scholarly journals Optical properties of annealed As30Te67Ga3 thin films grown by thermal evaporation

2018 ◽  
Vol 12 (3) ◽  
pp. 209-217 ◽  
Author(s):  
Alaa Abd-Elnaiem ◽  
Samar Moustafa
Keyword(s):  
Optical Properties ◽  
Glass Transition ◽  
Chalcogenide Glasses ◽  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Energy Gap ◽  
Dielectric Constants ◽  
Heating Rates ◽  
Optical Energy Gap ◽  
Wide Range

Chalcogenide glasses have received lots of attention because of their superior optical properties. To optimize these properties and expand areas of applications, more studies are required to establish the extent to which the parameters can be tuned over a wide range of annealing temperatures and heating rates. To do this, bulk and thin ?150 nm As30Te67Ga3 films were prepared by melt-quenching and thermal evaporation techniques, respectively. The phase transition was investigated using differential scanning calorimeter (DSC) while the crystal structures were studied by X-ray diffraction (XRD). Characteristic temperatures such as the glass transition, crystallization and melting temperature of the bulk glass were found to depend on the heating rate. The activation energy of glass transition was 167.29 kJ/mol while the energy of crystallization was 103.98 kJ/mol. XRD results indicated that the annealed films showed more crystallinity, larger average crystallite size, lower dislocation density and lower strain as annealing temperature increased. According to the Avrami exponent, a combination of two and three-dimensional crystal growth with heterogeneous nucleation are possible mechanisms for the crystallization process. Moreover, optical constants such as the optical band gap, refractive index, extinction coefficient, high-frequency dielectric constants, real and imaginary parts of dielectric constants were found to strongly depend on the annealing temperature. The optical energy gap decreased from 1.1 to 0.89 eV as the annealing temperature increased from 373 to 433K. These results indicate that thermal annealing is a major factor that can be used to tune the crystal structure, and hence the optical properties of As30Te67Ga3 system.

scholarly journals Influence of annealing temperature on the structural and optical properties of As30Te70 thin films

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 ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Glass Transition ◽  
Extinction Coefficient ◽  
Chalcogenide Glasses ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Optical Parameters ◽  
Optical Energy Gap

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.

scholarly journals Effect of Annealing Temperature on the Optical Properties of TiO2 Thin Films Prepared by Pulse Laser Deposition

2015 ◽  
Vol 56 ◽  
pp. 63-70 ◽  
Author(s):  
Kadhim A. Aadim ◽  
Khalid Haneen Abass ◽  
Qunoot M. Hadi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Pulse Laser Deposition ◽  
Pulse Laser ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Dielectric Constants ◽  
Laser Deposition ◽  
Pulse Laser Deposition Technique ◽  
Wide Range

TiO2 thin films were prepared by pulse laser deposition technique on glass substrates with laser power 700 mJ and 900 shot at distance 1cm under vacuum of 10-2 mbar with different annealing temperature (273, 373, 423)K. The influences of the annealing temperature on the optical properties of TiO2 thin films were mainly investigated. TiO2 is a wide band gap n-type semi-conductor that has a wide range of applications. It was found that the optical properties of TiO2 thin films were dependent on the annealing temperature. The values of optical energy gap decreases from (3.4 to 3.2) eV when increasing annealing temperature. The optical constants such as refractive index, extinction coefficient, real and imaginary dielectric constants as a function of wavelength were determined.

scholarly journals "Effect Of Thermal Annealing On The Optical Properties Of Thin Films Of Polymer Blend (PMMA:PVC:PS) "

2018 ◽  
Vol 5 (1) ◽  
pp. 1-7
Author(s):  
Ali N. Sabbar ◽  
Karar M. Talib ◽  
Hassan T. Badh
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Optical Properties ◽  
Thermal Annealing ◽  
Polymer Blend ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Weather Conditions ◽  
Dielectric Constants ◽  
Casting Technique

"In this paper, we report upon preparation and optical properties of the polymer blend (50%PMMA:25%PVC:25%PS) thin films. The thin films have been prepared with specific ratios using the casting technique at normal weather conditions. The films were subjected to heat treatment in varying temperatures for three hours. The results showed that increase thermal annealing temperature leads to decrease values of the direct and indirect energy gap, but increase the extinction coefficient and optical conductivity. The refractive index, real and imaginary dielectric constants showed a heterogeneous behaviour. Thermal annealing by 80 oC and up leads to deformation the thin films.

scholarly journals Structural and optical properties for PVA- PEG-MnCl2 composites

2019 ◽  
Vol 15 (32) ◽  
pp. 99-113
Author(s):  
Mahdi Hasan Suhail
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Polymer Blend ◽  
Extinction Coefficient ◽  
Energy Gap ◽  
Dielectric Constants ◽  
Structural And Optical Properties ◽  
Optical Energy Gap ◽  
X Ray ◽  
Amorphous Structures

Polymer films of PEG and PVA and their blend with differentconcentrations of MnCl2 (0, 2, 4, 6 and 10 %.wt) were study usingcasting technique. The X-ray spectra of pure PEG, PVA andPVA:PEG films and with addition of 2% concentrations from(MnCl2) show amorphous structures. The results for FTIR show theinteraction between the filler and polymer blend results indecreasing crystallinity with rich amorphous phase. Thisamorphous nature confirms the complexation between the filler andthe polymer blend. The optical properties of (PVA:PEG/MnCl2)contain the recording of absorbance (A) and explain that theabsorption coefficient (α), refractive index (n), extinction coefficient(ko) and the dielectric constants (real and imaginary part) increasewith increasing the concentration of Composite (PVA:PEG/MnCl2).The optical energy gap for electrons transitions both are direct andindirect allowed.

scholarly journals Annealing effect on the optical properties of organic semiconductor Alq3: C60 blend thin films

2019 ◽  
Vol 16 (39) ◽  
pp. 1-10
Author(s):  
Lamiaa K. Abbas
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Bulk Heterojunction ◽  
Chemical Bonds ◽  
Optical Energy Gap ◽  
Heat Treated ◽  
Infra Red ◽  
Uv Visible

The effect of heat treatment using different annealing temperatures on optical properties of bulk heterojunction blend (BHJ) Alq3: C60 thin films which are fabricated by the spin coating technique were investigated in this study. The films have been coated on a glass substrate with speed of 2000 rpm for one min and treated with different annealing temperature (373, 423 and 473) K under vacuum. The optical properties and the chemical bonds structure of blends as-deposited and heat treated have been studied by UV-Vis spectroscopic and Fourier Transform-Infra Red (FTIR) measurements respectively. The results of UV visible show that the optical energy gap decreasing with increasing the annealing temperature for the ratio (100:1) while decreasing with increasing the annealing temperature for ratio (100:10). The FTIR spectra measurement were applied to know the type of the bonds of Alq3: C60 BHJ thin films.

scholarly journals Optical Properties for SeTe Thin Films

2008 ◽  
Vol 5 (4) ◽  
pp. 577-580
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Chalcogenide Glasses ◽  
Thermal Evaporation ◽  
Energy Gap ◽  
Glass Substrates ◽  
Optical Gap ◽  
Varying Thickness ◽  
Amorphous Nature ◽  
Constituent Elements

Chalcogenide glasses SeTe have been prepared from the high purity constituent elements .Thin films of SeTe compound have been deposited by thermal evaporation onto glass substrates for different values of film thickness . The effect of varying thickness on the value of the optical gap is reported . The resultant films were in amorphous nature . The transmittance spectra was measured for that films in the wavelength range (400-1100) nm . The energy gap for such films was determined .

scholarly journals Synthesis and Investigation of the Structure and Optical Properties of Nano -Ni-Cr Films

2020 ◽  
pp. 2251-2256
Author(s):  
Jinan H. Awadh
Keyword(s):  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Energy Gap ◽  
Amorphous Structure ◽  
Thermal Evaporation Technique ◽  
Optical Energy Gap ◽  
Average Roughness ◽  
Afm Analysis ◽  
Evaporation Technique ◽  
Xrd Patterns

The thermal evaporation technique was used to prepare the Ni-Cr films with a thickness of 200 nm and a rate of deposition  of 0.22nm/Sec. The annealing was performed at 373 and 473 K. The structural and optical analyses of the grown layers were achieved and XRD patterns showed amorphous structure transferred to polycrystalline for film annealed at 373 and 473 K. AFM analysis showed that the surface of Ni-Cr films is homogenous and the average roughness, optical energy gap and absorption coefficient were increased with increasing annealing temperature (Ta).

INFLUENCE OF ANNEALING ON THE STRUCTURAL AND OPTICAL CHARACTERISTICS OF INDIUM OXIDE THIN FILMS PREPARED USING THERMAL EVAPORATION IN A VACUUM METHOD

2016 ◽  
pp. 4415-4421
Author(s):  
Saleem A. Hussain ◽  
Eman .A. Al-Hilo ◽  
Alyaa H Hatem
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Thermal Evaporation ◽  
Energy Gap ◽  
Optical Parameters ◽  
Optical Energy Gap ◽  
Calculated Energy ◽  
Average Grain Size ◽  
Before And After ◽  
Different Temperatures

In the work, the structures and the optical parameters were studied for In2O3 thin films Before and after annealing at different temperatures (400 and 500 ) thin films were prepared on glass substrate by by vacuum thermal evaporation. The X-Ray diffraction showed that In2O3, In2O3 Plasticizedthin films which were prepared to have a polycrystalline cubic structure. The most preferential orientation is along the (321) direction for all deposited In2O3 films. Some parameters of the films were calculated as the average grain size and the dislocation density. Optical properties measurement transmittance (T) of the film shows that they have high transmittance (82.7%) is obtained for at annealing 500 . The optical properties such as absorption coefficient (α) using the transmittance measurement from an UV-vis spectrophotometer, with a range of wavelength (300-1100) nm. And also calculated energy gap for thin films. and also calculated energy gap for thin films, the result has been shown that the optical energy gap increasing with increasing annealing.

scholarly journals The effect of heat treatment on the optical properties of organic semiconductor (NiPc/C60) thin films

2019 ◽  
Vol 16 (39) ◽  
pp. 33-41
Author(s):  
Atheer M. Mkhaiber
Keyword(s):  
Crystal Structure ◽  
Thin Films ◽  
Optical Properties ◽  
Optical Absorption ◽  
Annealing Temperature ◽  
Energy Gap ◽  
Optical Absorption Spectra ◽  
Optical Energy Gap ◽  
Optical Energy ◽  
Glass Substrates

Thin films of the blended solution of (NiPc/C60) on glass substrates were prepared by spin-coated method for three different ratios (100/1, 100/10 and 100/100). The effects of annealing temperature and C60 concentration on the optical properties of the samples were studied using the UV-Vis absorption spectroscopy and FTIR spectra. The optical absorption spectrum consists of two main bands, Q and B band, with maxima at about (602-632) nm and (700-730) nm for Q1 and Q2 respectively, and (340-375) nm for B band. The optical energy gap were determined from optical absorption spectra, The variation of optical energy gap with annealing temperature was nonsystematic and this may be due to the improvement in crystal structure for thin films. While the energy gap decreased by increasing the concentration of C60 approaches from the energy gap of this compound.

scholarly journals Depending the Structure and Optical Properties of Cadmium Telluride Films on the Doping process

2018 ◽  
Vol 29 (1) ◽  
pp. 160
Author(s):  
Iman Hameed Khudayer
Keyword(s):  
Optical Properties ◽  
Cadmium Telluride ◽  
Energy Gap ◽  
Dielectric Constants ◽  
Optical Measurements ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
X Ray ◽  
Evaporation Technique ◽  
Effect Of Doping

The purpose of the present paper is to study the effect of doping by different materials on the structure and the optical properties of Cadmium Telluride films which prepared by rate deposition (4.21 nmn/sec) and thickness (≈ 200 nm) in vacuum by use thermal evaporation technique at a substrate temperature (300K), we are studying the effect of doping by different material (Antimony, Aluminum and Silver) on the structural1and optical2 properties of CdTe thin films. The structural properties of these films have been studied by using X-ray diffraction methods. The optical measurements indicated that Cadmium Telluride films have a direct optical energy gap (Egopt), and it decreases when we doped this films by different materials (Sb, Al and Ag) with the same ratio doping. The optical constants refractive index (n), extinction coefficient (k), absorption coefficient (α) and dielectric constants (r and i) were also studied.

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