of these materials were studied in depth. The thermal properties of these materials were studied by Simultaneous Thermogravimetric Analysis (STA) and the purpose is to find a suitable temperature for phase formation.The annealing temperature for ZnO and doped ZnO material were chosen based on the thermal profile of the materials. The phases of the materials were studied by X-Ray Diffraction (XRD). XRD revealed that the nanostructures for ZnO and doped ZnO can be obtained at low temperature of 300 °C to 500 °C. According to the FESEM results, the morphology of the materials changed from long nanorods to spherical like-shape as annealing temperature increases. The size and morphologies of the materials were also temperature dependent. The band gaps of these materials were determined using UV-Vis Spectrophotometry. It was found that band gap changes occur with respect to morphology and size. It was also found that substitutional doping with Cu and Mn in ZnO leads to the narrowing in band gap. To further understand the reasons behind the band gap change, the chemical states and chemical environments of these materials were identified through X-Ray Photoelectron Spectroscopy (XPS). It was observed in valence band (VB) studies from XPS that introduction of dopants (Cu and Mn) in ZnO host material leads to additional new energy levels in the energy gap of ZnO. Thus,the band gaps of doped ZnO were modified according to the dopant atom. 2015 Thesis https://ir.uitm.edu.my/id/eprint/15791/ https://ir.uitm.edu.my/id/eprint/15791/2/15791.pdf text en public phd doctoral Universiti Teknologi MARA Faculty Applied Sciences
institution	Universiti Teknologi MARA
collection	UiTM Institutional Repository
language	English
topic	Nanostructures Nanocomposites
spellingShingle	Nanostructures Nanocomposites Kasim, Muhd Firdaus Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim
description	The structural and optical properties of ZnO can be modified by doping. The most important issue in this research is band gap. This is because band gaps of materials can be the criteria for its usage in various device applications. The motivation for this research is to obtain substitutionally doped ZnO with various band gap values. This will enhance the light absorption properties of the modified materials. Modified ZnO materials can be used in future applications such as solar cells, gas sensors,optoelectronic devices and etc with improved performance. In this work, Copper (Cu) and Manganese (Mn) will be used as dopant in ZnO nanostructures. Fundamental studies of ZnO and Cu and Mn doped ZnO were studied. Synthesis and characterization of ZnO and (TM=Cu, Mn) doped ZnO nanostructures are analysed and the relationship with their band gaps were investigated. The nanostructures were successfully synthesized via a simple sol-gel method without using any chelating agents. The fundamental properties such as thermal behaviour, crystal structure, size, morphology, electronic configuration, oxidation states, valence band, chemical environment and band gap of these materials were studied in depth. The thermal properties of these materials were studied by Simultaneous Thermogravimetric Analysis (STA) and the purpose is to find a suitable temperature for phase formation.The annealing temperature for ZnO and doped ZnO material were chosen based on the thermal profile of the materials. The phases of the materials were studied by X-Ray Diffraction (XRD). XRD revealed that the nanostructures for ZnO and doped ZnO can be obtained at low temperature of 300 °C to 500 °C. According to the FESEM results, the morphology of the materials changed from long nanorods to spherical like-shape as annealing temperature increases. The size and morphologies of the materials were also temperature dependent. The band gaps of these materials were determined using UV-Vis Spectrophotometry. It was found that band gap changes occur with respect to morphology and size. It was also found that substitutional doping with Cu and Mn in ZnO leads to the narrowing in band gap. To further understand the reasons behind the band gap change, the chemical states and chemical environments of these materials were identified through X-Ray Photoelectron Spectroscopy (XPS). It was observed in valence band (VB) studies from XPS that introduction of dopants (Cu and Mn) in ZnO host material leads to additional new energy levels in the energy gap of ZnO. Thus,the band gaps of doped ZnO were modified according to the dopant atom.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Kasim, Muhd Firdaus
author_facet	Kasim, Muhd Firdaus
author_sort	Kasim, Muhd Firdaus
title	Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim
title_short	Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim
title_full	Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim
title_fullStr	Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim
title_full_unstemmed	Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim
title_sort	synthesis, characterization and band gaps of zno, zn(1-x)cuxo and zn(1-x)mnxo nanomaterials / muhd firdaus kasim
granting_institution	Universiti Teknologi MARA
granting_department	Faculty Applied Sciences
publishDate	2015
url	https://ir.uitm.edu.my/id/eprint/15791/2/15791.pdf
_version_	1783733452334432256

Synthesis, characterization and band gaps of ZnO, Zn(1-x)CuxO and Zn(1-x)MnxO nanomaterials / Muhd Firdaus Kasim

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