CO Sensor based on Thin Film of ZnO Nanoparticles

MRS Advances ◽  
2017 ◽  
Vol 2 (49) ◽  
pp. 2695-2700 ◽  
Author(s):  
Carlos Aquino López ◽  
Guillermo Carbajal-Franco ◽  
Fernanda Márquez Quintana ◽  
Alejandro Ávila Garcia

ABSTRACTIn this research, zinc chloride has been used as precursor and zinc oxide nanostructures have been synthesized by Sol-Gel process, using deionized water and 2-propanol as solvents in order to evaluate their influence on the final materials and their properties. Thin films of synthesized samples were deposited on glass substrates by the dipping method. The structure and morphology of crystals were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. The electrical response of the samples to CO was investigated at different operating temperatures and sensitivity curves are presented for samples synthesized in water and 2-propanol (IsOH) solvents. The SEM analysis revealed that ZnO thin films have yielded to different morphologies depending on the solvent, and material was found on the non-immersed side of the substrate attributable to migration during the dip-coating process. XRD analysis shows that the samples present the ZnO wurtzite structure. In EDS analysis it was found the presence of chlorine on the sample, opening the possibility the presence of zinc oxychloride.

2016 ◽  
Vol 36 (3) ◽  
pp. 309-320 ◽  
Author(s):  
Wei-Ming Chiu ◽  
Jhih-Siao Syu ◽  
Peir-An Tsai ◽  
Jyh-Horng Wu

Abstract Organic/inorganic hybrid materials were formed using the sol-gel process, in which SiO2/fluoroalkyl-trialkoxysilane (FAS)/2-hydroxyethyl methacrylate (2-HEMA)/trimethylolpropane triacrylate (TMPTA) and SiO2/3-(trimethoxysilyl)propyl methacrylate (MSMA)/ 2-HEMA/TMPTA thin films were formed on a glass substrate using dip coating. Experimental results revealed that FAS and MSMA improved the pencil hardness of SiO2/2-HEMA/TMPTA thin films without affecting their optical properties. FAS strengthened the hydrophobic and hydrophilic characteristics of SiO2/2-HEMA/TMPTA thin films more than did MSMA. However, an excess of FAS and an increase in withdrawal rates deteriorates the gloss, because both increased the SiO2 content, reducing the reflectivity.


2005 ◽  
Vol 12 (05n06) ◽  
pp. 793-797 ◽  
Author(s):  
F. E. GHODSI ◽  
M. MAFAKHERI ◽  
A. NOVINROOZ

Thin films of Al 2 O 3 were prepared by the sol–gel process. Dip-coating technique was used for deposition of the Al 2 O 3 thin films onto glass substrates. Optical and structural properties of the films were investigated with respect to the annealing temperature (100–500°C). The structure of these films was determined by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was performed for the analysis of surface morphology. For determination of the optical constants of Al 2 O 3 thin films, UV-Visible spectrophotometry measurements were carried out. Annealing temperature affects the structural and optical properties of the Al 2 O 3 thin films. The refractive index and extinction coefficient of the films at 550 nm wavelength increase from 1.56 to 1.66, and from 3.41 × 10-5 to 5.54 × 10-5, respectively while optical band gap and thickness of the films decrease from 4.15 eV to 4.11 eV, and 360 nm to 260 nm, respectively, by increasing annealing temperature from 100°C to 500°C.


2010 ◽  
Vol 17 (05n06) ◽  
pp. 445-449 ◽  
Author(s):  
SUHUA FAN ◽  
QUANDE CHE ◽  
FENGQING ZHANG

The (100)-oriented Ca0.4Sr0.6Bi4Ti4O15(C0.4S0.6BTi ) thin film was successfully prepared by a sol-gel method on Pt/Ti/SiO2/Si substrate. The orientation and formation of thin films under different annealing schedules were studied using XRD and SEM. XRD analysis indicated that (100)-oriented C0.4S0.6BTi thin film with degree of orientation of I(200)/I(119) = 1.60 was prepared by preannealing the film at 400°C for 3 min followed by rapid thermal annealing at 800°C for 5 min. SEM analysis further indicated that the (100)-oriented C0.4S0.6BTi thin film with a thickness of about 800 nm was mainly composed of equiaxed grains. The remanent polarization and coercive field of the film were 16.1 μC/cm2 and 85 kV/cm, respectively.


2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Marek Nocuń ◽  
Sławomir Kwaśny

AbstractIn our investigation, V doped SiO2/TiO2 thin films were prepared on glass substrates by dip coating sol-gel technique. Chemical composition of the samples was studied by X-ray photoelectron spectroscopy (XPS). Transmittance of the samples was characterized using UV-VIS spectrophotometry. Subsequently band-gap energy (Eg) was estimated for these films. Powders obtained from sols were characterized by FTIR spectroscopy. It was found that vanadium decreases optical band gap of SSiO2/TiO2 films.


2013 ◽  
Vol 448-453 ◽  
pp. 3041-3045
Author(s):  
Fei Bi ◽  
Xiang Ting Dong ◽  
Jin Xian Wang ◽  
Gui Xia Liu ◽  
Wen Sheng Yu

PVP/[Y(NO3)3+Al (NO3)3] composite nanobelts were fabricated via electrospinning combined with sol-gel process and novel structure of Y3Al5O12(denoted as YAG for short) nanobelts have been obtained after calcination of the relevant composite nanobelts. The structural properties were characterized by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). XRD analysis indicated that the composite nanobelts were amorphous, and YAG nanobelts were cubic in structure with space group Ia3d. FTIR analysis manifested that pure YAG nanobelts were formed at 900oC. SEM analysis and histograms revealed that the width of the composite nanobelts and YAG nanobelts were 3.5 μm and 2.4 μm, and the thickness were 240 nm and 112 nm, respectively, under the 95% confidence level. The formation mechanism of YAG nanobelts was discussed in detail.


Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3738 ◽  
Author(s):  
A. Smalenskaite ◽  
M. M. Kaba ◽  
I. Grigoraviciute-Puroniene ◽  
L. Mikoliunaite ◽  
A. Zarkov ◽  
...  

In this study, new synthetic approaches for the preparation of thin films of Mg-Al layered double hydroxides (LDHs) have been developed. The LDHs were fabricated by reconstruction of mixed-metal oxides (MMOs) in deionized water. The MMOs were obtained by calcination of the precursor gels. Thin films of sol–gel-derived Mg-Al LDHs were deposited on silicon and stainless-steel substrates using the dip-coating technique by a single dipping process, and the deposited film was dried before the new layer was added. Each layer in the preparation of the Mg-Al LDH multilayers was separately annealed at 70 °C or 300 °C in air. Fabricated Mg-Al LDH coatings were characterized by X-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and atomic force microscopy (AFM). It was discovered that the diffraction lines of Mg3Al LDH thin films are sharper and more intensive in the sample obtained on the silicon substrate, confirming a higher crystallinity of synthesized Mg3Al LDH. However, in both cases the single-phase crystalline Mg-Al LDHs have formed. To enhance the sol–gel processing, the viscosity of the precursor gel was increased by adding polyvinyl alcohol (PVA) solution. The LDH coatings could be used to protect different substrates from corrosion, as catalyst supports, and as drug-delivery systems in medicine.


2010 ◽  
Vol 36 (6) ◽  
pp. 1791-1795 ◽  
Author(s):  
Chien-Yie Tsay ◽  
Kai-Shiung Fan ◽  
Yu-Wu Wang ◽  
Chi-Jung Chang ◽  
Yung-Kuan Tseng ◽  
...  

2014 ◽  
Vol 91 ◽  
pp. 13-18 ◽  
Author(s):  
A. Prichodko ◽  
V. Jonauske ◽  
M. Cepenko ◽  
A. Beganskiene ◽  
A. Kareiva

Calcium hydroxyapatite (Ca10(PO4)6(OH)2, CHAp), tricalcium phosphate (Ca3(PO4)2, TCP) and calcium oxide (CaO) are the main components of inorganic part of human bones. Such synthetic nanocomposites could be very important implantable materials and using as substitute material for human hard tissues (bones and teeth). In this study, an aqueous sol-gel chemistry route has been developed to prepare nanostructured CHAp thin films on stainless steel substrate. For the preparation of thin films dip-coating and spin-coating techniques were used. The final samples were obtained by calcination of coatings for different time at 1000 °C. For the characterization of surface properties, the X-ray powder diffraction (XRD) analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM) and the contact angle measurements were recorded.


2015 ◽  
Vol 1109 ◽  
pp. 593-597
Author(s):  
M.F. Nasir ◽  
Mohd Hannas ◽  
Mohamad Hafiz Mamat ◽  
Mohamad Rusop

This project has been focused on the electrical and optical properties on the effect of Indium doped zinc oxide (ZnO) thin films at different dopant concentrations. These thin films were doped with different In dopant concentrations at 1 at%, 1.5 at%, 2 at%, 3 at%, 4 at% and 5 at% was selected as the parameter to optimize the thin films quality while the annealing temperature is fixed 500 oC. In doped ZnO solutions were deposited onto the glass substrates using sol-gel spin coating method. This project was involved with three phases, which are thin films preparation, deposition and characterization. The thin films were characterized using Current Voltage (I-V) measurement and UV-Vis-NIR spectrophotometer for electrical properties and optical properties. The electrical properties show that the resistivity is the lowest at 4 at% In doping concentration which is 8.27× 103Ωcm-1The absorption coefficient spectrum obtained from UV-Vis-NIR spectrophotometer measurement shows all films exhibit very low absorption in the visible (400-800nm) and near infrared (NIR) (>800nm) range but exhibit high absorption in the UV range.


2010 ◽  
Vol 150-151 ◽  
pp. 112-117 ◽  
Author(s):  
Min Xian Shi ◽  
Wei Mao ◽  
Yan Qin ◽  
Zhi Xiong Huang ◽  
Dong Yun Guo

Pb(Zr0.53Ti0.47)O3 thin films with thickness of 120nm, 190nm, 310nm, 440nm and 630nm were deposited on Pt/Ti/SiO2/Si substrates by sol-gel process through repeating spining process 2 times, 4 times, 6 times, 8 times and 10 times respectively. The structures of PZT films were investigated by SEM and XRD analysis. The ferroelectric hysteresis loops were recorded by Radiant Precision Workstation and dielectric properties were measured using an Agilent HP4294A impedance analyzer. X-ray diffraction indicated that with the film thickness increasing, the diffraction intensity increased. The thickness of PZT film had great effect on ferroelectric and dielectric properties. Conclusively when the film thickness was about 310nm, the PZT thin films possessed better ferroelectric and dielectric properties.


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