scholarly journals Observation of high nonlinearity in Bi doped BixIn35-xSe65 thin films with annealing

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Priyadarshini ◽  
Subhashree Das ◽  
D. Alagarasan ◽  
R. Ganesan ◽  
S. Varadharajaperumal ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Phase Transformation ◽  
Annealing Temperature ◽  
Dielectric Constants ◽  
Nonlinear Properties ◽  
Linear Refractive Index ◽  
Non Linear ◽  
Optical Bandgaps ◽  
The Impact

AbstractThe present work demonstrates the impact of thermal annealing on the structural, linear, and non-linear optical characteristics of thermally evaporated BixIn35-xSe65 (x = 0, 5, 10, 15 at%) thin films. The prominent crystalline phases have been developed for all annealed films at 450 °C whereas the films remain amorphous at 350 °C annealing. The XRD and Raman analysis showed the phase transformation of Bi-doped films and new Bi2Se3 phases developed upon annealing at 450 °C. The phase transformation induced change increased the linear and nonlinear properties with great extent as seen from the UV–visible optical studies. The direct and indirect optical bandgaps decreased with annealing temperature and also with Bi % content due to the formation of surface dangling bonds near the crystallite sites. The static linear refractive index and high-frequency dielectric constants were increased with annealing. The third-order non-linear susceptibility and non-linear refractive index were found to be greatly influenced by annealing temperature and increased with bismuth content. The FESEM micrographs also showed the phase transformation and EDX analysis showed the composition. The results obtained from the materials showed the potentiality to be useful for photovoltaic and optoelectronic applications.

scholarly journals Determination of non-linear refractive index of laser crystals and ceramics via different optical techniques

2020 ◽  
Vol 8 ◽  
pp. 100065
Author(s):  
Laurent Lamaignère ◽  
Guido Toci ◽  
Barbara Patrizi ◽  
Matteo Vannini ◽  
Angela Pirri ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Techniques ◽  
Linear Refractive Index ◽  
Non Linear ◽  
Laser Crystals

scholarly journals Annealing Effect on Some Optical Properties of Cr2O3 Thin Films Prepared by Spray Pyrolysis Technique

2011 ◽  
Vol 8 (2) ◽  
pp. 561-565
Author(s):  
Baghdad Science Journal
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Optical Properties ◽  
Absorption Coefficient ◽  
Spray Pyrolysis ◽  
Annealing Temperature ◽  
Spray Pyrolysis Technique ◽  
Annealing Effect ◽  
Before And After

Cr2O3 thin films have been prepared by spray pyrolysis on a glass substrate. Absorbance and transmittance spectra were recorded in the wavelength range (300-900) nm before and after annealing. The effects of annealing temperature on absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant and optical conductivity were expected. It was found that all these parameters increase as the annealing temperature increased to 550°C.

Nb-H Thin Films: On Phase Transformation Kinetics

2017 ◽  
Vol 371 ◽  
pp. 160-165
Author(s):  
Vladimir Burlaka ◽  
Kai Nörthemann ◽  
Astrid Pundt
Keyword(s):  
Thin Films ◽  
Phase Transformation ◽  
Scanning Tunneling ◽  
State Change ◽  
Transformation Kinetics ◽  
Tunneling Microscopy ◽  
Fast Phase ◽  
Phase Transformation Kinetics ◽  
Local Lattice ◽  
The Impact

It was recently shown that phases forming in thin films undergo a coherency state change depending on the film thickness. For Nb-H thin films, the coherency state was reported to change at about 38 nm. In this study the impact of the coherency state on the phase transformation kinetics is investigated for Nb films of two different film thicknesses (25 nm and 80 nm), below and above the state change thickness. The phase transformation in thin metal-hydrogen films can be studied by surface topography analyses via scanning tunneling microscopy (STM) because of the strong local lattice expansion of the hydride precipitates. STM on Nb-H reveals fast phase transformation kinetics for the 25 nm Nb-film, and much slower kinetics for the 80 nm film. This is suggested to be related to the change in the coherency between the Nb-matrix and the hydride precipitates.

CORONENE ORGANIC FILMS: OPTICAL AND SPECTRAL CHARACTERISTICS UNDER ANNEALING TEMPERATURE INFLUENCES

2021 ◽  
pp. 2150081
Author(s):  
ERMAN ERDOGAN
Keyword(s):  
Refractive Index ◽  
Annealing Temperature ◽  
Film Growth ◽  
Low Cost ◽  
Spectral Characteristics ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Optical Bandgap ◽  
Dielectric Constants ◽  
Optical Parameters

In this study, spin coating, which is a chemical film layer thin film deposition method, was used for coronene films that were grown on Si substrates annealed at 325, 350 and 375[Formula: see text]K to examine the impacts on the optical properties of films. This method allows for easy control of the deposition parameters such as concentration, temperature and time as well as enables the film growth at low cost. Optical (UV–Vis) spectral measurements in the wavelength range from 200[Formula: see text]nm to 800[Formula: see text]nm were used to extract the bandgap information and to calculate various optical parameters of the spin-coated coronene films. The electronic transitions on the absorption of photons of suitable energy are of indirect allowed type. The corresponding optical bandgap ([Formula: see text]) was determined. Complex dielectric constants, dissipation factor, optical and electrical conductances and refractive index of coronene films were analyzed as a function of temperature. As the film annealing temperature was increased, the dielectric constants and the refractive index values increased, whereas the optical bandgap and electrical and optical conductivity values decreased.

Study the Nonlinearity Characteristics of Organic-Semiconductor (CuPc) Prepared Via Pulsed Laser Deposition Technique with Different Thickness

2019 ◽  
Vol 27 ◽  
pp. 11-20 ◽  
Author(s):  
Mohammed T. Hussein ◽  
Reem R. Mohammed
Keyword(s):  
Refractive Index ◽  
Absorption Spectrum ◽  
Pulsed Laser Deposition ◽  
Copper Phthalocyanine ◽  
Wave Length ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Deposition Technique ◽  
Linear Refractive Index ◽  
Non Linear

The optical absorption spectrum, Photoluminesces, and non-linear optical properties for Copper Phthalocyanine (CuPc) thin films (150,300 and 450 nm) respectively have been investigated via pulsed laser deposition technique. The absorption spectrum indicted that there are two bands one in UV around 330 nm which called B-band and the second in Visible around 650nm which called Q-band. Photoluminescence spectrum related to deposit samples has been determined with different thicknesses. From closed and open aperture Z-scan data non-linear absorption coefficient and non-linear refractive index have been calculated respectively using He-Ne laser which have beam waist of (24.2 μm), wave-length of (632.8 nm) and Rayleigh thickness was 2.9 mm. Through dividing closed by open apertures, non-linear refractive index was calculated accurately. Finally, the study also showed the suitability of the deposited films as an optical limiter at the wavelength 632.8 nm.

Stiff Polyimides: Chain Orientation And Anisotropy Of The Optical And Dielectric Properties Of Thin Films

1991 ◽  
Vol 227 ◽  
Author(s):  
D. Boese ◽  
S. Herminghaus ◽  
D. Y. Yoon ◽  
J. D. Swalen ◽  
J. F. Rabolt
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Dielectric Properties ◽  
Dielectric Constants ◽  
Polyimide Films ◽  
Lorenz Equation ◽  
Out Of Plane ◽  
Large Anisotropy ◽  
Uv Visible

ABSTRACTThin films of poly(p-phenylene biphenyltetracarboximide), prepared by thermal imidization of the precursor poly(amic acid) on substrates, have been investigated by optical waveguide, UV-visible, infrared (IR), and dielectric spectroscopies. The polyimide films exhibit an extraordinarily large anisotropy in the refractive indices with the in-plane index n║ = 1.852 and the out-of-plane index n┴ = 1.612 at 632.8 nm wavelength, indicating a strong preference of polymer chains to orient along the film plane. No discernible effect of the film thickness on this optical anisotropy is found in the range of ca. 0.4 μm to 7.8 μm in thickness. The frequency dispersion of the in-plane refractive index to 1.06 μm wavelength is consistent with the results calculated by the Lorentz-Lorenz equation from the UV-visible spectrum. The contribution from the entire IR range from 7000 to 200 cm,−1 computed by the Spitzer-Kleinmann dispersion relations from the measured spectra, adds ca. 0.07 to the in-plane refractive index n║. Approximately the same increase is assumed for the out-of-plane index n┴, based on the tilt-angle dependent IR results. Application of the Maxwell relation leads to the out-of-plane dielectric constant ε┴≃2.8 at ca. 1013 Hz, as compared with the measured value of ca. 3.0 at 106 Hz. Assuming this small difference to remain the same for the in-plane dielectric constants ε║, we obtain a a very large anisotropy in the dielectric properties of these polyimide films with the estimated in-plane dielectric constant ε║≃3.5 at ca. 1013 Hz, and ε.≃3.7 at 106 Hz.

scholarly journals Effect of Vacuum Annealing on the Optoelectric and Morphological Properties of F16CuPc Thin Films

2012 ◽  
Vol 9 (1) ◽  
pp. 294-300 ◽  
Author(s):  
Raji Koshy ◽  
C. S. Menon
Keyword(s):  
Thin Films ◽  
Annealing Temperature ◽  
Vacuum Annealing ◽  
Band Gap Energy ◽  
Dielectric Constants ◽  
Morphological Properties ◽  
Optical Data ◽  
Organic Transistors ◽  
Reflectivity Spectra ◽  
Electrical Study

The effect of vacuum annealing temperature on optical and electrical properties of vacuum evaporated F16CuPc thin films have been studied spectrophotometer and Kiethely electrometer respectively. The band gap energy both fundamental and excitonic remains unchanged when the annealing temperature increased. The optical constants of thin films are obtained by means of thin film spectrophotometry. From the electrical study, the activation energies of the films, in the intrinsic region and impurity region have been determined from the Arrhenious plots of lnσversus1000/T. Optical data have been obtained from both absorption and reflectivity spectra over the wavelength range 200-800 nm. The absorption coefficient α and extinction coefficient k are estimated from the spectrum. The mechanism of optical absorption follows the rule of direct transition. Using α and k, the refractive index and the dielectric constants are determined. The SEM investigations are F16CuPc thin films are expected to find application in the fabrication of optoelectronic devices such as organic transistors and LED devices.

Effect of Annealing Temperature on the Optical Parameters of CdS Thin Films Prepared by Thermal Evaporation Method

2013 ◽  
Vol 747 ◽  
pp. 329-332
Author(s):  
Thitinai Gaewdang ◽  
Ngamnit Wongcharoen ◽  
Tiparatana Wongcharoen
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Annealing Temperature ◽  
Thermal Evaporation ◽  
Optical Parameters ◽  
Spectral Transmission ◽  
Dispersion Energy ◽  
Thermal Evaporation Method ◽  
Transmission Data ◽  
Cds Thin Films

CdS thin films were prepared by thermal evaporation onto glass substrate in vacuum better than 5.5x10-5 mbar. The obtained films were subsequently annealed in a pure nitrogen atmosphere at temperature between 100 to 500°C for 30 min. The crystal structure and surface morphology of the as-deposited and annealed films were investigated by XRD and SEM, respectively. Optical band gap and Urbach tail values of the films, determined from spectral transmission data, were found to be slightly varied in the range 2.36-2.40 eV and 110-160 meV, respectively, due to annealing temperature. The refractive index of the films was also evaluated from the spectral transmission data. The dependence of the refractive index on the wavelength obeys the single oscillator model, from which the important parameters such as refractive index, extinction coefficient, oscillator energy (E0) and dispersion energy (Ed) of the films with different annealing temperatures were determined. From the experimental results, the optical parameters of the films are obviously influenced by annealing temperature.

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