scholarly journals Variations of Optical and Structural Properties of CoxOy Thin Films with Thermal Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
A. B. C. Ekwealor ◽  
S. U. Offiah ◽  
S. C. Ezugwu ◽  
F. I. Ezema

The effects of thermal treatment on the optical and structural properties of cobalt oxide CoxOy thin films synthesized in the pores of PVP by chemical bath deposition technique were investigated. Films deposited were crystalline. The optical properties of the films were got from absorbance, transmittance reflectance, refractive index, absorption coefficient, and extinction coefficient measurements. The synthesized CoxOy films turned out to be cobalt oxyhydroxide , CoO(OH), nanocrystals. The crystals obtained were of size 41.84 nm; however, as annealing temperature increased, the size decreased to 16.28 nm. The absorption coefficient, refractive index, and extinction coefficient were found to increase with increase in annealing temperature though not sequentially. For the same energy ranges of the incident photons, the absorption coefficient and refractive index ranged from 0.2 to 1.8 and from 1.4 to 2.3, respectively. The energy band-gap of the films ranged from 1.96 eV to 2.22 eV.

2011 ◽  
Vol 8 (2) ◽  
pp. 561-565
Author(s):  
Baghdad Science Journal

Cr2O3 thin films have been prepared by spray pyrolysis on a glass substrate. Absorbance and transmittance spectra were recorded in the wavelength range (300-900) nm before and after annealing. The effects of annealing temperature on absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant and optical conductivity were expected. It was found that all these parameters increase as the annealing temperature increased to 550°C.


2001 ◽  
Vol 703 ◽  
Author(s):  
Hiroki Yamamoto ◽  
Takashi Naito ◽  
Kazuyuki Hirao

ABSTRACTOptical non-linearity of cobalt oxide with SiO2-TiO2 additives was investigated, and the change mechanism of the refractive index (n) and extinction coefficient (k), based on the relation between band structure and optical non-linearity of the thin films, was discussed. Refractive index and extinction coefficient of Co3O4 thin films in the ground state were 3.17 and 0.42, respectively. Both n and k decreased by irradiation from a pulse laser with 650 nm of wavelength (1.91eV). These values in the excited state were 2.91 and 0.41, respectively. n2 estimated from the change of n and k was −2.8 ×10−11 m2/W. The film had a band gap corresponding to 2.06eV, indicating that it was widened by the band filling effect during the laser irradiation at 1.91eV, and this led to the decrease in absorption coefficient and refractive index.


2013 ◽  
Vol 334-335 ◽  
pp. 290-293 ◽  
Author(s):  
N. Baydogan ◽  
T. Ozdurmusoglu ◽  
Huseyin Cimenoglu ◽  
A.B. Tugrul

Doped ZnO:Al thin films were deposited on glass substrates by the solgel dip technique. Optical parameters such as the refractive index and the extinction coefficient tend to change with increasing annealing temperature.


Author(s):  
Abubakr Mahmoud Hamid ◽  
Hassan Wardi Hassan ◽  
Fatima Ahmed Osman

Solar energy is already has being widely successfully used in residential and industrial setting for thermal and electrical application such as space technology, communication, etc. I. Aims: The aim of this study the effect of the annealing temperature in improvement optical properties of titanium oxide nanostructure doped iron oxide for use in thin film. Study Design: The spray pyrolysis deposition method used for preparation the nanostructure material. Place and Duration of Study: This study was conducted in department of physics and department of materials sciences, Al-Neelain University, between January 2016 and January 2019.  Methodology: Thin films of Titanium Oxide (TiO2) doped Iron Oxide (Fe2O3) have been prepared by chemical spray pyrolysis deposition technique. A laboratory designed glass atomizer was used for spraying the aqueous solution. Which has an output nozzle about 1 mm. then film were deposited on preheated cleaned glass substrates at temperature of 400°C. we used different concentration to study optical parameters. A 1.5 g TiO2 powder of anatase structure doped with 1.5 g of Fe2O3 was mixed with 2 ml of ethanol and stirred using a magnetic stirrer for 30 minutes to form TiO2 paste to obtain the starting solution for deposition and spray time was 10 s and spray interval 2 min was kept constant. The carrier gas (filtered compressed air) was maintained at a pressure of 105 Nm-2, and distance between nozzle and substrate was about 30 cm ± 1 cm. Thickness of sample was measured using the weighting method and was found to be around 400nm. Optical transmittance and absorbance were record in wavelength range of (200-1100) nm using UV-Visible spectrophotometer (Shimadzu Company Japan). Results: The results obtained showed that the optical band gap decreased from 5.6eV before annealing to (3.9, 3.26, 3.24 and 3.27 eV) after annealing temperature at(450° – 500°) for TiO2:Fe2O3 thin films, this result refer to the broadening of  secondary levels that product by TiO2: doping to the Fe2O2thin films. Also the results showed the variation of refractive index with wavelength for different concentration after annealing temperature at (450° – 500°) of TiO2: Fe2O3 films from this figure, it is clear that n decrease with low concentration and increase with high concentration after annealing temperature that mean the density is decreased of this films. In addition the extinction coefficient of TiO2:Fe2O3 thin films recorded before annealing and with different concentration (1.1, 1.2, 1,5 and 1,6) and in the range of (300 – 1200) nm and at annealing temperature from (450° – 500°). It observed from that the extinction coefficient, decrease sharply with the increase of wavelength for all prepared films and all the sample after annealing is interference between them accept the sample before annealing is far from the other sample. Conclusion: The TiO2 thin film shows better result after annealing; By exposing temperature during annealing process degree at (450o- 500o) is found to be the best temperature for annealing TiO2 thin film. The study concluded that an annealing temperature Contributes to the improvement of optical properties related to increasing the efficiency of the solar cell, especially the refractive index, energy gap, extinction coefficient.


In this work, we studied the effect of annealing temperature on the structural and solid state properties of AlZnO thin films using Chemical bath deposition technique. The thin films grown was annealed at various temperatures of 100oC, 150oC to 200oC The morphological and structural properties were studied using XRD and SEM, while the optical properties were studied using UVVIS Spectroscopy from where the bad gap, dielectric constant, refractive index, extinction coefficient and optical conductivity were deduced from the theoretical equations.From the result, it is observed that there is effect of annealing temperature on these properties such that the grain size and x-ray characteristics depicted different characteristics at these various temperatures.


2010 ◽  
Vol 7 (1) ◽  
pp. 168-173
Author(s):  
Baghdad Science Journal

Sb2S3 thin films have been prepared by chemical bath deposition on a glas sub Absorbance and transmittance spectra were recorded in the wavelength range (30-900) nm. The effects of thickness on absorption coefficient, reflectance, refractive index, extinction coefficient, real and imaginary parts of dielectric constant were estimated. It was found that the reflectivity, absorption coefficient , extinction coefficient, real part of dielectric constant and refractive index, all these parameters decrease as the thickness increased, while the imaginary part of the dielectric constant increase as the thickness increased.


Author(s):  
Wasmaa Abdulsattar Jabbar

Copper oxide prepared with various contains of Manganese by chemical spray pyrolysis. Some optical properties are studied from recording the absorption spectra via UV-Visible spectrophotometer in the range of 460-900 nm. The absorbance increased with increasing Mn-contain in the CuO thin films, and the absorption coefficient. Extinction coefficient and refractive index are decreased with increasing Mn-contain in the CuO thin films, also the energy gap shifted from 2 eV to 1.91 eV after 4%Mn additive.


2017 ◽  
Vol 35 (2) ◽  
pp. 335-345 ◽  
Author(s):  
A.M. Abd-Elnaiem ◽  
M. Mohamed ◽  
R.M. Hassan ◽  
A.A. Abu-Sehly ◽  
M.A. Abdel-Rahim ◽  
...  

Abstract Chalcogenide glasses have attracted much attention largely due to their interesting physical and chemical properties. Though few published articles exist on the As-Te system, little is known about the optical properties of eutectic or near eutectic composition of As-Te system upon heat treatment. Therefore, this paper reports the effects of annealing temperature on the structural and optical parameters of As30Te70 thin films. The bulk and thin films of 150 nm thick As30Te70 chalcogenide glasses were prepared by melt-quenching and thermal evaporation techniques, respectively. The glass transition and crystallization reactions of the bulk samples were investigated using differential scanning calorimetry (DSC). The influence of annealing temperature on the transformation of the crystal structure was studied by X-ray diffraction (XRD), while the surface morphology of the annealed samples was examined using scanning electron microscope (SEM). The optical band gap, refractive index and extinction coefficient were also calculated. The DSC scans showed that the melting temperature remains constant at 636.56 K. In addition, other characteristic temperatures such as the glass transition temperature, the onset crystallization temperature, and the crystallization peak temperature increase with increasing the heating rate. The crystalline phases for the as-prepared and annealed films consist of orthorhombic As, hexagonal Te, and monoclinic As2Te3 phases. Furthermore, the average crystallite size, strain, and dislocation density depend on the annealing temperature. The optical absorption results revealed that the investigated films have a direct transition, and their optical energy gap decreases from 1.82 eV to 1.49 eV as the annealing temperature increases up to 433 K. However, the refractive index, extinction coefficient, dielectric constant and the ratio of free carrier concentration to its effective mass, increase with increasing the annealing temperature.


2018 ◽  
Vol 26 (10) ◽  
pp. 249-256
Author(s):  
Waleed Khalid Kadhim

In this paper I present the preparation of (Sb2o3) thin films using thermal evaporation in vacuum, procedure with different thickness  (100 ,150 ,200 ,and 250) nm, by using ( hot plate) from Molybdenum matter at temperature in ( 9000c) and the period of time (15mint) ,the prepared in a manner thermal evaporation in a vacuum and precipitated on glass bases, pure Antimony Trioxide (sb2o3 ) thin films with various condition have been successfully deposited by (T.E.V) on glass slide substrates. The substrates temperature of about 100oC and the vacuum of about 10-6 torr, to investigated oxidation of evaporated, measure spectra for prepared films in arrange of wavelength (250 – 1100 nm). The following optical properties have been calculated: the absorption coefficient, the forbidden (Eg) for direct and indirect transitions "absorbance, refractive index,  extinction coefficient, real and imaginary parts" of the dielectric constant.


Author(s):  
J. Damisa ◽  
J. O. Emegha ◽  
I. L. Ikhioya

Lead tin sulphide (Pb-Sn-S) thin films (TFs) were deposited on fluorine-doped tin oxide (FTO) substrates via the electrochemical deposition process using lead (II) nitrate [Pb(NO3)2], tin (II) chloride dehydrate [SnCl2.2H2O] and thiacetamide [C2H5NS] precursors as sources of lead (Pb), tin (Sn) and sulphur (S). The solution of all the compounds was harmonized with a stirrer (magnetic) at 300k. In this study, we reported on the improvements in the properties (structural and optical) of Pb-Sn-S TFs by varying the deposition time. We observed from X-ray diffractometer (XRD) that the prepared material is polycrystalline in nature. UV-Vis measurements were done for the optical characterizations and the band gap values were seen to be increasing from 1.52 to 1.54 eV with deposition time. In addition to this, the absorption coefficient and refractive index were also estimated and discussed.


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