Films Of Different Thicknesses Research Articles

Low organic content hybrid perovskite (Cs1-xDMAx)Pb(Br1-xIx)3 with increased stability for solar cell fabrication

Hybrid perovskites with reduced organic content have brought great interest for solar cells applications. Particularly, adding inorganic cations increase material stability, by providing an adequate tolerance factor. However, these cations lead to lower absorption coefficient than using only organic cations, therefore it is necessary to implement strategies for having films with appropriate thickness and good light absorption properties. In this work, several experiments were performed with ((Cs1-xDMAx)Pb(Br1-xIx)3 perovskite films of different thicknesses, resulting in devices with photovoltaic conversion efficiency (PCE) near 80% of the reference MAPbI3 cell, high purity phase, appropriate morphology, and higher stability. The perovskite successfully maintained integrity for 12 days in air with relative humidity between 30 and 40%, indicating the fulfillment of the study's objectives.

Kinetics of corrosion reactions on press hardened steel in atmospheric conditions under thin electrolyte films

Steels with high mechanical performance are prone to hydrogen embrittlement and environmental assisted cracking. Under atmospheric corrosion conditions, the source of hydrogen can be the steel corrosion process itself or galvanic coupling with a metallic coating. Electrochemical behaviour of Press Hardened Steel (PHS) under electrolyte films of different thicknesses using local electrochemical techniques was studied on a fundamental level. Scanning Vibrated Electrode Technique (SVET) was applied to study the evolution and localization of the corrosion process during PHS immersion in NaCl electrolyte. Kelvin Probe (KP) was used as a reference electrode to obtain cathodic and anodic polarization curves on PHS surfaces which were covered by thin electrolyte films (60 to 500 µm) of 0.1 M NaOH and 0.6 M NaCl. For both electrolytes, a strong increase in the oxygen reduction rate due to the decreasing of electrolyte thickness has been clearly demonstrated. Data are correlated well with a theoretical plot determined by Nernst-Fick equation. The influence of the rust layers on the kinetics of corrosion reactions under thin electrolyte films was investigated using KP.

Pseudocapacitive performance of amorphous ruthenium oxide deposited by successive ionic layer adsorption and reaction (SILAR): Effect of thickness

Developing and fabricating effective, affordable electrode materials for supercapacitors is still a challenge. Electrical conductivity, a large surface area, dynamic faster electron transport, and other customizable qualities are present in metal oxide materials while being inexpensive to manufacture. In this work, successive ionic layer adsorption and reaction (SILAR) method was employed for deposition of amorphous ruthenium oxide (RuO2) thin films of different thicknesses on a stainless steel substrate. At 1.56 mg cm−2 thickness amorphous RuO2 achieved a maximum specific capacitance (Cs) of 1146 F g−1 at a scan rate of 5 mV s−1 with 87% capacitance retention up to 5000 cycles. These findings bolster the idea of cost effective deposition of amorphous RuO2 material for supercapacitor applications.

InSnO:N homojunction thin-film transistors fabricated at room temperature

Nitrogen-doped indium tin oxide (ITON) thin films of different thicknesses were deposited by radio frequency magnetron sputtering. The crystallinity, surface morphologies, and chemical compositions of the thin films were found to be influenced by film thickness, and changes in these factors eventually caused changes in the conductivity of the thin films. Therefore, we used ultrathin ITON thin films as channels and an 85-nm-thick ITON as the source/drain electrodes to fabricate thin-film transistors. The optimal device fabricated at room temperature (∼25 °C) has a threshold voltage of −2.5 V and a field-effect mobility of 10.31 cm2/(V∙s).

Blast-Resistant Window Anchors. I: Experimental Investigation

A comprehensive experimental investigation was conducted on blast-resistant window anchors involving 46 tests of double-pane insulated glass units (IGUs) anchored to structural steel, reinforced concrete, concrete block masonry, and stone masonry substrates. The tests were conducted using a shock tube. The windows were glazed with security films of different thickness. Different number and spacing of steel anchors were used to secure the window frames to substrates. Each window was subjected to two levels of blast loads, consisting of 28 kPa, 207 kPa-ms, and 69 kPa, 621 kPa-ms reflected pressure–impulse combinations. The windows were instrumented to measure anchor forces. The anchors developed out-of-plane shear forces and in-plane axial tension associated with postbreak membrane action. The results indicate that anchor shear forces show variations with window stiffness, substrate type, and anchor arrangements, often developing lower forces than those computed based on the static application of blast loads, indicating significant inertia resistance. Rigid substrates produce higher anchor forces. In addition to the experimental results, the paper presents single-degree-of-freedom analysis results for anchor force computation, indicating good correlations with experimental data.

MoS2 Synthesized by Atomic Layer Deposition as Cu Diffusion Barrier

AbstractMiniaturization in integrated circuits requires that the Cu diffusion barriers located in interconnects between the Cu metal line and the dielectric material should scale down. Replacing the conventional TaN with a 2D transition metal dichalcogenide barrier potentially offers the opportunity to scale to 1–2 nm thick barriers. In this article, it is demonstrated that MoS2 synthesized by atomic layer deposition (ALD) can be employed as a Cu diffusion barrier. ALD offers a controlled growth process at back‐end‐of‐line (BEOL) compatible temperatures. MoS2 films of different thicknesses (i.e., 2.2, 4.3, and 6.5 nm) are tested by time‐dependent dielectric breakdown (TDDB) measurements, demonstrating that ALD‐grown MoS2 can enhance dielectric lifetime by a factor up to 17 at an electric field of 7 MV cm−1. Extrapolation to lower E‐fields shows that the MoS2 barriers prepared by ALD have at least an order of magnitude higher median‐time‐to‐failure during device operation at 0.5 MV cm−1 compared with MoS2 barriers prepared by other methods. By scaling the thickness further down in future work, the ALD MoS2 films can be applied as ultrathin Cu diffusion barriers.

Tanzânia grass haylage wrapped in films of different thicknesses

ABSTRACT The purpose of this study was to evaluate the production of gases, temperature, fermentation characteristics, chemical composition and aerobic stability of Tanzânia grass haylage wrapped in films of different thicknesses. Gas production and temperature were evaluated on storage days in 4 × 5 factorial scheme (four films: 27, 10, 11 and 13 µm and five storage times: 0, 7, 15, 30 and 60 days). Fermentation characteristics were evaluated in 4 × 4 factorial scheme (four films: 27, 10, 11 and 13 µm and four storage times: 7, 15, 30 and 60 days). Aerobic stability was evaluated in 4 × 3 factorial scheme (four films: 27, 10, 11 and 13 µm and three times of exposure to air: 0, 48 and 96 h). The lowest pH value of the evaluated haylages was found at 60 days. The largest population of lactic acid bacteria and smallest populations of enterobacteria were observed in the haylage wrapped in the film of 13 µm at 60 days. The haylage wrapped in the film of 13 µm had the highest values of dry matter and crude protein. When using Tanzânia grass for haylage making, it is recommended to use the polyvinyl chloride film of 13 µm and storage time of 60 days.

A wear monitoring method and influencing factors of water-lubricated polymer bearings based on improved ultrasonic reflection coefficient amplitude spectrum and ultrasonic reconfiguration calculation

The water-lubricated thrust bearings of the marine Rim-Driven Thruster (RDT) are usually composed of polymer composites, which are prone to serious wear under harsh working conditions. Ultrasonic is an excellent non-destructive monitoring technology, but polymer materials are characterized by viscoelasticity, heterogeneity, and large acoustic attenuation, making it challenging to extract ultrasonic echo signals. Therefore, this paper proposes a wear monitoring method based on an improved ultrasonic reflection coefficient amplitude spectrum, introducing an ultrasonic transfer function to mathematically resolve the attenuation coefficients in the propagation model, and using a differential evolutionary algorithm to invert the thickness, sound velocity, density, and attenuation coefficients of polymer bearings simultaneously. The effects of different influencing factors on the ultrasonic signal and identification results are explored, including probe contact pressure, surface roughness and surface inclination; In order to remove the influence of water film overlap on the identification of polymer bearing thickness, a water film separation method based on time-frequency domain ultrasonic reconfiguration is proposed to construct the ultrasonic theoretical time domain waveform of the bearing. An ultrasonic wear measurement system is built to record the ultrasonic echoes of PEEK test blocks with different pressures to the probe, surface roughness, and tilt angles. The experiment is carried out on the water film calibration test rig, using a high-precision spiral micrometer to simulate the mixing of water films of different thicknesses with polymer test block and collecting ultrasonic signals. The results show that the method has a thickness identification error of approximately 0.5% for PEEK specimens with different probe contact pressure, roughness, and tilt angle, and the reconfiguration thickness identification error is less than 1% for the full range of water film overlap.

Thickness dependent microstructural and magnetic studies of iron embedded PVA nanocomposite films

This paper presents the structural and magnetic properties of polyvinyl alcohol/iron (PVA/Fe) nanocomposite films. Iron (Fe) films of different thicknesses were deposited on a PVA substrate using ion beam sputtering. The Fe nanoparticle layer thickness ranges from 3 to 50 nm on the PVA substrate. Grazing incidence x-ray diffraction has been carried out to study the structural behavior of the prepared films. An atomic force microscope records the indicated remarkable change in the roughness of the nanocomposite film as a result of initiation of vertical growth of sputtered Fe nanoparticles.Magneto-optic Kerr effect (MOKE) magnetometry and MOKE spectroscopy have been employed to evaluate the magnetic property and simultaneously study the real time growth of the magnetic domain structure for both 0° and 90° azimuthal angles. MOKE microscopic images indicated the magnetization reversal commensurate with the hysteresis loop of the nanocomposites. All the films show soft ferromagnetic behavior. Gradual development of the domain structure is observed in the MOKE micrograph with the increase in the thickness of Fe nanoparticle deposition. Ex situ magnetic force micrographs of the magnetic domain structures supported the observation of MOKE microscopic studies, which indicated switching of in-plane magnetization to out-of-plane magnetization near an Fe nanoparticle deposition thickness of 40 nm. The PVA matrix appears to be an effective material to support the growth of magnetic properties in the PVA/Fe nanocomposite system. The evolution of Fe nanostructures on PVA and the resulting magnetic behavior have been discussed.

Rapid direct growth of graphene on single-crystalline diamond using nickel as catalyst

Although theoretical investigations indicate that the successful combination of graphene and diamond would give interesting properties, only a limited number of reports dealing with the subject have been published. Here, we present a rapid thermal process (RTP) which involves nickel (Ni) as metal catalyst for a direct growth of graphene on diamond at a temperature of 1073 K for 60 s. This process operates with a combination of a lower temperature and for a shorter duration than what has previously been reported. Thin Ni films of different thicknesses were deposited on top of (100) single-crystalline diamond. After RTP, the coverage of monolayer graphene was found to be around 20% shown by the intensity ratio between the 2D- and G-peak using Raman spectroscopy on 50 nm thick Ni films. In addition, x-ray photoelectron spectroscopy and atomic force microscopy analysis were conducted. For electrical characterization, Hall-effect measurements were performed at temperatures between 80 and 360 K.

Growth, Structure, and Magnetic Properties of Artificially Layered NiMn in Contact to Ferromagnetic Co on Cu3Au(001)

Single‐crystalline antiferromagnetic artificially layered [Ni/Mn] films of different thicknesses, covered by ferromagnetic Co layers, are deposited on . Their structural and magnetic properties are characterized by low‐energy electron diffraction (LEED) and magneto‐optical Kerr effect, respectively, and compared with disordered alloy films with the same Ni/Mn ratio and the same film thickness. LEED intensity‐versus‐energy curves show that the perpendicular interatomic lattice distance is decreased in the artificially layered [Ni/Mn] samples in comparison to the disordered alloy films. At the same time, the artificially layered [Ni/Mn] films exhibit higher coercivity and exchange bias of the adjacent Co layer compared to those of . This is discussed as a consequence of the different interatomic lattice distance, presumably caused by an ordered buckling in the artificially layered [Ni/Mn] samples, leading to a stronger interlayer exchange coupling.

Thermomagnetic Instabilities in Nb Films Deposited on Glass Substrates

In this work, we provide a systematic study of the magnetic field penetration process and avalanche formation in niobium films of different thicknesses deposited on glass substrates. The research was carried out by means of direct visualization of the magnetic flux using magneto-optical imaging. The experimental data were compared with theoretical predictions for the development of thermomagnetic instabilities in the form of finger or dendritic flux avalanches in thin films. Analysis of the temperature and thickness dependence of threshold magnetic field at which superconductor first becomes unstable, as well as the flux penetration depth corresponding to this field allows the evaluation of the thermal and superconducting parameters of the studied films, such as heat transfer coefficient across the film-substrate boundary, thermal conductivity, critical current density.

SERS Detection of Rhodamine-6G on Ion Beam Nanostructured Ultra-Thin Gold (Au) Films: A Correlation between Fractal Growth, Water Contact-Angle and Raman Intensity

SERS (Surface Enhanced Raman Scattering) detection of rhodamine-6G on gold nanostructures (Au–NS) of various sizes under ion beam irradiation is presented. On a glass substrate, Au thin films of different thicknesses (∼2, 3 and 5 nm) were deposited by thermal evaporation. Subsequent irradiation using 10 keV Ar+ at different fluences has been able to modify the size of Au-NS. Ion beam-induced sputtering and diffusion processes control the formation of Au-NS. The reduction in Au content during ion beam sputtering is confirmed by Rutherford Backscattering Spectroscopy (RBS), which also validates tuning the size and structures of Au-NS. The wettable characteristics of Au-NS surfaces are controlled by two competing statistical factors of sputtering and surface diffusion. A correlation between the water contact angle, rms roughness, and the detection of rhodamine-6G (R6G) by SERS is presented. The current study sheds light on the mechanism(s) of SERS chemical detection for wider metallic surfaces.

Investigations of dielectric properties of cadmium selenide thin films

Thin Films of different thickness of Cadmium Selenide (CdSe) were prepared by using thermal evaporation technique on a glass substrate, and investigation of dielectric properties as a function of frequency in the range up to 1 MHZ using Auto Lab Potentiostat/Galvanostat meter was conducted. Preliminary data for complex parameters i.e. complex dielectric constant (ε*), complex impedance (Z*), electric modulus (M*), tangent loss (δ) and conductivity (σ) has been calculated. All these properties are used to explore various processes that contribute to the dielectric spectroscopy investigation.

Controlling the thickness and composition of stainless steel surface oxide film for anodic sulfide removal

Hydrogen sulfide is hazardous and toxic, and is present at many waste streams of industry processes. Anodic sulfide oxidation is a potentially effective approach to remove sulfide in aqueous media. This study therefore prepared and optimized surface oxide film on AISI 304 stainless steel (SS) as active and stable anode for sulfide removal. Among stainless steel samples of different anodization pretreatment duration, the anode with 15 min pretreatment (SS-15) resulted in the best sulfide removal at the same testing conditions, and achieved 48% and 18% improvement in terms of sulfide removal efficiency compared with the untreated SS and graphite, respectively. ANOVA-based tests (overall and for pairwise comparisons) also suggest the data are indeed valid. When anode potential was set no more than 1.62 V vs. reversible hydrogen electrode (RHE), direct sulfide oxidation dominated; and further increase in anode potential would initiate oxygen evolution reaction (OER) which contributed to indirect sulfide oxidation. Surface characterization found that the varying corrosion pretreatment duration led to oxide films of different thickness and chemical composition. The pretreatment duration from 15 min to 90 min increased the oxide film thickness from 178 nm to 264 nm and decreased the composition of FeOOH and NiOOH, which were most likely the catalytic active species for sulfide oxidation revealed by high-resolution XPS. Electrochemical analysis confirmed that the smaller thickness and enriched FeOOH/NiOOH composition in SS-15 led to a lower charge transfer resistance, a lower mass transfer resistance, and meanwhile a greater material stability. Depth profiling via high-resolution XPS identified metallic Fe inside oxide films and its presence may also promote the conductivity of the oxide film. This study demonstrated that anodization pretreatment of stainless steel was able to prepare effective and stable anode for electrochemical sulfide removal by controlling the thickness and composition of oxide films.

Bio-materials for sustainable textile-based sensing applications

The paper is devoted to the production of biodegradable nonwovens (films) based on bacterial cellulose, the study of its physical and mechanical properties and the possibility of designing garments made from this fabric. As a result of the research, samples of bacterial cellulose films of different thicknesses were obtained, the relationship between changes in film thickness and cultivation time was established, the structure of biodegradable films was determined, the values of microfibrils forming them were revealed, and the physical and mechanical properties of bacterial cellulose were studied. A comparative analysis of the obtained biomaterials with commercial samples of composite eco-materials was carried out using synthetic leather made from Mexican cactus waste. The data collected is valuable for further research in the design of eco-friendly and biodegradable materials for both casual wear and textiles, as well as smart biomaterials for the engineering of sustainable textile-based sensors.

Modulation of epsilon-near-zero wavelength and enhancement of third-order optical nonlinearity in ITO/Au multilayer films

We report the modulation of epsilon-near-zero (ENZ) wavelength and enhanced third-order nonlinearity in indium tin oxide (ITO)/Au multilayer films. The samples consisting of five-layer 40 nm ITO films spaced by four-layer ultrathin Au films of different thickness, i.e., ITO(40 nm)/[Au(x)/ITO(40 nm)]4, were prepared by magnetron sputtering at room temperature. The ENZ wavelength in the multilayer films is theoretically calculated and experimentally confirmed. The nonlinear refractive index and nonlinear absorption coefficient of the samples of x=0, 2, 3, 4 nm were determined using the Z-scan method at a wavelength of 1.064 µm. The large nonlinear refractive index n2=1.12×10-13 m2/W and nonlinear absorption coefficient β=-1.78×10-7 m/W in the sample of x = 4 nm are both four times larger than those in the single-layer ITO film. The large optical nonlinearity due to the ENZ enhancement and carrier concentration is discussed. The results indicate that the ITO/Au multilayer films are promising for advanced all-optical devices.

Analysis of current-voltage curves of ZnO thin films under dark and optical stimulus

In this work, we are reporting the current conduction mechanism in ZnO thin films of various thicknesses under the dark and optical stimulus. The ZnO thin films of different thicknesses (45, 70, 110, 160, 220 nm) were grown on a glass substrate at 250 °C using the spray pyrolysis method. For photoconductivity measurements, electrodes were made using silver paste by putting a ∼1 mm gap between the electrodes. The photocurrent under UV illumination increases with increasing film thickness. Linear fitting of the data suggests the major role of space charges in the film for the rise in the photocurrent. Therefore the obtained conduction mechanism is found to be space charge-limited conduction in ZnO thin films under UV illumination.

Anomalous hysteresis loops of ferrimagnetic Gd-Co films of different thickness near the magnetic compensation temperature

Triple hysteresis loops were observed for amorphous ferrimagnetic Gd-Co films near the magnetic compensation temperature, which can be a consequence of both the spin-flop transition and the chemical composition gradient. In the work, an assessment of the possible chemical inhomogeneity of the films based on magnetic measurements was carried out and its relationship with the thickness of the samples was observed. Keywords: amorphous magnetic films, perpendicular magnetic anisotropy, ferrimagnetism, magnetic domain structure, magnetic hysteresis.

Optimization of Pulsed Laser Deposition Parameters for Single-Crystalline (011) Oriented Tetragonal Pzt Thin Films

Recent advances in nanotechnology applications require the processing of high-quality thin films. A systematic study of the optimization of Pulsed deposition parameters for (110) oriented tetragonal PZT thin films is reported in this work. Prior to film deposition, a highly tetragonal Pb(Zr0.5, Ti0.95) or PZT 05/95 was selected to be deposited on (110) oriented Strontium titanate, SrTiO3 substrate, STO(110) to insure small compressive misfit strain. Unlike SRO, the LSOM bottom electrode was then successfully grown at 620 °C, 1.0 J/cm2 and a target-substrate distance of 3.9 cm. Finally, deposition parameters of PZT were progressively optimized through monitoring film morphological changes. Monocrystalline PZT films of different thicknesses with layer–by–layer growth mode were finally realized at a deposition temperature of 550 °C, laser energy of 1.0 J/cm2, background pressure of 200 mTorr O2, while deposition rate was 3 Hz and target-substrate distance of 3.1 cm. The optimal film growth rate was finally estimated to be 0.3 nm/100 Pulses.