EFFECT OF RAPID THERMAL ANNEALING ON MICROSTRUCTURE AND OPTICAL PROPERTIES OF ZnO NANORODS

2011 ◽  
Vol 10 (01n02) ◽  
pp. 65-68 ◽  
Author(s):  
R. CHAKRABORTY ◽  
SOUMEN DHARA ◽  
P. K. GIRI

In this work, we have investigated the influence of rapid thermal annealing (RTA) on structural and optical properties of ZnO nanorods synthesized by a mechanochemical reaction route using a planetary ball mill for different reaction time durations. Optical properties of as-grown and RTA-annealed samples are studied by UV–visible absorption and photoluminescence (PL), while structural studies are performed using X-ray diffraction line profile analysis and transmission electron microscopy. X-ray diffraction pattern of each sample is accompanied by characteristic wurtzite peaks of zinc oxide and exhibits the decrease in full width half maxima of the peaks after RTA. Williamson–Hall plot of each pattern is done to correlate the effect of strain of as-synthesized and RTA-treated samples. UV–visible absorption spectra show distinct redshift of excitonic absorption peaks with respect to those of as-synthesized samples. Interestingly, in PL spectra, the broad visible emission peaks observed for as-synthesized samples are eliminated completely for annealed samples. However, some of the constituent peaks in the UV–blue region of the PL spectra redshifted due to the grain growth and strain reduction.

2010 ◽  
Vol 148-149 ◽  
pp. 832-836
Author(s):  
Ke Zou ◽  
You Shi Wu ◽  
Jin Bo Zhao ◽  
Li Li Wu

ZnO nanorods doped with Ce4+ ions have been synthesized by a solvothermal method. The concentration level of Ce4+ additive was varied systematically from 1 to 10 mol. %. The structural and optical properties of Ce4+ -doped nanostructures are investigated using X-ray diffraction, transmission electron micrograph, UV-visible absorption and photoluminescence Spectroscopy. The results showed that the concentration increase of Ce4+ doping induce the enhancement of photoluminescence.


2018 ◽  
Vol 15 (35) ◽  
pp. 24-28
Author(s):  
Saba J. Kadhem

PMMA/TiO2 homogeneous thin films were deposited by using plasma jet system under normal atmospheric pressure and room temperature. PMMA/TiO2 nanocomposite thin film synthesized by plasma polymerization. Titanium oxide was mixed with Methyl Methacrylate Monomer (MMA) with specific weight ratios (1, 3 and 5 grams of TiO2 per 100 ml of MMA). Optical properties of PMMA/TiO2 nanocomposite thin films were characterized by UV-Visible absorption spectra using a double beam UV-Vis-NIR Spectrophotometer. The thin films surface morphological analysis is carried out by employing SEM. The structure analysis are achieved by X-ray diffraction. UV-Visible absorption spectra shows that the increasing the concentration of titanium oxide added to the polymer leads to shift the peak position (λmax) toward the infrared region of the electromagnetic spectrum. Also the peak width increases when the concentration of TiO2 increases. It can be controlled optical energy band gap of PMMA/TiO2 nanocomposite thin films by changing concentration of TiO2. SEM indicate a uniform distribution of titanium oxide particles in PMMA matrix. The x-ray diffraction pattern indicated that the thin films have amorphous structure.


2018 ◽  
Vol 73 (8) ◽  
pp. 601-609 ◽  
Author(s):  
Bei Wang ◽  
Pei-Zhi Zhang ◽  
Xin Chen ◽  
Ai-Quan Jia ◽  
Qian-Feng Zhang

AbstractA series of guanidinium chloride derivatives have been synthesized by condensation of 1,3-diaminoguanidine monohydrochloride with heteroaromatic formaldehydes in good yields. All compounds were characterized by nuclear magnetic resonances and infrared spectroscopies, and the molecular structures of four compounds were determined by single crystal X-ray diffraction. The optical properties of these guanidinium chloride derivatives with fluoride anions were investigated, showing selective color changes from colorless to yellow or orange, red-shifted in the ultraviolet/visible absorption spectra.


2013 ◽  
Vol 40 (1) ◽  
pp. 0106003
Author(s):  
王健 Wang Jian ◽  
谢自力 Xie Zili ◽  
张韵 Zhang Yun ◽  
滕龙 Teng Long ◽  
李烨操 Li Yecao ◽  
...  

2019 ◽  
Vol 34 (3) ◽  
pp. 242-250 ◽  
Author(s):  
J. Anike ◽  
R. Derbeshi ◽  
W. Wong-Ng ◽  
W. Liu ◽  
D. Windover ◽  
...  

Structural characterization and X-ray reference powder pattern determination have been conducted for the Co- and Zn-containing tridymite derivatives Ba(Co1−xZnx)SiO4 (x = 0.2, 0.4, 0.6, 0.8). The bright blue series of Ba(Co1−xZnx)SiO4 crystallized in the hexagonal P63 space group (No. 173), with Z = 6. While the lattice parameter “a” decreases from 9.126 (2) Å to 9.10374(6) Å from x = 0.2 to 0.8, the lattice parameter “c” increases from 8.69477(12) Å to 8.72200(10) Å, respectively. Apparently, despite the similarity of ionic sizes of Zn2+ and Co2+, these opposing trends are due to the framework tetrahedral tilting of (ZnCo)O4. The lattice volume, V, remains comparable between 626.27 Å3 and 626.017 (7) Å3 from x = 0 to x = 0.8. UV-visible absorption spectrum measurements indicate the band gap of these two materials to be ≈3.3 and ≈3.5 eV, respectively, therefore potential UV photocatalytic materials. Reference powder X-ray diffraction patterns of these compounds have been submitted to be included in the Powder Diffraction File (PDF).


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Honghui Teng ◽  
Shukun Xu ◽  
Dandan Sun ◽  
Ying Zhang

Fe-doped TiO2nanotubes (Fe-TNTs) have been prepared by ultrasonic-assisted hydrothermal method. The structure and composition of the as-prepared TiO2nanotubes were characterized by transmission electron microscopy, X-ray diffraction, and UV-Visible absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of MO under visible light. The UV-visible absorption spectra of the Fe-TNT showed a red shift and an enhancement of the absorption in the visible region compared to the pure TNT. The Fe-TNTs were provided with good photocatalytic activities and photostability and under visible light irradiation, and the optimum molar ratio of Ti : Fe was found to be 100 : 1 in our experiments.


2002 ◽  
Vol 755 ◽  
Author(s):  
Damien Pauwels ◽  
Alain Demourgues ◽  
Alain Tressaud

ABSTRACTRare earth-based mixed-anions (O, S, F) compounds have been prepared by solid state route. The structures have been determined on the basis of powder diffraction (X-ray/neutrons) refinement and/or single crystal analysis. They have been described as a stacking of [Sx] 2x- layers and fluorite type blocks. The evaluation of the rare earth environment (bondlength, number of neighbors) can be directly related to the bandgap and to the UV-visible absorption in the La-based compounds.


1983 ◽  
Vol 23 ◽  
Author(s):  
D.L. Kwong ◽  
R. Kwor ◽  
B.Y. Tsaur ◽  
K. Daneshvar

ABSTRACTThe formation of composite TaSi2/n+ Poly-Si silicide films through the use of rapid thermal annealing (RTA) is investigated by x-ray diffraction, four point probe, scanning Auger microprobes (SAM) with ion sputter etching, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and capacitance-voltage (C-V) measurements. 0.2 μm polysilicon is deposited on oxidized Si wafer by LPCVD and doped with phosphorus. A layer of 2200 A TaSix is then co-sputtered on polysilicon samples from separate targets. These as-deposited films are then annealed by RTA in an argon ambient for 1 sec. and 10 sec. at various temperatures. X-ray diffraction and SAM results show the rapid formation of a uniform stoichiometric tantalum disilicide via Si migration from polysilicon. TEM micrographs show simlilar results for samples annealed at 1000°C in furnace for 30 min. or by RTA for 1 sec., exhibiting average grain size greater than 1000 A. Sheet resistance of samples annealed by furnace annealing and RTA are comparable. SEM micrographs indicate that the surface morphology of the RTA-annealed sample is superior to that obtained by furnace annealing. These results show that RTA may offer a practical solution to low-resistivity silicide formation in VLSI circuits.


2012 ◽  
Vol 502 ◽  
pp. 164-168
Author(s):  
Ling Xu ◽  
Han Mei Hu ◽  
Hai Yan Xu

Novel mace-like (wolf-teeth clubs) CdS nanostructures were successfully prepared on a large scale using CdCl2•2.5H2O and NH2CSNH2 as starting materials through a convenient mixed-solvothermal route. The as-synthesized products were characterized by X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDX), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. The experimental results reveal that the morphology of CdS products was greatly affected by the volume ratio of anhydrous ethanol and distilled water. The possible mechanism for the formation of mace-like CdS nanostructures is simply discussed.


1996 ◽  
Vol 441 ◽  
Author(s):  
Wen-Jie Qi ◽  
Zhi-Sheng Wang ◽  
Zhi-Guang Gu ◽  
Guo-Ping Ru ◽  
Guo-Bao Jialig ◽  
...  

AbstractThe ion-beam-sputtered polycrystalline SiGe film and its doping properties have been studied. Boron and phosphorus have been doped into the sputtered poly-SiGe film by ion implantation and diffusion. To activate the implanted impurities, both rapid thermal annealing and fiirnace annealing have been used. The electrical measurements show that boron and plhosphorus can be doped into sputtered SiGe films and effectively activated by both ion implantation with post-annealing and diffiision. Hall mobilities as high as 31 cm2/V-s and 20 cm2/V.s have been obtained in B-difflhsed and P-diffused SiGe films, respectively. The x-ray diffraction spectra of the sputtered Sifie filhn show its typical polycrystalline structure with (111), (220) and (311) as the preferential orientations.


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