Search

This study is aimed to have an understanding of the formation of silicon vacancy (SiV) colour centres in diamond during thin film growth of diamond in microwave plasma CVD reactor. The study focusses on different sources of silicon impurities in the chamber and the possibility of controlling the formation of SiV during growth for various applications. Diamond thin films were grown on different substrates and their photoluminescence (PL) spectra were analysed to understand the role of substrate material and residual silicon in the chamber for the formation of SiVs. The predominant contribution to SiV formation was found to be the residual silicon in the chamber originating from the quartz components exposed to the plasma. In the films grown on silicon substrate, there is also substrate contribution to the PL signal. Controlling the formation of SiVs in polycrystalline diamond can pave the way to optically integrate SiVs to different photonic structures. [ABSTRACT FROM AUTHOR]

This study examines how current collector support chemistry (sodiophilic intermetallic Na2Te vs. sodiophobic baseline Cu) and electrodeposition rate affect microstructure of sodium metal and its solid electrolyte interphase (SEI). Capacity and current (6 mAh cm−2, 0.5–3 mA cm−2) representative of commercially relevant mass loading in anode‐free sodium metal battery (AF‐SMBs) are analyzed. Synchrotron X‐ray nanotomography and grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) are combined with cryogenic ion beam (cryo‐FIB) microscopy. Highlighted are major differences in film morphology, internal porosity, and crystallographic preferred orientation e.g. (110) vs. (100) and (211) with support and deposition rate. Within the SEI, sodium fluoride (NaF) is more prevalent with Te−Cu versus sodium hydride (NaH) and sodium hydroxide (NaOH) with baseline Cu. Due to competitive grain growth the preferred orientation of sodium crystallites depends on film thickness. Mesoscale modeling delineates the role of SEI (ionic conductivity, morphology) on electrodeposit growth and onset of electrochemical instability. [ABSTRACT FROM AUTHOR]

Molecular dynamics simulations were performed to investigate the growth of hydrocarbon films with a surface at temperatures from 300 to 1000 K. The results show that C2H is the main precursor of film growth. The formed C:H films are mainly unsaturated and dominated by double bonds and CN3 carbon atoms. The evolution of the C:H film is considered under the bombardment of the two major ions (Ar+ and C2H3+) with energies ranging from 50 to 100 eV. Film sputtering is significant above 50 eV, while at lower energies, the atoms of the C2H3+ ions can be incorporated and contribute to the growth. [ABSTRACT FROM AUTHOR]

The growth of magnesium silicide on porous silicon under high vacuum conditions (10–5–10‒6 Torr) without the chemical removal of silicon oxide and in a limited temperature range of preliminary annealing (Ta = 450°C) is tested for the first time. It is found that the minimum substrate temperature at which deposited magnesium begins to destroy silicon oxide and interact with silicon by forming magnesium silicide (Mg2Si) is 290°C. In the solid phase reaction of magnesium with porous silicon, the optimum temperature at which, after the destruction of silicon oxide, the formation of a continuous Mg2Si film begins is 350°C. It is shown that, at an annealing temperature Ta = 420°C, only a Mg2Si island film of good crystalline quality is formed. The formation of magnesium silicide in all cases is confirmed by X-ray diffraction, scanning electron microscopy, Raman spectroscopy, or Raman micromapping. It is established that the reflection spectrum of the Mg2Si/PS/Si system corresponds to the reflection from porous silicon with a partial increase at 500–900 nm due to the contribution to reflection from magnesium silicide, which increases with increasing film thickness. It is proved that after the heat treatment of porous silicon and the growth of magnesium silicide with a thickness of up to 90 nm, PS photoluminescence is retained, the radiation of which is recorded with partial attenuation in the Mg2Si film without changing the spectral composition, both immediately after growth and after long-term storage under atmospheric conditions (up to 8 months). [ABSTRACT FROM AUTHOR]

Co-condensation of mixed SiGe nanoclusters and impingement of SiGe nanoclusters on a Si substrate were applied using molecular dynamics (MD) simulation in this study to mimic the fast epitaxial growth of SiGe/Si heterostructures under mesoplasma chemical vapor deposition (CVD) conditions. The condensation dynamics and properties of the SiGe nanoclusters during the simulations were investigated first, and then the impingement of transient SiGe nanoclusters on both Si smooth and trench substrate surfaces under varying conditions was studied theoretically. The results show that the mixed nanoclusters as precursors demonstrate potential for enhancing epitaxial SiGe film growth at a high growth rate, owing to their loosely bound atomic structures and high mobility on the substrate surface. By varying cluster sizes and substrate temperatures, this study also reveals that smaller clusters and higher substrate temperatures contribute to faster structural ordering and smoother surface morphologies. Furthermore, the formed layers display a consistent SiGe composition, closely aligning with nominal values, and the cluster-assisted deposition method achieves the epitaxial bridging of heterostructures during cluster impingement, highlighting its additional distinctive characteristics. The implications of this work make it clear that the mechanism of fast alloyed epitaxial film growth by cluster-assisted mesoplasma CVD is critical for extending it as a versatile platform for synthesizing various epitaxial films. [ABSTRACT FROM AUTHOR]

We report the growth, structural characterization, and transport studies of Bi2Se3 thin film on single crystalline silicon (Si), Si/SiO2, quartz, and glass substrates by thermal evaporation method. Our results show that 300 °C is the optimum substrate temperature to obtain the c -axis (001) oriented Bi2Se3 films on all the substrates. The film grown on the Si substrate has the minimum crystalline disorder. The energy-dispersive x-ray spectroscopy results show that film on Si substrate is bismuth deficient, the film on Si/SiO2 substrate is selenium deficient, and the film on quartz substrate is near perfect stoichiometric providing a way to tune the electronic properties of Bi2Se3 films through substrate selection. The film grown on quartz shows the highest mobility (2.7 × 104 cm2 V-1s−1) which drops to 150 cm2 V-1s−1 for Si, 60 cm2 V-1s−1 for Si/SiO2, and 0.9 cm2 V-1s−1 for glass substrate. Carrier concentration is n-type for Bi2Se3 films on Si (∼1018 cm−3), quartz (∼1018 cm−3) and Si/SiO2 (∼1019 cm−3) substrate with a clear indication of frozen out effect around 50 K for Si/SiO2 and Si substrate. Longitudinal resistivity of Bi2Se3 film on Si/SiO2 substrate shows different behavior in three different temperature regions: temperature dependent resistivity region due to electron–phonon scattering, a nearly temperature independent resistivity region due to electron–phonon and electron–ion scattering, and a quantum coherent transport region. [ABSTRACT FROM AUTHOR]

Plasma‐assisted epitaxially grown silicon (plasma‐epi Si) is a new silicon‐based material with a tailorable nanostructure. Nanovoids can be introduced into plasma‐epi Si during growth, enabling the bottom‐up fabrication of porous Si for applications such as batteries, hydrogen storage, and even explosives. To fully control the nanostructure of plasma‐epi Si, its growth dynamics must be studied. In this study, the correlation between hydrogen incorporation and defect nanostructures in plasma‐epi Si grown under various process conditions is investigated, and the experimental results are supported by molecular dynamics simulations. The nanostructural evolution during growth suggests a model in which plasma‐epi Si shows two growth stages distinguished by different dominant defect nanostructures. In the initial growth stage, the nanostructure can be controlled by the deposition conditions, whereas the nanostructure is dominated by interconnected voids, forming a porous structure. In the subsequent bulk growth stage, the material growth is less sensitive to the deposition conditions, whereas the nanostructure becomes prevalent isolated defects. In the results of this study, different strategies for the plasma‐epi Si growth process for different applications are suggested. In these results, a better understanding of this new material may be provided and the discovery of various applications for bottom‐up‐grown porous Si is facilitated. [ABSTRACT FROM AUTHOR]

Solution method provides a low‐cost and environmentally friendly route for the fabrication of Cu2ZnSn(S,Se)4 (CZTSSe) thin‐film solar cells. However, uncontrollable quality of the CZTSSe absorber layer will severely limit the device's performance. In this study, it is find that the thickness and the quality of the formed precursor is not stable because of the variation of the viscosity of the precursor solution. Combined by different characterization methods, the results disclose that such change is strongly related to the reflected color of the first coating layer during precursor growth. Further studies disclose that only by maintaining the appropriate reflected color can a well‐crystallized CZTSSe film be prepared, thereby obtaining good solar cell efficiency. This semi‐empirical pattern is confirmed by thin‐film interference theory. Under the guidance of this method, CZTSSe absorbers with high quality are obtained easily, and the highly efficient CZTSSe solar cell can be fabricated easily. This study provides a feasible and effective strategy to obtain the optimal structure and composition of CZTSSe film toward the production of highly efficient kesterite solar cells, which can also be widely applied to the preparation of other films by solution‐based method. [ABSTRACT FROM AUTHOR]

Plasma‐assisted epitaxially grown silicon (plasma‐epi Si) is a new silicon‐based material with a tailorable nanostructure. Nanovoids can be introduced into plasma‐epi Si during growth, enabling the bottom‐up fabrication of porous Si for applications such as batteries, hydrogen storage, and even explosives. To fully control the nanostructure of plasma‐epi Si, its growth dynamics must be studied. In this study, the correlation between hydrogen incorporation and defect nanostructures in plasma‐epi Si grown under various process conditions is investigated, and the experimental results are supported by molecular dynamics simulations. The nanostructural evolution during growth suggests a model in which plasma‐epi Si shows two growth stages distinguished by different dominant defect nanostructures. In the initial growth stage, the nanostructure can be controlled by the deposition conditions, whereas the nanostructure is dominated by interconnected voids, forming a porous structure. In the subsequent bulk growth stage, the material growth is less sensitive to the deposition conditions, whereas the nanostructure becomes prevalent isolated defects. In the results of this study, different strategies for the plasma‐epi Si growth process for different applications are suggested. In these results, a better understanding of this new material may be provided and the discovery of various applications for bottom‐up‐grown porous Si is facilitated.

This work is devoted to the study of the morphology and structure of 3C-SiC/Si films obtained by the high-temperature chemical vapor deposition (HT CVD) method. Epitaxial growth is achieved by transforming the crystal by coordinated substitution of atoms, in which the overall structure of bonds between atoms is not destroyed. At the first stage of the conversion, the first half of silicon atoms Si is successively replaced by carbon atoms C as a result of reaction of Si with gas CO, and an epitaxial layer of cubic silicon carbide SiC-3C is obtained. At the second stage, the remaining half of Si atoms is consistently replaced by C atoms due to the reaction of SiC with CF4 gas. Depending on the orientation of the silicon surface, the pressure of the reagent gas, the temperature and time of growth, carbon structures with various properties are obtained, from nanodiamonds to nanotubes and onion carbon. The key feature of this method is that the substrate orders the resulting structures using the initial chemical bonds between atoms in silicon. Photographs of the surface of the structures are presented, demonstrating the features of silicon carbide film growth at different levels of the substrate holder. Analysis of rotational X-ray diffraction patterns showed the presence of silicon carbide films of the 3-C polytype. [ABSTRACT FROM AUTHOR]

The growth features of a hydrate film at the interface between liquid carbon dioxide and pure water and sodium dodecyl sulfate solution were studied. It was found in all cases that in a Teflon cell a hydrate film is formed on the contact surface of the liquid phases, after which no visible changes are observed for an indefinitely long time. In experiments with pure water in a steel cell after the water-CO2 surface is covered with hydrate the hydrate film is slowly deformed as a result of growth along the line of contact between the hydrate and the cell wall. In experiments with a solution of sodium dodecyl sulfate the deformation of the hydrate film is much more pronounced, and the degree of conversion of the water into hydrate is increased significantly. [ABSTRACT FROM AUTHOR]

Abstract Chemical engineering tailors functional materials to meet the demands of physical and chemical properties, accelerating materials discovery and design in a multidisciplinary field. However, stereotyped synthetic paradigms in physical and chemical approaches obstruct the effective integration of multiple advantages of respective materials exploration methods. Solid state reaction is often considered separately with wet chemistry synthesis route, such as film growth using physical vapor deposition and hydrothermal methods. Here, the controlled growth of FeSe thin films by physical deposition techniques followed by the chemical engineering to create heterogenous interface in FeSe films via a solution‐based environment is demonstrated. The two‐step route allows an expanded crystal structure and enhanced superconducting transition temperature from 3.6 to 38 K, providing a new strategy to design functional hybrid materials.

The preparation of two-dimensional magnetic materials is a key process to their applications and the study of their structure and morphology plays an important role in the growth of high-quality thin films. Here, the growth, structure, and morphology of Cr1+δTe2 films grown by molecular beam epitaxy on mica with variations of Te/Cr flux ratio, growth temperature, and film thickness have been systematically investigated by scanning tunneling microscopy, reflection high-energy electron diffraction, scanning electron microscope, and X-ray photoelectron spectroscopy. We find that a structural change from multiple phases to a single phase occurs with the increase in growth temperature, irrespective of the Cr/Te flux ratios, which is attributed to the desorption difference of Te atoms at different temperatures, and that the surface morphology of the films grown at relatively high growth temperatures (≥ 300 °C) exhibits a quasi-hexagonal mesh-like structure, which consists of nano-islands with bending surface induced by the screw dislocations, as well as that the films would undergo a growth-mode change from 2D at the initial stage in a small film thickness (2 nm) to 3D at the later stage in thick thicknesses (12 nm and 24 nm). This work provides a general model for the study of pseudo-layered materials grown on flexible layered substrates. [ABSTRACT FROM AUTHOR]

Although the performance of qubits has been improved in recent years, the differences in the microscopic atomic structure of the Josephson junctions, the core devices prepared under different preparation conditions, are still underexplored. In this paper, the effects of the oxygen temperature and upper aluminum deposition rate on the topology of the barrier layer in the aluminum-based Josephson junctions have been presented by classical molecular dynamics simulations. We apply a Voronoi tessellation method to characterize the topology of the interface and central regions of the barrier layers. We find that when the oxygen temperature is 573 K and the upper aluminum deposition rate is 4 Å/ps, the barrier has the fewest atomic voids and the most closely arranged atoms. However, if only the atomic arrangement of the central region is considered, the optimal rate of the aluminum deposition is 8 Å/ps. This work provides microscopic guidance for the experimental preparation of Josephson junctions, which helps to improve the performance of qubits and accelerate the practical application of quantum computers. [ABSTRACT FROM AUTHOR]

• Mean field approximation models surface-reaction kinetics with dissociation. • Derived coupled non-linear differential equations for growth model. • Dissociation rates impact on film growth kinetics demonstrated. • Numerical integration aligns well with result from kinetic Monte Carlo simulations. We utilize mean field approximation to derive a set of coupled non-linear differential equations for a surface-reaction growth model, incorporating dissociative adsorption processes. These equations account for inaccessible sites caused by the height differences in the growing film, which inhibit dissociative adsorption. Numerical integration of these equations highlights the substantial effect of dissociation rates on growth kinetics, showing excellent agreement with prior kinetic Monte Carlo simulations, offering crucial insights into the interaction between dissociative adsorption and surface growth dynamics. [ABSTRACT FROM AUTHOR]

Metal–organic chemical vapor deposition (MOCVD) is an important method for growing metal–oxide semiconductor films. However, owing to problems associated with gas-phase parasitic reactions and wall deposition, this method achieves low growth efficiency and affects the film quality. Computational fluid dynamics (CFD) has been widely used in MOCVD research and can be employed to investigate the flow field and the chemical vapor deposition (CVD) process in the reactor. In this study, considering the growth of zinc oxide and indium oxide as examples, a four-step reaction mechanism is proposed based on a combination of the multi-step reaction mechanism and experimental results. The effect of chemical reactions on the film growth rate is studied based on the Arrhenius plot and experimental results. A new flow stability map is proposed, and the flow field stability under different pressures is investigated to explore the influence of the flow field on the film growth rate. Results show that the deposition rate is influenced by both the gas-phase parasitic reactions and the effect of the flow field on the source component distribution. Furthermore, the causes and factors influencing sidewall deposition are revealed. [ABSTRACT FROM AUTHOR]

The effect of energetic ion bombardment on the properties of tantalum thin films was investigated. To achieve such energetic ion bombardment during the process the Ta thin films were deposited by deep oscillation magnetron sputtering (DOMS), an ionized physical vapor deposition technique related to high power impulse magnetron sputtering. The peak power was between 49 and 130 kW and the substrate was silicon at room temperature and ground potential. The directionality and the energy of the depositing species was controlled by changing the ionization fraction of the Ta species arriving at the substrate at different peak powers. In this work, the surface morphology (AFM), microstructure (SEM), structure (XRD) and hardness and Young's modulus (nanoindentation) of the films were characterized. The ion energy distributions (IEDs) were measured using an electrostatic quadrupole ion energy and mass spectrometer (HIDEN EQP 300). The IEDs showed that the DOMS process applies a very energetic (up to 120 eV) ion bombardment on the growing tantalum films. Therefore, with such conditions it was possible to deposit pure α-Ta (of 2 μm of thickness) without the use of additional equipment, i.e., without substrate bias or substrate heating. Conditions are therefore significantly different than in previous works, offering a much simpler and cheaper solution to up-scale for industrial operation.

The effect of energetic ion bombardment on the properties of tantalum thin films was investigated. To achieve such energetic ion bombardment during the process the Ta thin films were deposited by deep oscillation magnetron sputtering (DOMS), an ionized physical vapor deposition technique related to high power impulse magnetron sputtering. The peak power was between 49 and 130 kW and the substrate was silicon at room temperature and ground potential. The directionality and the energy of the depositing species was controlled by changing the ionization fraction of the Ta species arriving at the substrate at different peak powers. In this work, the surface morphology (AFM), microstructure (SEM), structure (XRD) and hardness and Young's modulus (nanoindentation) of the films were characterized. The ion energy distributions (IEDs) were measured using an electrostatic quadrupole ion energy and mass spectrometer (HIDEN EQP 300). The IEDs showed that the DOMS process applies a very energetic (up to 120 eV) ion bombardment on the growing tantalum films. Therefore, with such conditions it was possible to deposit pure α-Ta (of 2 μm of thickness) without the use of additional equipment, i.e., without substrate bias or substrate heating. Conditions are therefore significantly different than in previous works, offering a much simpler and cheaper solution to up-scale for industrial operation.

[Display omitted] • Early Nb 3 Sn growth mechanisms were compared on various Nb substrates. • Nb surface determined the distribution and morphology of nucleated Sn and Nb 3 Sn. • Pre-deposition Nb oxidation determines the NbO surface sites present during growth. • NbO atomic structure contributes to poor Nb 3 Sn growth. • Nb grain boundaries do not preferentially nucleate Nb 3 Sn but prevent Sn loss. The enhanced accelerating performance of Nb 3 Sn-coated Nb superconducting radio frequency (SRF) cavities is severely limited by quenching sites at material defects formed during the Nb 3 Sn film growth procedure. In this work, we aimed to understand the complex surface-mediated interactions that drive initial Nb 3 Sn formation during the Sn vapor deposition procedure used to fabricate Nb 3 Sn coated SRF cavities. Nb substrates were modified, coated with Sn, and then characterized using an ultra-high vacuum (UHV) chamber equipped with metal deposition and in situ surface analysis capabilities. The atomic structure of the Nb oxide surface was modified to assess how the Nb surface defect density and crystallographic orientation impact the size of nucleated Sn islands and relative Nb 3 Sn growth rates. Formed Nb 3 Sn/Nb surfaces were visualized using ex situ scanning electron microscopy (SEM) and post-deposition annealing revealed Sn desorption and Nb 3 Sn degradation pathways. Finally, we showed that the Sn deposition conditions can be modified to overcome the growth barriers that are imposed by the Nb morphology. This study provides a unique bridge between fundamental growth studies in pristine conditions with observed phenomena of Nb 3 Sn grown on realistic cavity surfaces. [ABSTRACT FROM AUTHOR]

The magnetic field-assisted electrodeposition of iron–nickel thin films on different substrates (aluminum, silver, and brass) was investigated. The process was performed galvanostatically in a sulfate solution. The same chemical and electrical conditions were applied for each sample growth, but the time restrictions and the external magnetic field orientation were changeable. The obtained results show a variation of surface morphology and composition dependence on the selected surfaces as a consequence of the presence and orientation of the external magnetic field. We discussed that the FeNi crystal structure depends on the film thickness. The results show the reduction of the film thickness after the external magnetic field application—a decrease of deposition rate.The FeNi alloy's morphology, composition, and magnetic properties were investigated by scanning electron microscopy (SEM), X-ray diffraction, energy dispersive X-ray spectroscopy (EDX), and Mössbauer spectroscopy (MS). [ABSTRACT FROM AUTHOR]

This work aims at extending the understanding of the formation processes of (Cs0.07FA0.93)PbI3 perovskite layers deposited by a two-step vapour method. In a first step, an inorganic CsI/PbI2 precursor stack is deposited by thermal evaporation (TE). A chemical vapour deposition (CVD) is then used to convert the precursor into the perovskite layer by reaction with a chemical vapour of formamidinium iodide (FAI). Here we show how crystallinity and morphology of the TE precursor layer are both influenced not only by the substrate surface properties but also by the thermal treatment in the initial phase of the CVD process. Furthermore, we provide insights on the evolution of perovskite film formation and show how a uniform elemental composition is achieved by the diffusion of cesium through PbI2 during the CVD conversion reaction.

Organic light-emitting diodes (OLEDs) have great potential for display, lighting, and near-infrared (NIR) applications due to their outstanding advantages such as high efficiency, low power consumption, and flexibility. Recently, it has been found that the ultrathin emitting nanolayer technology plays a key role in OLEDs with simplified structures through the undoped fabricated process, and exciplex-forming hosts can enhance the efficiency and stability of OLEDs. However, the elementary structure and mechanism of the energy transfer process of ultrathin emitting nanolayers within interface exciplexes are still unclear. Therefore, it is imminently needed to explore the origin of ultrathin emitting nanolayers and their energy process within exciplexes. Herein, the mechanism of films growing to set ultrathin emitting nanolayers (

The low‐dimensional carbon allotropes have become a prominent topic of research due to their unprecedented strength and prospective physical properties. The Ar+ ion‐stimulated plasma deposition of the one‐dimensional carbon chains always presented a challenging task that still lacks a theoretical description. In this study, we propose a selective deposition quality criterion for the massive simulations planned to reveal the conditions for the synthesis of carbyne‐containing films, in particular, linear‐chained carbon by means of molecular dynamics. [ABSTRACT FROM AUTHOR]

Although the performance of qubits has been improved in recent years, the differences in the microscopic atomic structure of the Josephson junctions, the core devices prepared under different preparation conditions, are still underexplored. In this paper, the effects of the oxygen temperature and upper aluminum deposition rate on the topology of the barrier layer in the aluminum-based Josephson junctions have been presented by classical molecular dynamics simulations. We apply a Voronoi tessellation method to characterize the topology of the interface and central regions of the barrier layers. We find that when the oxygen temperature is 573 K and the upper aluminum deposition rate is 4 Å/ps, the barrier has the fewest atomic voids and the most closely arranged atoms. However, if only the atomic arrangement of the central region is considered, the optimal rate of the aluminum deposition is 8 Å/ps. This work provides microscopic guidance for the experimental preparation of Josephson junctions, which helps to improve the performance of qubits and accelerate the practical application of quantum computers.

The distinctive glow features of low-temperature RF CH4/Ar plasma chemical vapor deposition and its correlation with plasma-deposited film characterizations were investigated. The optical emission spectroscopy diagnosis data and deposition results clearly indicated that, during CH4/Ar glow discharge, the CH and C2 species resulted from the low-energy electron-impact dissociation of CH4 molecules that formed the deposition species, but the strong Ar emission lines were related to nondeposition species such as the argon atom. The results of the optical emission analysis indicated that the possible contribution of atmospheric pressure plasma-deposited film growth occurs primarily owing to a combination of electron-impact–dissociation and ionization. [ABSTRACT FROM AUTHOR]

The authors propose and demonstrate that thermal laser evaporation can be applied to all solid, nonradioactive elements in the periodic table. By depositing thin films, they achieve growth rates exceeding 1 Å/s with output laser powers less than 500 W using identical beam parameters for many different elements. The source temperature is found to vary linearly with the laser power within the examined power range. High growth rates are possible using free-standing sources for most of the elements tested, eliminating the need for crucibles. [ABSTRACT FROM AUTHOR]

The magnetic field-assisted electrodeposition of iron–nickel thin films on different substrates (aluminum, silver, and brass) was investigated. The process was performed galvanostatically in a sulfate solution. The same chemical and electrical conditions were applied for each sample growth, but the time restrictions and the external magnetic field orientation were changeable. The obtained results show a variation of surface morphology and composition dependence on the selected surfaces as a consequence of the presence and orientation of the external magnetic field. We discussed that the FeNi crystal structure depends on the film thickness. The results show the reduction of the film thickness after the external magnetic field application—a decrease of deposition rate.The FeNi alloy’s morphology, composition, and magnetic properties were investigated by scanning electron microscopy (SEM), X-ray diffraction, energy dispersive X-ray spectroscopy (EDX), and Mössbauer spectroscopy (MS).

Tribofilms are critical for the management of wear and the control of friction. This study focused on the tribological properties of tribofilms to clarify their antiwear and low-friction mechanisms. By monitoring tribofilm growth and measuring friction-coefficient mapping, we found that a tribofilm was generated in a dynamic process of formation and wear. The friction coefficient decreased with an increase in film thickness. The friction coefficient distributions of the tribofilms depended on the chemical nature more than the surface morphology. ZDDP formed a tribofilm with good antiwear properties, whereas MoDTC accelerated the tribofilm formation and decreased the friction coefficient.

We report a simple and fast microwave-assisted method to grow silver nanoparticle films with tunable plasmon resonance band. Microwaving time controls nucleation and growth as well as particle agglomeration, cluster formation, particle morphology, and the plasmonic properties. Films produced with times shorter than 30 s presented a single well-defined plasmon resonance band (~ 400 nm), whereas films produced with times longer than 40 s presented higher wavelength resonances modes (> 500 nm). Plasmon band position and intensity can be easily tuned by controlling microwaving time and power. SEM and AFM images suggested the growth of asymmetrical silver nanoparticles. Simulated extinction spectra considering particles as spheres, hemispheres, and spherical caps were performed. The films were employed to enhance the sensitivity of ionizing radiation detectors assessed by optically stimulated luminescence (OSL) via plasmon-enhanced luminescence. By tuning the plasmon resonance band to overlap with the OSL stimulation (530 nm), luminescence enhancements of greater than 100-fold were obtained, demonstrating the importance of tuning the plasmon resonance band to maximize the OSL intensity and detector sensitivity. This versatile method to produce silver nanoparticle films with tunable plasmonic properties is a promising platform for developing small-sized radiation detectors and advanced sensing technologies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Hydrate wettability controls oil plugging potential. • Hydrate wettability gives low-cost initial screening. • Increasing the oil concentration decreases the hydrate wettability. • Wettability decreases with an increased amount of asphaltenes. • Polar oil fractions contribute more to hydrate wettability than non-polar fractions. Hydrate surface wettability is a fundamental aspect to better understand agglomeration present in oil bearing petroleum pipelines. Coupling these measurements with hydrate film growth gives further information on kinetic effects that may also be present from natural surfactants in different oils. In situ measurements of wettability (quantified by the contact angle) and film growth rates were performed on cyclopentane hydrate surfaces at atmospheric pressure and subcooling of 4 °C. Contact angle and film growth results were obtained for the baseline system (pure cyclopentane), one model oil, and seventeen natural oils (diluted to 0.02 vol% in cyclopentane). Results showed a wide variety of contact angles and film growth values where higher asphaltene contents in the oils corresponded to higher contact angles and lower film growth rates, thought to be from better alignment of natural surfactant molecules at the hydrate/hydrocarbon interface. It was also shown for select oils that increasing the oil concentration in the cyclopentane increases the contact angle and decreases the film growth rate compared to the baseline system. For select oils that had higher contact angles, increasing the water content of the system decreases their contact angle and film growth compared to the baseline system. Isolating different oil fractions for select oils also shows which fractions tend to play a larger role in wettability behavior. Typically, the fractions with more surface active components (asphaltene and resins) are shown to contribute to the higher contact angle and slower film growth rates for select oils. Evidence of the competition between film growth and capillary suction of water into the hydrate has been shown, and a mechanistic breakdown of three different transient scenarios has been proposed. Each of these observed interfacial behaviors gives information on what can be expected from larger scale phenomena, including hydrate agglomeration, with very small oil samples. [ABSTRACT FROM AUTHOR]

The paper presents the analysis of formation of interfacial layer during deposition of diamond like carbon film (DLC) on the 316L stainless steel by capacitive plasma discharge in the CH4 atmosphere. The structure of the interfacial layer of DLC film was strongly affected by the temperature increase during the initial stages of the process. Initially, thin interfacial layer of 5 nm has been formed. As the temperature had reached 210°C, the second phase of the process was marked by the onset of carbon atoms diffusion into the steel and by the interface thickness increase. Finally, the growth of chromium carbide interface, the upward diffusion of chromium and nickel atoms to film, the etching and the decrease of the DLC film thickness were observed at 233°C. These investigations were carried out ex-situ by spectroscopic ellipsometry, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy.

We report the growth, structural characterization, and transport studies of Bi 2 Se 3 thin film on single crystalline silicon (Si), Si/SiO 2 , quartz, and glass substrates by thermal evaporation method. Our results show that 300 °C is the optimum substrate temperature to obtain the c -axis (001) oriented Bi 2 Se 3 films on all the substrates. The film grown on the Si substrate has the minimum crystalline disorder. The energy-dispersive x-ray spectroscopy results show that film on Si substrate is bismuth deficient, the film on Si/SiO 2 substrate is selenium deficient, and the film on quartz substrate is near perfect stoichiometric providing a way to tune the electronic properties of Bi 2 Se 3 films through substrate selection. The film grown on quartz shows the highest mobility (2.7 × 10 4 cm 2 V -1 s -1 ) which drops to 150 cm 2 V -1 s -1 for Si, 60 cm 2 V -1 s -1 for Si/SiO 2 , and 0.9 cm 2 V -1 s -1 for glass substrate. Carrier concentration is n-type for Bi 2 Se 3 films on Si (∼10 18 cm -3 ), quartz (∼10 18 cm -3 ) and Si/SiO 2 (∼10 19 cm -3 ) substrate with a clear indication of frozen out effect around 50 K for Si/SiO 2 and Si substrate. Longitudinal resistivity of Bi 2 Se 3 film on Si/SiO 2 substrate shows different behavior in three different temperature regions: temperature dependent resistivity region due to electron-phonon scattering, a nearly temperature independent resistivity region due to electron-phonon and electron-ion scattering, and a quantum coherent transport region., (© 2024 IOP Publishing Ltd.)

Solution method provides a low-cost and environmentally friendly route for the fabrication of Cu 2 ZnSn(S,Se) 4 (CZTSSe) thin-film solar cells. However, uncontrollable quality of the CZTSSe absorber layer will severely limit the device's performance. In this study, it is find that the thickness and the quality of the formed precursor is not stable because of the variation of the viscosity of the precursor solution. Combined by different characterization methods, the results disclose that such change is strongly related to the reflected color of the first coating layer during precursor growth. Further studies disclose that only by maintaining the appropriate reflected color can a well-crystallized CZTSSe film be prepared, thereby obtaining good solar cell efficiency. This semi-empirical pattern is confirmed by thin-film interference theory. Under the guidance of this method, CZTSSe absorbers with high quality are obtained easily, and the highly efficient CZTSSe solar cell can be fabricated easily. This study provides a feasible and effective strategy to obtain the optimal structure and composition of CZTSSe film toward the production of highly efficient kesterite solar cells, which can also be widely applied to the preparation of other films by solution-based method., (© 2023 Wiley-VCH GmbH.)

The changes in tungsten (W) film growth and resistance are studied using different titanium nitride (TiN) and tantalum nitride (TaN) underlayer films. The underlayers are analyzed by surface characterization techniques to obtain the differences in surface morphology and grain sizes that influence the growth of W on these films. Different precursors and processes used for TiN deposition affect the W growth and film properties. It is important to monitor the changes in incoming TiN resistance as a part of the W process qualification. This enables maintaining W process stability and reducing fab downtime due to false fails. [ABSTRACT FROM AUTHOR]

This study focuses on the deposition conditions, structural and mechanical properties of Cr films obtained by magnetron sputtering with hot target, and using high power pulsed supply with pre-ionization (pulse frequency 500 Hz, duty cycle 4% in the range of averaged power from 15 to 40 W/cm2). It has been found that hot target leads to a tenfold increase in the energy flux to the substrate compared to magnetron sputtering with cooled target. Intense sublimation from the target allows increasing the deposition rate of Cr films of about an order of magnitude. Moreover, the increase in the magnetron power may be accompanied by less heating of the substrates when depositing films of the same thickness. High power pulsed magnetron sputtering (HPPMS) with sublimating Cr hot target can be characterized by a combined mode in the film structure formation, leading to the formation of pores at the initial stage of growth. Cr films with a thickness of about 10 μm, obtained using a hot target, have lower surface roughness, hardness, and Young's modulus compared with sputtered Cr from a cooled target. • Features of deposition conditions at HPPMS of hot and cooled Cr targets were investigated. • In the case of hot target, the energy fluxes entering the substrate are at least 10 times higher. • Sublimation of the Cr target at HPPMS can lead to the formation of pores in the deposited films. • Hardness, Young's modulus and roughness of Cr films deposited by hot target HPPMS are lower than in the case of cooled one. [ABSTRACT FROM AUTHOR]

The grain size evolution of polycrystalline thin films, which form by competitive grain overgrowth as commonly interpreted using the van der Drift model, is understood to follow a power-law scaling of the average grain size d with film thickness h , i.e. d ∝ h α . While simulations have identified a growth exponent α = 0.4 for three-dimensional growth, previous experimental studies did not confirm this value, instead finding α values in the range of ∼0.5–0.7. Here we study competitive grain overgrowth using a system of ZnO thin films grown by low-pressure metal–organic chemical vapor deposition. We present quantitative data on the evolution of grain size and orientation across the thickness of thin films, obtained by automated crystal orientation mapping of "double-wedge" transmission electron microscopy samples. The data from a -textured ZnO films, grown under three different conditions, are compared against van der Drift model predictions of self-similarity of the grain size distribution and the power-law scaling. The results are further interpreted by comparing to simulations of faceted polycrystalline film growth, which we adapt to the ZnO system by including idiomorphic growth shapes with a six-fold symmetry and random or biased nuclei orientations. As well as showing the predicted self-similarity of grain size distributions during growth, for the first time our experimental data confirm a power-law growth exponent of α = 0.4, as also predicted by the simulations using randomly oriented nuclei. Nevertheless, interpretation of this result is contingent on the absence of factors such as textured nucleation and renucleation during film growth. Indeed, only one film, grown at a higher ratio of H 2 O/DEZ precursor gases, displaying random initial nucleation, and minimal grain renucleation during growth, shows a proper conformance to the model nature and predictions. Image 1 [ABSTRACT FROM AUTHOR]

Dynamic in-situ spectroscopic ellipsometry (iSE) was employed to investigate the growth mechanism of the tantalum oxide (TaO) film on silicon wafer substrate deposited by reactive gas-timing RF magnetron sputtering compared with conventional reactive sputtering. The effect of reactive gas timing parameter on physical structure and optical property were analyzed by both the continuous and island film growth model with Tauc-Lorentz optical model. The variation of refractive index, film thickness and void volume fraction were obtained from dynamic fits of iSE data indicated that the growth process of the amorphous TaO thin films was divided into two regimes: the nucleation stage and continuous-layer stage. These stages were observed during deposition although the initial film growth stage corresponds to the island film growth model. The study demonstrates that sputtered TaO by the RGT technique at the O 2 on-off gas timing has played a crucial factor in improving the formation of nucleation stage and that the deposited TaO thin films were high deposition rate with high refractive index. The complementary field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM) showed a good agreement with the film thickness and morphology obtained from dynamic iSE measurement. The real-time monitoring of iSE offers important evidences to understand the growth mechanism of reactive gas-timing technique. • Tantalum oxide thin films were deposited by reactive gas-timing RF magnetron sputtering compare. • The film growth process of the sputtered TaO thin films were studied using dynamic iSE. • The O 2 on-off gas timing has played a crucial factor in improving the formation of nucleation stage. • The deposition rate, refractive index and void volume fraction depends on the on–off gas-timing sequence. • The dynamic iSE results shows good agreement with the complementary FE-SEM and TEM measurements. [ABSTRACT FROM AUTHOR]

Studying size effects on the modification of thin film physical properties requires the preparation of films with desired microstructures and stress states. For the model system of epitaxial niobium thin films on sapphire [ 11 2 ¯ 0 , miscut < 0.1°] substrates surface topographies and stress states were systematically studied depending on the films' thickness (5 nm – 100 nm) and the deposition temperature (470 °C to 870 °C). Initial stresses, domain structures and textures of the films were characterized using X-ray diffraction techniques. The films' surface topographies were measured by scanning tunneling microscopy and atomic force microscopy, and classified into three different regimes: smooth (2D), rough (3D) and pitted (or 'meander-like'). Determination of the regimes' transition temperatures enables the tuning of the films microstructures and related stress states for each film thickness. • Topography of epitaxial Nb films depends on film thickness and deposition temperature. • Film surface splits up in 2D and 3D morphologies. • Tayloring of film topography and stress state is possible. • Proper sputter conditions for smooth films with thickness varying from 5 nm to 100 nm are deduced. [ABSTRACT FROM AUTHOR]