Optical Properties of Ferrite Powders of NixCo1-xFe2O4 System

The aim of this work was to create and study of ferrite nickel-cobalt powders, using sol-gel technology with participation of auto-combustion. It is studied the optical properties of the powders depending on the degree of substitution of cobalt cations on nickel cations. As a result of analysis of the absorption spectra is revealed that for all investigated powders inherent allowed direct transition of electrons from the valence band to the conduction band. It was shown that the optical band gap increases with increasing concentration of nickel cations in the composition of ferrites.

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Exploring Burstein–Moss type effects in nickel doped hematite dendrite nanostructures for enhanced photo-electrochemical water splitting

Physical Chemistry Chemical Physics ◽

10.1039/c9cp04132j ◽

2019 ◽

Vol 21 (36) ◽

pp. 20463-20477 ◽

Cited By ~ 14

Author(s):

Soniya Gahlawat ◽

Jaspreet Singh ◽

Ashok Kumar Yadav ◽

Pravin P. Ingole

Keyword(s):

Optical Properties ◽

Band Gap ◽

Water Splitting ◽

Conduction Band ◽

Optical Band Gap ◽

Doped Semiconductors ◽

Electrochemical Water Splitting

The Burstein–Moss suggests which that the optical band gap of degenerately doped semiconductors increases when all states close to the conduction band get populated is important to obtain different optical properties for the same material.

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Properties of TiO2 Thin Film Prepared by Sol-Gel Dip Coating

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.723.528 ◽

2015 ◽

Vol 723 ◽

pp. 528-531

Author(s):

Jun Wang ◽

Ling Yun Bai

Keyword(s):

Thin Film ◽

Thin Films ◽

Refractive Index ◽

Optical Properties ◽

Band Gap ◽

Optical Band Gap ◽

Sol Gel ◽

Dip Coating ◽

Gel Method ◽

Glass Substrates

TiO2 thin films were prepared on glass substrates by sol-gel method. The effect of withdraw speed on the thickness and optical properties of TiO2 thin films was investigated. The films were transparent in the visible wavelength. The thickness of the TiO2 films was increased from 90 nm for the withdraw speed of 1000 μm/s to 160 nm for the withdraw speed of 2000 μm/s. While, The refractive index of the TiO2 thin film decreased from 2.38 to 2.07. It may be due to the porosity of the film was increased. The optical band-gap of the films was around 3.45 eV.

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X-ray Spectroscopic Studies of the Bulk Electronic Structure of InGaN Alloys

MRS Proceedings ◽

10.1557/proc-743-l10.11 ◽

2002 ◽

Vol 743 ◽

Author(s):

Cormac McGuinness ◽

James E. Downes ◽

Philip Ryan ◽

Kevin E. Smith ◽

Dharanipal Doppalapudi ◽

...

Keyword(s):

Electronic Structure ◽

Band Gap ◽

Valence Band ◽

Absorption Spectra ◽

Conduction Band ◽

Partial Density ◽

Significant Shift ◽

Band Shift ◽

X Ray ◽

X Ray Absorption

ABSTRACTSynchrotron radiation excited soft x-ray emission and soft x-ray absorption spectroscopies are applied to the study of the electronic structure of InxGa1-xN alloys with (0 ≤ x ≤ 0.29). The elementally resolved partial density of states of the valence and conduction bands may be measured using these spectroscopies. The x-ray absorption spectra indicate that the conduction band broadens considerably with increasing indium incorporation. The band gap evolution as a function of indium content derives primarily from this broadening of the conduction band states. The emission spectra indicate that motion of the valence band makes a smaller contribution to the evolution of the band gap. This gap evolution differs from previous studies on the AlxGa1-xN alloy system, which observed a linear valence band shift through the series (0 < x < 1). Instead in the case of InxGa1-xN the valence band exhibits a significant shift between x = 0 and x = 0.1 with minimal movement thereafter. Furthermore, evidence of In 4d -N 2p and Ga 3d- N 2p hybridisation is reported. Finally, the thermal stability of an In011Ga089N film was investigated. Both emission and absorption spectra were found to have a temperature dependent shift in energy, but the overall definition of the spectra was unaltered even at annealing temperatures well beyond the growth temperature of the film.

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Studying of the optical properties of poly (vinyl alcohol) films using Aluminum sulphate as additive by measuring allowed direct transition energy gap

Baghdad Science Journal ◽

10.21123/bsj.8.1.103-109 ◽

2011 ◽

Vol 8 (1) ◽

pp. 103-109

Author(s):

Baghdad Science Journal

Keyword(s):

Activation Energy ◽

Band Gap ◽

Absorption Spectra ◽

Vinyl Alcohol ◽

Optical Band Gap ◽

Energy Gap ◽

Poly Vinyl Alcohol ◽

Direct Transition ◽

Aluminum Sulphate ◽

Optical Activation

The change in the optical band gap and optical activation energy have been investigated for pure Poly (vinyl alcohol)and Poly (vinyl alcohol) doped with Aluminum sulphate to proper films from their optical absorption spectra. The absorption spectra were measured in the wave range from (200-700) nm at temperature range (25-140) 0C. The optical band gap (Eg) for allowed direct transition decrease with increase the concentration of Aluminum sulphate. The optical activation energy for allowed direct transition band gap was evaluated using Urbach- edges method. It was found that ?E increases with increasing the concentration of Al2 (SO4)3 and decreases when temperature increases.

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Structural and Optical Properties of ZnO Thin Films Prepared by Molecular Precursor and Sol–Gel Methods

Crystals ◽

10.3390/cryst10020132 ◽

2020 ◽

Vol 10 (2) ◽

pp. 132 ◽

Cited By ~ 4

Author(s):

Theopolina Amakali ◽

Likius. S. Daniel ◽

Veikko Uahengo ◽

Nelson Y. Dzade ◽

Nora H. de Leeuw

Keyword(s):

Thin Films ◽

Optical Properties ◽

Band Gap ◽

Optical Band Gap ◽

Sol Gel ◽

Zno Thin Films ◽

Structural And Optical Properties ◽

Gel Method ◽

Sol Gel Method ◽

Molecular Precursor

Zinc oxide (ZnO) is a versatile and inexpensive semiconductor with a wide direct band gap that has applicability in several scientific and technological fields. In this work, we report the synthesis of ZnO thin films via two simple and low-cost synthesis routes, i.e., the molecular precursor method (MPM) and the sol–gel method, which were deposited successfully on microscope glass substrates. The films were characterized for their structural and optical properties. X-ray diffraction (XRD) characterization showed that the ZnO films were highly c-axis (0 0 2) oriented, which is of interest for piezoelectric applications. The surface roughness derived from atomic force microscopy (AFM) analysis indicates that films prepared via MPM were relatively rough with an average roughness (Ra) of 2.73 nm compared to those prepared via the sol–gel method (Ra = 1.55 nm). Thin films prepared via MPM were more transparent than those prepared via the sol–gel method. The optical band gap of ZnO thin films obtained via the sol–gel method was 3.25 eV, which falls within the range found by other authors. However, there was a broadening of the optical band gap (3.75 eV) in thin films derived from MPM.

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Morphological and Optical Properties of Different Mg Percentage of ZnO/Mg Thin Films Prepared by Sol-Gel Spin-Coating and Immersion Method

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1107.637 ◽

2015 ◽

Vol 1107 ◽

pp. 637-642 ◽

Cited By ~ 1

Author(s):

Aadila Aziz ◽

R. Mohamed ◽

A.N. Afaah ◽

N.A.M. Asib ◽

M. Rusop ◽

...

Keyword(s):

Thin Films ◽

Optical Properties ◽

Band Gap ◽

Spin Coating ◽

Optical Band Gap ◽

Sol Gel ◽

Immersion Method ◽

Weight Percentage ◽

Tauc Plot ◽

Vis Spectroscopy

We have successfully demonstrated ZnO/Mg thin films on Mg seeded-template by using sol-gel spin-coating and immersion technique. By increasing weight percentage of Mg, zinc particles become agglomerate and displayed flower formed as displayed in FESEM characterization. It was observed that the morphology of the zinc particles on Mg seeded-template change from inconsistently distribution for 1 and 3 % into cluster flower-like of zinc particles for 5 and 7 % weight percentage of Mg. The optical properties of the ZnO/Mg thin films were examined by UV-Vis spectroscopy and the Tauc plot methods was used to estimate the optical band gap. The study reveals that, 7 % weight percentage of Mg was recorded as the highest transmittance which is more than 60 % in visible wavelength compared to others. With the rise weight percentage of Mg, the transmittance of the thin films was increased except for 5 %. This gradually downgraded to below 60 % of transmission most probably due to the grain size that becomes bigger. The optical band gap can be tuned by using different Mg percentage to the ZnO/Mg thin films.

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Improvement Optical Properties of PVA/ TiO2 and PVA/ ZnO Nanocomposites

Al-Mustansiriyah Journal of Science ◽

10.23851/mjs.v29i3.629 ◽

2019 ◽

Vol 29 (3) ◽

pp. 118 ◽

Cited By ~ 1

Author(s):

Nadheer J. Mohammed ◽

Zahraa S. Rasheed ◽

Ashraf S. Hassan

Keyword(s):

Optical Properties ◽

Absorption Spectra ◽

Zno Nanoparticles ◽

Optical Band Gap ◽

Energy Gap ◽

Pulsed Laser ◽

Pulsed Laser Ablation ◽

Optical Absorption Spectra ◽

Direct Transition ◽

Laser Ablation Technique

The optical properties of polyvinyl alcohol (PVA) doped TiO2 and ZnO nanoparticles respectively, were studied. PVA/TiO2 and PVA/ZnO nanoparticles were prepared by the pulsed laser ablation technique (PLA).The optical properties of PVA/ TiO2 and PVA/ ZnO nanocomposite solution have been investigated by transmittance data and absorption spectra. The optical band gap (Eg) was determined and the optical absorption spectra showed that a direct transition. The energy gap of PVA/ ZnO nanoparticles have been observed the decreases its value and increasing in the optical conductivity as compared to PVA/ TiO2.The refractive index (n), extinction coefficient (k) and dielectric constant have been also investigated; it was found that all the above parameters affects by doping.

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Structural and Optical Properties of Nanohybrid PMMA/TiO2

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.667.63 ◽

2013 ◽

Vol 667 ◽

pp. 63-67 ◽

Cited By ~ 2

Author(s):

N.A.A. Aziz ◽

M.F. Achoi ◽

Saifollah Abdullah ◽

Mohamad Rusop Mahmood

Keyword(s):

Optical Properties ◽

Band Gap ◽

Spin Coating ◽

Optical Band Gap ◽

Sol Gel ◽

Molar Concentration ◽

Structural And Optical Properties ◽

Tio2 Particles ◽

Coating Method ◽

Uv Range

Preparation of nanohybrid PMMA/TiO2 hybrid was reported by using mixture sol-gel spin coating method. This studied involve modification band gap of TiO2 at different molar concentration of TTiB precursor. AFM image show TiO2 particles encapsulated with PMMA matrix. From UV-Vis spectroscope, we have found as increase of TTiB precursor molar concentration, optical band gap is 3.34 eV, increase in UV-range from 3.25 eV. This study suggested for improvement of optical band gap TiO2 coated glass.

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Sol-gel growth of Ni doped CdS on glass substrates: effect of spin coating speed and dopant concentration

Nanoscience &Nanotechnology-Asia ◽

10.2174/2210681210999200423120817 ◽

2020 ◽

Vol 10 ◽

Author(s):

Atefeh Nazari Setayesh ◽

Hassan Sedghi

Keyword(s):

Thin Films ◽

Optical Properties ◽

Spin Coating ◽

Optical Band Gap ◽

Dopant Concentration ◽

Rotation Speed ◽

Sol Gel ◽

Band Gap Energy ◽

Gap Energy ◽

Glass Substrates

Background: In this work, CdS thin films were synthesized by sol-gel method (spin coating technique) on glass substrates to investigate the optical behavior of the film. Methods: Different substrate spin coating speeds of 2400, 3000, 3600 rpm and different Ni dopant concentrations of 0 wt.%, 2.5 wt.%, 5 wt.%) were investigated. The optical properties of thin films such as refraction index, extinction coefficient, dielectric constant and optical band gap energy of the layers were discussed using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. Results: It can be deduced that substrate rotation speed and dopant concentration has influenced the optical properties of thin films. By decreasing rotation speed of the substrate which results in films with more thicknesses, more optical interferences were appeared in the results. Conclusion: The samples doped with Ni comparing to pure ones have had more optical band gap energy.

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