Effects of Reaction Conditions on Deposition of Ferrites from Alkaline Metal Hydroxide Gels

1997 ◽  
Vol 495 ◽  
Author(s):  
Karl F. Schoch ◽  
Theodore R. Vasilow

ABSTRACTFormation of ferrites from aqueous solution of metal salts is a well known process involving precipitation of metal hydroxides followed by oxidation of the resulting gel. The purpose of the present work was to determine the effects oxygen flow rate on the progress of the reaction and on the structure and properties of the resulting precipitate. The reaction was carried out at 70°C with pH of 10.5 and oxygen flow rate of 2,4, or 8 standard liters per hour. The progress of the reaction was monitored by following the oxidation-reduction potential of the solution, which changes dramatically after the Fe(II) is consumed. The reaction rate increased with increasing oxygen flow rate. The Mg content of the precipitate was lower than that of the reaction mixture, possibly because of the pH of the reaction mixture. X-ray diffraction and infrared spectroscopy confirmed formation of a ferrite under these conditions.

2021 ◽  
Vol 903 ◽  
pp. 51-56
Author(s):  
Lavanya Mekala ◽  
Sunita Ratnam Srirangam ◽  
Rajesh Kumar Borra ◽  
Subba Rao Thota

In the present work, reactive DC magnetron sputtering method is used to deposit TiO2 thin films on glass substrates. The structural, surface morphology and optical studies of TiO2 thin films were discussed by varying the oxygen flow rates from 1 to 4 sccm. X-ray diffraction patterns of TiO2 thin films show amorphous nature. The surface morphological and elemental composition of TiO2 thin films were examined by field emission scanning electron microscopy and energy dispersive X-ray spectroscopy. From the optical absorption spectra, the shifting of absorption edge towards the longer wavelength leads to the decrement of optical bandgap from 3.48 to 3.19 eV with an increase of oxygen flow rate from 1 to 4 sccm.


2007 ◽  
Vol 31 ◽  
pp. 129-131 ◽  
Author(s):  
M.J. Chiang ◽  
C.W. Wu ◽  
H.E. Cheng

Copper oxide, a direct band gap semiconductor with band gap about 1.21-1.51 eV, has been regarded as a promising material for photovoltaic. Nanocrystalline copper oxide films have been synthesized on Si by dc sputtering method. The effects of oxygen flow rate and deposition temperature on the microstructure of nanocrystalline copper oxide films were investigated. X-ray diffraction analysis shows that a broaden peak of Cu2O (111) at 36.720 was observed at the deposition condition of DC power 150 W, pressure 2*10-2 Torr, substrate temperature 100 °C, Ar flow rate 15 sccm and O2 flow rate 1sccm. With increasing the oxygen flow rate to 3 and 5 sccm, CuO (-111) could be observed at 36.58o. The increase of oxygen flow rate resulted in the film formation from Cu2O to CuO. SEM pictures show that copper oxide films exhibit nanosize grains. X-ray diffraction patterns of CuO films deposited at 50~200 °C show that only (-111) plane is obtained. The SEM pictures show that the grain size increases with the deposition increases.


2013 ◽  
Vol 667 ◽  
pp. 333-337
Author(s):  
S. Ahmad ◽  
N.D. Md Sin ◽  
M.N. Berhan ◽  
Mohamad Rusop Mahmood

Zinc Oxide (ZnO) thin films were deposited on thermally oxidized SiO2 by varying the oxygen flow rate. The deposition process were done using radio frequency (RF) magnetron sputtering at various oxygen flow rate ranging from 0 to 40 sccm. The surface morphology and crystallinity were analyzed by field emission scanning electron microscopy (FESEM) and X-Ray Diffractometer (XRD) respectively. The average thickness and deposition rate decreases with an increase of oxygen content. The grain size was measured by FESEM and it was found that it is also decreasing with the increased of oxygen flow rate. The films grown with 10 sccm oxygen shows the highest (002) peak however it is expected that the sample deposited with 40 sccm oxygen exhibit the highest sensitivity toward NH3 gas due to the highest surface to volume ratio.


Photonics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 53
Author(s):  
Chuan Li ◽  
Jang-Hsing Hsieh ◽  
Y. R. Chuang

Metal oxynitrides are compounds between nitrides and oxides with a certain level of photocatalytic functions. The purpose of this study is to investigate an appropriate range of oxygen flow rate during sputtering for depositing tantalum oxynitride films. The sputtering process was carried out under fixed nitrogen but variable oxygen flow rates. Post rapid thermal annealing was conducted at 800 °C for 5 min to transform the as-deposited amorphous films into crystalline phases. The material characterizations of annealed films include X-ray diffraction and Raman spectroscopy for identifying crystal structures; scanning electron microscope for examining surface morphology; energy-dispersive X-ray spectroscopy to determine surface elemental compositions; four-point probe and Hall effect analysis to evaluate electrical resistivity; UV-visible-NIR spectroscopy for quantifying optical properties and optical bandgaps. To assess the photocatalytic function of oxynitride films, the degradation of methyl orange in de-ionized water was examined under continuous irradiation by a simulated solar light source for six hours. Results indicate that crystalline tantalum oxynitride films can be obtained if the O2 flow rate is chosen to be 0.25–1.5 sccm along with 10 sccm of N2 and 20 sccm of Ar. In particular, films deposited between 0.25 and 1.5 sccm O2 flow have higher efficiency in photodegradation on methyl orange due to a more comprehensive formation of oxynitrides.


2021 ◽  
Vol 903 ◽  
pp. 91-97
Author(s):  
Pathan Parhana ◽  
M.V. Lakshmaiah

Zinc Oxide (ZnO) thin films were deposited on glass substrate by radio frequency (RF)reactive magnetron sputtering technique at variable Oxygen flow rates while Argon flow rates waskept constant. The effect of oxygen flow rate on structural, electrical, optical properties of nanostructured ZnO thin films were investigated by X-ray diffractometer, scanning eletron microscopy(SEM), Hall effect measurements and UV-Visible spectrophotometer. X-ray diffraction (XRD) datareveals films are polycrystalline hexagonal structure with (002) peak as a preferred orientation andcrystallite size was found to be in range12 nm-16 nm.The electrical resistivity of films decreasesfrom 10-1 Ω-cm to 10-2 Ω-cm. All deposited ZnO thin films shows high transmittance above 95% inthe visible range 360 nm-800 nm. The optical band gap and refractive indices have been calculatedusing UV-Vis transmission spectra. Oxygen gas flow rates found to have large impact onoptoelectronic properties of ZnO films.


Author(s):  
Suresh Addepalli ◽  
Uthanna Suda

Thin films of TixSi1-xO2 were deposited on silicon and quartz substrates by DC reactive magnetron sputtering of Ti80Si20 composite target at different oxygen flow rates. The deposited films were characterized for their chemical composition and core level binding energies using X-ray photoelectron spectroscope, surface morphology with scanning electron microscope, optical absorption with spectrophotometer and refractive index by ellipsometer. The thickness of the deposited films was 100 nm. The oxygen content in the films increased with increase of oxygen flow rate. Films with Ti0.7Si0.3O2 were achieved at oxygen flow rates ≥ 8 sccm. X-ray diffraction studies indicated the grown of amorphous films. X-ray photoelectron spectra of the films showed the characteristic core level binding energies of TixSi1-xO2. Optical band gap of the films decreased from 4.15 to 4.07 eV with increase of oxygen flow rate from 2 sccm to 10 sccm respectively.


2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Claudia Maria Simonescu ◽  
Valentin Serban Teodorescu ◽  
Camelia Capatina

This paper presents the obtaining of copper sulfide CuS (covelite) from Cu(CH3COO)2.H2O and thioacetamide (TAA) system. The reaction was conducted in presence or absence of sodium-bis(2-ethylhexyl) sulfosuccinate (Na-AOT). The effects of various reaction parameters on the size and on the shape of nanoparticles have been examined. CuS obtained was characterized by X ray diffraction, IR spectroscopy, TEM � transmission electron microscopy and SAED selected area electron diffraction. The influence of surfactant to the shape and size of CuS (covellite) nanocrystals was established. The size of the nanocrystals varied from 10-60 nm depending on the reaction conditions such as quantity of surfactant.


Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 373
Author(s):  
Wen-Yen Lin ◽  
Feng-Tsun Chien ◽  
Hsien-Chin Chiu ◽  
Jinn-Kong Sheu ◽  
Kuang-Po Hsueh

Zirconium-doped MgxZn1−xO (Zr-doped MZO) mixed-oxide films were investigated, and the temperature sensitivity of their electric and optical properties was characterized. Zr-doped MZO films were deposited through radio-frequency magnetron sputtering using a 4-inch ZnO/MgO/ZrO2 (75/20/5 wt%) target. Hall measurement, X-ray diffraction (XRD), transmittance, and X-ray photoelectron spectroscopy (XPS) data were obtained. The lowest sheet resistance, highest mobility, and highest concentration were 1.30 × 103 Ω/sq, 4.46 cm2/Vs, and 7.28 × 1019 cm−3, respectively. The XRD spectra of the as-grown and annealed Zr-doped MZO films contained MgxZn1−xO(002) and ZrO2(200) coupled with Mg(OH)2(101) at 34.49°, 34.88°, and 38.017°, respectively. The intensity of the XRD peak near 34.88° decreased with temperature because the films that segregated Zr4+ from ZrO2(200) increased. The absorption edges of the films were at approximately 348 nm under 80% transmittance because of the Mg content. XPS revealed that the amount of Zr4+ increased with the annealing temperature. Zr is a potentially promising double donor, providing up to two extra free electrons per ion when used in place of Zn2+.


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