scholarly journals Characteristics of PEO Incorporated with CaTiO3 Nanoparticles: Structural and Optical Properties

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3484
Author(s):  
Shujahadeen B. Aziz ◽  
Muaffaq M. Nofal ◽  
Mohamad A. Brza ◽  
Sarkawt A. Hussein ◽  
Khaled H. Mahmoud ◽  
...  
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
Calcium Titanate ◽  
Polymer Modification ◽  
X Ray Diffraction ◽  
Suitable Candidate ◽  
Solution Cast ◽  
Direct Band ◽  
Optical Dielectric ◽  
Composite Samples

In this research, direct band gap polymer composites with amorphous phase, which are imperative for optoelectronic devices applications were synthesized. The solution cast technique was used to produce polyethylene oxide (PEO)/calcium titanate (CaTiO3) nanocomposite (NC) films. The X-ray diffraction (XRD) confirms the growth of amorphous nature within PEO with CaTiO3 addition. The optical band gaps of pure PEO and PEO/CaTiO3 NC films were calculated using analysis of ultraviolet–visible (UV-Vis) spectra. The change in absorption edge toward lower photon energy is evidence of polymer modification. The dispersion behavior of the refractive index of PEO was manipulated to a higher wavelength upon doping with CaTiO3. Upon adding CaTiO3 to the pure PEO polymer, the dielectric constant and refractive index were considerably modified. The band gap shifts from 4.90 eV to 4.19 eV for the PEO incorporated with an optimum portion of 8 wt. % of CaTiO3. The types of the electronic transition in composite samples were specified, based on the Taucs model and the optical dielectric loss. The alteration of UV/Vis absorption spectra of the NC film was considered a suitable candidate to be applied in nanotechnology-based devices. The spherulites ascribed to the crystalline phase were distinguished through the optical microscopy (OM) study.

scholarly journals Steps Toward the Band Gap Identification in Polystyrene Based Solid Polymer Nanocomposites Integrated with Tin Titanate Nanoparticles

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2320 ◽  
Author(s):  
Ahang M. Hussein ◽  
Elham M. A. Dannoun ◽  
Shujahadeen B. Aziz ◽  
Mohamad A. Brza ◽  
Rebar T. Abdulwahid ◽  
...  
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
Polymer Nanocomposites ◽  
Absorption Edge ◽  
Optical Band Gap ◽  
Solid Polymer ◽  
Optical Parameters ◽  
Optical Dielectric Constant ◽  
Solution Cast ◽  
Optical Dielectric

In the current study, the film fabrication of polystyrene (PS) based polymer nanocomposites (NCs) with tuned refractive index and absorption edge was carried out using the solution cast method. X-ray diffraction (XRD) and ultraviolet-visible (UV-Vis) light characterization techniques were performed. The structural and optical properties of the prepared films were specified. The hump of PS decreased significantly when SnTiO3 nanoparticles (NPs) were introduced. Sharp and high intense peaks of SnTiO3 NPs at a high filler ratio were observed. The crystalline size was determined for SnTiO3 NPs from the sharp crystalline peaks using Debye-Scherrer’s equation and was found to be 25.179 nm, which is close enough to that described by the supplier. Several optical parameters, such as absorption coefficient (α), refractive index (n), and optical dielectric properties, were investigated. The absorption spectra were tuned with increasing SnTiO3NPs. Upon the addition of the NPs to the PS host polymer, the absorption edge undergoes shifting to lesser photon energy sides. The optical dielectric constant (ε′) was correlated to the refractive index. The study of the optical band gap was conducted in detail using both Tauc’s model and the optical dielectric loss (ε″) parameter. The results showed that the ε″ parameter is noteworthy to be measured in the optical band gap study of materials.

The Optical Performance of Holmium Oxide Doped Tellurite Glass for Potential Optical Fiber

2021 ◽  
Vol 317 ◽  
pp. 95-99
Author(s):  
Muhammad Noorazlan Abd Azis ◽  
Halimah Mohamed Kamari ◽  
Suriani Abu Bakar ◽  
Azlina Yahya ◽  
Umar Saad Aliyu
Keyword(s):  
Refractive Index ◽  
Band Gap ◽  
Tellurite Glass ◽  
Optical Band Gap ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
Gap Energy ◽  
Xrd Method ◽  
Nonlinear Pattern

Borotellurite glass had been widely applied in the field of optical communications and devices. In this work, holmium oxides doped borotellurite glass had been successfully fabricated via conventional melt-quenched technique. The structural properties of holmium doped tellurite glass were found using x-ray diffraction (XRD) method. The nonexistence of sharp peaks in XRD pattern shows that the inclusion of holmium tellurite glass leads to the formation long range of disorderness. The optical properties of the glass system such as refractive index and optical band gap energy are investigated using UV-Vis spectrophotometer. The value of refractive index is found in nonlinear trend along with holmium oxides concentration. It is found that the refractive index is more than 2 at 0.01, 0.03 and 0.04 of holmium concentrations. The optical band gap energy was found in similar trend with refractive index which is in nonlinear pattern.

SHIFT OF BAND GAP FROM DIRECT TO INDIRECT AND OPTICAL RESPONSE OF LiF UNDER PRESSURE

2013 ◽  
Vol 27 (09) ◽  
pp. 1350061 ◽  
Author(s):  
A. SAJID ◽  
G. MURTAZA ◽  
A. H. RESHAK
Keyword(s):  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Lithium Fluoride ◽  
Pressure Range ◽  
Pressure Effect ◽  
Indirect Transition ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap

We hereby are reporting the transition pressure at which lithium fluoride ( LiF ) compound transforms from direct band gap to indirect band gap insulator on the basis of FP-LAPW calculations. The fundamental band gap of LiF compound suffers direct to indirect transition at a pressure of 70 GPa. The study of the pressure effect on the optical properties e.g. dielectric function, reflectivity, refractive index and optical conductivity of LiF in the pressure between 0–100 GPa, shows that this pressure range is very critical for LiF compound as there are significant changes in the optical properties of this compound.

Properties of CdS Thin Films Grown by Chemical Bath Deposition as a Function of Bath Temperature

2009 ◽  
Vol 609 ◽  
pp. 243-247 ◽  
Author(s):  
H. Moualkia ◽  
S. Hariech ◽  
M.S. Aida
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Chemical Bath Deposition ◽  
Bath Temperature ◽  
Band Gap Energy ◽  
X Ray Diffraction ◽  
Glass Substrates ◽  
Cds Thin Films ◽  
Direct Band

The present work deals with the preparation and characterization of cadmium sulfur (CdS) thin films. These films are prepared by chemical bath deposition on the well cleaned glass substrates. The thickness of the samples was measured by using profilometer DEKTAK, structural and optical properties were studied by X-ray diffraction analysis, and UV-visible spectrophotometry. The optical properties of the films have been investigated as a function of temperature. The band gap energy and Urbach energy were also investigated as a function of temperature. From the transmittance data analysis the direct band gap ranges from 2.21 eV to 2.34 eV. A dependence of band gap on temperature has been observed and the possible raisons are discussed. Transmission spectra indicates a high transmission coefficient (75 %). Structural analysis revealed that the films showed cubic structure, and the crystallite size decreased at a higher deposition temperature.

Structural and Electronic Properties of (CdTe)1−x(In2Te3)x Films Grown by Close-spaced vapor Transport Combined with Free Evaporation

2000 ◽  
Vol 15 (8) ◽  
pp. 1811-1815 ◽  
Author(s):  
M. Zapata-Torres ◽  
Y. P. Mascarenhas ◽  
M. A. Santana-Aranda ◽  
J. Luyo-Alvarado ◽  
M. Melé-Lirandez ◽  
...  
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Single Phase ◽  
Vapor Transport ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Structural And Electronic Properties ◽  
Direct Band ◽  
Transmission Measurements

The structural and electronic properties of (CdTe)1−x(In2Te3)x thin films as a function of substrate temperature were studied using x-ray diffraction, energy dispersive x-ray analysis, and Raman, transmission, and modulated transmission spectroscopies. The films were grown by the close-spaced vapor transport technique combined with free evaporation; CdTe and In2Te3 were used as sources. From x-ray diffraction the presence of mixed phases and differences in composition were detected, and good correlation with Raman spectroscopy was found. Transmission spectroscopy suggested the possibility of a modulation of the band gap of the alloy from a value as low as 0.5 eV up to 1.5 eV. Single-phase films presented a direct band gap of around 1.15 eV, as obtained from modulated transmission measurements.

Optical Properties of PZT, PLZT, and PNZT Thin Films

1991 ◽  
Vol 243 ◽  
Author(s):  
Chien H. Peng ◽  
Jhing-Fang Chang ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Band Gap ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Pzt Films ◽  
Direct Band ◽  
Band Transition ◽  
La Doped

AbstractOptical properties were investigated for undoped, La-doped, and Nd-doped Pb(ZrxTi1-x)O3 thin films deposited on sapphire substrates by metalorganic decomposition (MOD) process. Refractive index and extinction coefficient of these films were calculated from transmission spectra in the wavelength range of 300 to 2000 nm. The packing densities of these films were calculated from the refractive index data by using the effective medium approximation. Band gap energies of these films were also reported under the assumption of direct band-to-band transition. The refractive index and band gap energy of PZT films showed a linear dependence on Zr/Ti ratio. The refractive index decreased, while the band gap energy increased with increasing zirconium content. It was also found that both La-doped and Nd-doped PZT films had higher refractive indices than those of undoped PZT films with the same Zr/Ti ratio (50/50).

Variation of Optical Band Gap Width of PVA Films Doped with Aluminum Iodide

2011 ◽  
Vol 383-390 ◽  
pp. 3257-3263 ◽  
Author(s):  
Omed Ghareb Abdullah ◽  
Sarkawt Abubakr Hussen
Keyword(s):  
Dielectric Constant ◽  
Band Gap ◽  
Localized States ◽  
Complex Dielectric Constant ◽  
Energy Gaps ◽  
Solution Cast ◽  
Aluminum Iodide ◽  
Gap Width ◽  
Solution Cast Method ◽  
Composite Samples

Polymer composite of polyvinyl alcohol (PVA), Aluminum Iodide have been prepared by solution cast method for different doping concentrations. The absorption of pure and doped films have been investigated in the visible and ultraviolent wavelength regions. It was found that the optical absorption is due to direct and indirect transitions, and the optical energy gaps values shifted to lower energies on Aluminum Iodide doping concentration for all transitions, while the band edge width of the tail localized states increase with increasing Aluminum Iodide concentration. The band gap of all films shows to be decrease after thermal treatment. The optical constants refractive index n, extinction coefficient k, the complex dielectric constant have been also calculated. The dielectric constant increased in the composite samples as compared with the pure PVA sample prepared by the same method.

Influence of different materials on the microstructure and optical band gap of α-Fe2O3 nanoparticles

2014 ◽  
Vol 32 (2) ◽  
pp. 193-197 ◽  
Author(s):  
P. Mallick
Keyword(s):  
Band Gap ◽  
Crystallite Size ◽  
Optical Band Gap ◽  
Strain Analysis ◽  
The Other ◽  
Fe2o3 Nanoparticles ◽  
Direct Band Gap ◽  
Direct Band ◽  
Indirect Band Gap ◽  
Composite Samples

AbstractComposites of hematite (α-Fe2O3) nanoparticles with different materials (NiO, TiO2, MnO2 and Bi2O3) were synthesized. Effects of different materials on the microstructure and optical band gap of α-Fe2O3 nanoparticles were studied. Crystallite size and strain analysis indicated that the pure α-Fe2O3 nanoparticles were influenced by the presence of different materials in the composite sample. Crystallite size and strain estimated for all the samples followed opposite trends. However, the value of direct band gap decreased from ∼2.67 eV for the pure α-Fe2O3 nanoparticles to ∼2.5 eV for α-Fe2O3 composites with different materials. The value of indirect band gap, on the other hand, increased for all composite samples except for α-Fe2O3/Bi2O3.

scholarly journals Size- and Temperature-control Optical Direct/indirect Band Tuning in Layered Compounds: Band Gap Engineering

2021 ◽  
Author(s):  
M. Miah
Keyword(s):  
Grain Size ◽  
Band Gap ◽  
Layered Compounds ◽  
Exciting Light ◽  
Interband Transitions ◽  
X Ray Diffraction ◽  
Band Gap Engineering ◽  
X Ray ◽  
Direct Band ◽  
Varshni Relation

Abstract The X-ray diffraction (XRD) is studied in thermally evaporated cadmium iodide (CdI2) thin films with various thicknesses. The grain size, calculated from the XRD, is found to increase with increasing the thickness of the film, while the reflectivity and refractive index decease with increasing the wavelength of the exciting light. The optical absorption spectra show both allowed direct and indirect interband transitions across a fundamental gap in CdI2. It is found that both indirect and direct band gap (Eg) decrease with increasing the thickness of the film and that the indirect Eg is lower than the direct Eg by an amount of about 0.7 eV. The direct Eg is also decreased with increasing both the grain size and temperature. However, the temperature dependence of Eg follows the Varshni relation. Our results highlight the possibility of engineering or tuning the Eg of CdI2 by controlling the thickness of the film, grain size as well as temperature.

scholarly journals Оптические свойства пленок ниобата бария стронция SBN61

2018 ◽  
Vol 60 (5) ◽  
pp. 993
Author(s):  
В.Б. Широков ◽  
А.В. Павленко ◽  
Д.В. Стрюков ◽  
Ю.В. Ревинский
Keyword(s):  
Refractive Index ◽  
Single Crystal ◽  
Band Gap ◽  
Optical Transmission ◽  
Visible Range ◽  
Transmission Spectra ◽  
X Ray Diffraction ◽  
Dispersion Parameters ◽  
X Ray ◽  
Optical Transmission Spectra

AbstractHeteroepitaxial Sr_0.61Ba_0.39Nb_2O_6 films have been formed on MgO(001) substrates by RF deposition in an oxygen atmosphere. The film orientation with respect to the substrate is investigated using X-ray diffraction. The permittivity dispersion parameters in the visible range are determined by measuring optical transmission spectra. The films are found to have a wider band gap and a smaller refractive index as compared with the single-crystal material.

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