Kevin Alvin Eswar | Universiti Teknologi Mara (original) (raw)

Papers by Kevin Alvin Eswar

Research paper thumbnail of Aquilaria malaccensis and Pandanus amaryllifolius mediated synthesis of tin oxide nanoparticles: The effect of the thermal calcination temperature

Materials Today: Proceedings

Research paper thumbnail of ISSN 2159-0427/130212/06/$60.00 © 2013 Global Scientific Publishers 130212-1

Post annealing effect on thin film composed ZnO nano-particles on porous silicon

Research paper thumbnail of Annealing Heat Treatment of ZnO Nanoparticles Grown on Porous Si Substrate Using Spin-Coating Method

Advances in Materials Science and Engineering, 2014

ZnO nanoparticles were successfully deposited on porous silicon (PSi) substrate using spin-coatin... more ZnO nanoparticles were successfully deposited on porous silicon (PSi) substrate using spin-coating method. In order to prepare PSi, electrochemical etching was employed to modify the Si surface. Zinc acetate dihydrate was used as a starting material in ZnO sol-gel solution preparation. The postannealing treatments were investigated on morphologies and photoluminescence (PL) properties of the ZnO thin films. Field emission scanning electron microscopy (FESEM) results indicate that the thin films composed by ZnO nanoparticles were distributed uniformly on PSi. The average sizes of ZnO nanoparticle increase with increasing annealing temperature. Atomic force microscopic (AFM) analysis reveals that ZnO thin films annealed at 500°C had the smoothest surface. PL spectra show two peaks that completely correspond to nanostructured ZnO and PSi. These findings indicate that the ZnO nanostructures grown on PSi are promising for application as light emitting devices.

Research paper thumbnail of Porosity and thickness effect of porous silicon layer on photoluminescence spectra

Nucleation and Atmospheric Aerosols, 2018

The porous silicon nanostructures was prepared by electrochemical etching of p-type silicon wafer... more The porous silicon nanostructures was prepared by electrochemical etching of p-type silicon wafer. Porous silicon prepared by using different current density and fix etching time with assistance of halogen lamp. The physical structure of porous silicon measured by the parameters used which know as experimental factor. In this work, we select one of those factors to correlate which optical properties of porous silicon. We investigated the surface morphology by using Surface Profiler (SP) and photoluminescence using Photoluminescence (PL) spectrometer. Different physical characteristics of porous silicon produced when current density varied. Surface profiler used to measure the thickness of porous and the porosity calculated using mass different of silicon.Photoluminescence characteristics of porous silicon depend on their morphology because the size and distribution of pore its self will effect to their exciton energy level. At J=30 mA/cm2 the shorter wavelength produced and it followed the trend of porosi...

Research paper thumbnail of Electrochemical impedance spectroscopy analysis of porous silicon prepared by photo-electrochemical etching: current density effect

Applied Physics A, May 1, 2014

ABSTRACT Electrical impedance characteristics of porous silicon nanostructures (PSiNs) in frequen... more ABSTRACT Electrical impedance characteristics of porous silicon nanostructures (PSiNs) in frequency function were studied. PSiNs were prepared through photo-electrochemical etching method at various current densities (15–40 mA/cm2) and constant etching time. The atomic force microscope images of PSiNs show that pore diameter and roughness increase when current density increases to 35 mA/cm2. The surface roughness subsequently decreases because of continuous etching of pillars, and a second etching process occurs. Photoluminescence spectra show blue and red shift with increasing applied current density that is attributed to PSiNs size. Variations of electrical resistance and capacitance values of PSiNs were measured using electrochemical impedance spectroscopy analysis. These results indicate that PSiNs prepared at 20 mA/cm2 current density have uniform porous structures with a large number of pillars. Furthermore, this PSiNs structure influences large values of charge transfer resistance and double layer capacitance, indicating potential application in sensors.

Research paper thumbnail of Bio-synthesized Tin Oxide Nanoparticles (SnO2 NPs) as a Photocatalyst Model

Zenodo (CERN European Organization for Nuclear Research), May 5, 2023

In the textile industries, most of the consumers attracted to colored fabrics. Unfortunately, the... more In the textile industries, most of the consumers attracted to colored fabrics. Unfortunately, the substance that use to color fabrics contributes serious environmental pollution. In this work, we have designed an environmental-friendly to control the negative effect using solution-based approach. By using this method, the cost can be reduced up to one-fourth from the commercial price. The non-toxic materials of tin (iv) oxide nanoparticles (SnO2NPs) were synthesized via green bio-synthesis. Bio-synthesis was conducted using the bioactive compound in Aquilaria Malaccensis (agarwood) leaves extracts. The photocatalytic activity of methylene blue (MB) degradation was investigated. The photocatalytic degradation was found to 82 % and 80 % with the presence of UV light, and fluorescent light, respectively. Both of the measurement has been done within 70 minutes. The result shows that SnO2 NPs could be the best option for efficiently, economically, and ecologically treating dye-polluted water.

Research paper thumbnail of Optical properties of nanoporous structure ZnO

International Journal of Materials Engineering Innovation, 2016

This paper presents an efficient method to prepare ZnO nanoporous structure via immersion of Si s... more This paper presents an efficient method to prepare ZnO nanoporous structure via immersion of Si substrate with catalyst assistance (gold) in the mixture of zinc nitrate hexahydrate (Zn(NO 3) 2 .6H 2 O) and urea (CH 4 N 2 O). Photoluminescence (PL) spectra of nanoporous ZnO revealed it had strong UV emission with low oxygen defect. Optical properties are found to be significantly affected by varying the Zn2+: urea ratio but from surface morphology observation, the porous structure was stable and seemingly unchanged.

Research paper thumbnail of Comparative study of surface, elemental, structural and optical morphologies of titanium dioxide-zinc oxide (TiO2-ZnO) and titanium dioxide-zinc oxide/graphene (TiO2-ZnO/Gn)

Materials Today: Proceedings, 2023

Research paper thumbnail of Performance Evaluation of Crack-Like ZnO/PSi Nanostructure Chemical Solution Sensor via Electrochemical Impedance Technique

Journal of The Electrochemical Society, 2020

Research paper thumbnail of Structural and Optical Properties of TIPS Pentacene Thin Film Exposed to Gamma Radiation

Materials Research-ibero-american Journal of Materials, 2022

This study investigates the effects of Gamma-irradiation on the structural, morphological and opt... more This study investigates the effects of Gamma-irradiation on the structural, morphological and optical properties of 3,16-bis(tri isopropyl silylethynyl)pentacene (TIPS Pentacene) organic semiconductor films. The TIPS Pentacene thin films were irradiated at 10 to 300 kGy at a dose rate of 1.58 kGy/hr. The films were characterized using X-Ray Diffractometer (XRD), Atomic Force Microscopy (AFM) and Ultraviolet-Visible Spectroscopy (UV-Vis). The XRD analysis showed that the pre-irradiated thin films were of crystalline structure, indicating a broad wave diagram. The XRD and AFM results show that these variations can be attributed to the radiation-induced local heating and microscopic atomic mobility. Based on the UV-Vis results, the thin films exhibit approximately 70% optical transmittance in the visible region at pre-irradiation. At post-irradiation, optical transmittance decreased to 55% at the maximum absorbed dose. The corresponding optical bandgap decreased from 1.87 to 1.50 eV after a total ionizing dose of 300 kGy. The findings showed that TIPS Pentacene thin film has good mitigation towards gamma irradiation and can withstand harsh radiation while retaining its semiconductor properties. It is a potential candidate for flexible electronics for space applications.

Research paper thumbnail of Optical Properties of Nano-Porous Structure ZnO Prepared by Catalytic-Immersion Method

IOP conference series, Jun 6, 2013

This paper presents an efficient method to prepare ZnO nano-porous structure via immersion of Si ... more This paper presents an efficient method to prepare ZnO nano-porous structure via immersion of Si substrate with catalyst assistance (gold) in the mixture of zinc nitrate hexahydrate (Zn(NO 3) 2 .6H 2 O) and urea (CH 4 N 2 O). Photoluminescence (PL) spectra of nanoporous ZnO revealed it had strong UV emission with low oxygen defect. Optical properties are found to be significantly affected by varying the Zn 2+ : urea ratio but from surface morphology observation, the porous structure was stabile and seemingly unchanged.

Research paper thumbnail of Morphological and optical properties of Nb-doped ZnO nanoparticles

Materials Today: Proceedings

Research paper thumbnail of The structural properties of flower-like ZnO nanostructures on porous silicon

Research paper thumbnail of Developing high-sensitivity UV sensors based on ZnO nanorods grown on TiO2 seed layer films using solution immersion method

Sensors and Actuators A: Physical, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of The optimization of CNT-PVA nanocomposite for mild steel coating: Effect of CNTs concentration on the corrosion rate of mild steel

Carbon Nanotubes (CNTs) are molecular-scale tubes of graphitic carbon which have outstanding mech... more Carbon Nanotubes (CNTs) are molecular-scale tubes of graphitic carbon which have outstanding mechanical and magnetic properties with extraordinary strength. It can be said that CNTs can be used in coating application to prevent corrosion and lower the rate of corrosion on steel. However, CNT alone cannot be used for coating purposes. Therefore, by combining it with polymer to produce a nanocomposite thin film, it can be used for nanocoating on mild steel substrate. Polyvinyl alcohol (PVA) was chosen due to its high strength and high modulus polymer fibers and has the possibilities of improving the physicochemical properties of carbon nanotubes. Carbon nanotubes and polyvinyl alcohol (CNT-PVA) nanocomposite were prepared by using sol-gel method and coated as thin film on mild steel substrate by using spin coating. Sol-gel is a convenient technique used for the production of nanocomposite aqueous solution. Five samples were prepared at the different concentration of CNTs-PVA to verify the corrosion rate application. The samples were then characterized by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) obtaining the structural properties, surface morphology and topography of samples. Raman spectroscopy was used to determine the microraman spectra of CNTs which showed the quality and purity of samples. Finally, corrosion test was done to measure the corrosion rate of samples at the different concentration of CNTs/PVA nanocomposite.Carbon Nanotubes (CNTs) are molecular-scale tubes of graphitic carbon which have outstanding mechanical and magnetic properties with extraordinary strength. It can be said that CNTs can be used in coating application to prevent corrosion and lower the rate of corrosion on steel. However, CNT alone cannot be used for coating purposes. Therefore, by combining it with polymer to produce a nanocomposite thin film, it can be used for nanocoating on mild steel substrate. Polyvinyl alcohol (PVA) was chosen due to its high strength and high modulus polymer fibers and has the possibilities of improving the physicochemical properties of carbon nanotubes. Carbon nanotubes and polyvinyl alcohol (CNT-PVA) nanocomposite were prepared by using sol-gel method and coated as thin film on mild steel substrate by using spin coating. Sol-gel is a convenient technique used for the production of nanocomposite aqueous solution. Five samples were prepared at the different concentration of CNTs-PVA to verify the corrosion rate app...

Research paper thumbnail of The fabrication of nitrogen detector porous silicon nanostructures

Research paper thumbnail of Two-Step Deposition Method of Nanostructured ZnO Thin Films with Various Precursor Concentrations: The High Crystal Quality Enhances the Final Properties

Advanced Science Letters, 2015

Sur un théorème de M. Weingarten, et sur la théorie de surfaces applicables Annales de la faculté... more Sur un théorème de M. Weingarten, et sur la théorie de surfaces applicables Annales de la faculté des sciences de Toulouse 1 re série, tome 5, n o 3 (1891), p. E1-E34 <http://www.numdam.org/item?id=AFST_1891_1_5_3_E1_0> © Université Paul Sabatier, 1891, tous droits réservés. L'accès aux archives de la revue « Annales de la faculté des sciences de Toulouse » (http://picard.ups-tlse.fr/~annales/) implique l'accord avec les conditions générales d'utilisation (http://www.numdam.org/conditions). Toute utilisation commerciale ou impression systématique est constitutive d'une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright. Article numérisé dans le cadre du programme Numérisation de documents anciens mathématiques http://www.numdam.org/

Research paper thumbnail of The Fabrication of PSi/ZnO Nanostructures as Chemical Sensors for the Detection of Ethanol in Solution Using an Electrochemical Impedance Technique

Applied Mechanics and Materials, 2015

In this work, porous silicon (PSi) was prepared by electrochemical etching and used as a template... more In this work, porous silicon (PSi) was prepared by electrochemical etching and used as a template for ZnO nanostructures. ZnO nanostructures were grown using the catalytic immersion method at different molar ratio concentrations of the precursor and stabilizer. The ZnO nanostructures were analyzed using FESEM and photoluminescence (PL) spectrometry, before tested with ethanol solution. The population of the ZnO nanostructures on PSi increased with the concentration and followed the surface morphology of PSi. The photoluminescence spectra of ZnO show two dominant peaks in the UV and visible regions. When the concentration of the precursor increased, the PL peaks in the visible region (630 nm) shifted towards the blue region of the spectrum. The PSi/ZnO nanostructure chemical sensor has a large surface area, reversing sensor and fast response in ethanol. The performance of the sensor was affected by the morphology and defect structures of the ZnO nanostructures layer.

Research paper thumbnail of Porosity and thickness effect of porous silicon layer on photoluminescence spectra

2013 International Conference on Technology, Informatics, Management, Engineering and Environment, 2013

ABSTRACT

Research paper thumbnail of Surface Morphology of Seeded Nanostructured ZnO on Silicon by Sol-Gel Technique

Advanced Materials Research, 2013

Nanostructured ZnO as a seeded was prepared by sol-gel technique on p-type silicon in various low... more Nanostructured ZnO as a seeded was prepared by sol-gel technique on p-type silicon in various low molarities. Zinc acetate, Diethanolamine (DEA), and isopropyl were use as starting material, stabilizer, and solvent respectively. Atomic Force Microscopy (AFM) analysis shows smooth surface and uniform layer were produced in low molarities of precursor. The surface morphology of nanostructured ZnO was analyzed by Field Emission Scanning Electron Microscopic (FESEM). It is found that the nanostructured ZnO were successfully deposited on the silicon substrate with size ~10 nm to ~35 nm. Photoluminescence spectroscopy was employed to study the band gap in room temperature. It shows that very low intensity of PL in 0.05m and 0.1 m. PL intensity become more obvious starting from 0.15 m of precursor concentration.

Research paper thumbnail of Aquilaria malaccensis and Pandanus amaryllifolius mediated synthesis of tin oxide nanoparticles: The effect of the thermal calcination temperature

Materials Today: Proceedings

Research paper thumbnail of ISSN 2159-0427/130212/06/$60.00 © 2013 Global Scientific Publishers 130212-1

Post annealing effect on thin film composed ZnO nano-particles on porous silicon

Research paper thumbnail of Annealing Heat Treatment of ZnO Nanoparticles Grown on Porous Si Substrate Using Spin-Coating Method

Advances in Materials Science and Engineering, 2014

ZnO nanoparticles were successfully deposited on porous silicon (PSi) substrate using spin-coatin... more ZnO nanoparticles were successfully deposited on porous silicon (PSi) substrate using spin-coating method. In order to prepare PSi, electrochemical etching was employed to modify the Si surface. Zinc acetate dihydrate was used as a starting material in ZnO sol-gel solution preparation. The postannealing treatments were investigated on morphologies and photoluminescence (PL) properties of the ZnO thin films. Field emission scanning electron microscopy (FESEM) results indicate that the thin films composed by ZnO nanoparticles were distributed uniformly on PSi. The average sizes of ZnO nanoparticle increase with increasing annealing temperature. Atomic force microscopic (AFM) analysis reveals that ZnO thin films annealed at 500°C had the smoothest surface. PL spectra show two peaks that completely correspond to nanostructured ZnO and PSi. These findings indicate that the ZnO nanostructures grown on PSi are promising for application as light emitting devices.

Research paper thumbnail of Porosity and thickness effect of porous silicon layer on photoluminescence spectra

Nucleation and Atmospheric Aerosols, 2018

The porous silicon nanostructures was prepared by electrochemical etching of p-type silicon wafer... more The porous silicon nanostructures was prepared by electrochemical etching of p-type silicon wafer. Porous silicon prepared by using different current density and fix etching time with assistance of halogen lamp. The physical structure of porous silicon measured by the parameters used which know as experimental factor. In this work, we select one of those factors to correlate which optical properties of porous silicon. We investigated the surface morphology by using Surface Profiler (SP) and photoluminescence using Photoluminescence (PL) spectrometer. Different physical characteristics of porous silicon produced when current density varied. Surface profiler used to measure the thickness of porous and the porosity calculated using mass different of silicon.Photoluminescence characteristics of porous silicon depend on their morphology because the size and distribution of pore its self will effect to their exciton energy level. At J=30 mA/cm2 the shorter wavelength produced and it followed the trend of porosi...

Research paper thumbnail of Electrochemical impedance spectroscopy analysis of porous silicon prepared by photo-electrochemical etching: current density effect

Applied Physics A, May 1, 2014

ABSTRACT Electrical impedance characteristics of porous silicon nanostructures (PSiNs) in frequen... more ABSTRACT Electrical impedance characteristics of porous silicon nanostructures (PSiNs) in frequency function were studied. PSiNs were prepared through photo-electrochemical etching method at various current densities (15–40 mA/cm2) and constant etching time. The atomic force microscope images of PSiNs show that pore diameter and roughness increase when current density increases to 35 mA/cm2. The surface roughness subsequently decreases because of continuous etching of pillars, and a second etching process occurs. Photoluminescence spectra show blue and red shift with increasing applied current density that is attributed to PSiNs size. Variations of electrical resistance and capacitance values of PSiNs were measured using electrochemical impedance spectroscopy analysis. These results indicate that PSiNs prepared at 20 mA/cm2 current density have uniform porous structures with a large number of pillars. Furthermore, this PSiNs structure influences large values of charge transfer resistance and double layer capacitance, indicating potential application in sensors.

Research paper thumbnail of Bio-synthesized Tin Oxide Nanoparticles (SnO2 NPs) as a Photocatalyst Model

Zenodo (CERN European Organization for Nuclear Research), May 5, 2023

In the textile industries, most of the consumers attracted to colored fabrics. Unfortunately, the... more In the textile industries, most of the consumers attracted to colored fabrics. Unfortunately, the substance that use to color fabrics contributes serious environmental pollution. In this work, we have designed an environmental-friendly to control the negative effect using solution-based approach. By using this method, the cost can be reduced up to one-fourth from the commercial price. The non-toxic materials of tin (iv) oxide nanoparticles (SnO2NPs) were synthesized via green bio-synthesis. Bio-synthesis was conducted using the bioactive compound in Aquilaria Malaccensis (agarwood) leaves extracts. The photocatalytic activity of methylene blue (MB) degradation was investigated. The photocatalytic degradation was found to 82 % and 80 % with the presence of UV light, and fluorescent light, respectively. Both of the measurement has been done within 70 minutes. The result shows that SnO2 NPs could be the best option for efficiently, economically, and ecologically treating dye-polluted water.

Research paper thumbnail of Optical properties of nanoporous structure ZnO

International Journal of Materials Engineering Innovation, 2016

This paper presents an efficient method to prepare ZnO nanoporous structure via immersion of Si s... more This paper presents an efficient method to prepare ZnO nanoporous structure via immersion of Si substrate with catalyst assistance (gold) in the mixture of zinc nitrate hexahydrate (Zn(NO 3) 2 .6H 2 O) and urea (CH 4 N 2 O). Photoluminescence (PL) spectra of nanoporous ZnO revealed it had strong UV emission with low oxygen defect. Optical properties are found to be significantly affected by varying the Zn2+: urea ratio but from surface morphology observation, the porous structure was stable and seemingly unchanged.

Research paper thumbnail of Comparative study of surface, elemental, structural and optical morphologies of titanium dioxide-zinc oxide (TiO2-ZnO) and titanium dioxide-zinc oxide/graphene (TiO2-ZnO/Gn)

Materials Today: Proceedings, 2023

Research paper thumbnail of Performance Evaluation of Crack-Like ZnO/PSi Nanostructure Chemical Solution Sensor via Electrochemical Impedance Technique

Journal of The Electrochemical Society, 2020

Research paper thumbnail of Structural and Optical Properties of TIPS Pentacene Thin Film Exposed to Gamma Radiation

Materials Research-ibero-american Journal of Materials, 2022

This study investigates the effects of Gamma-irradiation on the structural, morphological and opt... more This study investigates the effects of Gamma-irradiation on the structural, morphological and optical properties of 3,16-bis(tri isopropyl silylethynyl)pentacene (TIPS Pentacene) organic semiconductor films. The TIPS Pentacene thin films were irradiated at 10 to 300 kGy at a dose rate of 1.58 kGy/hr. The films were characterized using X-Ray Diffractometer (XRD), Atomic Force Microscopy (AFM) and Ultraviolet-Visible Spectroscopy (UV-Vis). The XRD analysis showed that the pre-irradiated thin films were of crystalline structure, indicating a broad wave diagram. The XRD and AFM results show that these variations can be attributed to the radiation-induced local heating and microscopic atomic mobility. Based on the UV-Vis results, the thin films exhibit approximately 70% optical transmittance in the visible region at pre-irradiation. At post-irradiation, optical transmittance decreased to 55% at the maximum absorbed dose. The corresponding optical bandgap decreased from 1.87 to 1.50 eV after a total ionizing dose of 300 kGy. The findings showed that TIPS Pentacene thin film has good mitigation towards gamma irradiation and can withstand harsh radiation while retaining its semiconductor properties. It is a potential candidate for flexible electronics for space applications.

Research paper thumbnail of Optical Properties of Nano-Porous Structure ZnO Prepared by Catalytic-Immersion Method

IOP conference series, Jun 6, 2013

This paper presents an efficient method to prepare ZnO nano-porous structure via immersion of Si ... more This paper presents an efficient method to prepare ZnO nano-porous structure via immersion of Si substrate with catalyst assistance (gold) in the mixture of zinc nitrate hexahydrate (Zn(NO 3) 2 .6H 2 O) and urea (CH 4 N 2 O). Photoluminescence (PL) spectra of nanoporous ZnO revealed it had strong UV emission with low oxygen defect. Optical properties are found to be significantly affected by varying the Zn 2+ : urea ratio but from surface morphology observation, the porous structure was stabile and seemingly unchanged.

Research paper thumbnail of Morphological and optical properties of Nb-doped ZnO nanoparticles

Materials Today: Proceedings

Research paper thumbnail of The structural properties of flower-like ZnO nanostructures on porous silicon

Research paper thumbnail of Developing high-sensitivity UV sensors based on ZnO nanorods grown on TiO2 seed layer films using solution immersion method

Sensors and Actuators A: Physical, 2020

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Research paper thumbnail of The optimization of CNT-PVA nanocomposite for mild steel coating: Effect of CNTs concentration on the corrosion rate of mild steel

Carbon Nanotubes (CNTs) are molecular-scale tubes of graphitic carbon which have outstanding mech... more Carbon Nanotubes (CNTs) are molecular-scale tubes of graphitic carbon which have outstanding mechanical and magnetic properties with extraordinary strength. It can be said that CNTs can be used in coating application to prevent corrosion and lower the rate of corrosion on steel. However, CNT alone cannot be used for coating purposes. Therefore, by combining it with polymer to produce a nanocomposite thin film, it can be used for nanocoating on mild steel substrate. Polyvinyl alcohol (PVA) was chosen due to its high strength and high modulus polymer fibers and has the possibilities of improving the physicochemical properties of carbon nanotubes. Carbon nanotubes and polyvinyl alcohol (CNT-PVA) nanocomposite were prepared by using sol-gel method and coated as thin film on mild steel substrate by using spin coating. Sol-gel is a convenient technique used for the production of nanocomposite aqueous solution. Five samples were prepared at the different concentration of CNTs-PVA to verify the corrosion rate application. The samples were then characterized by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM) obtaining the structural properties, surface morphology and topography of samples. Raman spectroscopy was used to determine the microraman spectra of CNTs which showed the quality and purity of samples. Finally, corrosion test was done to measure the corrosion rate of samples at the different concentration of CNTs/PVA nanocomposite.Carbon Nanotubes (CNTs) are molecular-scale tubes of graphitic carbon which have outstanding mechanical and magnetic properties with extraordinary strength. It can be said that CNTs can be used in coating application to prevent corrosion and lower the rate of corrosion on steel. However, CNT alone cannot be used for coating purposes. Therefore, by combining it with polymer to produce a nanocomposite thin film, it can be used for nanocoating on mild steel substrate. Polyvinyl alcohol (PVA) was chosen due to its high strength and high modulus polymer fibers and has the possibilities of improving the physicochemical properties of carbon nanotubes. Carbon nanotubes and polyvinyl alcohol (CNT-PVA) nanocomposite were prepared by using sol-gel method and coated as thin film on mild steel substrate by using spin coating. Sol-gel is a convenient technique used for the production of nanocomposite aqueous solution. Five samples were prepared at the different concentration of CNTs-PVA to verify the corrosion rate app...

Research paper thumbnail of The fabrication of nitrogen detector porous silicon nanostructures

Research paper thumbnail of Two-Step Deposition Method of Nanostructured ZnO Thin Films with Various Precursor Concentrations: The High Crystal Quality Enhances the Final Properties

Advanced Science Letters, 2015

Sur un théorème de M. Weingarten, et sur la théorie de surfaces applicables Annales de la faculté... more Sur un théorème de M. Weingarten, et sur la théorie de surfaces applicables Annales de la faculté des sciences de Toulouse 1 re série, tome 5, n o 3 (1891), p. E1-E34 <http://www.numdam.org/item?id=AFST_1891_1_5_3_E1_0> © Université Paul Sabatier, 1891, tous droits réservés. L'accès aux archives de la revue « Annales de la faculté des sciences de Toulouse » (http://picard.ups-tlse.fr/~annales/) implique l'accord avec les conditions générales d'utilisation (http://www.numdam.org/conditions). Toute utilisation commerciale ou impression systématique est constitutive d'une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright. Article numérisé dans le cadre du programme Numérisation de documents anciens mathématiques http://www.numdam.org/

Research paper thumbnail of The Fabrication of PSi/ZnO Nanostructures as Chemical Sensors for the Detection of Ethanol in Solution Using an Electrochemical Impedance Technique

Applied Mechanics and Materials, 2015

In this work, porous silicon (PSi) was prepared by electrochemical etching and used as a template... more In this work, porous silicon (PSi) was prepared by electrochemical etching and used as a template for ZnO nanostructures. ZnO nanostructures were grown using the catalytic immersion method at different molar ratio concentrations of the precursor and stabilizer. The ZnO nanostructures were analyzed using FESEM and photoluminescence (PL) spectrometry, before tested with ethanol solution. The population of the ZnO nanostructures on PSi increased with the concentration and followed the surface morphology of PSi. The photoluminescence spectra of ZnO show two dominant peaks in the UV and visible regions. When the concentration of the precursor increased, the PL peaks in the visible region (630 nm) shifted towards the blue region of the spectrum. The PSi/ZnO nanostructure chemical sensor has a large surface area, reversing sensor and fast response in ethanol. The performance of the sensor was affected by the morphology and defect structures of the ZnO nanostructures layer.

Research paper thumbnail of Porosity and thickness effect of porous silicon layer on photoluminescence spectra

2013 International Conference on Technology, Informatics, Management, Engineering and Environment, 2013

ABSTRACT

Research paper thumbnail of Surface Morphology of Seeded Nanostructured ZnO on Silicon by Sol-Gel Technique

Advanced Materials Research, 2013

Nanostructured ZnO as a seeded was prepared by sol-gel technique on p-type silicon in various low... more Nanostructured ZnO as a seeded was prepared by sol-gel technique on p-type silicon in various low molarities. Zinc acetate, Diethanolamine (DEA), and isopropyl were use as starting material, stabilizer, and solvent respectively. Atomic Force Microscopy (AFM) analysis shows smooth surface and uniform layer were produced in low molarities of precursor. The surface morphology of nanostructured ZnO was analyzed by Field Emission Scanning Electron Microscopic (FESEM). It is found that the nanostructured ZnO were successfully deposited on the silicon substrate with size ~10 nm to ~35 nm. Photoluminescence spectroscopy was employed to study the band gap in room temperature. It shows that very low intensity of PL in 0.05m and 0.1 m. PL intensity become more obvious starting from 0.15 m of precursor concentration.