scholarly journals Optical constants acquisition and phase change properties of Ge2Sb2Te5 thin films based on spectroscopy

RSC Advances ◽  
2018 ◽  
Vol 8 (37) ◽  
pp. 21040-21046 ◽  
Author(s):  
Zemin Xu ◽  
Chaonan Chen ◽  
Zhewei Wang ◽  
Ke Wu ◽  
Haining Chong ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Phase Change ◽  
Extinction Coefficient ◽  
Optical Constants ◽  
Post Treatment ◽  
Chalcogenide Films ◽  
Treatment Processes

The refractive index and extinction coefficient of Ge2Sb2Te5 chalcogenide films can be subtly tuned with post-treatment processes.

Substrate Temperature Effect on Optical Constants of Gd2O3 Thin Films

2010 ◽  
Vol 442 ◽  
pp. 96-101 ◽  
Author(s):  
M.F. Wasiq ◽  
M.Y. Nadeem ◽  
Franck Chollet ◽  
S. Atiq
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Substrate Temperature ◽  
Band Gap ◽  
Extinction Coefficient ◽  
Optical Constants ◽  
Urbach Energy ◽  
Band Gap Energy ◽  
Oxide Material ◽  
Atomic Force

Effect of substrate temperature on lanthanide oxide material Gd2O3 thin films deposited by e-beam evaporation has been reported in the present work. Optical properties and surface morphology of as deposited films have been measured using spectrophotometry and atomic force microscopy respectively. Optical constants such as refractive index, extinction coefficient, band gap and Urbach energy have been determined by analysis of experimentally recorded absorption, transmittance and reflection data in wavelength range 200-800nm. Optical band gap energy shows decreasing while Urbach energy shows increasing behavior with increasing temperature. Extinction coefficient and refractive index with varying wavelengths are also calculated. Surface topographies of all samples are studied by atomic force microscope (AFM) and root mean square (RMS) value of roughness is observed increasing with increasing substrate temperature.

Optical Properties of Cu2ZnSnSe4 Nanocrystalline Thin Films for Photovoltaic Devices

2015 ◽  
Vol 789-790 ◽  
pp. 90-94
Author(s):  
Anderson Dussan ◽  
Heiddy P. Quiroz ◽  
Jorge A. Calderón ◽  
Sandra M. López
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Refractive Index ◽  
Optical Properties ◽  
Extinction Coefficient ◽  
Optical Constants ◽  
High Surface ◽  
Photovoltaic Devices ◽  
Xrd Patterns ◽  
Nanocrystalline Thin Films

Presents a study of optical properties from transmittance measurements as a function of wavelength to CZTSe thin films (Cu2ZnSnSe4) using Bhattacharyya model and basic elements from the Swanepoel theory. The optical constants such as the absorption coefficient (α), the refractive index (n), the extinction coefficient (k) and physical properties such as gap (Eg), the real and imaginary part of the dielectric function (ε1 and ε2) and the film thickness (d), were determined. Gap values between 1.2 and 1.7 eV were obtained for compound when the mass (MX) of ZnSe was varied during the deposition stage. Inhomogeneity and high surface roughness were observed by SEM measurements for all samples. Size grain varying between 458.16 and 630.28 nm were obtained while the ZnSe binary mass varied from 0.171 to 0.153 g. Refractive index and extinction coefficient of Cu2ZnSnSe4 films were obtained for λ = 800 nm. A decrease of ε1 and ε2 was observed as the wavelength increases; it is associated with the presence of binary phases in the XRD patterns.

scholarly journals Optical constants of sputtered beryllium thin films determined from photoabsorption measurements in the spectral range 20.4–250 eV

2020 ◽  
Vol 27 (1) ◽  
pp. 75-82
Author(s):  
Mikhail Svechnikov ◽  
Nikolay Chkhalo ◽  
Alexey Lopatin ◽  
Roman Pleshkov ◽  
Vladimir Polkovnikov ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Synchrotron Radiation ◽  
Initial Data ◽  
Absorption Coefficient ◽  
Energy Range ◽  
Transmission Coefficient ◽  
Radiation Source ◽  
Optical Constants ◽  
Free Standing

In this work, the refractive index of beryllium in the photon energy range 20.4–250 eV was experimentally determined. The initial data include measurements of the transmittance of two free-standing Be films with thicknesses of 70 nm and 152 nm, as well as reflectometric measurements of similar films on a substrate. Measurements were carried out at the optics beamline of the BESSY II synchrotron radiation source. The absorption coefficient β was found directly from the transmission coefficient of the films, and the real part of the polarizability δ was calculated from the Kramers–Kronig relations. A comparison is carried out with results obtained 20 years ago at the ALS synchrotron using a similar methodology.

The Influence of Bi Content on the Properties of Bismuth Ferrite Thin Films Fabricated by Magnetron Sputtering

2013 ◽  
Vol 745-746 ◽  
pp. 131-135
Author(s):  
Hu Rui Yan ◽  
Nuo Fan Ding ◽  
Gang Wu ◽  
Ping Xiong Yang ◽  
Jun Hao Chu ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Magnetron Sputtering ◽  
Extinction Coefficient ◽  
Energy Gap ◽  
Lattice Mismatch ◽  
Bismuth Ferrite ◽  
Film Surface ◽  
Si Substrate ◽  
Impurity Phases

In the process of BiFeO3 film preparation by magnetron sputtering, Bi element is volatile, leading to the films which often appear impurity phases. Therefore, Both Bi excessive 5% (B1.05FO) and 8% (B1.08FO) BFO film in Si substrate were prepared by magnetron sputtering. X-Ray Diffraction (XRD) results showed that the BFO thin films fabricated in the Si substrate are perovskite structure, that the B1.08FO film appeared less impurity phases than B1.05FO film, and that stress due to substrate lattice mismatch caused the shift of XRD patterns. In Raman study, it was concluded that both B1.08FO film and B1.05FO film appeared ten Raman peaks in the range from 50cm-1 to 800cm-1, and that B1.08FO Raman peaks intensity was stronger in 137.1cm-1.168.5cm-1 and 215.3cm-1. Spectroscopic ellipsometry test showed that the refractive index and the extinction coefficient of B1.05FO film were 2.25 and 0.07 respectively in 600 nm with 2.67eV of energy gap; the refractive index and the extinction coefficient of B1.08FO film were 2.14 and 0.05 in 600 nm respectively with 2.71eV of energy gap. Atomic Force Microscope (AFM) was used to characterize the film surface morphology, finding that the B1.08FO film prepared in Si substrate was denser while grain size and surface roughness were smaller.

Optical Nonlinearity of Sputtered Co3O4-SiO2-TiO2 Thin Films

2001 ◽  
Vol 703 ◽  
Author(s):  
Hiroki Yamamoto ◽  
Takashi Naito ◽  
Kazuyuki Hirao
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Excited State ◽  
Absorption Coefficient ◽  
Extinction Coefficient ◽  
Ground State ◽  
Optical Nonlinearity ◽  
Tio2 Thin Films ◽  
Change Mechanism ◽  
Band Filling

ABSTRACTOptical non-linearity of cobalt oxide with SiO2-TiO2 additives was investigated, and the change mechanism of the refractive index (n) and extinction coefficient (k), based on the relation between band structure and optical non-linearity of the thin films, was discussed. Refractive index and extinction coefficient of Co3O4 thin films in the ground state were 3.17 and 0.42, respectively. Both n and k decreased by irradiation from a pulse laser with 650 nm of wavelength (1.91eV). These values in the excited state were 2.91 and 0.41, respectively. n2 estimated from the change of n and k was −2.8 ×10−11 m2/W. The film had a band gap corresponding to 2.06eV, indicating that it was widened by the band filling effect during the laser irradiation at 1.91eV, and this led to the decrease in absorption coefficient and refractive index.

Determination of refractive index, extinction coefficient and thickness of thin films by the method of waveguide mode excitation

2013 ◽  
Vol 43 (12) ◽  
pp. 1149-1153 ◽  
Author(s):  
V I Sokolov ◽  
N V Marusin ◽  
V Ya Panchenko ◽  
A G Savelyev ◽  
V N Seminogov ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Extinction Coefficient ◽  
Waveguide Mode ◽  
Mode Excitation

scholarly journals Spectral data of refractive index and extinction coefficient for thin films of titanium group metals used for fabrication of optical microstructures

Data in Brief ◽  
2020 ◽  
Vol 28 ◽  
pp. 104903
Author(s):  
Dmitrij A. Belousov ◽  
Vadim S. Terent'ev ◽  
Evgeny V. Spesivtsev ◽  
Victor P. Korolkov
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Spectral Data ◽  
Extinction Coefficient

scholarly journals An optical examination of thin films. I.—The optical constants of mercury

1934 ◽  
Vol 145 (854) ◽  
pp. 115-126 ◽  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Constants ◽  
Relative Phase ◽  
Reflection Coefficients ◽  
Angle Of Incidence ◽  
Clean Surface ◽  
Phase Retardation ◽  
Optical Examination ◽  
Approximate Equations

Drude originally suggested that the properties of films on both absorbing and non-absorbing substrates could be studied by an optical method, since the reflecting properties of a surface are modified by the presence of a film. This method has in part been used by various workers, with some success. For liquid surfaces, or for smooth surfaces of solids, such as are obtained by cleavage or after suitable polishing, it is possible to measure “the relative phase retardation,” Δ, and “the ratio of the reflection coefficients,” tan ψ, which define the reflecting properties. From the values of Δ and ψ for a clean surface, the refractive index, n , and the absorption coefficient, k , characteristic of the material can be found from the approximate equations n = sin ϕ tan ϕ cos 2ψ/(1 + cos Δ sin 2ψ), (1.1) k = sin Δ tan 2ψ, (2.1) where ϕ is the angle of incidence.

scholarly journals Structural, Optical Constants and Photoluminescence of ZnO Thin Films Grown by Sol-Gel Spin Coating

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Abdel-Sattar Gadallah ◽  
M. M. El-Nahass
Keyword(s):  
Thin Films ◽  
Dielectric Constant ◽  
Refractive Index ◽  
Spectral Range ◽  
Spin Coating ◽  
Optical Constants ◽  
Sol Gel ◽  
Free Carrier ◽  
Zno Thin Films ◽  
Free Carrier Absorption

We report manufacturing and characterization of low cost ZnO thin films grown on glass substrates by sol-gel spin coating method. For structural properties, X-ray diffraction measurements have been utilized for evaluating the dominant orientation of the thin films. For optical properties, reflectance and transmittance spectrophotometric measurements have been done in the spectral range from 350 nm to 2000 nm. The transmittance of the prepared thin films is 92.4% and 88.4%. Determination of the optical constants such as refractive index, absorption coefficient, and dielectric constant in this wavelength range has been evaluated. Further, normal dispersion of the refractive index has been analyzed in terms of single oscillator model of free carrier absorption to estimate the dispersion and oscillation energy. The lattice dielectric constant and the ratio of free carrier concentration to free carrier effective mass have been determined. Moreover, photoluminescence measurements of the thin films in the spectral range from 350 nm to 900 nm have been presented. Electrical measurements for resistivity evaluation of the films have been done. An analysis in terms of order-disorder of the material has been presented to provide more consistency in the results.

Optical properties of Al-doped ZnO thin films obtained by the method of high-frequency magnetron sputtering

2021 ◽  
pp. 2150189
Author(s):  
A. Kashuba ◽  
H. Ilchuk ◽  
R. Petrus ◽  
I. Semkiv ◽  
O. Bovgyra ◽  
...  
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Optical Properties ◽  
Magnetron Sputtering ◽  
High Frequency ◽  
Optical Constants ◽  
Zno Thin Films ◽  
Optical Parameters ◽  
Single Oscillator ◽  
Doped Zno

The optical constants and thickness of Al-doped ZnO (ZnO:Al(2.5 wt.%)) thin films prepared by high-frequency magnetron sputtering method are determined. ZnO:Al thin films are crystallized in the hexagonal structure from XRD studies. The optical constants and the bandgap of the films under study have been determined. Optical properties (refractive index [Formula: see text], absorption coefficient [Formula: see text], extinction coefficient [Formula: see text], dielectric functions [Formula: see text] and optical conductivity [Formula: see text]) of thin films and thickness [Formula: see text] can be determined from the transmission spectrum. The dispersion of the refractive index was explained using a single oscillator model. Single oscillator energy and dispersion energy are obtained from fitting. Optical parameters of the films were determined using the Cauchy, Sellmeier and Wemple models. The increasing value of dispersion parameter for polycrystalline thin films than for single crystals is observed. The fundamental absorption edge position (3.26 eV) in the transmittance spectrum of studied thin films corresponds to the values that are typical for ZnO:Al compound. No significant increase of the bandgap width was revealed by comparing ZnO:Al thin films with the known results of the optical studies of ZnO thin films. Possible reasons of such behavior were analyzed and the influence of bandgap increase on spectral behavior of optical functions are investigated. The material optical parameters such as normalized integrated transmission, zero and high-frequency dielectric constant, density of state effective mass ratio were also calculated.

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