The effect of graphene and cobalt on ethanol sensing performance of ZnO based sensor prepared by sol–gel method

Author(s):  
Sadaf Nejatinia ◽  
Sara Khadem Charvadeh ◽  
Abbas Bagheri Khatibani

Abstract The sol gel method was used to synthesize pure zinc oxide, graphene doped zinc oxide, cobalt doped zinc oxide and graphene/cobalt doped zinc oxide samples to investigate their sensing properties. Different physical properties of the samples have been investigated and compared through X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and Fourier transform infrared spectroscopy (FTIR). Using the XRD results, the lattice parameter increased with doping of the samples. Based on the analyses, the formation of zinc oxide in all samples and the related signs of graphene and cobalt were approved. By the aid of an electric circuit, all of the samples were exposed to different concentrations of ethanol. The best response/recovery time was reported for all samples at 3000 ppm. Doping of the samples had a significant effect on reducing the response/recovery time and increasing the sensitivity, which is a significant case for semiconductor gas sensors.

2021 ◽  
Vol 24 (3) ◽  
pp. 38-42
Author(s):  
Marwa Mudfer Alqaisi ◽  
◽  
Alla J. Ghazai ◽  

In this work, pure Zinc oxide and tin doped Zinc oxide thin films nanoparticles with various volume concentrations of 2, 4, 6, and 8V/V% were prepared by using the sol-gel method. The optical properties were investigated by using UV-Visible spectroscope, and the value exhibits the direct allowed transition. The average of transmittance was around ~(17-23) %in visible region. The optical energy band gap was calculated with wavelength (300-900) nm for pure ZnO and Sn doped ZnO thin films which decreases with increasing concentration from 3.4 eV to 3.1 eV respectively and red shift. The real dielectric(εr) and the imaginary dielectric εiare the same behavior of the refractive index(n) the extinction coefficient (k) respectively. The optical limiting properties were studied by using an SDL laser with a wavelength of 235 nm. ZnO and doping thin films an found efficient as optic limiting and depend on the concentration of the all samples.


2013 ◽  
Vol 756 ◽  
pp. 91-98 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah

Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900 °C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900°C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-raySpectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealingtemperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. Normal 0 21 false false false MS X-NONE X-NONE MicrosoftInternetExplorer4 Terbium –substituted yttrium iron garnet (Tb1.5Y1.5Fe5O12) films nanoparticles were successfully prepared by a sol-gel method. The films were deposited on the quartz substrate using spin coating technique. To study effect of annealing temperature, the annealing process was executed at 700, 800 and 900°C in air for 2 hours. The X-ray diffraction (XRD) proved that the pure phase of garnet structure was detected for the film annealed at 900 °C. The lattice parameter increased with the increment of annealing temperature and the highest value of 12.35 Å was obtained at 900 °C. Field Emission Scanning Electron Microscope (FE-SEM) results showed that the particle size increased from 43nm to 56nm as annealing temperature increased from 700 to 900 °C. The film’s thickness also affected by increasing of annealing temperature and become thin at 900 °C due to densification process occurred at high annealing temperature. The elemental compositions of the Tb1.5Y1.5Fe5O12 film were detected using an Energy Dispersive X-ray Spectroscopy (EDX). Magnetic properties at room temperature were measured using a Vibrating Sample Magnetometer (VSM).The saturation magnetization Ms increased with the annealing temperature and showed a high value of 104emu/cm3, but the coercivity Hc of the film was decreased due to the increment of the particle size. st1\:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}


2012 ◽  
Vol 02 (01) ◽  
pp. 10-15 ◽  
Author(s):  
Muhammad Saleem ◽  
Liang Fang ◽  
Aneela Wakeel ◽  
M. Rashad ◽  
C. Y. Kong

2012 ◽  
Vol 121 (1) ◽  
pp. 217-220 ◽  
Author(s):  
M.S. Kim ◽  
K.G. Yim ◽  
S. Kim ◽  
G. Nam ◽  
D.Y. Lee ◽  
...  

2011 ◽  
Vol 495 ◽  
pp. 323-326 ◽  
Author(s):  
Ming Zhao ◽  
Li Hui Sun ◽  
Ji Fan Hu ◽  
Hong Wei Qin

The La1-xCaxFeO3 nanocrystalline powders were prepared by sol-gel method. These powders crystallized as perovskite orthorhombic structure. With an increase of Ca content, the resistance of La1-xCaxFeO3 sensors in air decreases at first, undergoes a minimum at x=0.3, and then increases again. La1-xCaxFeO3-based sensors show sensitive responses to CO. Among those La1-xCaxFeO3-based sensors, the sensor with x=0.2 shows the highest response to 200 ppm CO at operating temperatures below 325°C. The highest response S=(RCO-Rair)/RCO for the La0.8Ca0.2FeO3 based sensor to 200 ppm CO is 87% with response time 15 s and recovery time 60 s at an operating temperature of 100°C.


2013 ◽  
Vol 265 ◽  
pp. 758-763 ◽  
Author(s):  
A. Kumar ◽  
N. Huang ◽  
T. Staedler ◽  
C. Sun ◽  
X. Jiang

2019 ◽  
Vol 1145 ◽  
pp. 012020
Author(s):  
S Kuznetsova ◽  
E Mongush ◽  
K Lisitsa

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