scholarly journals Photocatalytic Performance of ZnO: Al Films under Different Light Sources

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Prashant Pradhan ◽  
Juan Carlos Alonso ◽  
Monserrat Bizarro
Keyword(s):  
White Light ◽  
Irradiation Time ◽  
Zno Films ◽  
Light Sources ◽  
X Ray Diffraction ◽  
Treatment Processes ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Very High ◽  
High Degradation Rate

ZnO and Al doped ZnO films were produced by spray pyrolysis. The films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectroscopy, and photoluminescence. Their photocatalytic activity was evaluated by the decomposition of the methyl orange dye using different light sources: ultraviolet light, artificial white light, and direct sunlight. The films were also tested under darkness for comparison. The ZnO films were able to degrade the test pollutant under UV and sunlight in more than a 60% after 180 min of irradiation and a scarce degradation was obtained using white light. However, the Al doped ZnO films presented a very high degradation rate not only under UV and sunlight (100% degradation), but also under white light (90% degradation after the same irradiation time). An unexpected high degradation was also obtained in the dark, which indicates that a nonphotonic process is taking place parallel to the photocatalytic process. This can be due to the extra electrons—provided by the aluminum atoms—that migrate to the surface and produce radicals favoring the decomposition process even in the dark. The high activity achieved by the ZnO: Al films under natural conditions can be potentially applied to water treatment processes.

scholarly journals Effect of Oxygen Pressure on Transport Propeties of Al-doped ZnO Films Grown by PED

2012 ◽  
Vol 22 (2) ◽  
pp. 155 ◽  
Author(s):  
Ngo Dinh Sang ◽  
Pham Hong Quang ◽  
Do Quang Ngoc
Keyword(s):  
Oxygen Pressure ◽  
Room Temperature ◽  
High Resistivity ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Pulsed Electron Deposition ◽  
Doped Zno ◽  
Higher Carrier Mobility ◽  
Effect Of Oxygen ◽  
Very High

Al-doped ZnO films were grown by pulsed electron deposition (PED) at room temperature and 400 oC and at the oxygen pressure ranged from 3 mTorr to 20 mTorr. Transport properties were measured by van der Pauw technique. Crystallinity of the films was characterized by X-ray diffraction. It was found that the films grown at room temperature have a very high resistivity due to poor crystallinity. For the films grown at 400 o C, the obtained results indicate that the film grown at a lower pressure has a higher carrier mobility as well as a higher carrier concentration, resulting in a lower resistivity. This phenomenon has been discussed in term of the concentration of oxygen vacancies and the number of traps for carriers.

Preparation and Characterization of Zn1-XMnxO Thin Films on SiO2 Substrates

2012 ◽  
Vol 560-561 ◽  
pp. 820-824
Author(s):  
Yue Zhi Zhao ◽  
Fei Xiong ◽  
Guo Mian Gao ◽  
Shi Jing Ding
Keyword(s):  
Thin Films ◽  
Rf Magnetron Sputtering ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Flat Surfaces ◽  
Atomic Force ◽  
Mn Content ◽  
Doped Zno ◽  
Mn Doped

Mn-doped ZnO thin films were prepared on SiO2substrates by using a radio-frequency(rf) magnetron sputtering in order to investigate structure and optical proprieties of the films. X-ray diffraction (XRD), Atomic force microscope (AFM) and UV-VIS spectrophotometry were employed to characterize the Mn-doped ZnO films. The results showed that the shape of the XRD spectrum was remarkably similar to that of the un-doped ZnO film; the film had mainly (002) peak, and indicate that the structure of the films was not disturbed by Mn-doped. The film had rather flat surfaces with the peak-to-tail roughness of about 25nm. Mn-doping changed the band gap of the films, which increased with the increase of the Mn content.

Antibacterial Activity of Nickel -Doped ZnO\MWCNTs hybrid Prepared by Sol-Gel technique

2021 ◽  
Author(s):  
Selma M.H. AL-Jawad ◽  
Zahraa S. Shakir ◽  
Duha S. Ahmed
Keyword(s):  
Antibacterial Activity ◽  
Sol Gel ◽  
Inhibition Zone ◽  
Sem Analysis ◽  
Morphological Properties ◽  
X Ray Diffraction ◽  
Zno Nps ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Doped Zno

ZnO/MWCNTs hybrid and doped with different concentration of Nickel element prepared by using Sol-gel been technique reported. All samples were prepared and characterized by X-Ray Diffraction Analysis (XRD), Energy Dispersive X-ray Spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FE-SEM), and UV-Vis spectroscopy have been identified the structural, optical and morphological properties. X-ray diffraction showed the polycrystalline nature with hexagonal wutzite structure of hybrid and doped with Nickel. The crystalline size of the hybrid nanostructure was increasing from 23.73 nm to 34.59 nm. Besides, the UV-Vis spectroscopy showed a significant decrease in the band gap values from 2.97 eV to 2.01 eV. Whereas the FE-SEM analysis confirm the formation spherical shapes of ZnO NPs deposited on cylindrical tubes representing the MWCNTs. The antibacterial activity reveals that the inhibition zone of Ni doped-ZnO/MWCNTs hybrid was 28.5 mm, 26.5 mm toward E. coli and S. aureus bacteria, respectively.

scholarly journals Surfactant-Free Microwave-Assisted Synthesis of Fe-Doped ZnO Nanostars as Photocatalyst for Degradation of Tropaeolin O in Water under Visible Light

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Tsz-Lung Kwong ◽  
Ka-Fu Yung
Keyword(s):  
Visible Light ◽  
Photocatalytic Degradation ◽  
Irradiation Time ◽  
Catalyst Loading ◽  
Orthogonal Experimental Design ◽  
Microwave Assisted Synthesis ◽  
X Ray ◽  
Microwave Assisted ◽  
Vis Spectroscopy ◽  
Doped Zno

Iron-doped zinc oxide nanostar was synthesized by the microwave-assisted surfactant-free hydrolysis method. The as-synthesized Fe-doped ZnO nanostars catalyst was fully characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), and diffuse reflectance UV-vis spectroscopy (UV-DRA). The photocatalytic activity of the photocatalyst was investigated for the photocatalytic degradation of Tropaeolin O under visible light irradiation. It is observed that the doping of Fe ions enhances the absorption of the visible light and thus the photocatalytic degradation rate of Tropaeolin O would increase. Despite the Taguchi orthogonal experimental design method, the photocatalytic conversion could be achieved at 99.8% in the Fe-doped ZnO catalyzed photodegradation reaction under the optimal reaction conditions of catalyst loading (30 mg), temperature (60°C), light distance (0 cm), initial pH (pH = 9), and irradiation time (3 h). The Fe-doped ZnO photocatalyst can also be easily recovered and directly reused for eight cycles with over 70% conversion.

The Effect of the Cu Source on Optical Properties of Cu-Doped ZnO Films

2014 ◽  
Vol 936 ◽  
pp. 618-623
Author(s):  
Lung Chien Chen ◽  
Xiu Yu Zhang ◽  
Kuan Lin Lee
Keyword(s):  
Optical Properties ◽  
Copper Acetate ◽  
Copper Nitrate ◽  
Zno Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ultrasonic Spray ◽  
Spray Method ◽  
Potential Applications ◽  
Doped Zno

Cu-doped ZnO (CZO) films have been widely discussed due to its potential applications in semiconductor devices, such as gas sensors or solar cells, but few articles were reported to show the effect on properties of CZO films by using different Cu sources. The article demonstrates that CZO films have been prepared by using different Cu source via a simple ultrasonic spray method, in which copper nitrate and copper acetate were used as copper sources. Optical properties of CZO films prepared by copper nitrate and copper acetate were investigated by transmittance and photoluminescence measurement. The X-ray diffraction analysis and field emission scanning electron microscopy were used to investigate the composition and the morphology of the films. The CZO films prepared by using copper acetate shows better optical properties by comprehensive analysis.

Properties of Li-Doped ZnO Films Deposited on Diamond Films

2013 ◽  
Vol 544 ◽  
pp. 234-237
Author(s):  
Mei Ai Lin ◽  
Lin Jun Wang ◽  
Jian Huang ◽  
Ke Tang ◽  
Bing Ren ◽  
...  
Keyword(s):  
Diamond Films ◽  
Hall Effect Measurement ◽  
Zno Films ◽  
Radio Frequency Magnetron Sputtering ◽  
X Ray Diffraction ◽  
X Ray ◽  
Doped Zno ◽  
Effect Of Oxygen ◽  
Reactive Gas

Li-doped zinc oxide (ZnO) films were deposited on nucleation side of freestanding diamond (FSD) films by the radio frequency magnetron sputtering method. The effect of oxygen partial pressure on structural, optical and electrical properties of the ZnO films was investigated by X-ray diffraction (XRD) Raman spectroscopy, semiconductor characterization system and Hall effect measurement system. The results showed that the introduction of oxygen as a reactive gas was helpful to improve the crystalline quality of Li-doped ZnO films.

scholarly journals Growth of Zn1−x CdxO nanocrystalline thin films by sol-gel method and their characterization for optoelectronic applications

2014 ◽  
Vol 32 (4) ◽  
pp. 688-695 ◽  
Author(s):  
Munirah Munirah ◽  
Ziaul Khan ◽  
Mohd. Khan ◽  
Anver Aziz
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Visible Region ◽  
Zno Thin Films ◽  
Band Edge Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cd Doping ◽  
Vis Spectroscopy ◽  
Doped Zno

AbstractThis paper describes the growth of Cd doped ZnO thin films on a glass substrate via sol-gel spin coating technique. The effect of Cd doping on ZnO thin films was investigated using X-ray diffraction (XRD), UV-Vis spectroscopy, photoluminescence spectroscopy, I–V characteristics and field emission scanning electron microscopy (FESEM). X-ray diffraction patterns showed that the films have preferred orientation along (002) plane with hexagonal wurtzite structure. The average crystallite sizes decreased from 24 nm to 9 nm, upon increasing of Cd doping. The films transmittance was found to be very high (92 to 95 %) in the visible region of solar spectrum. The optical band gap of ZnO and Cd doped ZnO thin films was calculated using the transmittance spectra and was found to be in the range of 3.30 to 2.77 eV. On increasing Cd concentration in ZnO binary system, the absorption edge of the films showed the red shifting. Photoluminescence spectra of the films showed the characteristic band edge emission centred over 377 to 448 nm. Electrical characterization revealed that the films had semiconducting and light sensitive behaviour.

Preparation of Al-doped ZnO Nanoparticulate Film for Optoelectronic Applications

2010 ◽  
Vol 1247 ◽  
Author(s):  
Thu V. Tran ◽  
Shinya Maenosono
Keyword(s):  
Electron Microscopy ◽  
Optical Transmittance ◽  
X Ray Diffraction ◽  
High Concentration ◽  
Polar Solvents ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Doped Zno ◽  
Optoelectronic Applications

AbstractAl-doped ZnO (AZO) nanoparticles (NPs) were synthesized by the solvothermal decomposition. The as-synthesized AZO NPs were characterized by X-ray diffraction and transmission electron microscopy. These NPs were well dispersible in non-polar solvents at high concentration to produce AZO nanoink. The AZO nanoparticulate films were prepared from AZO nanoink by spin coating technique. Thickness, surface morphology, optical transparency and conductivity of the films were characterized by surface profilometer, scanning electron microscopy, UV-Vis spectroscopy and Hall measurements. The AZO nanoparticlulate films had highly optical transmittance and well electrical conductivity, which are potential for optoelectronic applications.

Optical Properties of Cu-Doped ZnO Films Prepared by Cu Solution Coating

2015 ◽  
Vol 15 (10) ◽  
pp. 7664-7670 ◽  
Author(s):  
Bunyod Allabergenov ◽  
Seok-Hwan Chung ◽  
Sungjin Kim ◽  
Byeongdae Choi
Keyword(s):  
Grain Size ◽  
Optical Properties ◽  
Hexagonal Wurtzite Structure ◽  
Zno Films ◽  
X Ray Diffraction ◽  
Coating Method ◽  
Higher Temperature ◽  
Doped Zno ◽  
Process Energy ◽  
Beam Deposition

This work demonstrates the fabrication of Cu-doped ZnO films by Cu solution coating method. Cu ink was spin coated on ZnO thin films prepared by e-beam deposition. After curing and annealing at high temperatures, structural, morphological and optical properties of the films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectrofluorometer, respectively. The XRD results showed that ZnO films formed polycrystalline with a hexagonal wurtzite structure, and the grain size increased with increasing the annealing temperature from 500 to 850 °C. The changes in lattice parameters were caused by grain size, strain, and residual stress. Morphological analysis have revealed that the Cu-doped ZnO film after annealing at 500 °C has flat surface with uniformly distributed grain size, which became porous after higher temperature annealing process. Energy dispersive spectroscopy (EDS) and photoluminescence spectras have shown the presence of Zn, Cu, and O elements, and combined violet, blue, green and weak red emissions between 350 and 650 nm in the ZnO films, respectively.

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