Atomic Composition Of Films Research Articles

Atomic composition, structure, and electrical properties of In1-xGaxSb films deposited by magnetron sputtering

This article reports the formation of polycrystalline In1-xGaxSb films (x = 0, 0.2, 0.4, 0.5, and 1) deposited by magnetron sputtering on SiO2/Si substrates and a comprehensive characterization of their atomic composition, structure, and electrical properties. The structural and electrical characteristics of the films can be easily tuned by varying the stoichiometry of the compounds. The atomic composition of the films was investigated with particle induced x-ray emission and Rutherford backscattering spectrometry (RBS) techniques (the latter as a function of depth), while grazing incidence x-ray diffraction analysis yielded valuable information about the structure of the films. In1-xGaxSb films were polycrystalline, with crystallite sizes in the range 18–42 nm. Combining RBS and scanning electron microscopy results, it was possible to infer the overall density and also the density of the crystalline portion of the films, which turned out to be significantly distinct. A non-negligible fraction of oxygen atoms has been detected in all films, most prominently in the ternary ones, contributing to the formation of high density amorphous In2O3 and Ga2O3 in films with 40% and 50% Ga, while amorphous antimony oxide phases are predominant in the binaries as well as the ternary compound with 20% Ga. The electrical characterization of the films was performed using four point and Hall effect methods and the results show a consistent increase in resistivity with Ga concentration.

Atomic Composition and Morphology of Thin Films of Resveratrol Deposited on Oxidized Silicon and Polycrystalline Gold Surfaces

The atomic composition of films of a polyphenol antioxidant, namely, resveratrol (RVL), with a thickness of up to 50 nm thermally deposited on an oxidized silicon surface is studied by the method of X-ray photoelectron spectroscopy (XPS). It is found that the surface area of pores in the RVL film is about 15% of the total surface area. The results of studying the stability of the RVL films when their surface is treated with Ar+ ions of 3 keV under the electric current of 1 μA passing through the sample for 30 s are given. The treatment gives rise to an increase in the area of pores to 30–40%, while the ratio of the concentration of C atoms to the concentration of O atoms in the RVL film both before and after the treatment of the surface with ions does not correspond to the chemical formula of RVL molecules. Using the method of atomic force microscopy (AFM) in contact mode with a scanning area size of about 10 × 10 μm, RVL coatings deposited on the oxidized silicon and polycrystalline Au surfaces are studied. It is found that the RVL films produce grainy and porous coatings on the substrate surfaces. The typical size of grains in the sample surface plane is 150–300 nm, and the characteristic elevation reaches 30 nm.

Ge-rich SiGe thin film deposition by co-sputtering in in-situ and ex-situ solid phase crystallization for photovoltaic applications

This study investigates the properties of high Ge content silicon-germanium thin films in the non-hydrogenated state (Ge-rich SiGe) deposited on glass by RF magnetron co-sputtering in both in-situ and ex-situ solid phase crystallization (SPC) at various temperatures, such as RT to 550°C. The structural and optical characteristics of SiGe films have been explored systematically by optimizing growth temperature. Atomic composition of films was determined by EDX, which showed up to 77at% of Ge. Structural properties were characterized by XRD, which revealed all samples to be in amorphous nature. The results from Raman and UV–VIS–IR transmittance measurements showed that the properties of amorphous Si0.23Ge0.77 films improved at 450°C in both in-situ and ex-situ SPC processes. In addition, EDX exposed an advantage of in-situ process over ex-situ due to the incorporation of oxygen during ex-situ thermal annealing. Possible deposition at low substrate temperature as found here suggests that these Si0.23Ge0.77 films have a substantial potential to be used in thin film Si-based solar cells.

Changes in characteristics of gadolinium, titanium, and erbium oxide films on the SiC surface under microwave treatment

The effect of microwaves on properties of Ti, Gd, and Er oxide films deposited on silicon carbide was studied using optical absorption and photoluminescence methods. The atomic composition of films was analyzed in relation to the microwave treatment time. It was shown that exposure to microwaves results in the appearance of an additional band in the photoluminescence spectra of the structures under study. It was shown that microwave treatment leads to an increase in the sample transmittance, which indicates an improvement in integrated characteristics of structures.

Optical Constants of CuInSe2 Thin Films Prepared by Two-Stage Process

Thin film CuInSe2 chalcopyrite semiconductors have been prepared on glass substrates by means of two-stage process. The structural properties and atomic compositions of films were determined by energy-dispersive analysis of x-rays (EDAX) and x-ray diffraction (XRD) measurements. Reflectance and transmittance measurements were performed on the films in the photon wavelength range of 300–2200 nm. The samples used in the measurements have different Cu/In ratios. The reflectance and transmittance spectra were analyzed on the basis of multiple reflection model considering the absorbing film on a non-absorbing substrate and then complex refractive-index n*(E) = n(E) + ik(E) and complex dielectric constant ε*(E) = ε1(E) + iε2(E) were determined. It has been concluded that the films having higher Cu/In ratios show stronger absorption at low photon energy region than those having lower Cu/In ratios.

Structure, composition and microhardness of (Ti,Zr)N and (Ti,Al)N coatings prepared by DC magnetron sputtering

The composition, structure and microhardness of (Ti,Zr)N and (Ti,Al)N thin films deposited by DC reactive magnetron sputtering technique have been studied. The films were synthesized with a single magnetron source by co-sputtering route using constituent elemental targets under different conditions of nitrogen gas flow and substrate bias. The X-ray diffraction (XRD) analysis indicated the formation of fcc (Ti,Zr)N and (Ti,Al)N phases. The atomic composition of films, determined by backscattering techniques, varied with deposition conditions. The microhardness of the films estimated by J-H model is closely related to the atomic composition of the films, particularly to their nitrogen content.

Influence of desorption on the composition of high-temperature superconducting thin films during magnetron sputtering

Results are presented of investigations to study how desorption caused by interaction between the surface of condensation and the plasma particles affects the composition of thin films of Y-Ba-Cu-O high-temperature superconductors during magnetron sputtering. An analysis of the current-voltage characteristics of Langmuir probes was used to determine the floating potential of the substrate at various working gas pressures. Electron Auger spectroscopy was used to determine the atomic composition of films obtained at various substrate bias voltages. It was established that during magnetron sputtering of Y-Ba-Cu-O films the formation of the condensate composition may be strongly influenced by selective desorption of components from the substrate and the surrounding structural elements as a result of bombardment by plasma ions accelerated in the floating potential field.

Mechanisms of cation defect formation in epitaxial YBa 2Cu 3O 7− x films

Errors inherent in electron probe microanalysis of YBa 2Cu 3O 7 films and the atomic composition of films with a resolution of 2 μm have been found. Critical temperature values have been determined from the temperature dependence of the electron beam induced voltage (EBIV). Having plotted these results on a triple phase diagram of oxides, we found two tie lines with highest T c (ridges) and two tie lines with lowest T c (valleys). A mechanism of cation defect formation was proposed which accounts for the presence of this topology. The mechanism was verified by reconstructing cation defects observed in TEM images.