Effect of Er doping on optical band gap energy of TiO2 thin films prepared by spin coating

Â Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 â‰¤ x â‰¤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the systemâ€™s network.

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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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Effect of thickness on the optical properties of Gaas thin films

Journal of Bangladesh Academy of Sciences ◽

10.3329/jbas.v37i1.15684 ◽

2013 ◽

Vol 37 (1) ◽

pp. 83-91 ◽

Cited By ~ 13

Author(s):

Chitra Das ◽

Jahanara Begum ◽

Tahmina Begum ◽

Shamima Choudhury

Keyword(s):

Thin Films ◽

Dielectric Constant ◽

Refractive Index ◽

Band Gap ◽

Optical Band Gap ◽

Visible Region ◽

Solar Spectrum ◽

Band Gap Energy ◽

Optical Parameters ◽

Gap Energy

Effect of thickness on the optical and electrical properties of gallium arsenide (GaAs) thin films were studied. The films of different thicknesses were prepared by vacuum evaporation method (~10-4 Pa) on glass substrates at a substrate temperature of 323 K. The film thickness was measured in situ by a frequency shift of quartz crystal. The thicknesses were 250, 300 and 500 nm. Absorption spectrum of this thin film had been recorded using UV-VIS-NIR spectrophotometer in the photon wavelength range of 300 - 2500 nm. The values of some important optical parameters of the studied films (absorption coefficient, optical band gap energy and refractive index; extinction co-efficient and real and imaginary parts of dielectric constant) were determined using these spectra. Transmittance peak was observed in the visible region of the solar spectrum. Here transmittance showed better result when thicknesses were being increased. The optical band gap energy was decreased by the increase of thickness. The refractive index increased by increasing thickness while extinction co-efficient and real and imaginary part of dielectric constant decreased. DOI: http://dx.doi.org/10.3329/jbas.v37i1.15684 Journal of Bangladesh Academy of Sciences, Vol. 37, No. 1, 83-91, 2013

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A simple spectrophotometric method for determination of the optical constants and band gap energy of multiple layer TiO2 thin films

Materials Chemistry and Physics ◽

10.1016/j.matchemphys.2003.09.030 ◽

2004 ◽

Vol 83 (1) ◽

pp. 169-177 ◽

Cited By ~ 111

Author(s):

Monjoy Sreemany ◽

Suchitra Sen

Keyword(s):

Thin Films ◽

Band Gap ◽

Spectrophotometric Method ◽

Optical Constants ◽

Band Gap Energy ◽

Tio2 Thin Films ◽

Gap Energy ◽

Multiple Layer

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Effects of Nitrogen Doping on Optical Properties of Tungsten Oxide Thin Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.616-618.1773 ◽

2012 ◽

Vol 616-618 ◽

pp. 1773-1777

Author(s):

Xi Lian Sun ◽

Hong Tao Cao

Keyword(s):

Thin Films ◽

Refractive Index ◽

Optical Properties ◽

Band Gap ◽

Tungsten Oxide ◽

Nitrogen Doping ◽

Optical Band Gap ◽

Band Gap Energy ◽

Gap Energy ◽

Tungsten Oxide Thin Films

In depositing nitrogen doped tungsten oxide thin films by using reactive dc pulsed magnetron sputtering process, nitrous oxide gas (N2O) was employed instead of nitrogen (N2) as the nitrogen dopant source. The nitrogen doping effect on the structural and optical properties of WO3 thin films was investigated by X-ray diffraction, transmission electron microscopy and UV-Vis spectroscopy. The thickness, refractive index and optical band gap energy of these films have been determined by analyzing the SE spectra using parameterized dispersion model. Morphological images reveal that the films are characterized by a hybrid structure comprising nanoparticles embeded in amorphous matrix and open channels between the agglomerated nanoparticles. Increasing nitrogen doping concentration is found to decrease the optical band gap energy and the refractive index. The reduced band gaps are associated with the N 2p orbital in the N-doped tungsten oxide films.

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