Effects of Annealing Treatment on Structural, Optical and Morphology Characteristics of ZnO Nanostructures

2012 ◽  
Vol 626 ◽  
pp. 967-970 ◽  
Author(s):  
Siti Khadijah Mohd Bakhori ◽  
Chuo Ann Ling ◽  
Shahrom Mahmud
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Treatment ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Zno Nanostructures ◽  
Zno Nanostructure ◽  
Band Emission ◽  
Transmission Electron ◽  
Xrd Patterns

The ZnO nanostructure produced by CFCO or French process were undergone annealing treatment at 700°C in oxygen and nitrogen ambient. Subsequently, the characteristics of structural, optical and morphology of ZnO nanostructures were investigated using X-ray diffraction (XRD), photoluminescence (PL) and transmission electron microscopy (TEM) respectively. The crystallite size of the nanostructures were calculated from full width half maximum (FWHM) of (101) peak in XRD patterns and the size is around 42 nm. PL measuremment were carried out and the near band edge emission (NBE) is increase in wavelength or namely redshifted. Moreover, deep band emission (DBE) is observed at 520 nm for ZnO annealed in nitrogen, which commonly regarded as the defect level of oxygen vacancies. The investigation continues with conducting transmission electron microscopy (TEM) to demonstrate the mophology of as grown nanostructures and annealed in both nitrogen and oxygen ambient.

Photoluminescence and Raman Studies of Annealed ZnO Nanostructures

2012 ◽  
Vol 501 ◽  
pp. 179-183 ◽  
Author(s):  
Siti Khadijah Mohd Bakhori ◽  
Chuo Ann Ling ◽  
Shahrom Mahmud
Keyword(s):  
Optical Signal ◽  
High Mode ◽  
Raman Shift ◽  
Near Band Edge ◽  
Band Edge Emission ◽  
Zno Nanostructures ◽  
Zno Nanostructure ◽  
Band Emission ◽  
Crystallite Sizes ◽  
Tem Microscopy

The influence of annealing on the optical properties of as-grown ZnO nanostructures prepared in pellets has been investigated by photoluminescence (PL) and Raman spectroscopy. The annealing temperatures of ZnO nanostructure at 600°C, 650°C and 700 °C were conducted in oxygen (O2) and nitrogen (N2) ambient. The near band edge emission (NBE) of samples recorded in the PL spectra demonstrates significant changes on optical signal whereby the NBE is redshifted after O2 annealed and became slightly higher in N2 annealed. Apart from that, weak green luminescence (GL) namely deep band emission (DBE) is observed centre at 532.95 nm (2.23 eV) and 511.00 nm (2.42 eV) for annealed in O2 and N2 respectively, whereas lower DBE observed in as-grown ZnO. On the other hand, Raman shift reveal the phonon mode of the ZnO nanostructures and the E2 (high) mode were downshifted as annealed in O2 ambient, and upshifted in N2 ambient. The downshift and upshift of the E2 (high) mode are correlated to tensile and compressive stress. Moreover the crystallite sizes were calculated from FWHM of XRD and TEM microscopy reveals the nanoplates structure of ZnO nanostructures.

Synthesis of ZnO with Different Morphology and its Photocatalytic Property

2011 ◽  
Vol 110-116 ◽  
pp. 547-552 ◽  
Author(s):  
Yu Xin Wang ◽  
Jing Xu ◽  
Xing Guo Cheng ◽  
Hong Fang Xu ◽  
Li Jun Liu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photocatalytic Property ◽  
Zno Nanostructures ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Zno Nanomaterials ◽  
Scanning Electron

ZnO nanostructures with different morphology have been successfully fabricated by a simple relative low temperature approach at 90 °C for 5 h without surfactant assistance. These structures can be easily tailed using varied concentrations of sodium hydroxide (NaOH) and different amounts of the hydrazine hydrate (N2H4·H2O). X-ray diffraction (XRD) result proves the formation of ZnO with wurtzite structure. Microstructure as revealed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicates that the rod-like and chrysanthemum-like ZnO nanostructures contain many radial nanorods, which grow along the [0001] direction. Furthermore, the as-prepared ZnO nanomaterials exhibit high activity on the photo-catalytic degradation of typical persistent organic pollutants (POPs), indicating that they are promising as semiconductor photo-catalysts.

Modulated Structures in Ion Implanted Al-Fe System

1983 ◽  
Vol 27 ◽  
Author(s):  
K.V. Jata ◽  
D. Janoff ◽  
E.A. Starke
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Purity ◽  
Annealing Treatment ◽  
Modulated Structure ◽  
Transmission Electron ◽  
Modulated Structures ◽  
Ion Energies ◽  
High Purity Aluminum ◽  
Al Matrix

ABSTRACTThe results of transmission electron microscopy studies of iron implantation into high purity aluminum foils are described. For both 50 and 100 + 50 keV incident ion energies, modulated structure has been detected in the as-implanted foils. Upon annealing at 793 K the modulated structure decomposes into the Al matrix and Al3Fe precipitates for the 50 keV implantation. A similar annealing treatment for the 100 + 50 keV implantation indicates that the modulated structure is more stable, although some Fe3Al precipitation occurs.

Microstructure and dielectric properties of Ba(Cd1/3Ta2/3)O3 microwave ceramics synthesized with a boron oxide sintering aid

2004 ◽  
Vol 19 (12) ◽  
pp. 3526-3533 ◽  
Author(s):  
Shaojun Liu ◽  
Jian Sun ◽  
Richard Taylor ◽  
David J. Smith ◽  
N. Newman
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Annealing Treatment ◽  
Hexagonal Structure ◽  
Microwave Properties ◽  
Microwave Ceramics ◽  
Sintering Aid ◽  
Boron Doped ◽  
Transmission Electron ◽  
Liquid Sintering

The use of boron as a sintering aid reduces the sintering temperature, enhances the sintering density, and improves the microwave properties of Ba(Cd1/3Ta2/3)O3 ceramic dielectrics. Observations by transmission electron microscopy indicate that the liquid sintering mechanism contributes to the improvement in sintering density for boron concentrations exceeding 0.5 wt%. The introduction of as small as 0.01% boron also results in the production of high-density samples (∼95%), presumably indicating that a point defect mechanism may also play an important role in the sintering process. X-ray diffraction data combined with high-resolution transmission electron microscopy images show that boron-doped Ba(Cd1/3Ta2/3)O3 ceramic material has a well-ordered hexagonal structure. Annealing treatment is found to improve the microwave properties. The best sample has a dielectric constant of 32, a temperature coefficient of resonant frequency of 80 ± 15 ppm/°C, and a quality factor of >25,000 at 2 GHz.

Raman Spectroscopy Analysis of Nitrogen Ion Implantation in Silicon and Correlation with Transmission Electron Microscopy

1992 ◽  
Vol 279 ◽  
Author(s):  
A. PéRez-Rodríguez ◽  
A. Romano-Rodríguez ◽  
J. R. Morante ◽  
J. Esteve ◽  
J. Montserrat
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Raman Spectra ◽  
Annealing Treatment ◽  
Structural Features ◽  
Spectroscopy Analysis ◽  
Subsurface Region ◽  
Transmission Electron ◽  
Nitrogen Ion

ABSTRACTIn this work Si samples implanted with nitrogen (N+ or N2+) at a dose of 1017 cm−2 are characterized by Raman spectroscopy and cross section transmission electron microscopy (XTEM). The correlation between the Raman spectra obtained with different excitation wavelengths and XTEM observations allows to determine the structural features related to the layers contributing to the total spectra. The evolution of these features with the annealing treatments (up to 1150°C) is studied. The results obtained show, after the annealing treatment at the highest temperature, the presence of silicon nitride precipitates in the silicon subsurface region, and the formation of a nitrogen rich polycrystalline Si layer with Si3N4 grains. The Raman spectra from the subsurface region show a remaining shift of -0.15 cm−1 when compared to the spectra from unimplanted Si. This shift, together with the similar shape of both Raman lines, suggests the presence in this region of an average tensile stress of 37.5 MPa.

scholarly journals A New Method of Synthesizing Black Birnessite Nanoparticles: From Brown to Black Birnessite with Nanostructures

2008 ◽  
Vol 2008 ◽  
pp. 1-8 ◽  
Author(s):  
Marcos A. Cheney ◽  
Pradip K. Bhowmik ◽  
Shizhi Qian ◽  
Sang W. Joo ◽  
Wensheng Hou ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ambient Air ◽  
New Method ◽  
Bet Surface Area ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Excellent Thermal Stability ◽  
Transmission Electron ◽  
Xrd Patterns

A new method for preparing black birnessite nanoparticles is introduced. The initial synthesis process resembles the classical McKenzie method of preparing brown birnessite except for slower cooling and closing the system from the ambient air. Subsequent process, including wet-aging at7∘Cfor 48 hours, overnight freezing, and lyophilization, is shown to convert the brown birnessite into black birnessite with complex nanomorphology with folded sheets and spirals. Characterization of the product is performed by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), thermogravimetric analysis (TGA), andN2adsorption (BET) techniques. Wet-aging and lyophilization times are shown to affect the architecture of the product. XRD patterns show a single phase corresponding to a semicrystalline birnessite-based manganese oxide. TEM studies suggest its fibrous and petal-like structures. The HRTEM images at 5 and 10 nm length scales reveal the fibrils in folding sheets and also show filamentary breaks. The BET surface area of this nanomaterial was found to be 10.6 m2/g. The TGA measurement demonstrated that it possessed an excellent thermal stability up to400∘C. Layer-structured black birnessite nanomaterial containing sheets, spirals, and filamentary breaks can be produced at low temperature (−49∘C) from brown birnessite without the use of cross-linking reagents.

scholarly journals Near Band Edge excitation in 2D materials by Transmission Electron Microscopy

2016 ◽  
pp. 807-808
Author(s):  
Frédéric Fossard ◽  
Léonard Schué ◽  
Etienne Gaufrès ◽  
Amandine Andrieux ◽  
François Ducastelle ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
2D Materials ◽  
Band Edge ◽  
Near Band Edge ◽  
Transmission Electron

scholarly journals Hydrothermal Preparation of Silver Doping Zinc Oxide Nanoparticles: Studys, Characterization and Photocatalytic Activity

2018 ◽  
Vol 34 (4) ◽  
pp. 1898-1907 ◽  
Author(s):  
Hassan A. Habeeb Alshamsi ◽  
Batool S. Hussein
Keyword(s):  
Electron Microscopy ◽  
Photocatalytic Activity ◽  
Zno Nanoparticles ◽  
Hydrothermal Process ◽  
Hexagonal Structure ◽  
Infrared Spectrometry ◽  
Zno Nanostructures ◽  
Hydrothermal Preparation ◽  
Zno Nanostructure ◽  
Transmission Electron

In this study , we report the prepared of ZnO nanoparticles and Ag doped ZnO nanostructure via a hydrothermal process. The obtained nanostructures were characterized using different characterization techniques such as X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) , atomic force microscopy (AFM) ,Fourier transform infrared spectrometry (FTIR)and UV/Visible spectrophotometer.The XRD results showed the wurtzite hexagonal structure of the ZnO Nanoparticles. Furthermore, the morphology of ZnO and Ag-ZnO nanostructures was obtained from SEM and AFM. The photocatalytic degradation of Cibacron Brilliant Yellow 3G-P (CB) dye was studied in presence of visible light using Ag-ZnO nanostructures as a photocatalyst. There are numerous factors which has an effect on the efficiency color removal of this process. Hence a study was conducted on the effect of several parameters on Ag-ZnO like amount of catalyst, CB dye concentration and pH of solution. Results showed Ag doping ZnO with 3% loading shows photocatalytic removal about 65% after 120 min which influenced superior photocatalytic activity than pure ZnO.

TEM recombination studies of dislocations in indium phosphide

1986 ◽  
Vol 44 ◽  
pp. 814-815
Author(s):  
S. Myhajlenko ◽  
H. J. Hutchinson ◽  
J. W. Steeds
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Indium Phosphide ◽  
Electric Fields ◽  
Surface Recombination ◽  
Near Band Edge ◽  
Transmission Electron ◽  
Dislocation Type ◽  
Main Observation ◽  
Band Edge Luminescence

We have reported the use of transmission electron microscopy (TEM) with simultaneous cathodoluminescence (CL) for the study of defects in opto-electronic semiconductors such as InP and ZnSe. The effect of individual dislocations on the efficiency of the near band edge luminescence was investigated; the main observation reported for InP was the quenching at some dislocations of the exciton-related emission. No correlation was found between dislocation type and luminescence behaviour. Further, during the course of this work, a better appreciation has been gained of factors which are important in transmission CL studies, for example, the effects of excitation, strain, surface recombination, electric fields and optical interference. We describe some of them here and new results from dislocation groups in InP.

scholarly journals Synthesis and Characterization of Birnessite and Cryptomelane Nanostructures in Presence of Hoffmeister Anions

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Marcos A. Cheney ◽  
Robin Jose ◽  
Arghya Banerjee ◽  
Pradip K. Bhowmik ◽  
Shizhi Qian ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Manganese Dioxide ◽  
Chloride Ion ◽  
Reduction Reaction ◽  
X Ray Diffraction ◽  
Hydrothermal Conditions ◽  
Transmission Electron ◽  
Xrd Patterns

The effect of Hoffmeister anions , , and on the structure and morphology of birnessite and cryptomelane-type manganese dioxide nanostructures, produced by the reduction reaction of and in aqueous acidic media, was studied. The syntheses were based on the decomposition of aqueous in presence of HCl for birnessite-type and acidified for cryptomelane-type manganese dioxide under soft hydrothermal conditions. They were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM) techniques. XRD patterns show the formation of birnessite for the first synthesis and a mixture of cryptomelane and birnessite-types for the second synthesis. XRD data revealed that the Hoffmeister anions have a significant effect on the nanostructures of birnessite. The sulphate ion-treated birnessite has the smallest crystals, whereas the chloride ion-treated birnessite has the largest crystals. Their TEM and HRTEM studies revealed a transformation from nanoplatelet morphology for chloride-treated samples to nanofibrous morphology for sulphate-treated birnessite. For the cryptomelane nanostructures, Hoffmeister anions also show a profound effect on their crystalline structures as determined by XRD analyses revealing a transformation of the cryptomelane phase to birnessite phase of . This transformation is also supported by TEM and HRTEM studies.

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