DiDomenico Model Research Articles

Investigation of the nonlinear optical characteristics of the La0.7Sr0.3MnO3 nano-perovskite under (iron, cobalt, and nickel) substitution for manganese by Z-Scan technique and Wemple–DiDomenico model

The investigation in this study focused on examining the nonlinear optical (NLO) properties of La0.7Sr0.3XO3 (X= Mn, Co, Ni, or Fe) nano-perovskite powders utilizing the Z-scan technique. To achieve this objective, first, the samples were synthesized using the co-precipitation procedure, and after that, the prepared materials were examined using a field emission scanning electron microscope (FE-SEM) and X-ray diffraction (XRD) to confirm the nanoscale morphology and structure of the prepared samples, respectively. Based on the FE-SEM and XRD outcomes, the nanosized nature of the materials has been verified. To analyze the NLO characteristics of the nanopowders, the Z-scan technique with a continuous wave 532 nm Nd: YAG laser was employed on laser incident powers of P0 = 15 mW, and 30 mW. This is to determine the third-order nonlinear optical susceptibility, nonlinear refractive index (NLR, n2), and nonlinear absorption coefficient (NLA, β) values. For La0.7Sr0.3MnO3, the NLR and the NLA (precisely two phonon absorption) responses displayed at the 3.3339×10−9 m2/W and 0.0485 m/W values, respectively, measured for P0 = 15 mW. It is evident from the results that after the Ni, Fe, or Co substitution for manganese in the La0.7Sr0.3MnO3 measured for P0 = 15 mW, the obtained results showed a decrement in the NLA response for all samples and a decrement in the NLR response for all samples except Co substitution. Moreover, to accurately ascertain linear susceptibility, dispersion energy, and the density of polarizable constituents from the acquired z-scan data, we employed Miller’s generalized rule as introduced by the Wemple–DiDomenico model and additionally utilized the relationship proposed by Fournier and Snitzer. The implications of the substitution process and the dimensions of the crystallites, along with their interrelation with nonlinear parameters, are thoroughly examined. The remarkable and encouraging nonlinear optical coefficients demonstrated by these synthesized nanopowders suggest their viability as significant materials for the fabrication of innovative optical devices.

Comparative study on structural, morphological, and optical properties of MS/Fe3O4 nanocomposites and M-doped Fe3O4 nanopowders (M = Mn, Zn)

In the present work, the un-doped, M-doped magnetite (Fe3O4); (M = Mn, Zn), and MS/Fe3O4 composite nanopowders with a cubic spinel-type structure and average crystallite size range from 8.30 to 12.33 nm were synthesized by co-precipitation method. The FESEM images revealed the shape of particles are spherical with a grain size in the range of 33.44–49.77 nm. Through the analysis of reflectance data using Tauc’s model, the direct band gap energies of 2.98 eV, 2.93 eV, 3.01 eV, 2.85 eV, and 2.95 eV were determined for Un-doped Fe3O4, Mn-doped Fe3O4, Zn-doped Fe3O4, MnS/Fe3O4 composite, and ZnS/Fe3O4 composite NPs respectively. The parameters such as extinction coefficient and refractive index of the nanoparticles were computed by the Kramers–Kronig (K–K) method. Non-linear optical (NLO) parameters were computed from DRS data using the Wemple–Di-Domenico (WDD) model. The calculated third-order NLO susceptibility χ(3)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\chi }^{(3)}$$\\end{document} and also electrical susceptibility χe\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\chi }_{\\left(e\\right)}$$\\end{document} represented the maximum value for MnS/Fe3O4 composite NPs compared to the other samples. Considering the advanced optical parameters of MS/Fe3O4 composite samples, these particles can be suitable candidates for non-linear optical applications.

The influence of the incorporation of Mn atoms in CdO nanoparticles on structural pathways, linear, and non-linear optical characteristics for optoelectronic devices

The paper discusses the synthesis and characterization of Cd[Formula: see text]Mn[Formula: see text]O nanoparticles using the precipitation method for potential optoelectronic applications. X-ray diffraction analysis revealed a cubic polycrystalline structure, with a decrease in crystallite size as Mn concentration increased. UV–Vis spectroscopy data showed changes in the band gap with varying Mn concentrations, with [Formula: see text] decreasing from 2.523[Formula: see text]eV to 2.304[Formula: see text]eV as Mn content increased up to 3%. However, with further increases in Mn content, [Formula: see text] increased to 2.332[Formula: see text]eV. The study also estimated various optical properties, providing valuable insights into the optical behavior of Cd[Formula: see text]Mn[Formula: see text]O nanoparticles. In addition to the aforementioned characterizations, the paper explores the influence of Mn content on dispersion parameters using Wemple Di-Domenico models. The dispersion energy ([Formula: see text]) was found to increase from 13.502[Formula: see text]eV to 14.170[Formula: see text]eV, while the single oscillator energy ([Formula: see text]) decreased from 3.483[Formula: see text]eV to 3.142[Formula: see text]eV with increasing Mn content. This suggests that the incorporation of Mn into CdO alters its optical properties significantly. Furthermore, the study calculated non-linear optical coefficients, such as the third-order non-linear susceptibility ([Formula: see text](3)) and non-linear refractive index ([Formula: see text]), for CdO nanostructured powder doped with Mn. These findings indicate the potential suitability of Cd[Formula: see text]Mn[Formula: see text]O nanoparticles for applications in the fields of optics and electronic devices, highlighting their potential for use in advanced technologies requiring tailored optical properties and nonlinear behavior.

Efficacy of Ni2+ on modification the structure, ultrasonic, optical, and radiation shielding behaviors of potassium lead borate glasses

This paper presents the method of preparing (60 − x) B2O3–20 K2O–20 PbO–x NiO, coded as (NiO x), and x = (0–10 mol%) glass systems fabricated through the melt-quench technique. The prepared glass was characterized through X-ray diffraction spectra (XRD); the mechanical behavior of the glass samples was investigated using the ultrasonic technique, Fourier transform infrared (FTIR) spectra, the optical reflectance R(λ), refractive index (n), optical conductivity (σopt), the dispersion parameters of the studied samples were deduced using Wemple and Di-Domenico models. The results obtained were reported in detail. One of the fundamental parameters used to evaluate the interaction of radiation with shielding material was the mass attenuation coefficient (μm), which was obtained using Phy/X software and PHITS code program. It was used to calculate radiation interaction parameters, e.g., linear (μL) attenuation coefficient, effective atomic number (Zeff), half value layer HVL, mean free path (MFP) and the average atomic cross section, σt. Comparing the shielding behavior of the glass samples revealed that (NiO 10) glass demonstrated the highest μm and μL compared to the other samples. The maximum μm values equal 48.13, 48.73, 49.42, 50.59, and 51.08 cm2/g for (NiO 0) to (NiO 10), recorded at 0.015 MeV, respectively. This study shows that increasing the amount of NiO in the preferred glass samples leads to achieving high-performance radiation shielding materials.Graphical abstract

Linearization and characterization of the Wemple – DiDomenico model of ZnO/Ni/ZnO tri-layer thin films prepared by ALD and DC magnetron sputtering

Our present work is devoted to analyzing the influence of Ni on the optical properties of ZnO thin films deposited on glass and Si (100) substrates, with the use of ALD for ZnO deposition and DC magnetron sputtering for Ni interlayer deposition. The compositions as well as the crystalline structure of various multilayer thicknesses of Ni (10, 30, 50, and 70 nm), that sandwiched between ZnO Films (70 nm), before being optically characterized, were carried out by the X-ray diffraction (XRD). Based on the XRD results, the crystallite size was increased with the increase of the Ni interlayer concentration. Additionally, the material densities for both ZnO and Ni show the expected close-to-bulk values in all formations, where the large cavities between atoms, on the films make the dislocation density become smaller and the surface roughness values decrease as well, with the increase of Ni interlayer concentration. Different optical properties were observed for different Ni content. The optical absorption coefficient (α), refractive index (n), and extinction coefficient (k) have been deduced from the transmission T(λ) and absorption measurements A(λ). The optical energy gap Egoptare estimated from Tauc΄s extrapolation procedure and the Kubelka-Munk approach. The static refractive index (no), the oscillator energy (Eo), and the dispersion energy (Ed) are calculated using the Wemple-DiDomenico (WDD) theoretical model. Analysis of third-order nonlinear optical properties in crystalline ZnO/Ni/ZnO are being detailed. These promising results imply that the high-quality films produced by ALD, show how the insertion of Ni could enhance the quality of the optical properties of ZnO films.

Energy-Gap-Refractive Index Relations in Semiconductors—Using Wemple–DiDomenico Model to Unify Moss, Ravindra, and Herve–Vandamme Relationships

The refractive index of solids gauges their transparency to incident light, while the energy gap determines the threshold for light absorption. This paper provides a mathematical formulation for the relationship between the refractive index and the energy gap. It is also established that this formulation aided in the unification of the Moss, Ravindra, and Herve–Vandamme relationships.

Influence of tungsten oxide concentration on structural, morphological, compositional, linear and non-linear optical properties, and vibrational properties on NiO:WO3 thin films

Mixed nickel-tungsten oxide, NiO:WO3 (90:10, 85:15) thin films with different tungsten oxide (WO3) concentrations of 10 and 15% were deposited using the radio frequency (RF) sputtering technique. An X-ray diffraction analysis reported the amorphous nature of the films. A SEM study showed smooth morphology. EDAX confirms the compositional purity, in which the nickel content decreases, while the tungsten and oxygen content increase with an increased WO3 concentration. The average transmittance of the NiO:WO3 (90:10, 85:15) films decreases from 79 to 75% as a consequence of increased thickness. The Urbach energy (Eu) enhances because of increased defects (localized states) inside the films induced by tungsten oxide addition. The energy bandgap decreases from 2.66 to 2.48 eV due to the formation of new localized energy states inside the band gap (Eg). The refractive index (n) acquired from different proposed models for the entire UV–Vis–NIR region has increased with increasing WO3 concentration, implying the escalation in densification (or packing density) of prepared films. The optical parameters like n, k, ε1, ε2, electronic polarizability (αp), optical conductivity (σop), electric conductivity (σe), volume and the surface energy loss function (VELF AND SELF) vary with WO3 concentration. The dispersion energy parameters (Eo, Ed), resulting from the Wemple and Didomenico (WD) model, decreases. The optical non-linear susceptibility, χ(3), decreased with increasing WO3 concentration. The photoluminescence (PL) emissions were perceived at 368 nm and 423 nm, assignable to 3 d8 Ni2+ ions transitions. Micro-Raman detected peaks at 570 cm−1 and 1100 cm−1 ascribing Ni–O bond vibrations, whereas the peak spotted at 870 cm−1 is ascribed to a W–O bond vibration. The deposited films are good enough for electrochromic and optoelectronic device fabrications.

Wavelength-dependent elasto-optic tensor elements from acoustic Bragg diffraction

We report measurements of the elasto-optic constants p11 and p21 as a function of wavelength, for a variety of commercial glasses. The measurements were made using an apparatus based on the Dixon–Cohen design, in which the intensity of light diffracted from an acoustic pulse train is used to extract the elasto-optic tensor, using also data on the index of refraction and speed of sound. A variety of glass compositions were studied, and characterized compositionally using electron microprobe analysis; mechanically using speed of sound measurements; optically, via wavelength-dependent index of refraction; and structurally, using Raman and NMR spectroscopies. The final elasto-optic data were fit using the Wemple–DiDomenico model, and the results interpreted in terms of the effective band gap and deformation potentials, which were found to be sensitive to the different chemical bonds found in the glasses.

Investigation on Bi-induced changes on linear and non-linear optical parameters of As45-Se (55-x)-Bix chalcogenide glasses for photonic application

The Bi-incorporated As45-Se(55-x)-Bix (x = 0, 2, 4, 6 at.%) chalcogenide glasses have been synthesized by deploying the conventional melt quenching method. The non-appearance of the peak in the X-ray diffraction pattern confirms the amorphous characteristics of these materials. The alteration in non-linear and linear optical properties has been investigated from UV–Vis spectroscopy data and associated empirical formulae. Tauc's plot show that the values of optical band gap energies decrease from 1.82 eV to 1.59 eV, while the assessed Urbach energies increase from 0.048 eV to 0.056 eV with Bi addition. The reflection and transmission data have been analyzed within the range of 300–800 nm. Various important optical parameters like refractive index, absorption coefficient, extinction coefficient, surface and volume energy loss functions, optical density, skin depth, third-order nonlinearity, thermal emissivity, etc., have been investigated. The Wimple Didomenico model has been used to analyze several dispersion parameters. The Chemical bond approach model has been used to estimate the cohesive energy, which is found to decrease from 2.761 eV to 2.747 eV. The increase in non-linear refractive index and third-order non-linear optical susceptibility indicates the possibility of these materials being used in optical switching devices as well as photonic devices.

Evaluation of surface roughness, linear and nonlinear optical parameters of a mixture of sudan black b and polymer films for optical limiting application

A film of a mixture of sudan black b (SBB) dye and a poly methyl methacrylate (PMMA) is fabricated by casting. X-ray diffraction measurement proves the SBB/PMMA film's structure is amorphous. The scanning probe microscope confirmed that the SBB/PMMA film has a good quality and homogeneous surface. The SBB/PMMA film's optical constants are estimated via the transmittance, absorbance, and reflectance spectra. The indirect optical band gap is calculated and found to be 1.49 eV. The single oscillator energy, Eo, the dispersion energy, Ed, and the static refractive index, no, are computed by using Wemple and DiDomenico model. Semi-empirical relation, Z-scan, and diffraction ring patterns are three methods used to determine the film's nonlinear refractive index value. The SBB/PMMA film exhibited a high nonlinear refractive index (n2 = 7.83 × 10−7 cm2/W) and nonlinear absorption coefficient (β = 9.3 × 10−3 cm/W), calculated by the Z-scan method. Under a continuous wave laser beam, the property of the optical limiting of the film is examined. The film exhibited optical limiting properties with a limiting threshold value of 5 mW.

Effect of interchangeable proportions of ZnS and NiO nanoparticles on the optoelectronic and laser CUT-OFF filters properties of CMC/PVP blend

Carboxy-methyl cellulose (CMC)/ polyvinylpyrrolidone (PVP)/(1 − x)NiO–xZnS (x = 0, 0.25, 0.5, 0.75, 1) polymer blends were prepared using casting, sol–gel and solid state reaction methods. X-ray diffraction technique was used to determine the structure and crystallite size of the nanofillers. The crystalline feature of the blends and the nanofillers over the blends matrix were examined using the XRD technique. FTIR was used to confirm the formation of the blends. The effect of the interchangeable proportions of nanoparticles on the optoelectronic properties of the blends was examined using Wemple and DiDomenico model. The transmitted intensity is investigated with lasers at three different wavelengths. A reduction in transmittance makes the studied material promising as attenuating filters at doping levels starting from 75% NiO or less and 25% of ZnS and more even if at relatively high laser powers.

Investigation of Structural and Optical Characteristics of Biopolymer Composites Based on Polyvinyl Alcohol Inserted with PbS Nanoparticles

The film casting method is implemented to synthesize a series of films consisting of polyvinyl alcohol (PVA) films and 4 wt%, 8 wt%, and 12 wt% lead sulfide (PbS) nanoparticles (NPs). X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and Ultraviolet-visible (UV-vis) spectroscopy were used to ensure the impact of PbS loading on PVA properties, particularly optical ones. The FTIR results show a decrease in the intensity for all the bands and the XRD results show different features for the composites from that of the pure PVA. The optical properties, including optical transmission, surface reflection, and absorption, were investigated. Additionally, the significant optical parameters, for instance, the dielectric nature and refractive index of the films, were analyzed. The findings have shown that PbS NPs in the PVA films decrease UV and visible transmission through polymer composites and increase their ability to reflect the incident light. Tauc’s equation is applied to determine the optical bandgap energy (Eg) and verify whether it is direct or indirect. Using the relation between photon energy and optical dielectric loss, the Eg was measured and the type of electron transition was measured, which eases the exponent value (𝜸) specification from Tauc’s method. The Eg decreases from 6.3 eV to 5.25 eV when PbS NPs are added. The refractive index is improved from 1.27 to 2.16 for the polymer nanocomposite (NCPs) film with optimum PbS NPs. Then, the Wemple–DiDomenico model corresponding to a single oscillator is applied to the dispersive medium to determine the refractive index dispersion. Both the dispersive energy (Ed) and single-oscillator energy (Eo) are evaluated accurately. Moreover, the variation of both real and imaginary parts of the dielectric constant of polymer films were studied. Finally the optical parameters such as charge density, dielectric constant at high frequencies, optical mobility (µ), angular frequency (ωp), optical resistivity (ρ), and relaxation time (τ) of electrons are shown quantitatively. The ωp of the electron is increased from 1.06 × 1029 to 81.5 × 1029 Hz when the PbS NPs is added. The µ of the electrons is also increased from 4.85 to 6.22 cm2/(V·s) by adding the PbS NP.

Polymeric Solar Cell with 19.69% Efficiency Based on Poly(o-phenylene diamine)/TiO2 Composites.

Conducting poly orthophenylene diamine polymer (PoPDA) was synthesized via the oxidative polymerization route. A poly(o-phenylene diamine) (PoPDA)/titanium dioxide nanoparticle mono nanocomposite [PoPDA/TiO2]MNC was synthesized using the sol-gel method. The physical vapor deposition (PVD) technique was successfully used to deposit the mono nanocomposite thin film with good adhesion and film thickness ≅ 100 ± 3 nm. The structural and morphological properties of the [PoPDA/TiO2]MNC thin films were studied by X-ray diffraction (XRD) and scanning electron microscope (SEM). The measured optical properties of the [PoPDA/TiO2]MNC thin films such as reflectance (R) in the UV-Vis-NIR spectrum, absorbance (Abs), and transmittance (T) were employed to probe the optical characteristics at room temperatures. As well as the calculations of TD-DFT (time-dependent density functional theory), optimization through the TD-DFTD/Mol3 and Cambridge Serial Total Energy Bundle (TD-DFT/CASTEP) was employed to study the geometrical characteristics. The dispersion of the refractive index was examined by the single oscillator Wemple-DiDomenico (WD) model. Moreover, the single oscillator energy (Eo), and the dispersion energy (Ed) were estimated. The obtained results show that thin films based on [PoPDA/TiO2]MNC can be utilized as a decent candidate material for solar cells and optoelectronic devices. The efficiency of the considered composites reached 19.69%.

Determination of optical constants of vacuum annealed ZnO thin films using Wemple Di Domenico model, Sellmier's model and Miller's generalized rules

Thin films of zinc oxide (ZnO) were coated by a spin coater on the glass substrate and are annealed at 300 °C and 500 °C under the reduced atmosphere of 10−3 mbar. The structural properties were examined by X-ray diffractogram (XRD), atomic force microscopy (AFM), and optical study of ZnO thin films by UV–Vis spectrophotometer. The XRD study showed that the films had a preferred orientation towards the c-axis, and the AFM study revealed a columnar growth. Optical parameters such as band gap, Urbach energy, electron-phonon interaction strength, refractive index, carrier concentration to the effective mass (N/m*) ratio, carrier concentration, and plasma frequency were extracted from transmittance and absorption curves by using Wemple Di Domenico and Sellmier's models. The non-linear optical parameters such as susceptibility and refractive index are obtained from Miller's generalized rules. The optical bandgap was found to decrease with an increase in dopant concentrations and also with annealing temperature but for 0.5 M bandgap increase at 300°C. The Urbach energy follows the increasing trend for both increase in concentration and annealing temperature. This indicates vacuum annealing induces defect sites in the material under investigation.

Complex dielectric, electric modulus, impedance, and optical conductivity of Sr3−x Pb x Fe2TeO9 (x = 1.50, 1.88 and 2.17)

Abstract Sr3−x Pb x Fe2TeO9 (x = 1.50, 1.88 and 2.17) were synthesized in polycrystalline form via the solid-state reaction route in air, and were studied at room temperature using powder X-ray diffraction and ultraviolet visible spectroscopy techniques. The crystal structures were resolved by the Rietveld refinement method; x = 1.50 and 1.88 adopt a tetragonal phase (space group I4/mmm) while x = 2.17 adopts a hexagonal phase (space group R 3 ̄ $\bar{3}$ m). The direct bandgap energy (E g) of ∼1.89 eV for (x = 1.50), ∼1.87 eV for (x = 1.88) and ∼1.74 eV for (x = 2.17) was estimated from the Tauc plots of (αhʋ)2 versus photon energy. The Urbach energy (E U) was determined from the plots of logarithmic absorption coefficient versus hυ. Plots of the incident photon energy dependence of optical parameters such as refractive index, extinction coefficient, real and imaginary parts of the dielectric function, dielectric loss, real and imaginary parts of the complex optical conductivity, linear and nonlinear optical susceptibilities, real and imaginary parts of the electric modulus, real and imaginary parts of the impedance were obtained by means of ultraviolet visible spectrophotometer experiments. Additionally, the estimated values of the single oscillator energy, dispersion energy, static refractive index and high-frequency dielectric constant were obtained from the linear portion of the (n 2 − 1)−1 versus (hυ)2 plots using the Wemple–DiDomenico model.

Structural, Swanepoel’s method, optical and electrical parameters of vacuum evaporated Zn50Se50 thin films

Thin films of Zn50Se50 were prepared by the vacuum evaporation technique on glass substrates. The influence of annealing temperature (Tann.) on the structural and optical properties of ZnSe polycrystalline films was investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical transmittance T (λ). The crystalline phases that were found in the Zn50Se50 thin films are ZnSe, Se and Zn. The refractive index (n) and the thickness of the films (d) were calculated using Swanepoel’s method for the films annealed at (423 K). The mechanism of optical absorption follows the rule of direct transition. The values of band gap (EG) were found to decrease from about 2.933 to 2.635 eV with the increasin of the Tann. from 300 to 423 K. Urbach energy (EU) was calculated and found to the increase by increasing Tann. The dispersion of the n was discussed in terms of the single-oscillator Wemple and DiDomenico model. The Arrhenius formula was used to discuss the electrical conductivity (σDC), activation energy (ΔE) and preexponential factor (σo).

Materials for Optical Sensors of X-ray Irradiation Based on (GaxIn1 – x)2Se3 Films

(GaxIn1-x)2Se3 films with 0.1 ≤ x ≤ 0.4 were deposited by the thermal evaporation technique. As-deposited (GaxIn1-x)2Se3 films were irradiated using the wideband radiation of a Cu-anode X-ray tube at different exposure times. The spectral dependences of the refractive index and extinction coefficient are measured by the spectral ellipsometry technique. The optical transmission spectra of X-ray irradiated (GaxIn1-x)2Se3 films are studied for various irradiation times. Parameters of the Urbach absorption edge for X-ray-irradiated (GaxIn1-x)2Se3 thin films are determined and compared with those of non-irradiated films. The spectral dependences of the refractive indices of non-irradiated and X-ray-irradiated (GaxIn1-x)2Se3 films are described in the framework of the model developed by Cauchy, Sellmeier, Wemple, and DiDomenico, as well as by the optical-refractometric relation. The detailed variation of the parameters of the Wemple–DiDomenico model for non-irradiated and X-ray-irradiated (GaxIn1-x)2Se3 films has been analyzed. The perspective of applications of (GaxIn1-x)2Se3 films as the materials for optical sensors of X-rays is discussed.

Laser radiation effect on microstructural, linear, and nonlinear optical characteristics of Sn0.04Co0.06O2 nanostructured films

The influence of He-Ne laser radiation on linear and nonlinear optical characteristics of Co-doped SnO2 (Sn0.04Co0.06O2) thin film was studied before and after irradiation. 22 mW (633 nm) He-Ne laser beam was employed to irradiate the film with different exposure times (Texpo. = 1, 2, 5, 15, 20, 40, and 60 min). As grown and irradiated films were examined by X-ray diffraction (XRD), an atomic force microscope (AFM) was integrated with UV-VIS–NIR spectrophotometer. XRD pattern analysis showed that the crystallite size decreased as the exposure increased to 5 min, however, a further increase in Texpo from 15 to 60 min increased the crystallite size. Analysis of AFM micrographs shows that the roughness of the surface and root mean square roughness of the film depend on the increase in the laser exposure time. The optical studies of irradiated films show that the optical energy gap Eg decreases as the exposure time increases to 5 min and then raises as the film is irradiated for up to 60 min. This reduction was attributed to the elimination of the additional oxygen from the film, and the increase of Eg is explained by the Burstein–Moss effect. Swanepoel’s envelope method is used to calculate the linear optical parameters of the irradiated film from the light transmission spectrum, such as refractive index n, and extinction coefficient k. The results reveal that the global behavior of n and k increases with exposure time. The oscillator parameters of the irradiated film of different exposure times were evaluated from the single-oscillator Wemple–DiDomenico model, which was then used to calculate the nonlinear optical parameters such as n2 the nonlinear refractive index, and χ(3) the third-order nonlinear optical susceptibility. It is concluded that the He-Ne laser irradiation with different exposure times enhances the optoelectronic properties of Sn0.04Co0.06O2 nanocrystalline semiconductor thin film

Investigation of the Optical Properties for Quaternary Se60-xGe35Ga5Sbx (x = 0, 5, and 10) Chalcogenide Glass.

A quenching technique was used to prepare the chalcogenide system of the (x = 0, 5, and 10 at. %), which was deposited as thin films onto glass substrates using a thermal evaporation technique. X-ray diffraction patterns were used for structure examination of the fabricated compositions, which exposes the amorphous nature of the deposited samples. Meanwhile, the chemical compositions of the prepared samples were evaluated and calculated via the energy-dispersive X-ray spectroscopy (EDX), which was in agreement with the measured compositional element percentages of the prepared samples. Based on the optical reflectance R and transmittance T spectra from the recorded spectrophotometric data ranging from 350 to 2500 nm, the influence of the Sb element on the thin films’ optical properties was studied. The film thickness and the refractive index were calculated via Swanepoel’s technique from optical transmittance data. It has been observed that the films’ refractive index increases with increasing x value over the spectral range. The refractive index data were used to evaluate the dielectric constants and estimate dispersion parameters and using the Wemple–DiDomenico model. The optical energy gap was calculated for the tested compositions. The result of the optical absorption analysis shows the presence of allowed direct and indirect transitions.

Structural characteristics and optical properties of methylcellulose/polyaniline films modified by low energy oxygen irradiation

Methylcellulose (MC)/polyaniline (PANI) films are synthesized using solution cast method and irradiated with oxygen fluence 5x1017, 10x1017, and 15x1017 ions/cm2. The induced changes of MC/PANI structure upon irradiation are revealed using X-ray diffraction and infrared spectroscopy. Likewise SEM is used to investigate the morphology changes of irradiated campsites. Tauc's formula is used to estimate the optical band tail and optical band energy gap of pure and irradiated MC/PANI films. Moreover, dielectric constant, extinction coefficient, refractive index as well as electric modulus are estimated. Wemple Di-Domenico models are used to determine dispersion variables of pristine and irradiated films. Moreover, non-linear of optical susceptibility and refractive index are determined. The results show, 15x1017 ions/cm2 irradiation is more suitable for non-linear optical applications.