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.

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.

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.

Annealing Effects on Structural and Magnetic Properties of Al doped ZnO Thin Films

2011 ◽  
Vol 239-242 ◽  
pp. 2835-2838
Author(s):  
Yun Kai Qi ◽  
Jian Jun Gu ◽  
Li Hu Liu ◽  
Hui Yuan Sun
Keyword(s):  
Magnetic Properties ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Zno Films ◽  
Annealing Atmosphere ◽  
X Ray Diffraction ◽  
Annealing Effects ◽  
Order Of Magnitude ◽  
Doped Zno ◽  
A Charge

Al doped ZnO films have been prepared by dc magnetron sputtering. These films were annealed in different atmosphere and temperature. The crystal structures were analyzed by x-ray diffraction (XRD), and the magnetic properties were measured by a Physical Properties Measurement System (PPMS) with the magnetic field paralleled to the films plane. The results show the microstructure and magnetic properties were influenced by annealing atmosphere. Compared to the films annealed in vacuum, the films annealed in air shows obvious room temperature ferromagnetism, the magnetic moment increases about an order of magnitude. The room temperature ferromagnetism may be associated with a charge transfer between Al and Zn and the variational position of Al in ZnO films in different annealing ambience.

scholarly journals Structural and Enhanced Optical Properties of Stabilized γ‒Bi2O3 Nanoparticles: Effect of Oxygen Ion Vacancies

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1023 ◽  
Author(s):  
Ashish Chhaganlal Gandhi ◽  
Chia-Liang Cheng ◽  
Sheng Yun Wu
Keyword(s):  
Room Temperature ◽  
Excess Oxygen ◽  
Ambient Atmosphere ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Band Emission ◽  
Oxygen Ion ◽  
Integrated Intensity ◽  
Effect Of Oxygen

We report the synthesis of room temperature (RT) stabilized γ–Bi2O3 nanoparticles (NPs) at the expense of metallic Bi NPs through annealing in an ambient atmosphere. RT stability of the metastable γ–Bi2O3 NPs is confirmed using synchrotron radiation powder X-ray diffraction and Raman spectroscopy. γ–Bi2O3 NPs exhibited a strong red-band emission peaking at ~701 nm, covering 81% integrated intensity of photoluminescence spectra. Our findings suggest that the RT stabilization and enhanced red-band emission of γ‒Bi2O3 is mediated by excess oxygen ion vacancies generated at the octahedral O(2) sites during the annealing process.

Effect of defects on room-temperature ferromagnetism of Cr-doped ZnO films

2009 ◽  
Vol 60 (4) ◽  
pp. 214-217 ◽  
Author(s):  
L.J. Zhuge ◽  
X.M. Wu ◽  
Z.F. Wu ◽  
X.M. Chen ◽  
Y.D. Meng
Keyword(s):  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Zno Films ◽  
Doped Zno

Deposition of Thin Films of Silicon Carbide on Fused Quartz and on Sapphire by Laser Ablation of Ceramic Silicon Carbide Targets

1992 ◽  
Vol 285 ◽  
Author(s):  
L. Rimai ◽  
R. Ager ◽  
J. Hangas ◽  
E. M. Loaothetis ◽  
Nayef Abu-ageel ◽  
...  
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Energy Gap ◽  
Fused Silica ◽  
High Resistivity ◽  
Fused Quartz ◽  
Amorphous Sic ◽  
Very High

ABSTRACTAblation of ceramic silicon carbide with 351 nm excimer radiation was used to depositSIC films on fused silica and on sapphire. For deposition temperatures above 850° C, diffraction shows the films to be crystalline with the [111] axis preferentially oriented normally to the film. Optical spectra show an indirect energy gap at 2.2 eV, near that for the cubic polytype, although the 200 diffractions are absent. Room temperature resistivities range between .02 to .1 Ωcm. Deposition below 600° C yields amorphous SiC with no diffraction bands, low and variable optical band gap and very high resistivity.

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.

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