scholarly journals Soft x-ray optical constants of sputtered chromium thin films with improved accuracy in the L and M absorption edge regions

2018 ◽  
Vol 124 (3) ◽  
pp. 035107 ◽  
Author(s):  
Franck Delmotte ◽  
Julia Meyer-Ilse ◽  
Farhad Salmassi ◽  
Regina Soufli ◽  
Catherine Burcklen ◽  
...  
2019 ◽  
Vol 14 (29) ◽  
pp. 55-72
Author(s):  
Bushra A. Hasan

Alloys of InxSe1-x were prepared by quenching technique withdifferent In content (x=10, 20, 30, and 40). Thin films of these alloyswere prepared using thermal evaporation technique under vacuum of10-5 mbar on glass, at room temperature R.T with differentthicknesses (t=300, 500 and 700 nm). The X–ray diffractionmeasurement for bulk InxSe1-x showed that all alloys havepolycrystalline structures and the peaks for x=10 identical with Se,while for x=20, 30 and 40 were identical with the Se and InSestandard peaks. The diffraction patterns of InxSe1-x thin film showthat with low In content (x=10, and 20) samples have semicrystalline structure, The increase of indium content to x=30decreases degree of crystallinity and further increase of indiumcontent to x=40 leads to convert structure to amorphous. Increase ofthickness from 300 to 700nm increases degree of crystallinity for allindium content. Transmittance measurements were used to calculaterefractive index n and the extinction coefficient k using Swanepole’smethod. The optical constants such as refractive index (n), extinctioncoefficient (k) and dielectric constant (εr, εi) increases for low indiumcontent samples and decreases for high indium content samples,while increase of thickness increases optical constants for all xvalues. The oscillator energy E0, dispersion energy Ed, and otherparameters have been determined by Wemple - DiDomenico singleoscillator approach.


A scanning X-ray interferometer was used to measure the forward scattering amplitude for zirconium at a number of wavelengths near the K absorption edge. The precision of previous experiments has usually been limited by lack of knowledge of either the sample density or its shape. These problems have been eliminated by making simultaneous measurements at two X-ray wavelengths. This new measurement algorithm can be applied at any wavelength which is accessible to X-ray interferometers. The X-ray optical constants of elements with Z ≥ 10 can be determined over the range 0.1 Å<A< 5Å to a precision which is sufficient to rekindle theoretical interest in the subject.


2011 ◽  
Vol 10 (04n05) ◽  
pp. 985-988 ◽  
Author(s):  
N. S. DAS ◽  
K. K. CHATTOPADHYAY ◽  
B. SAHA ◽  
R. THAPA

Undoped and phosphorus doped nanocrystalline nickel oxide thin films have been synthesized on silicon and glass substrates by RF magnetron sputtering technique in pure Ar atmosphere. Proper phase formation was confirmed by X-ray diffraction analysis. Energy band gaps were determined using UV-Vis spectra. Formation of NiO nanoparticle of dimension ~15 nm was confirmed using HRTEM. Doping of phosphorus as an impurity was confirmed from EDX spectra and XPS studies. Spectroscopic ellipsometric studies were performed on such films and the spectra were analyzed with a suitable model. Optical constants were determined and refractive indices were found to increase with increase of phosphorus doping percentages.


2008 ◽  
Vol 15 (06) ◽  
pp. 787-791
Author(s):  
PEI ZHAO ◽  
RENG WANG ◽  
DINGQUAN LIU ◽  
FENGSHAN ZHANG ◽  
WEITAO SU ◽  
...  

The effects of the roughness of ZnS underlayer on the microstructure, optical, and electrical properties of nanometer Ag thin film have been investigated in this paper. Nanometer Ag thin films in glass/ ZnS /7.5 nm Ag /30 nm ZnS stacks have been deposited and analyzed. In the stacks, the underlayers of ZnS have been sputtered with various thicknesses to generate various surface roughnesses. The X-ray diffraction (XRD) has been used to study the crystal structure of Ag films. The surface topography and the roughness of ZnS underlayer have been analyzed by atomic force microscopy. The sheet resistant will become larger as the increasing of the roughness. The optical constants can be derived by fitting the transmission and reflectance spectrum. From optical constants comparison of Ag films, with the surface of the stack becoming rougher, it was found that the refractive index will increase but the extinction coefficient will decrease.


1994 ◽  
Vol 33 (10) ◽  
pp. 2013 ◽  
Author(s):  
Jianlin Cao ◽  
Mihiro Yanagihara ◽  
Masaki Yamamoto ◽  
Yoshinori Goto ◽  
Takeshi Namioka

1988 ◽  
Vol 143 ◽  
Author(s):  
B. Rodricks ◽  
F. Lamelas ◽  
D. Medjahed ◽  
W. Dos Passos ◽  
R. Smither ◽  
...  

AbstractWe demonstrate the simultaneous acquisition of high-resolution x-ray absorption spectra and scattering data, using a combination of energy-dispersive optics and a twodimensional CCD detector. Results are presented on the optical constants of Pt and on the reflectivity of a platinum-carbon multilayer at the LIII absorption edge of Pt.


2008 ◽  
Vol 130 (4) ◽  
Author(s):  
T. Giannakopoulou ◽  
N. Todorova ◽  
T. Vaimakis ◽  
S. Ladas ◽  
C. Trapalis

Ti O 2 is an excellent material for degradation of many environmental contaminants. Its photocatalytic activity is restricted by UV spectral region that can be extended to visible region using different doping techniques. Effect of fluorine-doping on the optical properties of sol-gel prepared TiO2 thin films is reported. Trifluoroacetic acid (CF3COOH) was used as fluorine source with starting concentrations of 5at.%, 10at.%, and 20at.% F to Ti. Gel films were deposited on SiO2∕soda lime glass substrates by dip-coating technique. After thermal treatment at 450°C fluorine containing TiO2 thin films were obtained. The crystallinity of the films was determined by X-ray diffraction (XRD). The X-ray photoemission spectrometry (XPS) was applied to determine valence state of the dopant and bonding element. The optical constants, namely, refractive index and the extinction coefficient, were obtained by fitting UV-visible theoretical transmittance curves to experimental ones. The simulated transmittance was calculated in the frames of the Forouhi–Bloomer (FB) dispersion model. The values of the FB energy band gap determined as onset of the absorption were compared with Tauc band gap values received by extrapolation of the linear part of the absorption edge. The XRD patterns reflect beginning of the anatase crystallization process. The XPS analysis reveals the presence of fluorine in the films in the form of titanium fluoride, titanium oxyfluorides, and nonstoichiometric TiO2−xFx. The linear part of the absorption edge of TiO2 films for mentioned fluorine concentrations gives slightly increased values of Tauc band gap (∼3.7eV) than that for bulk TiO2(∼3.2eV). Also, its broadening at lower frequencies with a FB band gap ∼2.7eV is observed. The results show that, although the fluorine is incorporated in the TiO2 lattice, it does not affect the crystallinity and band gap of the formed TiO2 film for the F∕Ti ratios used in the starting sols.


2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Meng Jiang ◽  
Yamei Li ◽  
Shaotang Li ◽  
Huaijuan Zhou ◽  
Xun Cao ◽  
...  

Spectroscopic ellipsometry study was employed for phase pure VO2(M1) thin films grown at different oxygen partial pressures by reactive magnetron sputtering. The optical constants of the VO2(M1) thin films have been determined in a photon energy range between 0.73 and 5.05 eV. The near-infrared extinction coefficient and optical conductivity of VO2(M1) thin films rapidly increase with decreasing O2-Ar ratios. Moreover, two electronic transitions can be uniquely assigned. The energy gaps correlated with absorption edge(E1)at varied O2-Ar ratios are almost the same (~2.0 eV); consequently, the absorption edge is not significantly changed. However, the optical band gap corresponding to semiconductor-to-metal phase transition(E2)decreases from 0.53 to 0.18 eV with decreasing O2-Ar ratios.


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