Multicomponent Films Research Articles

A Novel Combinatorial Approach to the Ferroelectric Properties in HfxZr1−xO2 Deposited by Atomic Layer Deposition

Since HfO2‐based ferroelectric films were reported in 2011, several doping/alloying elements have been introduced to secure interesting ferroelectric/antiferroelectric properties of Hf‐based fluorite‐structured thin films. Using a conventional approach by atomic layer deposition (ALD), an enormous number of experiments would be required to reveal the compositional effects of doping/alloying components in ternary and quaternary systems. Therefore, for a comprehensive study of the ferroelectric properties of HfxZr1−xO2, a novel combinatorial ALD technique that enables the fabrication of multicomponent films with a different composition ratio and thickness via saturated/non‐saturated ALD without changing the supercycle of each material is reported. The gradient of the amount of HfO2 over a 100 mm substrate is achieved using a lower Hf‐precursor temperature that results in an insufficient Hf‐precursor dose for saturated deposition. Systematic study on the HfxZr1−xO2 combinatorial library is carried out by spectroscopic ellipsometry, X‐ray photoelectron spectroscopy, and X‐ray diffraction. Furthermore, TiN/HfxZr1−xO2/TiN capacitors are fabricated to measure the remnant polarization. The obtained results clearly show the ferroelectric–antiferroelectric transition according to continuous composition change instead of discrete research. Therefore, a highly productive method for studying ferroelectricity changes in terms of a doping and a composition of HfO2‐based ferroelectric thin films through a novel ALD combinatorial approach is proposed.

Phase formation and structural evolution of multicomponent (CrFeCo)1-yNy films

The Cantor alloy (CoCrFeMnNi) and its variants, in bulk as well as thin films, have been extensively studied. They are known to exhibit cubic crystal structures and thermodynamic stability regardless of their complex chemical composition. Therefore, they may find use as hard, wear-resistant, corrosion and oxidation-resistant coatings. The addition of light elements, such as nitrogen, is known to help improve these properties further through processes such as amorphization and nitride compound formation. Here, we investigate the ternary CrFeCo system to study the effects of nitrogen addition. (CrFeCo) 1-y N y multicomponent thin films are grown on silicon substrates by DC magnetron sputtering. Changes in crystal structure, morphology, mechanical and electrical properties with gradual increases of nitrogen in the film are described and discussed. Increased addition of nitrogen from 14 at.% to 28 at.% in the film leads to a transformation from an fcc to a bcc crystal structure, affects both the mechanical and electrical properties. XPS analysis shows the tendency of nitrogen to bond with Cr over other metals. The films display hardness values between 7 and 11 GPa with resistivities values ranging between 28 and 165 μΩ cm. • Multicomponent (CrFeCo)Ny coatings deposited by reactive magnetron sputtering • Effect of nitrogen content on structure, morphology and composition was studied. • Phase formation and evolution with changes in nitrogen content • Mechanical and electrical properties of (CrFeCo)Ny thin films

Nanosecond laser ablation of composite thin films in liquid

We present a study on nanosecond laser ablation of thin composite films immersed in liquids. The composite films are obtained using a classical on-axis pulsed laser deposition technology, where the target consists of two sectors with different composition. Multicomponent films containing ZnO, TiO2, and Ag, are thus deposited on a substrate. The as-prepared composite films are then immersed in double distiled water and irradiated by nanosecond laser pulses. This results in the production of colloids composed by multicomponent nanoparticles. The optical properties of the colloids are evaluated by optical transmittance measurements in the UV-VIS spectral range. Transmission electron microscopy is used to visualize the nanostructures formed in the solution, as well as to evaluate their size distribution. The phase composition of the samples is determined by selected area electron diffraction.

Formulation and Characterization of Hydroxypropyl Methylcellulose Edible Films Containing Grape Seed Oil

AbstractNovel biobased multicomponent edible films from hydroxypropyl methylcellulose (HPMC) and grapeseed oil (GsO) are developed. This study investigates the effect of GsO concentration on some physical and physico‐chemical properties of the films. The hydrophobicity of the films increases, which is expressed in improved water vapor permeability and reduced moisture absorption. Color and penetration properties of the films are also investigated. The pure cellulose film is almost colorless, but it becomes darker with pale greenish yellow color from the grape seed oil. The break force of the films is independent from the grape seed oil concentration, but the break deformation and the deformation work of the films with GsO is much higher and these are more elastic. Finally, multicomponent films demonstrated strong antioxidant activity. The obtained results suggest that the new multicomponent films may be used as food active packaging.

Direct-ink coating techniques for Cu-based multicomponent semiconductor films

Thin film solar cells based on earth-abundant, non-toxic multicomponent chalcogenides have the potential to deliver cost-competitive solution for large-scale deployment. Direct deposition of new materials has been vigorously investigated to improve the device efficiency. In this paper, we report direct ink coating of Cu-based multicomponent solar absorber materials such as CuCdS2 (CCdS), Cu2CoSnS4 (CCoTS) and Cu2FeSnS4 (CFTS) in methanol and ethylene glycol. Films were first dried at 110 °C for 10 min. The precursor films were then heated at 200 °C in air for 20 min to achieve final crystalline phase. Structural and microstructural properties of the films deposited from methanol revealed that these films are compact and void free. However, films are comparatively rough and porous in case of ethylene glycol. The direct optical band gaps of CCdS, CCoTS and CFSTS films are 2.43, 1.3 and 1.4 eV, respectively. The electrical measurements reveal that the films have p-type conduction and are promising absorber materials for photovoltaic applications.

Parameters synergism in the preparation of TiN(100) transition layer with high structural integrity on Si(100): First‐principles calculations and experimental investigations

The mechanical properties of titanium nitride (TiN) and related multicomponent films have been studied for decades. However, the virtues of TiN(100) coatings themselves and of their binding ability to Si(100) substrate are to be studied to ensure the application of transition layer for upper sediment, while the synergism between various growth parameters needs a further understanding. Herein, we present the mechanical properties of TiN(100), (111) planes and binding nature of Si(100)/TiN(100) interface by first principle. Then, TiN(100) films were epitaxially grown by pulse laser deposition (PLD) method on Si wafers under different conditions, and the structures, valence states, and properties were tested. We have obtained a high‐quality deposit with the hardness of ~31 GPa, which can firmly adhere on the substrate with high structural integrity, thus can be employed for further deposition of other oxide films. In general, higher substrate temperature and laser energy will improve the quality of the film. We anticipate that this study can give some hints on the properties of different crystal faces and the relationship of preparation variables during growing process.

Investigation of charge transfer interaction in heterometallic precursors to control their surface reactivity for MOCVD of Pd-Cu alloy films

The work aims to study main factors determining surface reactions mechanism of the heterometallic MOCVD precursors for multicomponent inorganic films. A set of theoretical and experimental techniques is proposed to investigate the electronic structure of the copper-palladium precursor to control its surface reactivity in MOCVD of Pd-Cu alloy films. The surface and bulk charge distribution in the heterometallic precursors CuPdL4 (1) and Cu(hfa)2PdLF2 (2) and parent monometallic complexes was carried out using both experimental X-ray photoelectron (XPS) and X-ray emission (XES) spectroscopies and theoretical techniques (DFT calculations and NBO analysis). Comparison of calculated and experimental atomic charges for monometallic and heterometallic complexes revealed the electronic density redistribution on oxygen and metal atoms due to electronic charge transfer interaction between monometallic fragments in the heterocomplex, which was confirmed by NBO analysis. The charge transfer intensity appeared to be stronger for the fluorinated precursor 2, indicating its greater resistance to thermal dissociation into monometallic fragments compared to 1, which was confirmed by the data on the bimetallic films composition. Thus, the evidenced charge transfer interaction can be altered by changing the composition of the precursors to control their surface reactivity and films composition.

Property-Targeted Design of High-Entropy Alloys Based on Tailoring Through Solid-State Alloying from Multilayer Thin Films

Property-targeted alloys were designed by exploring the phase stability and mechanical behaviors of a series of AlCoCrFeNi-based multicomponent alloy films fabricated via grain boundary diffusion-assisted solid-state alloying from their multilayer films. For phase identification and hardness evaluation for the multicomponent alloy films, compositional-dependent property contour maps were constructed, and their deformation behaviors were investigated. The results indicate that the alloys revealed a solid solution phase with an FCC structure, whereas Sigma phase was also formed in alloys with a high concentration of Cr. Moreover, the concentration ratio of Co To Ni was dominant to improve solid-solution strengthening, as expected by atomic-level complexity related to the electronegativity difference, and to activate metastable deformation behaviors by reducing the stacking fault energy. Based on the screening results of the compositional-dependent behaviors in the films, consequently, we developed novel metastable CoCrFeNi-based high-entropy alloys with the outstanding tensile properties of 234 MPa in yield strength, 720 MPa in ultimate tensile strength, and 80 % in fracture strain through compositional tailoring the concentration ratio of Co to Ni. This approach shows prospects of property customization of multicomponent alloys

Recent Developments in Dendrite-Free Lithium-Metal Deposition through Tailoring of Micro- and Nanoscale Artificial Coatings.

Forty years after the failed introduction of rechargeable lithium-metal batteries and 30 years after the successful commercialization of the lower capacity, graphite-anode-based lithium-ion battery by Sony, demand for higher energy density batteries is leading to reinvestigation of the problem of dendrite growth that makes the metallic lithium anodes unsafe and prevented commercialization to begin with. One strategy to mitigate dendrite growth is to deposit thin, tailored, corrosion-passivating coatings on the metallic lithium, instead of allowing the metal to spontaneously react with the organic electrolyte solution to form its passivating solid electrolyte interface (SEI). The challenge is to find and to deposit a coating that is electronically insulating yet allows uniform permeation of Li+ at a high cycling rate, such that Li-metal is electrodeposited uniformly on the nanoscale below the tailored coating. Recently, a number of studies have examined multicomponent films, taking advantage of the properties of two different materials, which can be tuned separately or chosen for their complementary properties. Use of these multicomponent coatings will likely enable future researchers to create rationally designed SEIs capable of effectively suppressing the growth of Li dendrites. This review discusses recent developments in micro- and nanoscale tailored coatings to meet that need.

Photoluminescence and laser properties of active media based on ZnSe doped with Cr, Al, Na from spray pyrolysis deposited films

The prospects for using multicomponent films produced by aerosol spray pyrolysis for doping bulk ZnSe crystals with optically and electrically active impurities are shown for the first time. Lasing was obtained on ZnSe:Cr active elements doped during hot isostatic pressing treatment from CrS and CdS:Cr films. The lasing efficiency with respect to the absorbed radiation energy at a wavelength of 1.94 μm was about 54% for ZnSe:Cr doped from CrS film and 50% for ZnSe:Cr doped from CdS:Cr film, respectively. The luminescence and lasing characteristics of ZnSe:Cr active elements co-doped with Al and Na impurities were investigated. A high diffusion rate of Cr2+ ions into polycrystalline ZnSe doping process from sulfide films was observed.

Nanostructural evolution in vapor deposited phase-separating binary alloy films of non-equimolar compositions: Insights from a 3D phase-field approach

A rich variety of self-organized nanoscale patterns evolve during physical vapor deposition of phase-separating alloy films. However, our limited understanding of the fundamental mechanisms of morphological evolution during the vapor deposition of multi-component metallic films is a major hurdle in optimizing their mechanical and functional properties. Diffuse interface approaches, such as the phase-field method, can enable the prediction of nanostructured morphologies in a broad class of immiscible binary alloys by achieving a fundamental understanding of self-assembly mechanisms down to the nanometer scale. Here, we adopt a three-dimensional phase-field approach to numerically investigate the role of alloy compositions, deposition rates, and temperature on the morphological self-assembly of nanostructures in vapor deposited alloy films. We explain the influence of alloy composition and deposition parameters on the evolution of novel film morphologies such as perforated layered and aligned rods. Following an extensive parametric study, we construct morphology maps that help expand our knowledge of the different combinations of processing conditions that generate distinct nanoscaled morphologies. Finally, we expand and elucidate a theory based on the minimization of interfacial energy that underpins the mechanisms of morphological transitions in vapor deposition of immiscible alloy films for an entire composition range.

MONITORING COMPOSITION AND STRUCTURE OF MOCVD ZrO2-BASED MULTICOMPONENT FILMS BY INNOVATIVE MIXED METAL-ORGANIC PRECURSORS

Three volatile mixed-metal precursors [ZrL4Pb(hfa)2] (1), [ZrL4PbL2] (2), and [ZrL4La(dpm)3] (3) (L = 2-methoxy-2,6,6-trimethyl-3,5-heptanedionate; dpm = 2,2,6,6-tetramethyl-3,5-heptanedionate; hfa = 1,1,1,5,5,5-hexafluore-2,4-pentanedionate) are used to prepare ZrO2-based multicomponent films by metalorganic chemical vapor deposition (MOCVD). The deposition experiments are carried out in a hot-wall reactor at 600-750 °C on silicon substrates under 20 Torr in the presence of oxygen. According to X-ray powder diffraction, the main crystal phases in the films prepared from precursors 1 and 2 are solid solutions based on tetragonal and cubic ZrO2. Lead does not form separate crystal phases but is dissolved in the oxide form within the ZrO2 matrix, as is indicated by X-ray photoelectron spectroscopy data. La2Zr2O7 films are prepared from 3 using two ways of precursor supply: evaporation in argon and by direct liquid injection (DLI). It is shown that the composition and structure of obtained films are determined by the precursor composition. The results obtained for thermal behavior of precursors in condensed and gas phases are discussed.

Dy3+ and Tb3+ co-doped boro-phosphate sol–gel vitreous thin films

A new glass with the molar composition 20B2O3-60P2O5-10ZnO-5Dy2O3-5Tb2O3 was obtained by sol–gel method and deposited on silicate glass substrates by spin-coating, at different rotation speeds and number of layers. XRD proved the vitreous state of the thin films. FTIR spectroscopy revealed the borate, meta-phosphate and mixed boro-phosphate networks in the samples. SEM, combined with AFM, demonstrated the advantages of higher deposition speeds on the higher uniformity and lower roughness of the thin films. The proposed composition of the films was proved by EDS investigations, which identified all elements in the desired proportions. Absorption bands and luminescence emissions specific to Dy3+ and Tb3+ ions are identified. These multi-component films can be used for magneto-optical devices, laser mirrors and luminescent applications.

Multicomponent Sn–Mo–O-containing films formed in anodic alumina matrixes by ionic layer deposition

Multicomponent metal oxide compounds of the composition Sn–Mo–O, Sn–Ni–Mo–O and Sn–Bi–Mo–O were formed by successive ionic layer adsorption and reaction (SILAR) method deposition into anodic alumina matrixes. The growth mechanism of the Sn–Mo–O-containing films in the porous anodic alumina was investigated. It was found that the degree of pore filling, specific thickness and surface morphology of the deposited layer depend not only on the number of cycle’s treatment, but also on the composition of the used solutions. The morphology of Sn–Mo–O and Sn–Ni–Mo–O surfaces had granular structures, while Sn–Bi–Mo–O layer had flake-like structure. The differences in microstructure and deposition of the layers on the surface of the matrixes can be explained by the insufficient activation of anodic alumina pores before deposition. The investigations of the formed layers composition by the electron-probe X-ray spectral microanalysis showed that the ratio of tin to molybdenum in tin-molybdenum containing oxides changes. The Sn/Mo atomic ratio for Sn–Mo–O layer is 1.29/2.72; for Sn–Ni–Mo–O layer is 5.83/4.85; for Sn–Bi–Mo–O layer is 0.60/0.87. The using of SILAR method allows forming multicomponent films in the anodic alumina matrixes, which have great potential to applicate in high-sensitivity gas sensors.

Influence of substrate temperature on physical properties of MnSbInS4 thin films prepared by a simplified spray pyrolysis technique for photovoltaic applications

MnSbInS 4 multi-component semiconductor thin films are prepared by chemical spray pyrolysis on glass substrates at various substrate temperatures ranging from 250-400 °C with a constant spray time (5mins). The structural, morphological, optical and electrical properties of the thin films are investigated through different techniques such as X-ray diffraction (XRD), electron diffraction spectroscopy (EDS), UV-Vis absorption spectroscopy and four probe method. The X-ray spectra reveal that the MnSbInS 4 films are polycrystalline in nature with a cubic spinel structure having (220) plane as the preferred orientation. The energy dispersive analysis by X-ray (EDS) studies confirm the presence of Mn, In, Sb and S in the film grown at a substrate temperature of 250 °C. Optical measurements allow us to determine the absorption coefficient which is as high as (1.22 x 10 5 cm -1 ) at 250 ºC indicating that MnSbInS 4 compound has an absorbing property favorable for applications in solar cell devices. It is interesting to note that the structural homogeneity and crystallinity of the films is improved due to the decrease in absorption coefficient (α) and extinction coefficient (k) with an increase of substrate temperature. The observations from photoluminescence measurements reveal that the photoemission is mainly due to the donar-acceptor pair transitions. Moreover, from the electrical studies, it is observed that the electrical resistivity (ρ ) is strongly affected by substrate temperature and the lowest resistivity (ρ = 4.77 x 10 3 Ω m ) is obtained for the film grown at 400 ºC. Stylus profilometer was used to measure the film thickness and the values range between 768 nm (250 °C) to 617 nm (400 °C). This indicates that, as the substrate temperature increases, the thickness of the film decreases. Other important parameters like micro-strain (ε) and dislocation density (δ) which are commonly used to describe the structural analysis are also presented.

Effect of nitrogen content on microstructure and corrosion resistance of sputter-deposited multicomponent (TiNbZrTa)Nx films

Multicomponent (TiNbZrTa)Nx films were deposited on Si(100) substrates at room temperature using magnetron sputtering with a nitrogen flow ratio fN [fN = N2/(Ar + N2)], which was varied from 0 to 30.8%. The nitrogen content in the films varied between 0 and 45.2 at.%, i.e., x = 0 to 0.83. The microstructure was characterized by X-ray diffraction and electron microscopy. The metallic TiNbZrTa film comprised a dominant bcc solid-solution phase, whereas a single NaCl-type face-centred cubic structure was observed in all nitrogen-containing films (TiNbZrTa)Nx. The mechanical, electrical, and electrochemical properties of these films varied with nitrogen content. The maximum hardness was achieved at 22.1 ± 0.3 GPa when N = 43.0 at.%. The resistivities increased from 95 to 424 μΩcm with increasing nitrogen content. A detailed study of the variation of morphology and chemical bonding with nitrogen content was performed and the corrosion resistance of the TiNbZrTa nitride films was explored in 0.1 M H2SO4. While all the films had excellent corrosion resistances at potentials up to 2.0 V vs. Ag/AgCl, the metallic film and the films with low nitrogen contents (x < 0.60) exhibited an almost stable current plateau up to 4.0 V vs. Ag/AgCl. For the films with higher nitrogen contents (x ≥ 0.68), the current plateau was retained up to 2.0 V vs. Ag/AgCl, above which a higher nitrogen content resulted in a higher current. The decrease in the corrosion resistance at these high potentials indicate the presence of a potential-dependent activation effect resulting in an increased oxidation rate of the nitrides (present under the passive oxide film) yielding a release of nitrogen from the films. TEM results indicate that the oxide layer formed after this corrosion measurement was thick and porous for the film with x = 0.76, in very good agreement with the increased corrosion rate for this film. The results demonstrate that an increased nitrogen content in (TiNbZrTa)Nx system improves their mechanical properties with retained high corrosion resistance at potentials up to 2.0 V vs. Ag/AgCl in 0.1 M H2SO4. At even higher potentials, however, the corrosion resistance decreases with increasing nitrogen concentration for films with sufficiently high nitrogen contents (i.e. x ≥ 0.68).

Energy conversion systems: Molecular architecture engineering of metal precursors and their applications to vapor phase and solution routes

Abstract

Sol-Gel-Derived Bioactive and Antibacterial Multi-Component Thin Films by the Spin-Coating Technique.

Although metallic alloys commonly used as prosthetics are durable and mechanically strong, they are often bioinert and lack antibacterial properties. Implementing a bioactive glass material with antibacterial properties as a coating on a metallic substrate provides mechanical strength and bioactivity, as well as antibacterial properties. Many coating methods have been extensively investigated; however, most of them can be expensive, are difficult to scale up, or do not form thin films, which could prevent their translation to clinical practice. The formation of thin films by spin-coating multi-component solution-gelation (sol-gel)-derived glass with antibacterial and bioactive properties has not been achieved previously. For this study, stainless steel 316L substrates were spin-coated with a sol-gel-derived bioactive and antibacterial glass coating in SiO258.3-P2O57.1-CaO25.6-Al2O55.4-Ag2O2.1-Na2O1.5 wt% system (Ag-BG). A sol-gel processing condition that avoids elemental separation upon spin-coating when sintering happens at below the calcination temperature (500 °C) has been developed. This work demonstrates that silver reduction occurs when the concentrations of other cations such as Ca2+ and Na+ in the solution increase. Increasing the stirring duration time prior to the increase of cations, Ag+ ions are stabilized by aluminum tetrahedra, and their reduction to metallic silver does not occur. This study also shows that large dilution ratios (water:tetraethyl orthosilicate) greater than 25:1, accompanied by long stirring durations, produce morphologically homogeneous coatings. Using this strategy, thin films were formed with antibacterial properties against methicillin-resistant Staphylococcus aureus (MRSA) biofilm and biological responses that promote eukaryotic cell adhesion and proliferation. In total, the improved synthesis strategy opens new avenues for the development of novel bioactive and antibacterial thin-film coatings, as it reveals the processing characteristics that control the physicochemical and morphological properties of the formed films.

Developing multicomponent edible films based on chitosan, hybrid of essential oils, and nanofibers: Study on physicochemical and antibacterial properties

Plastic waste is one of the major threats to the environment, and an urgent need to replace synthetic plastics with sustainable materials is progressively growing. Herein, sustainable films based on chitosan, Satureja, and Thyme essential oils (EOs), and chitosan nanofibers (NF) were developed for the first time. To this end, 1% (w/w) of EOs and 2 wt% of NF were incorporated into the chitosan solution. Despite the very similar chemical structure of carvacrol and thymol, which are the major constituents of Satureja and Thyme EOs, respectively, they imposed notably different effects on the physicochemical properties of chitosan films. Thyme EO was more efficient at establishing hydrogen bonds with chitosan. The disruptive effect of EOs on the crystalline network of chitosan was demonstrated through X-ray diffraction analysis. Satureja and Thyme EOs decreased and increased the barrier property of the chitosan films against water vapor, respectively. However, the barrier property was greatly improved in the presence of chitosan nanofibers. Satureja EO exhibited a more efficient antibacterial property against E. coli rather than Thyme EO. The fruits and vegetables, coated by the chitosan/EO/NF system, were less perished as compared with the control and chitosan-coated samples indicating the promising potential of the developed system to be used as edible and sustainable films and coatings due to their enhanced antibacterial and barrier properties.

Lattice oxygen activation enabled by high-valence metal sites for enhanced water oxidation

Anodic oxygen evolution reaction (OER) is recognized as kinetic bottleneck in water electrolysis. Transition metal sites with high valence states can accelerate the reaction kinetics to offer highly intrinsic activity, but suffer from thermodynamic formation barrier. Here, we show subtle engineering of highly oxidized Ni4+ species in surface reconstructed (oxy)hydroxides on multicomponent FeCoCrNi alloy film through interatomically electronic interplay. Our spectroscopic investigations with theoretical studies uncover that Fe component enables the formation of Ni4+ species, which is energetically favored by the multistep evolution of Ni2+→Ni3+→Ni4+. The dynamically constructed Ni4+ species drives holes into oxygen ligands to facilitate intramolecular oxygen coupling, triggering lattice oxygen activation to form Fe-Ni dual-sites as ultimate catalytic center with highly intrinsic activity. As a result, the surface reconstructed FeCoCrNi OER catalyst delivers outstanding mass activity and turnover frequency of 3601 A gmetal−1 and 0.483 s−1 at an overpotential of 300 mV in alkaline electrolyte, respectively.