Films Of Different Compositions Research Articles

Corrosion, optical and magnetic properties of flexible iron nitride nano thin films deposited on polymer substrate

Iron nitride thin films of different compositions and thicknesses were deposited on flexible polymer substrate in Ar/N2 atmosphere by reactive magnetron sputtering under varying nitrogen flow rates. The nano structured films were characterized by X-ray diffraction, UV–visible spectrophotometer, electrochemical impedance (EIS), atomic force (AFM) and transmission electron microscopies. The dependence of their functional properties on coating and growth conditions was studied in detail. It was found that the thin films show a uniform permeability in the frequency range of 200MHz to 1Ghz and can be used in this range without appreciable changes. Decrease of nitrogen flow rate resulted in the smoother surfaces which in turn increase transmittance quality and corrosion resistance. Functional properties are dependent of nature, relative concentration of the iron nitride phases and film thickness. Surface integrity is excellent for180 nm thick sample because the films appear to be very dense and free from open pores. By keeping sputtering power stable at 110W, nitrogen flow rate of 10 sccm was ideal to develop the ferromagnetic γʹFe4N phase at room temperature.

Synthesis and characterization of ZnSxSe1-x films using Brush plating technique

ZnSxSe1-x films possess several interesting properties making them suitable for use in optoelectronic and optical applications. In this investigation, thin ZnSxSe1-x films were deposited for the first time by the brush plating technique. Thin films of ZnSxSe1-x were deposited at a constant current density of 80 mA cm-2 on titanium and conducting glass substrates at different temperatures in the range of 30 - 80°C. The precursors used were AR grade ZnSO4, sodium thiosulphate and sodium selenosulphate. XRD patterns of the films of different composition deposited at different temperatures exhibited hexagonal structure. An absorption coefficient of 104 cm-1 was observed. Extrapolation of the linear region to the hν axis yields the band gap in the range of 2.64 – 3.58 eV for the films deposited at different temperatures. EDAX study indicated that the composition of the films obtained were nearly equal to the composition of the precursors taken for deposition. X-ray photoelectron spectroscopy studies on the films of different composition deposited at 80°C. showed the spectra of Zn (2p), Se (3p1/2 and 3p3/2) and S (2p) levels. Atomic force microscope studies indicated that the surface roughness of the films increase from 1.04 – 5.45 nm as the ZnSe concentration increased. The grain size increases from 15 nm – 40 nm as the concentration of ZnSe increased.

Elastomagnetoresistive Properties of Films of 3d-Metalls Alloys

Magnetoresistive properties of 3d-metals alloys magnetostrictive films under application of elastic deformations were investigated. Linear stress was shown to have a significant effect on magnetoresistive effect in the films through the rotation of the easy magnetization axis. Dependencies of the relative change of resistivity were obtained in a cyclic deformation regime for films of different compositions.

Progress in the Design of New Photonics and Optoelectronics Elements Using Advantages of Contemporary Femto-Nanophotonics

We consider experimentally and theoretically the detection of quantum states in nanocluster semiconductor/metal structures upon the registration of hopping/tunneling electrical conductivity and possible mechanisms of realization of such states. We obtain nanostructured thin films on the substrates using different technologies, including laser ablation of solid surfaces. We show that it is possible to control the properties of the films by varying the topology of such synthesized systems. We analyze the features arising due to the specific conductivity of granular media revealed by the measured current–voltage characteristics and electrical resistance dependences for nanocluster bimetallic films of different compositions.

Titanium Nitride as a Strain Gauge Material

The performance of titanium nitride (Ti-N) thin films deposited by reactive magnetron sputtering for use as a strain gauge material was investigated. Films of different composition ranging from pure titanium to over-stoichiometric Ti-N were prepared by varying the nitrogen flow to total flow ratio ( $\alpha )$ . The atomic composition was measured using Rutherford backscattering spectrometry and energy-dispersive X-ray spectroscopy. The structure of the films was studied using X-ray diffraction and scanning electron microscopy, revealing the formation of a columnar film morphology consisting of cubic-Ti-N grains with preferential crystal orientations depending on the flow ratio $\alpha $ . The stability of the film resistivity was studied at 200 °C for 360 h. Films deposited at low ( $\alpha \leq 0.08$ ) and high ( $\alpha = 0.60$ ) nitrogen flows exhibited a stable behavior relative to films deposited with intermediate nitrogen flows. The longitudinal piezoresistive gauge factor was found to increase with increasing nitrogen flow before settling at values of 6–6.35. Finally, the temperature coefficient of resistivity was found to be less than 300 ppm/°C for the films with the highest gauge factors. The results demonstrate that the Ti-N films have a good potential as a strain gauge material, especially due to the relatively high gauge factor. [2016-0040]

The Nanode 3D Tin Anode for High Energy and High Rate

The Nanode is a nanoporous conductive membrane that provides a three dimensional matrix as a low cost support for electrodes. It is fabricated using commodity raw materials and chemicals, and manufacturing processes are in development for production on a roll-to-roll line. The Nanode is combined with tin and tin alloys to form high energy anodes for lithium ion batteries. A thin film of active material is applied to the extremely high surface area of the conductive substrate which acts as the current collector. This has been shown to achieve greater energy at higher discharge rates compared to graphite anodes. Testing has been performed from 1 to 10C discharge rates at 100% depth of discharge paired with commercial NCM cathodes. In addition, the nanoporous structure accommodates the expansion of the thin film of tin within its pores, reducing the overall electrode expansion/contraction occurring on charge/discharge of the anode. Altogether, the low cost production, high energy at high rate, and reduced expansion of this anode provide a beneficial combination of features for future lithium ion batteries. The Nanode technology also shows promise for applications beyond traditional lithium ion batteries, using alternative battery chemistries. This is made possible by the Nanode’s complex yet versatile electrode structure supported by a flexible manufacturing process that allows for the deposition of a range of metallic thin films of different compositions. These applications hold the potential to improve the energy density of rechargeable batteries beyond the limits of the traditional foil/particle approach, and they could reduce the cost of energy storage.

Electrodeposition and characterization of composition-graded CdSxSe(1–x) multilayer thin film structures

In this study, the electrodeposition of a composition-graded stacked CdSxSe(1–x) multilayer film is a matter which is reported for the first time. The electrodeposition was carried out using CdSO4, Na2S2O3 and SeO2 as precursors in an acid solution. Previously, an exhaustive electrochemical study was carried out in order to establish the best condition for the electrodeposition of this structure. In order to confirm the feasibility of the method proposed, CdSxSe(1–x) single-layer films of different composition were electrodeposited and characterized. The electrodeposition of the composition-graded stacked layer arrangement was potentiostatically performed through successive electrodeposition steps in a unique electrolytic solution in which its Se content is gradually increases. The characterization of both, single-layer films and multilayer structure was performed using different techniques, confirming the formation of an alloy between CdS and CdSe. Furthermore, the multilayer structure composition gradually changes from pure CdS to a rich selenium CdSxSe(1–x) compound as the electrolytic solution composition increases its SeO2, forming a depth bandgap graded material.

Spectroscopic ellipsometry study of compound-induced changes in chemical and optical properties of In2O3:Sn–ZnO:Al films

In this study, indium–zinc oxide (IZO) films of different compositions were deposited on quartz glass by alternate sputtering of ZnO:Al and In2O3:Sn targets at room temperature. Spectroscopic ellipsometry (SE) measurements were carried out over the wavelength range 193–1690nm in order to estimate the chemical, optical, and electrical properties of the IZO films using various dispersion models, i.e., the Tauc–Lorentz (TL), and Lorentz, Gaussian, and Drude models. The experimental results showed that the tail absorption was essentially affected by the Zn content and crystallinity of the film. The optical constants of the amorphous IZO films were accurately estimated using the TL and Drude models, and inclusion of the Lorentz model in the SE analysis overcame the inhomogeneity effect caused by preferential orientation growth. On the basis of these results, a k factor was defined and used to estimate the Zn contents of the IZO films. The variations in the k factors as a function of Zn content agreed well with those of the band gaps of the IZO films. Furthermore, for films with better conductivities, the resistivity values obtained using the SE and Hall methods were similar, but low carrier concentrations caused failure of the Drude model.

Comparative Analysis of Physical and Chemical Properties of Biodegradable Edible Films of Various Compositions

AbstractChemically synthesized polymeric films are widely used for packaging in the food industry, because they are easily and inexpensively produced from uniform raw materials and are both flexible and durable. A serious disadvantage of these films is that they are not biodegradable. The growth of environmental concerns over nonbiodegradable petrochemical‐based plastics raised interest in the use of biodegradable alternatives, originating from renewable sources. In this regard, the physical, chemical and mechanical properties of the biodegradable films of different composition are analyzed: gelatin‐based, cornstarch and carrageenan. The films were synthesized according to the existing technologies and the following characteristics were analyzed: film thickness, mechanical properties, integral light transmission coefficient and degradation of these films in biological mediums, chemical resistance of the films and their thermal properties.Practical ApplicationsThrough the experimental data the dependences for the prediction of physical–chemical, mechanical, optical and thermal properties of biodegradable films made of vegetable polysaccharides were obtained. The new biodegradable edible materials based on specially selected combinations of plant polysaccharides were created, which will be used in the production of edible packaging materials for foodstuffs or capsule shells for targeted delivery of biologically active substances in medicine. The detection of degradation patterns of biodegradable films based on plant polysaccharides was performed in different parts of the gastrointestinal tract, which can be used in the development of edible packaging materials for the food industry or capsule shells for targeted drug delivery in medicine. The optical behavior patterns of biodegradable edible films based on plant polysaccharides in the ultraviolet and visible regions of the spectrum were established with a view to provide subsequent creation of packaging materials for the food industry for long‐term storage of products.

聚乳酸/聚氧乙烯薄膜的性能研究

本文采用DSC测试了聚氧乙烯(PEO)和聚乳酸(PLA)的结晶温度(TC)和熔融温度(Tm)，用溶液共混方法制备了不同组成的PLA/PEO共混物薄膜，并对其进行了差示扫描量热(DSC)、广角X射线衍射(WAXD)及偏光显微镜(POM)分析。结果表明：共混物中薄膜PLA的结晶温度和熔融温度随PEO在共混物中含量的增加而减小；而熔融温度降低的幅度较小，但是都比PLA均聚物的熔融温度低；PLA在共混物薄膜中的结晶形态与PLA均聚物一致，但结晶尺寸相差很大。 The crystalline temperature and melt temperature of PEO were measured by DSC. PLA/PEO blend thin films of different composition were synthesized by solution blending, and the thin films were tested by Differential Scanning Calorimetry (DSC), Wide-Angle X-ray Diffraction (WAXD) and Po-larized Optical Microscope (POM). The results demonstrate that the crystalline temperature and the melting temperature of PLA decrease when the content of PEO in blend materials increases. The range of the decrease of the melting temperature is smaller. Its melting temperature is lower than the melting temperature of PLA homopolymer. Crystalline morphology in blends is consistent with PLA homopolymer, but the crystal size is difference.

Properties of Pulse Electrodeposited CuInGaSe2 Films

CuIn1-xGaxSe2 films of different composition (0< x <1), were pulse electrodeposited on indium tin oxide coated glass and molybdenum substrates at 50 % duty cycle and at room temperature. The films exhibited single phase chalcopyrite structure. The band gap of the films increased from 1.11 eV to 1.62 eV as the gallium concentration increased. The magnitude of the room temperature resistivity increased from 0.8 ohm cm to 23.52 ohm cm as the gallium concentration is increased. . Films of composition CuIn0.7Ga0.3Se2 exhibit maximum Voc. The power output characteristics after 80s photoetching indicates a Voc of 0.70V, Jsc of 20.0 mA cm-2, ff of 0.71 and h of 14.33 %, for 60 mW cm-2 illumination.

Lead-free (K0.5Na0.5)NbO3 thin films by pulsed laser deposition driving MEMS-based piezoelectric cantilevers

Thin film capacitors of the lead-free (K0.5Na0.5)NbO3 (KNN) with (100) orientation were grown on Pt/Ti/SiO2/SOI (silicon-on-insulator) substrates by pulsed laser deposition. The films are pure phases and do not show other crystal orientations. The remnant polarization Pr, saturation polarization Psat, longitudinal d33,f and transverse (d31,f and e31,f) piezoelectric coefficients of the KNN films were determined (Pr=12.6µC/cm2, Psat=25.0µC/cm2, d33,f=58pm/V, d31,f=−42pm/V and e31,f=−5.6C/m2). These values are well comparable with the highest values reported for lead-free films of different compositions and therefore these KNN films form a potential alternative to PZT films in lead-free MEMS applications.

Research of the morphological and structural properties of CdTe films obtained by chemical molecular beam deposition for thin film solar cells

CdTe films of different composition were obtained by chemical molecular beam deposition (CMBD). Their morphological and structural properties before and after heat treatment were investigated. The study of pictures of a scanning electron microscope and X-ray diffraction analysis showed that CdTe films have a well-oriented polycrystalline structure with a preferred orientation (111), size of film grains of 3–5 μm, and the structure of the (grains) films is denser. This conditions the possibility of growing CdTe films of different composition suitable for the manufacture of photovoltaic devices.

Properties of Pulse Electrodeposited CuInGaSe2 Films

CuIn1-xGaxSe2 films of different composition (0< x <1), were pulse electrodeposited on indium tin oxide coated glass and molybdenum substrates at 50 % duty cycle and at room temperature. The precursors used were 20 mM SeO2, 30 mM CuCl2 and the concentration of the Indium chloride and gallium chloride precursors were varied to obtain films of different composition. The deposition potential was maintained at – 0.8V (SCE). The pH was maintained at 1.5 by HCl. A microprocessor controlled pulse plating unit was used. Thickness of the films measured by Mitutoyo surface profilometer was in the range of 0.5 – 1.4 micrometer with increase of Indium concentration. The x-ray diffraction patterns of CuIn1-xGaxSe2 films of different composition. All the figures indicate the prominent peaks corresponding to (112), (220)/(204), (312)/(116). These care characteristic of the chalcopyrite phase. No other phases were observed in the x-ray diffractograms indicating the formation of single phase material. The peaks shifted from CuInSe2 side to CuGaSe2 side as the concentration of Ga increased in the films. Composition of the films was estimated by recording the EDS spectrum of the films deposited of different composition. It is observed that films with lower concentrations of Gallium were copper rich. As the gallium concentration increased, the films became nearly stochiometric. The tranmssion spectra exhibits interference fringes and the value of the refractive index was estimated by the envelope method. The refractive index decreases from 2.80 to 2.35 with wavelength. The band gap of the films increased from 1.11 eV to 1.62 eV as the gallium concentration increased ( from(αhν)2 vs hν plot ). The increase in band gap at lower duty cycles is due to the small crystallites. The values of the band gap agree well with the earlier report. The room temperature transport parameters were measured by Hall Van der Pauw technique by providing gold ohmic contact. The magnitude of the resistivity increased from 0.8 ohm cm to 23.52 ohm cm as the gallium concentration is increased. The resistivity values are comparable with an earlier report. The PEC cells using these films exhibited low photocurrent and photovoltage. The intensity of the light falling on the films deposited at different duty cycles was kept constant at 60 mW cm-2. Films of composition CuIn0.9Ga0.1Se2 exhibited maximum photo output. The photooutput was low, hence, in order to increase the photo outpout, the films of different composition were post heated in argon atmosphere at different temperatures in the range of 450 - 550°C for 15 min. Films of composition CuIn0.7Ga0.3Se2 exhibit maximum Voc. The power output characteristics after 80s photoetching indicates a Voc of 0.70V, Jsc of 20.0 mA cm-2, ff of 0.71 and h of 14.33 %, for 60 mW cm-2 illumination.

Surface Properties of Nanoscale Iron Garnet Films

Surface properties of nanoscale iron garnet films of different compositions prepared by reactive ion beam sputtering were examined by means of scanning probe microscopy. Atomic force microscope images of the film surfaces are represented for the films of different compositions and deposition times. The article presents the dependences of the roughness parameters on the film composition and thickness and on the energy of Ar+ ions by which the substrates were pre-treated. It was shown that the roughness parameters of the films' surface increase with the increase of Ar+ ions energy and the films' thickness.

(Dielectric Science & Technology Division Thomas D. Callinan Award) Boron Carbon Nitride Thin Films for Low-k Dielectric Interconnect and Optical Applications

New microprocessor CMOS technologies require interlayer dielectric materials with lower dielectric constant than those used in current technologies to meet RC delay goals and to minimize cross-talk. Silicon oxide or fluorinated silicon oxide (SiOF) materials having dielectric constant in the range of 3.6 to 4 have been used for many technology nodes. In order to meet the aggressive RC delay goals, new technologies require dielectric materials with k < 3. Boron carbide nitride (BCN) shows promise as a low dielectric constant material with good mechanical strength suitable to be used in newer CMOS technologies. BCN ternary system exhibits exceptional properties and attract much attention from mechanical, optical and electronic perspectives. BCN thin films contain interesting phases such as diamond, cubic BN (c-BN), hexagonal boron nitride (h-BN), B4C, β-C3N4. Attempts have been made to form a material with semiconducting properties between the semi metallic graphite and the insulating h-BN, or to combine the cubic phases of diamond and c-BN (BC2N heterodiamond) in order to merge the higher hardness of the diamond with the advantages of c-BN, in particular with its better chemical resistance to iron and oxygen at elevated temperatures. For optical applications, the deposition of BCN coatings on polymers is a promising method for protecting the polymer surface against wear and scratching. BCN films have high optical transparency and thus can be used as mask substrates for X-ray lithography. In this work, the deposition and characterization of amorphous thin films of boron carbon nitride (BCN) are reported. The BCN thin films were deposited by radio frequency (rf) magnetron sputtering technique. The BCN films were deposited by sputtering from a high purity B4C target with the incorporation of nitrogen gas in the sputtering ambient. Films of different compositions were deposited by varying the ratios of argon and nitrogen in the sputtering ambient. Investigation of the oxidation kinetics of these materials was performed to study high temperature compatibility of the material. Both the dielectric and optical properties seem to be sensitive to carbon and nitrogen content in the films.

In situ study of mass loss, shrinkage and stress development during drying of cast colloidal films

During constrained drying of binder-assisted colloidal coatings on rigid substrates, drying stress-induced defects such as cracks and warpage can often be observed due to the lateral confinement of the film by the substrate. The purpose of the current work is to understand the origin of these drying defects and to develop strategies for their avoidance by the adjustment of slurry composition or processing parameters. In this paper, the time-dependent drying behavior of colloidal ceramic coatings was studied in situ by observation of mass loss, drying shrinkage and drying stress by different methods, such as transparent substrate deflection and beam deflection methods. The stress development and the critical moment, at which cracks form, were investigated in films of different compositions with respect to solvent, particle size, binder and plasticizer. The origins of the measured differences in drying shrinkage, crack formation as well as residual stresses after drying were discussed.

Stable dielectric response in lead-free relaxor K0.5Na0.5NbO3–SrTiO3 thin films

K 0.5 Na 0.5 NbO 3– SrTiO 3 (KNN–STO) thin films of different compositions were prepared by the chemical solution deposition method. While structural investigations confirmed the formation of perovskite solid solution in all developed films, dielectric experiments revealed a relaxor broad dispersive maximum in the sample with 15 mol% of STO, exhibiting for a thin film high ε′ ~ 330 at ~ 210 K. The history-dependent effects of this relaxor sample were compared to those of KNN–STO ceramics and, furthermore, shown to be much weaker than in widely used lead-based ferroelectric and relaxor ( Pb , La )( Zr , Ti ) O 3 ceramics: While fatigue endurance results revealed a slight drop in polarization after 3 × 105 switching cycles, the results of aging of the dielectric constant revealed no notable decrease in its values after 106 s.

Study of growth kinetics and depth resolved composition of a-SiNx:H thin films by resonant soft X-ray reflectivity at the Si L2,3-edge

Abstract Angle dependent resonant soft X-ray reflectivity (R-SoXR) measurements in the energy range (82.67–206.7 eV) were performed on PECVD grown amorphous hydrogenated silicon nitride (a-SiN x :H) thin films of different compositions near the Si– L 2,3 edge (∼100 eV). The compositional difference is reflected in the optical density ( δ ) of the two films. It is demonstrated that R-SoXR can non-destructively distinguish between the compositional variations through the depth of a given thin film, whereby it becomes possible to differentiate between the growth kinetics of the films prepared under different conditions. The compositions determined from R-SoXR, are in qualitative agreement with those determined from Rutherford back scattering (RBS) and elastic recoil detection analysis (ERDA).

Collisions of low-energy Ar+, N2+, and D2+ ions with room-temperature and heated surfaces of mixed beryllium–tungsten thin films of different composition

Collisions of Ar+, N2+, and D2+ ions of incident energies 20–100eV with thin mixed beryllium–tungsten films of different composition (BeW(90:10); BeW(50:50); BeWO(60:22:11)) and different temperatures of the samples (room temperature, 150°C, 300°C) were investigated using a tandem mass spectrometer system. Mass spectra of product ions arising from Ar+ collisions with the three samples showed sputtering of the basic material of the sample substrate (Be+, BeH+, BeOH+; Li+, Na+, K+) and of hydrocarbon ions from the hydrocarbon coverage of the sample that decreased with increasing temperature. Sputtering of W+ or its compounds could not be detected. Normalized relative ion yields of Be+ and its compounds were not proportional to the Be content in the sample. Mass spectra from N2+ collisions were very similar to those of Ar+. Surface-induced dissociation of N2+ to N+ was not detected. The most conspicuous difference between mass spectra from D2+ impact and from Ar+ impact was a much lower sputtering efficiency of D2+ (by a factor of 50–100 or, for alkali ions, even more). The relative ion yield of Be+ strongly increased when the temperature of the sample was raised to 400°C and 450°C. A surface chemical reaction between the incident D2+ and surface Be leading to BeD+ was observed. The data may be of interest as basic information relevant to plasma–wall interactions in fusion devices.