Preparation Of Thin Films Research Articles

Producing Freestanding Single-Crystal BaTiO3 Films through Full-Solution Deposition.

Strontium aluminate, with suitable lattice parameters and environmentally friendly water solubility, has been strongly sought for use as a sacrificial layer in the preparation of freestanding perovskite oxide thin films in recent years. However, due to this material's inherent water solubility, the methods used for the preparation of epitaxial films have mainly been limited to high-vacuum techniques, which greatly limits these films' development. In this study, we prepared freestanding single-crystal perovskite oxide thin films on strontium aluminate using a simple, easy-to-develop, and low-cost chemical full-solution deposition technique. We demonstrate that a reasonable choice of solvent molecules can effectively reduce the damage to the strontium aluminate layer, allowing successful epitaxy of perovskite oxide thin films, such as 2-methoxyethanol and acetic acid. Molecular dynamics simulations further demonstrated that this is because of their stronger adsorption capacity on the strontium aluminate surface, which enables them to form an effective protective layer to inhibit the hydration reaction of strontium aluminate. Moreover, the freestanding film can still maintain stable ferroelectricity after release from the substrate, which provides an idea for the development of single-crystal perovskite oxide films and creates an opportunity for their development in the field of flexible electronic devices.

Optimizations of Liquid Phase Deposition Processes for Enhanced Photoelectrocatalytic Activities of Tungsten Oxide Thin Films.

This study focuses on the preparation of tungsten oxide (WO3) as the photoanode for water oxidations by the liquid phase deposition (LPD) technique and its optimizations to improve the photoelectrochemical performance. The alternative precursor large stock solution process was achieved to simplify the LPD process for WO3 thin film preparation. The effect of boric acid in the precursor solutions on the physicochemical properties of the deposited WO3 thin films was investigated. As a result, we found that the optimized concentration of boric acid realized the highest photoelectrochemical performance. Through the optimizations of reaction conditions and surface analyses, we concluded that the preparations of a semiconductor film via the LPD technique had the potential to obtain high-performance photoelectrocatalytic applications.

Preparation and Optical Properties of Thin Films of ZnIn2S4 (I, III) Polytype

Preparation and Optical Properties of Thin Films of ZnIn2S4 (I, III) Polytype

Structural Properties of Cs<sup>1+</sup> Doped H<sub>3</sub>PMo<sub>12</sub>O<sub>40</sub> Nanocrystalline Polyoxometalate Thin Films

The microwave assisted chemical bath deposition (MA-CBD) technique were used to deposite nanocrystalline thin films of polyoxometalates like phosphomolybdic acid (PMA) (H3PMo12O40) and Cesium (Cs+) doped phosphomolybdic acid (Cs-PMA) (Cs3-PMo12O40). Thermo gravimetric and Differential thermal analysis (TGDTA), Fourier transform infrared spectroscopy (FTIR), Energy dispersive X-ray analysis (EDAX), X-ray diffractometry (XRD) and Scanning electron microscopy (SEM) tools are used for the thermal, structural, morphological and compositional analysis of microwave treated H3PMo12O40 and Cs3- PMo12O40 thin films. The completion of decomposition process at 600 oC of Cs3-PMo12O40 compound is confirmed from TGDTA analysis. The polycrystalline spinel cubic crystal structure of H3PMo12O40 and Cs3-PMo12O40 thin films were confirmed from X-ray diffractometer. The crystallite size of H3PMo12O40 and Cs3-PMo12O40 compound found to be in the range of 50 - 53 nm. The formation of H3PMo12O40 and Cs3-PMo12O40 materials were confirmed from the presence of main four absorption peaks observed in the range from 800 cm-1 to 1100 cm-1. The SEM microphotographs analysis identify the microwave assisted H3PMo12O40 and Cs3-PMo12O40 films have spherical shaped porous nanocrystalline morphology. The grain size of H3PMo12O40 and Cs3-PMo12O40 synthesized material found to be in the range of 10 - 12 A˚ The stoichiometric preparation of H3PMo12O40 and Cs3-PMo12O40 thin films with presence of P, Mo, O and Cs peaks of metal ions is observed from EDAX spectra.

Insights and perspectives on PVDF/MgO NCs films: Structural and optical properties for optoelectronic device applications

In the current investigation, pure polyvinylidene fluoride (PVDF) and PVDF-MgO nanocomposite (NC) thin films are fabricated via solvent casting method using PVDF as a polymer matrix with different proportions of magnesium oxide (MgO) (0.5–2 wt%). The structural, morphological and optical properties of the prepared polymer NCs are studied by using XRD, FTIR, SEM, Raman and UV–Vis spectroscopy techniques. The α and β phases are detected in XRD measurements. MgO powder peaks are in good agreement with the reported literatures. The average crystallite size, lattice strain, and dislocation density of the prepared thin films are estimted by using Williamson-Hall (W-H) plot. SEM micrographs reveals the fluorine-containing carbon chain network that forms the spherulite and fiber-like structure in the PVDF/MgO NCs films. The Raman and FTIR spectra of PVDF/MgO and pure PVDF films are also evaluated. UV–Vis spectroscopy is used to examine the absorbance, transmittance, and reflectance spectra of pure PVDF and PVDF/MgO NCs thin films. The dipole polarization interaction causes the absorption coefficient, direct band gap, indirect band gap, optical activation energy, and skin depth of pure PVDF and PVDF/MgO thin films to decrease, whereas increasing the dielectric constant at high frequency value, refractive index, loss, optical conductivity, and dielectric constant per effective mass of NCs films. Optical dispersion parameters are estimated by the single oscillator model. The obtained results can be employed in the possible applications in supercapacitors. The method used for the preparation of thin films are inexpensive and eco-friendly.

CHARACTERIZATION OF COATINGS PREPARED FROM PREVULCANIZED NR/POLYANILINE LATEX

ABSTRACT Latex consisting of a NR/polyaniline (NR/PAni) blend is used in the preparation of thin elastic films. In this study, NR/PAni latex blends with different amounts of doped PAni and surfactants (sodium dodecylbenzene sulfonate [SDBS] and sodium dodecyl sulfate [SDS]) were prepared through prevulcanization. The films were prepared from prevulcanized latexes by casting in a petri dish or with the spin coating method. The conditions suitable for prevulcanization were investigated. The effect of doped PAni amounts and the surfactants SDBS and SDS on the mechanical, electrical conductivity, and physico-chemical surface properties and morphologies of NR/PAni films were characterized. The results indicated that PAni doped with dodecylbenzene sulfonic acid (DBSA) was well dispersed in NR latex in the presence of 0.01 mol/w% of SDBS. The highest amount of doped PAni that was dispersed was 17 w/w%. The properties of the blend of NR and DBSA-doped PAni were superior to those of the other blends. The compatibility between SDBS and DBSA was the dominant factor in improving the properties of the film prepared from the prevulcanized NR/PAni latex blend.

Influence of Deposition Parameters on the Plasmonic Properties of Gold Nanoantennas Fabricated by Focused Ion Beam Lithography.

The behavior of plasmonic antennas is influenced by a variety of factors, including their size, shape, and material. Even minor changes in the deposition parameters during the thin film preparation process may have a significant impact on the dielectric function of the film, and thus on the plasmonic properties of the resulting antenna. In this work, we deposited gold thin films with thicknesses of 20, 30, and 40 nm at various deposition rates using an ion-beam-assisted deposition. We evaluate their morphology and crystallography by atomic force microscopy, X-ray diffraction, and transmission electron microscopy. Next, we examined the ease of fabricating plasmonic antennas using focused-ion-beam lithography. Finally, we evaluate their plasmonic properties by electron energy loss spectroscopy measurements of individual antennas. Our results show that the optimal gold thin film for plasmonic antenna fabrication of a thickness of 20 and 30 nm should be deposited at the deposition rate of around 0.1 nm/s. The thicker 40 nm film should be deposited at a higher deposition rate like 0.3 nm/s.

Preparation of Cs2SnI6 perovskite thin films based on solvent engineering and their properties of photodetectors

Preparation of Cs2SnI6 perovskite thin films based on solvent engineering and their properties of photodetectors

Artifact-free sample preparation of metal thin films using Xe plasma-focused ion beam milling for atomic resolution and in situ biasing analyses

The focused ion beam (FIB) technique using Ga ion beams is generally employed for transmission electron microscopy (TEM) sampling owing to its location-specific beam controllability on materials. However, Ga ion beam bombardment-induced damage hinders reliable structural analysis. Furthermore, Ga ions implanted in the damaged surface layer substantially lower the chemical stability of the samples, such as metal thin films. Here, aiming for atomic-level interface structural analysis, we propose a useful approach for the TEM sample preparation of heteroepitaxial Ag/Cu metal films without physical damage or chemical instabilities using the Xe plasma FIB (PFIB) system. Xe plasma-assisted sampling ensured that the interface structure of the Ag/Cu metal film remained intact; in contrast, the sample prepared using the focused Ga ion beam was damaged by elemental mixing. Furthermore, the sample prepared by Xe plasma milling exhibited robust structural stability over time after exposure to air in contrast to the sample prepared by Ga-ion milling, which induced structural decomposition owing to oxidation. In addition to the static structural analysis, the Cu thin film sample prepared by Xe PFIB exclusively exhibited pristine structural properties under in situ electrical biasing experiments, thus confirming the feasibility of conducting a fundamental study of Cu electromigration without artifacts.

Study on the Preparation and PEC-Type Photodetection Performance of β-Bi2O3 Thin Films.

Bismuth-based compounds have been regarded as a kind of promising material due to their narrow bandgap, high carrier mobility, low toxicity, and strong oxidation ability, showing potential applications in the field of photoelectrochemical (PEC) activities. They can be applied in sustainable energy production, seawater desalination and treatment, optical detection and communication, and other fields. As a member of the broader family of bismuth-based materials, β-Bi2O3 exhibits significant advantages for applications in engineering, including high photoelectric response, stability in harsh environments, and excellent corrosion resistance. This paper presents the synthesis of β-Bi2O3 thin films utilizing the mist chemical vapor deposition (CVD) method at the optimal temperature of 400 °C. Based on the β-Bi2O3 thin film synthesized at optimal temperature, a PEC-type photodetector was constructed with the highest responsivity R of 2.84 mA/W and detectivity D of 6.01 × 1010 Jones, respectively. The photodetection performance was investigated from various points like illumination light wavelength, power density, and long-term stability. This study would broaden the horizontal and practical applications of β-Bi2O3.

Preparation and properties of Hydroxyapatite-Ti composite thin films by co-sputtering method for biocompatibility applications

In this paper, we report on enhancing the biocompatibility properties of Hydroxyapatite-Titanium (HA-Ti) thin films fabricated using the co-sputtering method. By adjusting the HA/Ti ratio through varying the sputtering power of Ti, we obtained HA-Ti thin films with different crystal structures, morphologies, and hydrophilic properties. HA-Ti thin films sputtered at different titanium powers of 80, 100, 120, 140, and 160 W will obtain thin films with larger grain sizes and poorer crystallinity, respectively. However, their hydrophilic properties increase as the contact angle decreases from 78° to 20° degrees. In vitro BHK cell tests indicated that the HA-Ti thin film had excellent biocompatibility. Therefore, this material is suitable for biological applications and has significant potential in medical implant technology.

Study on interface characteristics and electron spin manipulation of two-dimensional [formula omitted] (001) heterostructures

Among numerous strongly correlated electron materials, cobalt ions in perovskite oxide SrCoO3 (SCO) possess rich valence states, playing a crucial role in determining the functionality of the material. Meanwhile, thin film preparation techniques such as epitaxial growth and pulsed laser deposition have accelerated the research progress of two-dimensional SCO films. In this study, we primarily investigate the interface characteristics and electron spin of two-dimensional SrCoO3/LaAlO3 (SCO/LAO) (SCO/LAO) (001) heterostructures using density functional theory, revealing the influence of atomic layer thickness and doping on the heterostructure. Our research results indicate that SCO/LAO heterostructures exhibit metallic behavior and ferromagnetism, and doping with oxygen vacancies and Nb2+ ions leads to significant changes in electronic properties and magnetism of the heterostructure. These findings provide insights for the experimental synthesis of two-dimensional heterostructures and suggest that two-dimensional SCO/LAO (001) heterostructures possess rich interface properties with tremendous potential applications in electronic devices.

Preparation and characterization of chromium oxide thin films: The response of morphology, crystal structure, and electrical properties to oxygen pressure under magnetron sputtering

This study focuses on Cr2O3 prepared via reactive magnetron sputtering, a direct deposition technique that significantly impacts the microstructure and optoelectronic properties of the films. Reactive sputtering alters grain size, density, and surface morphology, which in turn affects the structural order and stoichiometry. By adjusting the ratio of process gases, particularly the oxygen partial pressure, the stoichiometry of the deposited films was controlled. This is crucial for managing the oxidation state of chromium and the concentration of free electrons. An optimal oxygen partial pressure of 75 % was identified, substantially reducing oxygen interstitial defects in the CrOx materials and enhancing conductivity by nearly two orders of magnitude. Additionally, increasing the oxygen partial pressure helped integrate more oxygen atoms into the lattice, transitioning the electronic structure from a metallic state in CrO2 to a semiconductive state in CrO3. This fine-tuning of oxygen doping not only adjusts carrier concentrations but also optimizes the photoelectric properties of the materials, achieving a tailored high band gap of 3.34 eV. This study highlights the potential of reactive magnetron sputtering to customize semiconductor materials through oxygen doping, offering a novel approach to enhance the versatility and application range of chromium oxide materials in advanced technological applications.

Preparation of Al2O3 thin films by RS-ALD and edge passivation application for TOPCon half solar cells

A rotary spatial atomic layer deposition (RS-ALD) method is proposed for the preparation of high-quality Al2O3 thin films and its application to the edge passivation of tunnel-oxide passivated contact (TOPCon) half solar cells. The high- quality Al2O3 thin films were prepared on silicon wafers by optimizing the process conditions with a process pressure of 4 Torr and a trimethylaluminum (TMA, (CH3)3Al) flow rate of 300 sccm. The Al2O3 thin films were annealed to analyse the transformation of the film crystal structure, surface morphology, and passivation properties. Compared to the half solar cells without edge passivation, the efficiency of the cell with only deposited Al2O3 increased by 0.098 %, and the module power increased by 3.08 W. The efficiency of the cell with deposited Al2O3 + annealing increased by a further 0.021–0.119 %, and the module power increased by a further 0.68–3.76 W.

Strategies for regulating crystallinity and surface quality based on solvent multistage volatilization

In this paper, Bi2212 superconducting thin films were prepared with metal acetate as salt source and a mixture of acetic acid and N,N-dimethylformamide (DMF) as solvent. The volatilization process of the solvent was regulated by changing the ratio of the mixed solvent, which in turn achieved the regulation of the surface morphology and crystallinity of the Bi2212 superconducting films. The mechanism of the mixed solvents on the crystallinity and surface quality of Bi2212 superconducting films was systematically investigated. The results showed that the Bi2212 superconducting films were all (00l) epitaxial growth. The grain size of Bi2212 increased continuously with the increase of the proportion of acetic acid in the solvents. The grain size of the largest grain size was 43.8 nm when the proportion of acetic acid was 80 %. However, the high proportion of acetic acid in the mixed solvents reduced the surface quality of Bi2212 thin films. The minimum surface roughness was 15.0 nm at 40 % acetic acid. All the samples exhibited good superconducting properties. This work provides a research basis for the systematic preparation of multicomponent oxide thin films.

One-Step Hydrothermal Deposition of AgSbS2-xSex Thin Films for Solar Cell Applications.

AgSbS2-xSex is a promising light-harvesting material for thin film solar cells, characterized by nontoxicity, high chemical stability, and excellent optoelectronic properties. However, the complex chemical composition of AgSbS2-xSex poses significant challenges to thin film preparation, giving rise to an intensive dependence on multi-step preparation methods. Herein, a hydrothermal method is developed for depositing AgSbS2-xSex films and achieves one-step preparation of this kind of thin film materials for the first time. This method can provide sufficient energy for atomic nucleation and adsorption on the substrate surface to promote nuclei aggregation and grow into films. Meanwhile, it achieves control of the chemical kinetics of the deposition solution by introducing EDTA-2Na as an additive and suppressing the enrichment of Ag2Se impurities at the substrate interface. As a result, a high-purity AgSbS2-xSex film with compact and flat morphology is prepared and assembled into solar cells. The device delivers a power conversion efficiency of 3.04% under standard illumination, which is currently the highest efficiency for AgSbS2-xSex solar cells fabricated by the one-step method. This study provides a facile and promising method for the controllable preparation of high-quality AgSbS2-xSex thin films and promoting their application in solar cells.

Collaborative Fabrication of High-Quality Perovskite Films for Efficient Solar Modules through Solvent Engineering and Vacuum Flash System.

The vacuum flash solution method has gained widespread recognition in the preparation of perovskite thin films, laying the foundation for the industrialization of perovskite solar cells. However, the low volatility of dimethyl sulfoxide and its weak interaction with formamidine-based perovskites significantly hinder the preparation of cell modules and the further improvement of photovoltaic performance. In this study, we describe an efficient and reproducible method for preparing large-scale, highly uniform formamidinium lead triiodide (FAPbI3) perovskite films. This is achieved by accelerating the vacuum flash rate and leveraging the complex synergism. Specifically, we designed a dual pump system to accelerate the depressurization rate of the vacuum system and compared the quality of perovskite film formed at different depressurization rates. Further, to overcome the limitations posed by DMSO, we substituted N-methylpyrrolidone as the ligand solvent, creating a stable intermediate complex phase. After annealing, it can be transformed into a uniform and pinhole-free FAPbI3 film. Due to the superior quality of these films, the large area perovskite solar module achieved a power conversion efficiency of 22.7% with an active area of 21.4 cm2. Additionally, it obtained an official certified efficiency of 22.1% with an aperture area of 22 cm2, and it demonstrated long-term stability.

Tuning properties of CTAB-HSA-AuNR nanocomposite antibacterial thin films

Protein-based biomaterials such as thin films have an edge over synthetic and bio-based polymers, due to their biodegradability in addition to other interesting properties. Proteins can be utilized to create such materials with specific functional characteristics. We report the preparation of transparent human serum albumin thin films in presence of CTAB-capped gold nanorods with different compositions of protein as well as the plasticizer i.e., sorbitol. The mechanical properties, surface topology, morphology, molecular structure, moisture content, total soluble material, biodegradability, antibacterial activity and optical properties have been investigated. Gold nanorods act as crosslinkers and sorbitol as a plasticizer increases plasticity and hardness of the films. The films deposited are biodegradable, water soluble and flexible in nature. AFM images reveal a pattern on the surface with different average heights with an increase in surface roughness with the addition of sorbitol. NINT studies show increased hardness and elastic modulus with the same amount of sorbitol but higher amounts of protein. Fourier Transform Infrared spectroscopy studies indicate the change in molecular structure of the films, in terms of a change in the hydrogen bonding network that impacts the water content and hardness of the films. Most importantly the films show antibacterial property, modulated by the composition used. The interesting features and the enhanced mechanical properties pave the path for potential applications of the films. The study shows that the optimization of the composition is crucial to achieve the desired film material with required properties.

Preparation and performance optimization of HfAlO hybrid gate dielectric thin films driven by solution

Preparation and performance optimization of HfAlO hybrid gate dielectric thin films driven by solution

Quantifying Organic Cation Ratios in Metal Halide Perovskites: Insights from X-ray Photoelectron Spectroscopy and Nuclear Magnetic Resonance Spectroscopy.

The employment of metal halide perovskites (MHPs) in various optoelectronic applications requires the preparation of thin films whose composition plays a crucial role. Yet, the composition of the MHP films is rarely reported in the literature, partly because quantifying the actual organic cation composition cannot be done with conventional characterization methods. For MHPs, NMR has gained popularity, but for films, tedious processes like scratching several films are needed. Here, we use mechanochemical synthesis of MA1-x FA x PbI3 powders with various MA+: FA+ ratios and combine solid-state NMR spectroscopy (ssNMR) and X-ray photoelectron spectroscopy (XPS) to provide a reference characterization protocol for the organic cations' quantification in either powder form or films. Following this, we demonstrate that organic cation ratio quantification on thin films with ssNMR can be done without scraping the film and using significantly less mass than typically needed, that is, employing a single ∼800 nm-thick MA1-x FA x PbI3 film deposited by pulsed laser deposition (PLD) onto a 1 × 1 in.2, 0.2 mm-thick quartz substrate. While background signals from the quartz substrate appear in the 1H ssNMR spectra, the MA+ and FA+ signals are easily distinguishable and can be quantified. This study highlights the importance of calibrating and quantifying the source and the thin film organic cation ratio, as key for future optimization and scalability of physical vapor deposition processes.