scholarly journals Conductivity and Density of States of New Polyphenylquinoline

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 934 ◽  
Author(s):  
Shamil R. Saitov ◽  
Dmitriy V. Amasev ◽  
Alexey R. Tameev ◽  
Vladimir V. Malov ◽  
Marine G. Tedoradze ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Band Gap ◽  
Density Of States ◽  
Optical Band Gap ◽  
Dark Conductivity ◽  
Localized States ◽  
Energy Distance ◽  
Temperature Dependences

Electrical, photoelectrical, and optical properties of thin films of a new heat-resistant polyphenylquinoline synthesized using facile methods were investigated. An analysis of the obtained temperature dependences of the dark conductivity and photoconductivity indicates the hopping mechanism of conductivity over localized states arranging at the energy distance of 0.8 eV from the Fermi level located inside the band gap of the investigated material. The optical band gap of the studied material was estimated from an analysis of the spectral dependences of the photoconductivity and absorption coefficient before (1.8–1.9 eV) and after (2.0–2.2 eV) annealing at temperatures exceeding 100 °C. The Gaussian character of the distribution of the localized states of density inside the band gap near the edges of the bands was established. A mechanism of changes in the optical band gap of the investigating polymer under its annealing is proposed.

scholarly journals Effect of gamma irradiation on structural, morphological and optical properties of p-quaterphenyl thin films

2018 ◽  
Vol 14 (2) ◽  
pp. 5624-5637
Author(s):  
A.A. Attia ◽  
M.M. Saadeldin ◽  
K. Sawaby
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Surface Morphology ◽  
Absorption Coefficient ◽  
Gamma Irradiation ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation Method ◽  
Single Oscillator Model

Para-quaterphenyl thin films were deposited onto glass and quartz substrates by thermal evaporation method. p-quaterphenyl thin films wereexposed to gamma radiation of Cobat-60 radioactive source at room temperature with a dose of 50 kGy to study the effect of ?-irradiation onthe structure and the surface morphology as well as the optical properties of the prepared films. The crystalline structure and the surface morphology of the as-deposited and ?-irradiated films were examined using the X-ray diffraction and the field emission scanning electron microscope. The optical constants (n & k) of the as-deposited and ?-irradiated films were obtained using the transmittance and reflectance measurements, in the wavelength range starting from 250 up to 2500 nm. The analysis of the absorption coefficient data revealed an allowed direct transition with optical band gap of 2.2 eV for the as-deposited films, which decreased to 2.06 eV after exposing film to gamma irradiation. It was observed that the Urbach energy values change inversely with the values of the optical band gap. The dispersion of the refractive index was interpreted using the single oscillator model. The nonlinear absorption coefficient spectra for the as-deposited and ?-irradiated p-quaterphenyl thin films were obtained using the linear refractive index.

scholarly journals Optical properties of CdO thin films

2010 ◽  
Vol 7 (1) ◽  
pp. 10-13
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Glass Substrate ◽  
Optical Band Gap ◽  
Spray Pyrolysis Technique ◽  
Cadmium Oxide ◽  
Localized States ◽  
Different Temperatures ◽  
Cdo Thin Films

Cadmium Oxide thin films were deposited on glass substrate by spray pyrolysis technique at different temperatures (300,350,400, 500)oC. The optical properties of the films were studied in this work. The optical band-gap was determined from absorption spectra, it was found that the optical band-gap was within the range of (2.5-2.56)eV also width of localized states and another optical properties.

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

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.

Absorber Films of Antimony Chalcogenides via Chemical Deposition for Photovoltaic Application

2004 ◽  
Vol 836 ◽  
Author(s):  
M. T. S. Nair ◽  
Y. Rodríguez-Lazcano ◽  
Y. Peña ◽  
S. Messina ◽  
J. Campos ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Chemical Deposition ◽  
Dark Conductivity ◽  
Glass Substrates ◽  
Photovoltaic Application ◽  
Sodium Selenosulfate ◽  
P Type ◽  
Antimony Chalcogenides

ABSTRACTAntimony sulfide thin films (300 nm) have been deposited on glass substrates at 1–10°C from chemical bath. When heated these become crystalline and photoconductive with optical band gap (direct) of 1.7 eV. Thin films formed from chemical baths containing SbCl3 and sodium selenosulfate are of mixed phase Sb2O3/Sb2Se3, which when heated in the presence of Se-vapor converts to single phase Sb2Se3 film with optical band gap of 1.1 eV. Such films possess dark conductivity of 10-8 ohm-1cm-1 and show photosensitivity of two orders. Reaction of Sb2S3-CuS in nitrogen at 400°C produces crystalline, photoconductive p-type CuSbS2 with optical band gap (direct) of 1.5 eV. By controlling the deposition and heating condition, (i)Sb2S3-(p)CuSbS2 layer is formed, which is utilized in a photovoltaic structure, (n)CdS:In-(i)Sb2S3-(p)CuSbS2, with a Voc of 345 mV and Jsc 0.18 mA/cm2 under 1 kW m-2 tungsten halogen illumination. In the case of a structure, CdS:Cl-Sb2S3-Cu2-xSe, Voc of 350 mV and Jsc of 0.5 mA/cm2 are observed.

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

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.

scholarly journals Effect of Ge Addition on the Optical Band Gap and Refractive Index of Thermally Evaporated Thin Films

2008 ◽  
Vol 2008 ◽  
pp. 1-4 ◽  
Author(s):  
Pankaj Sharma ◽  
S. C. Katyal
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Band Gap ◽  
Density Of States ◽  
Spectral Range ◽  
Transmission Spectrum ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Thermal Evaporation Technique ◽  
Evaporation Technique

The present paper reports the effect of Ge addition on the optical band gap and refractive index of thin films. Thin films of and were prepared by thermal evaporation technique at base pressure  Pa. Optical band gap and refractive index were calculated by analyzing the transmission spectrum in the spectral range 400–1500 nm. The optical band gap decreases while the refractive index increases with the addition of Ge to . The decrease of optical band gap has been explained on the basis of density of states; and the increase in refractive index has been explained on the basis increase in disorder in the system.

Single Phase CuO Thin Films Prepared by Thermal Oxidation in Air with Water Vapor

2015 ◽  
Vol 1109 ◽  
pp. 544-548 ◽  
Author(s):  
Jian Bo Liang ◽  
Xu Yang Li ◽  
Naoki Kishi ◽  
Tetsuo Soga
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Optical Properties ◽  
Water Vapor ◽  
Band Gap ◽  
Thermal Oxidation ◽  
Single Phase ◽  
Optical Band Gap ◽  
Structural And Optical Properties ◽  
Oxidation In Air

Single phase CuO films have been successfully synthesized by thermal oxidation of cupper foil in air with water vapor. The structural and optical properties of CuO films were investigated. It is observed that the grain size increases with increasing the oxidation temperature. The optical band gap of CuO film is determined by the transmittance and reflectance spectra.

QUANTUM SIZE EFFECT ON THE OPTICAL PROPERTIES OF RF MAGNETRON SPUTTERED NANOCRYSTALLINE CADMIUM OXIDE THIN FILMS

2011 ◽  
Vol 10 (04n05) ◽  
pp. 713-716 ◽  
Author(s):  
B. SAHA ◽  
R. THAPA ◽  
N. S. DAS ◽  
K. K. CHATTOPADHYAY
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Band Gap ◽  
Optical Band Gap ◽  
Quantum Confinement Effect ◽  
Cadmium Oxide ◽  
Quantum Size ◽  
Device Applications ◽  
Cdo Films ◽  
Different Thickness

CdO thin film with different thickness and different particle size are prepared through radio frequency magnetron sputtering technique. Quantum confinement effect causes the significant changes in their optical properties showing significant changes in the optical band gap. The CdO films are very highly conducting and transparent. Transparent and conducting thin films of CdO with effectively increased optical band gap are very useful for different device applications like solar cell, optoelectronic devices.

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