scholarly journals Optical Investigations of CdSe1-x Tex Thin Films

2011 ◽  
Vol 8 (1) ◽  
pp. 123-133 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Energy Gap ◽  
Fundamental Absorption Edge ◽  
Low Pressure ◽  
Direct Transition ◽  
Optical Energy Gap ◽  
Thermal Evaporation Method ◽  
Glass Substrates ◽  
Heat Treated

The alloys of CdSe1-xTex compound have been prepared from their elements successfully with high purity (99.9999%) which mixed stoichiometry ratio (x=0.0, 0.25, 0.5, 0.75 and 1.0) of (Cd, Se and Te) elements. Films of CdSe1-xTex alloys for different values of composition with thickness(0.5?m) have been prepared by thermal evaporation method at cleaned glass substrates which heated at (473K) under very low pressure (4×10-5mbar) at rate of deposition (3A?/s), after that thin films have been heat treated under low pressure (10-2mbar) at (523K) for two hours. The optical studies revealed that the absorption coefficient (?) is fairly high. It is found that the electronic transitions in the fundamental absorption edge tend to be allowed direct transition. It was also found that the optical energy gap vary non-linearly with composition (x) and have a minimum value at x=0.5 and increases after heat treatment. It is found that the optical constants vary non-linearly with composition, and the behavior inverse at x=0.5, and affected by heat treatment. The behavior of ?1 is similar to the behavior of n, while the behavior of ?2 is similar to the behavior of k.

scholarly journals Influence of Film Thickness and Heat Treatment on the Physical Properties of Mn Doped Sb2Se3 Nanocrystalline Thin Films

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
I. K. El Zawawi ◽  
Manal A. Mahdy ◽  
E. A. El-Sayad
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
Film Thickness ◽  
Energy Gap ◽  
Blue Shift ◽  
Amorphous Structure ◽  
Treatment Temperature ◽  
Optical Energy Gap ◽  
Heat Treated ◽  
Nanocrystalline Thin Films

Nanocrystalline thin films of Sb37.07Mn1.95Se60.98 with different thickness (7, 20, 40, and 80 nm) were successfully prepared via inert gas condensation technique. As-deposited films showed amorphous structure by grazing incident in-plane X-ray diffraction (GIIXD) technique. All films of different thicknesses were heat treated at 433 K for 90 min. The GIIXD pattern of annealed films showed nanocrystalline orthorhombic structure. The effect of thickness of annealed films on the structure and optical properties was studied. Calculated particle sizes are 20.67 and 24.15 for 40 and 80 nm thickness of heat treated film. High resolution transmission electron microscope HRTEM images and their diffraction patterns proved that 40 nm film thickness annealed at different temperature has nanocrystalline nature with observed (high) crystallinity that increases with annealing temperature. Blue shift of optical energy gap was observed from 1.68 to 2 eV with decreasing film thickness from 80 to 7 nm. Film thickness of 40 nm was exposed to different heat treated temperatures from 353 to 473 K to detect its effect on structure and optical and electrical properties. Blue shift from 1.73 to 1.9 eV was observed in its optical band gap due to direct transition as heat treatment temperature decreasing from 473 to 353 K. Electrical conductivity was studied for different heat treated films of thickness 40 nm, and intrinsic conduction mechanism is dominant. The activation energy Ea was affected by heat treatment process.

scholarly journals Effect of Pb percentage on optical parameters of PbxCd1-xSe thin films

2019 ◽  
Vol 14 (29) ◽  
pp. 1-7
Author(s):  
Farah Q. Kamil
Keyword(s):  
Thin Films ◽  
Thermal Evaporation ◽  
Energy Gap ◽  
Optical Measurements ◽  
Optical Parameters ◽  
Optical Energy Gap ◽  
Optical Energy ◽  
Glass Substrates

PbxCd1-xSe compound with different Pb percentage (i.e. X=0,0.025, 0.050, 0.075, and 0.1) were prepared successfully. Thin filmswere deposited by thermal evaporation on glass substrates at filmthickness (126) nm. The optical measurements indicated thatPbxCd1-xSe films have direct optical energy gap. The value of theenergy gap decreases with the increase of Pb content from 1.78 eV to1.49 eV.

scholarly journals Optical and Structural Properties of CdS Quantum Dots Synthesized Using (MW-CBD) Technique

2020 ◽  
pp. 44-52
Author(s):  
Ahmed Ahmed S. Abed ◽  
Sattar J. Kasim ◽  
Abbas F. Abbas
Keyword(s):  
Thin Films ◽  
Quantum Dots ◽  
Room Temperature ◽  
Energy Gap ◽  
Cds Nanoparticles ◽  
Cds Quantum Dots ◽  
Optical Energy Gap ◽  
Glass Substrates ◽  
High Adhesion ◽  
Uv Visible

In the present study, the microwave heating method was used to prepare cadmium sulfide quantum dots CdSQDs films. CdS nanoparticles size average obtained as (7nm). The morphology, structure and composition of prepared CdSQDs were examined using (FE-SEM), (XRD) and (EDX). Optical properties of CdSQDs thin films formed and deposited onto glass substrates have been studied at room temperature using UV/ Visible spectrophotometer within the wavelength of (300-800nm), and Photoluminescence (PL) spectrum. The optical energy gap (Eg) which estimated using Tauc relation was equal (2.6eV). Prepared CdS nanoparticles thin films are free from cracks, pinholes and have high adhesion to substrate.

Structural, Optical, and Optoelectrical Studies of Spray Pyrolyzed CuGaSnS4 Thin Films

2021 ◽  
Author(s):  
Islam M El radaf ◽  
Hnan Y Alzahrani
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Nonlinear Optical ◽  
Energy Gap ◽  
Structural Parameters ◽  
Stoichiometric Composition ◽  
Optical Energy Gap ◽  
Linear Absorption ◽  
Glass Substrates ◽  
D Values

Abstract We deposited CuGaSnS4 thin films on soda-lima glass substrates via a spray pyrolysis process. The X-ray diffraction of CuGaSnS4 films established the formation of an orthorhombic single phase. In addition, the structural parameters of the CuGaSnS4 films were estimated by Debye-Scherer’s formulas, which showed that an enhancement in crystallite size (D) values occurred by increasing the thickness of the investigated films. The EDAX pattern of CuGaSnS4 films confirms a stoichiometric composition. The optical results revealed that the CuGaSnS4 films possessed a direct optical energy gap (Eg). The Eg values were reduced from 1.50 to 1.38 eV with the increase in thickness. Also, there was an observed increase in the linear refractive index and the linear absorption coefficient values occurred due to the increased thickness. Finally, the optoelectrical constants of the sprayed CuGaSnS4 films such as the optical conductivity (σopt) and the optical free carrier concentration to effective mass (N_opt/m^* ) were enlarged with increasing film thickness. The nonlinear optical study showed that the increase in film thickness enhanced the nonlinear optical constants of CuGaSnS4 films. The hot-probe procedure shows that the sprayed CuGaSnS4 films expose p-type conductivity.

scholarly journals Structural and Optical Properties of (CdO)1-x(SnO2)x Thin Films Prepared by Pulsed Laser Deposition

2015 ◽  
Vol 59 ◽  
pp. 62-71
Author(s):  
Nahida B. Hasan ◽  
Ghusson H. Mohammed ◽  
Mohammed A. Abdul Majeed
Keyword(s):  
Thin Films ◽  
Pulsed Laser Deposition ◽  
Energy Gap ◽  
Optical Transition ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
X Ray Diffraction ◽  
Optical Energy Gap ◽  
Glass Substrates ◽  
Cdo Thin Films

CdO thin films have been deposited at different concentration of SnO2 (x= (0.0, 0.05, 0.1, 0.15 and 0.2)) Wt. % onto glass substrates by pulsed laser deposition technique (PLD) using Nd-YAG laser with λ=1064nm, energy=600mJ and number of shots=500. X-ray diffraction (XRD) results reveal that the deposited (CdO)1-x(SnO2)x thin films cubic structure and the grain size increase with increasing annealing temperature and increasing concentration of SnO2. The optical transition in the (CdO)1-x(SnO2)x thin films are observed to be allowed direct transition. The value of the optical energy gap decreases with increasing of annealing temperatures and increase with increasing concentration of SnO2 for all samples.

scholarly journals Structural and Optical Properties of Nanostructured Bismuth Oxide

2014 ◽  
Vol 34 ◽  
pp. 64-72 ◽  
Author(s):  
Reem Sami Ali
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Bismuth Oxide ◽  
Energy Gap ◽  
Structural And Optical Properties ◽  
Direct Transition ◽  
Optical Studies ◽  
Polycrystalline Structure ◽  
Optical Energy Gap ◽  
Sem Images

Thin films of bismuth oxide have been prepared utilizing vacuum evaporation. XRD anyalysis reveal that all the films were tetragonal polycrystalline structure with a preferred orientation along (002) plane. SEM images indicate that the grain size fall in the category of nanosize. AFM results assure that the nanonstructure behavior of thin films. Optical studies show that these films have a direct transition with optical energy gap equal to 2.5 eV.

Thickness Dependence of Structural and Optical Characteristics of AZO Thin Films for Organic Photovoltaic Cells

2011 ◽  
Vol 117-119 ◽  
pp. 1076-1079
Author(s):  
S.L. Wei ◽  
L.H. Zeng ◽  
Z.Y. Zhong ◽  
J.H. Gu
Keyword(s):  
Thin Films ◽  
Energy Gap ◽  
Visible Spectrum ◽  
Rf Magnetron Sputtering ◽  
Optical Characteristics ◽  
Hexagonal Crystal ◽  
Optical Energy Gap ◽  
Glass Substrates ◽  
Aluminum Doped Zinc Oxide ◽  
Deposited Films

Aluminum-doped zinc oxide (AZO) thin films with highly (002)-preferred orientation were grown on glass substrates by rf magnetron sputtering. The effect of thickness on structural and optical characteristics of the deposited films were investigated by X-ray diffractometer and spectrophotometer. The results show that the polycrystalline AZO films consist of the hexagonal crystal structures with c-axis as the preferred growth orientation normal to the substrate, and that the thickness significantly affects the crystal structure and optical properties of the thin films. With the increase of thickness, the crystallite size of the films increases, the lattice spacing, dislocation density, micro strain and optical energy gap decrease, and the average transmitance in the wavelength range of the visible spectrum also slightly decreases.

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.

IMPACT OF N DOPING ON THE PHYSICAL PROPERTIES OF ZnO THIN FILMS

2018 ◽  
Vol 25 (01) ◽  
pp. 1850035 ◽  
Author(s):  
NRIPASREE NARAYANAN ◽  
N. K. DEEPAK
Keyword(s):  
Thin Films ◽  
Energy Gap ◽  
Spray Pyrolysis Technique ◽  
Compositional Analysis ◽  
Optical Transmittance ◽  
Xrd Analysis ◽  
Zno Thin Films ◽  
Optical Energy Gap ◽  
Glass Substrates ◽  
N Doping

Structural, optical and electrical properties of bare and N monodoped ZnO thin films were investigated. The samples were prepared on glass substrates by spray pyrolysis technique. N doping resulted in p type electrical conductivity as evident from the Hall measurement results. XRD analysis confirmed the structural purity of all the films and compositional analysis by energy dispersive X-ray spectroscopy verified the inclusion of N in doped films in addition to Zn and O. Doping resulted in deterioration in crystallinity. Optical transmittance got diminished with doping due to the degradation in crystallinity as well as due to the presence of deep N related defects as evident from the photoluminescence spectra. Optical energy gap red-shifted with doping percentage due to the introduction of impurity levels near the valence band edge within the forbidden gap with acceptor doping.

scholarly journals Effect of Al-Doping on the Optical Properties of ZnO Thin Film Prepared by Thermal Evaporation Technique

2016 ◽  
Vol 7 ◽  
pp. 25-31 ◽  
Author(s):  
M. Musaab Khudhr ◽  
Khalid Haneen Abass
Keyword(s):  
Thin Films ◽  
Thermal Evaporation ◽  
Energy Gap ◽  
Dielectric Constants ◽  
Optical Parameters ◽  
Doping Content ◽  
Al Doping ◽  
Thermal Evaporation Method ◽  
Glass Substrates ◽  
Evaporation Technique

Aluminum doped ZnO (AZO) thin films doped has been prepared by thermal evaporation method onto glass substrates. The optical characterization has been studied by UV-Visible Spectrophotometer in the range (300-1100) nm. The transmittance increased with increasing Al-doping, while absorption decreases with increasing Al-doping content. The energy gap (Eg) values increased with increasing Al-doped in the ZnO:Al thin films. The refractive index, extinction coefficient, and real and imaginary dielectric constants obtained results show that doping content strongly affects the optical parameters of AZO thin films. Optical constants tend to decrease with increasing doping content.

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