Characterization Of Thin Films Research Articles

Characterization of High Entropy Oxide Thin Films by High-Resolution STEM-EELS.

Characterization of High Entropy Oxide Thin Films by High-Resolution STEM-EELS.

Nanoindentation Tests for Characterization of Hydroxyapatite Thin Films.

Nanoindentation Tests for Characterization of Hydroxyapatite Thin Films.

Challenges in porosity characterization of thin films: Cross-evaluation of different techniques

The review article provides an overview of the most important and popular techniques for evaluating the porosity of thin films developed for various applications. These methods include ellipsometric porosimetry (EP), positron annihilation (lifetime) spectroscopy (PAS/PALS), and grazing incidence small-angle x-ray scattering (GISAXS). Special attention is given to the challenges associated with interpreting the measured data and the inherent limitations of each method. It is demonstrated that EP, GISAXS, and PALS are all informative for studying the pore structure in thin films, with each method offering unique insights. GISAXS, in particular, allows for the evaluation of three-dimensional mesostructures, including pore arrangement, pore spacing, and structural order. On the other hand, PALS has a unique advantage in its capability to analyze extremely small isolated pores (free volume). The advantage of EP lies in its simplicity and the possibility to analyze multiple properties from the same set of measurements. The cross-evaluation of different methods offers important insights into the complex pore structure of materials, highlighting the significance of appropriate modeling and interpretation of data.

Synthesis and Characterization of TiN Thin Films by DC Reactive Magnetron Sputtering

In this work, the titanium nitride (TiN) thin films were prepared on Si-wafers by using the DC reactive magnetron sputtering from a pure titanium target. The influence of N2 flow rates, in the range of 1.0-4.0 sccm, on the as-deposited TiN film’s structure was characterized by several techniques. (i) The crystal structures were studied by GI-XRD. (ii) The film’s thicknesses, microstructures, and surface morphologies were analyzed by FE-SEM. (iii) The elemental composition of films was measured by EDS. (iv) The hardness was measured by the nano-indentation. (v) The color was identified by a UV-VIS spectrophotometer. The results showed that the as-deposited films were polycrystalline of B1-NaCl structure. The lattice constants were ranging from 4.211-4.239 Å. The as-deposited films showed a nano crystal size in the range of 17.8-24.6 nm. The thickness decreases from 1254 nm to 790 nm with following in the N2 flow rates. The concentration of Ti and N depended on the N2 flow rates. The cross-sectional analysis showed that the films had a compact-columnar structure. The hardness increased from 4 to 19 GPa with increasing in the N2 flow rates. The close to the color of 24K gold thin films in the CIE L*a*b* system was obtained by deposition in optimal N2 flow rates.

In situ characterization of Ni-rich NMC811 thin films prepared by sol-gel method using different scanning probe microscopy techniques

In this paper, LiNi0.8Co0.1Mn0.1O2 (NMC811) thin films were prepared by the sol-gel method based on different parameter conditions, and the microstructure and electrochemical properties of the films were compared to obtain the film sample under the best preparation parameters. In order to explain the formation mechanism of cell battery performance based on the NMC811 cathode at the nano scale, electrochemical strain microscopy, conductive atomic force microscopy and Kelvin probe force microscopy are specifically utilized to study the changes of NMC811 thin film in electrochemical deformation, conductivity, and potential distribution under different electrical and thermal fields. The results indicate that the local amplitude, conductivity, and electrical potential of thin film in the scanning region increases with the voltage from 0 V to 3 V and the temperature from 25 °C to 150 °C. However, the electrochemical deformation, conductivity, and potential of the film decrease significantly when the voltage is applied to 4 V or the temperature rises to 200 °C.These results provide visual evidence for the influence of external field on the phase structure change and lithium-ion diffusion behavior of NMC811 thin film.

Synthesis, Characterization, and Antibacterial Activity Test of Geothermal Silica/AgNO3 Thin Film

Geothermal silica waste offers convenient, economical, and environmentally friendly material with high hydrophobicity to produce thin films. Silica-thin films from geothermal waste using the sol-gel method, though, no addition of AgNO3 was conducted for antibacterial functions. This study aims to produce silica-thin films from geothermal waste with the addition of AgNO3 and analyze the antibacterial activity. The procedures carried out in this research were (i) an acid leaching process using HNO3; (ii) the production of silica thin film with and without the addition of AgNO3; (iii) thin film characterization including a water contact angle measurement (WCA), XRF, FTIR, XRD and SEM-EDX on silica thin film samples with and without the addition of AgNO3; and (iv) antibacterial activity test. The results show the optimum HNO3 concentration for the acid leaching process was 20%, yielding 99.08% SiO2 by mass. The WCA of the silica thin film in the presence and absence of AgNO3 reached a value of ±160°, indicating the addition of AgNO3 did not decrease the contact angle of the silica thin film. This research employed smart deconvolution of IR Spectra using Fityk software which reveals a higher area ratio for Si-O-Si relative to Si-OH. Furthermore, it was observed that the silica thin films exhibited an amorphous morphology, both without and with the addition of AgNO3, with Ag discovered to be dispersed on the thin film. However, despite the presence of Ag, both TF20 and TF20+Ag samples were found to be ineffective in inhibiting bacterial growth, as evidenced by bacteria-free zones on the samples.

Temperature-Dependent Sheet Resistance and Surface Characterization of Thin Copper Films Bonded to FR4 Composite under Mechanical Vibrations

Electrical boards, also called printed circuit boards, constitute the basis of most electronic devices. These boards are mainly fabricated of thin copper films bonded to fiber epoxy laminates, such as FR4. Being the most important functional component of these devices, they sometimes undergo mechanical stresses such as shock and vibration during transport and operation that can induce electrical failure and malfunction; hence, studies addressing the effects of vibrations on their electrical properties have important applications. In this paper, small cantilever samples made of bare copper bonded to FR4 with three isolated rectangular zones were studied to analyze, for the first time, variations in electrical properties such as sheet resistance and resistivity before and after 200 k, 500 k, and 800 k vibration cycles at three different temperatures (25, 35, and 45 °C). A significant rise in resistance equivalent to 1657% of the initial value was observed from 0 to 800 k vibration cycles. These changes were accompanied by a 95% decrease in conductivity, from 4.1 × 107 to 2.3 × 106 S/m, whereas very little change in the electrical properties was observed due to temperature rise. Surface analysis by ESEM showed cracks ~1 µm in width and several millimeters in length with a crack density of ~8 cracks per mm after 800 k cycles. The surface composition (100% copper) was not altered even upon a high number of vibration cycles, and static drop contact angle measurements of 117–119 degrees indicated an increase in the hydrophobicity of the surface attributed to increased surface roughness and the accumulation of very small air bubbles on the cracks.

Emerging opportunities for hybrid perovskite solar cells using machine learning

While there are several bottlenecks in hybrid organic–inorganic perovskite (HOIP) solar cell production steps, including composition screening, fabrication, material stability, and device performance, machine learning approaches have begun to tackle each of these issues in recent years. Different algorithms have successfully been adopted to solve the unique problems at each step of HOIP development. Specifically, high-throughput experimentation produces vast amount of training data required to effectively implement machine learning methods. Here, we present an overview of machine learning models, including linear regression, neural networks, deep learning, and statistical forecasting. Experimental examples from the literature, where machine learning is applied to HOIP composition screening, thin film fabrication, thin film characterization, and full device testing, are discussed. These paradigms give insights into the future of HOIP solar cell research. As databases expand and computational power improves, increasingly accurate predictions of the HOIP behavior are becoming possible.

Fabrication and Characterization of Sn1-XCuxO2 Thin Films Prepared by Chemical Spray Pyrolysis Technique

Fabrication and Characterization of Sn1-XCuxO2 Thin Films Prepared by Chemical Spray Pyrolysis Technique

High frequency characterization of PZT thin-films deposited by chemical solution deposition on SOI for integrated high speed electro-optic modulators

The increasing demand for high data rates and low power consumption puts silicon photonics at the edge of its capabilities. The heterogeneous integration of optical ferro-electric materials on silicon enhances the functionality of the silicon on insulator (SOI) platform to meet these demands. Lead zirconate titanate (PZT) thin films with a large Pockels coefficient and good optical quality can be directly integrated on SOI waveguides for fast electro-optic modulators. In this work, the relative permittivity and dielectric loss of PZT thin films deposited by chemical solution deposition on SOI substrates are analyzed at high frequencies. We extract ε r =1650−2129 and tan (δ) = 0.170 − 0.209 for the PZT thin films in the frequency range 1-67GHz. We show the possibility of achieving bandwidths beyond 60GHz via a Mach-Zehnder modulator with V π = 7V, suitable for next generation data communication systems.

Recent advances in covalent organic polymers‐based thin films as memory devices

AbstractCovalent organic polymers (COPs) have emerged as a promising class of materials for memory devices due to their unique electronic properties and potential for tunability. This review highlights recent advances in the field of COPs‐based thin films for memory applications, with a focus on the synthesis and characterization of COP thin films, their electronic properties, and their performance as memory devices. The potential of COPs‐based thin films as flexible memory devices is also discussed. Overall, the recent progress in COPs‐based thin films for memory applications suggests that these materials may have a significant impact on the development of next‐generation memory technologies.

Comprehensive characterization of different metallic thin films on highly oriented pyrolytic graphite substrate

Thin metallic films supported on highly oriented pyrolytic graphite (HOPG) with low surface roughness are needed to improve the performance of different industrial applications and devices. As a result, an experimental investigation of electron beam physical vapour deposition of M (= Ti, Au, and Ag) metals on HOPG substrate to form HOPG-M thin films with a nominal thickness of 10 nm is reported. The comprehensive characterizations of the films were performed using different characterization techniques. The findings show that the films formed had different morphologies and topographies where Ti film was continuous while Au and Ag films were made up of islands with some discontinuities. The surface chemistry shows that the Ti film existed in both metallic and oxidized states while the Au and Ag films existed in metallic states. Raman analysis shows that there were some variations in the molecular structures after deposition while FTIR analysis shows that different functional groups existed on the thin films. The surface wettability behaviour of the Ag film based on water contact angles was hydrophobic while the other samples were hydrophilic. This work provides an opportunity for further examination of the HOPG as a substrate for the preparation of different M thin films.

Surface and functional characterization of nanostructured thin films for environmental remediation

Nowadays, the presence of pollutants in water is an urgent problem to solve. The efficient removal of these contaminants from aqueous solutions requires advanced oxidation processes (AOPs). This can be accomplished by various approaches using materials that allow the rapid removal of pollutants with high degradation rates. In this work, we focused on the surface modification of TiO2 films for photocatalytic application in water remediation. In particular, with an appropriate surface functionalization with zirconium phosphate, we have improved the sensitivity to sunlight and the thermal stability of TiO2. The surface functionalization of the samples was verified by using TOF-SIMS, which allows us to obtain spatially resolved chemical information. This information is very helpful for an effective engineering of the material, in order to obtain the best performances for environmental remediation. To our knowledge, this is the first time that TOF-SIMS is used to monitor the evolution of photocatalytic reactions at the photoactive surface, getting information on degradation pathways taking place at the surface of the photoactive material under solar light irradiation. In this work, as a target molecule, we chose rhodamine B, a dye widely used in textile industry, among others. The investigation of the degradation pathways occurring directly at the samples’ surface can provide relevant information about the rate determining step of the reaction and give hints for tailored functionalization of materials for improving their photocatalytic performances.

Numerical analysis of the propagation modes of photo-switching PDMS-arylazopyrazole optical waveguide and thin-film spectroscopic characterization

Numerical analysis of the propagation modes of photo-switching PDMS-arylazopyrazole optical waveguide and thin-film spectroscopic characterization

Comprehensive characterization of Al-doped ZnO thin films deposited in confocal radio frequency magnetron co-sputtering

Al-doped ZnO thin films with varying Aluminium (Al) content were deposited by radio frequency magnetron co-sputtering of two ZnO and Al targets in confocal configuration. A comprehensive study of the effect of Al content variation on the structural, optical and electrical properties were studied for as-deposited films and after an annealing step under controlled argon atmosphere. Chemical composition analyses, performed by both X-ray photoelectron spectroscopy and energy dispersive X-ray spectrometry, show an Al content variation in the deposited films in the 0-14 at.% range by varying the Al target power from 0 to 30 W, while the Zn target power was kept constant at 200 W. All deposited films exhibit a wurtzite crystalline structure and a decreasing crystalline quality for Al content above 5 at.% as shown by grazing incidence X-ray diffraction patterns. Atomic Force Microscopy analysis revealed films with homogeneous and dense surface morphology with roughness in the one nm range. Carrier concentration, resistivity and photoluminescence vary significantly with Al content in the ZnO films and appear optimized for an Al content window ranging from 1.5 to 5.5 at. %. Both optical and electrical properties are improved by a post-annealing at 300°C under argon. A high figure of merit of 43.6 × 10-4 sq.Ω-1 was obtained for the ZnO film with Al content of 3.6 at.% after annealing at 300°C. Optimized properties are obtained for a higher Al content than the standard value of 2 at. % widely used in published works.

A step toward calculating the uncertainties in combined GIXRF‐XRR

AbstractThe combination of X‐ray reflectivity (XRR) and grazing incidence X‐ray fluorescence (GIXRF) is a surface sensitive analytical method, which can be used for the characterization of thin films and multilayered materials. Both of these techniques are implemented on the same experimental setup and make use of similar mechanical processes and the same fundamental physical concept required for a combined data analysis. The combination of these techniques removes ambiguous results for the characterization of nanometer layers, as well as nanometer depth profiles, resulting in more accurate characterization of thickness, roughness, density, and elemental composition. Due to the vast number of fitting parameters, the estimation of the thin film sample structure is a challenging task. In this paper, we propose a recursive method for estimating the uncertainties of data from GIXRF‐XRR analysis, based on a Bootstrap statistical method. This approach relies on re‐sampling a dataset to estimate statistics on a population by applying random weights. We applied this method on an as‐deposited chalcogenide germanium, antimony, and tellurium (GST) thin film with a carbon‐capping layer. We found good agreement between the experimental and the theoretical XRR‐GIXRF values for a sample structure model, of which the parameters were determined within a confidence interval using the bootstrap method. We also propose an approach for calculating the uncertainty on the solid angle of detection based on Monte Carlo simulations.

Impact of Strain Engineering on Antiferroelectricity in NaNbO3 Thin Films.

Thin films of NaNbO3 were grown on various substrates to investigate the effect of epitaxial strain on their structural and electrical properties. Reciprocal space maps confirmed the presence of epitaxial strain from +0.8% to -1.2%. A bulk-like antipolar ground state was detected via structural characterization for NaNbO3 thin films grown with strains ranging from a compressive strain of 0.8% to small tensile strains, up to -0.2%. For larger tensile strains on the other hand, no indication of antipolar displacements can be detected, even beyond the relaxation of the film at larger thicknesses. Electrical characterization revealed a ferroelectric hysteresis loop for thin films under a strain of +0.8% to -0.2%, while the films under larger tensile strain showed no out-of-plane polarization component. However, the films with a compressive strain of 0.8% present a saturation polarization of up to 55 μC·cm-2, more than twice as large for films grown under conditions with small strain, which is also larger than the highest values reported for bulk materials. Our results indicate the high potential for strain engineering in antiferroelectric materials, as the antipolar ground state could be retained with compressive strain. The observed enhancement of the saturation polarization by strain allows for substantial increase of energy density of the capacitors with antiferroelectric materials.

Characterization of CZO thin films prepared by Sol – Gel dip coating technique with varied concentrations and annealed at different temperatures

Zinc Oxide (ZnO) thin films doped with Cobalt (Co) is prepared on glass substratum by using Sol-Gel dip coating technique. Volume of Cobalt can be varied from 0% to 2% and annealed at various temperatures. The obtained films analyzed by availing the results of Energy Dispersive X-ray Spectroscopy (EDS), Scanning Electron Microscopy (SEM), X-ray Diffraction analysis (XRD) and Ultraviolet – Visible Spectroscopy (UV–Vis). The EDS result shows that Zn and Co particles are present in the thin films. The SEM result reveals that as concentration of the dopant increases subsequently the intermolecular space decreases and conductivity increases. The XRD pattern shows a dominant peak (002) and it confirms hexagonal wurtzite structure. The UV– Visible spectrum shows that the minimum range of absorbance occurs at the visible region. All these results show that the prepared films could be used as Transparent Conducting Oxides (TCO) in solar cells and other opto-electronic gadget applications.

Structural characterization of epitaxial γ-Ta2N thin films and AlN/γ-Ta2N heterostructures on SiC substrates

Tantalum nitride (γ-Ta2N) thin films were grown by radiofrequency plasma molecular beam epitaxy (MBE) on 3 in. diameter 6H- or 4H-SiC substrates. Epitaxial characteristics of these MBE grown layers were determined using high resolution x-ray diffraction (HRXRD) and transmission electron microscopy (TEM) measurements. HRXRD, TEM, and XRD reciprocal space map measurements show that γ-Ta2N on SiC grows pseudomorphically and stabilizes to a nearly pure γ-Ta2N phase. Structural properties of these layers are uniform across the 3 in. wafer diameter. Measured a and c lattice parameter values of a 43 nm thick γ-Ta2N film on 6H-SiC are 3.079 and 4.898 Å, respectively, and the film has an in-plane tensile strain of 1.03%. MBE growth of AlN/ γ-Ta2N /SiC heterostructures has also been demonstrated. Measured lattice a and c constants of AlN on γ-Ta2N /SiC are 3.120 and 4.974 Å, respectively. TEM and XRD show that SiC substrate and γ-Ta2N films have parallel epitaxial relation.

Influence of Thickness on Some Physical Characterization for Nanostructured MgO Thin Films

MgO Nanostructured thin films with different thicknesses (200, 400, and 600 nm) have been deposited by the chemical spray pyrolysis technique. The results confirm that the structure, morphology, optical, and electrical properties were all affected by the thickness of the film. MgO films' physical properties were examined using (XRD), (FE-SEM), (EDX), (AFM), (UV-Vis spectrophotometer), and the Hall Effect. According to the structural analysis, the films have a cubic magnesium oxide polycrystalline structure, with a preferred orientation (002). The average Crystalline Size and optical band gap are found in the range (20.79-18.99) nm and (3.439-3.162) eV respectively with an increase in thickness. The surface morphology of the films reveals that they are free of crystal defects such as holes and voids, as well as homogeneous and uniform. The EDS patterns show that the as-grown films contain magnesium and oxygen. The Hall Effect shows that electrical conductivity decreases with thickness. The experimental results show that film thickness influences the physical properties of as-grown MgO thin films and that thicker films can be used as an absorber layer in solar cell applications.