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Infra-red spectroscopy as an effective tool used to establish platelet like configuration in nanocrystalline silicon thin films (nc-Si:H). These films were deposited using 60 MHz assisted very high frequency plasma enhanced chemical vapor deposition process with varying pressure from 4 to 40 Pa. The deposited films were characterized by X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Atomic force microscopy (AFM), Raman spectroscopy (RS), Fourier transform infra-red spectroscopy (FTIR), Dark conductivity, UV-Vis Spectra and photosensitivity. Infra-red studies of these films reveals that the hydrogen bonding is a platelet like configuration (Si-H groups at 2033 cm− 1) located at grain boundaries resulting in crystalline grains wrapped with hydrogen rich amorphous tissues that provides good passivation resulting in less dangling bonds on grain boundary surface. Structural transformation from amorphous silicon (a-Si:H) to nanocrystalline (nc-Si:H) phase has been identified at pressure of 24 Pa. The increase in deposition pressure provides clear evidence of improved crystallinity (∼ 37%) which were depicted by increased grain size (∼ 12 nm), reduced hydrogen bonded content (∼ 5.0%), widening of optical gap (∼ 1.9 eV) with enhanced polymerization in the network. [ABSTRACT FROM AUTHOR]

The ultrathin SiC coating/melamine-derived porous carbon foam composite (SiC/PCF) was synthesized for the first time by the stable treatment of the commercial melamine foam (MF), carbonization stage of the steady MF, and chemical vapor deposition of the SiC thin films. The microstructure analysis demonstrated that the SiC/PCF composites with layered structures and altered dielectric response were fabricated eventually. The minimum reflection loss of −25.93 dB was obtained when the thickness was 1.05 mm and the measured frequency was 17.20 GHz. Meanwhile, the reflection loss could drop below −10 dB in the whole thickness with the frequency ranging from 3.00 to 18.00 GHz, which showed a more excellent microwave absorbing performance compared with PCF. Furthermore, the influencing mechanism of both the impedance matching ratio and attenuation constant was discussed to provide actual guidances in designing excellent microwave absorbing materials for functional applications. • We introduced a simple method to prepare the SiC/PCF composite. • The minimum reflection loss of −25.93 dB was obtained at 1.05 mm at 17.20 GHz. • The influencing mechanism of the SiC/PCF composite was discussed. • It provided actual guidances in designing excellent microwave absorbing materials. [ABSTRACT FROM AUTHOR]

Abstract In this study, a comparative analysis of the structural and thermoelectric properties of all possible Co-Sb-based phases in thin-film form for high-temperature applications is presented and discussed. A series of thin-film samples were prepared via radiofrequency co-sputtering on an oxidized silicon substrate. For improved crystallinity, the thin-film samples were subjected to heat treatment in the form of a high-temperature heating cycle where the temperature was slowly ramped up to about 760 K. The films were characterized using X-ray diffraction for phase identification and crystalline quality. Energy-dispersive spectroscopy was performed to determine the stoichiometric composition and homogeneity, whereas the surface morphology and microstructure were examined using scanning electron microscopy and atomic force microscopy. To investigate film performance at high temperatures, the electrical resistivity and Seebeck coefficient were measured at regular temperature intervals, and results were correlated with identified phases, composition, and crystalline quality. The CoSb phase was observed to have metallic features, the CoSb 2 phase had doped semiconductor characteristics, whereas the CoSb 3 -phase thin films showed typical semiconductor behavior. The CoSb 2 and CoSb 3 samples shows a transition of the Seebeck coefficient from positive to negative at a temperature range of 500–550 K and 550–600 K respectively. The thermoelectric power factor was evaluated from the measured parameters and maximum values of 3.2, 7.8, and 3.8 mWm−1·K−2 for the CoSb, CoSb 2 , and CoSb 3 thin films, respectively, are reported. We observed a wide range of structural and thermoelectric properties in the series of samples, demonstrating a route to tailoring and improving properties for maximal performance. Highlights • Thermopower depends upon both the carrier concentration and electron effective mass. • The presence of impurity phases shapes the magnitude of the Seebeck coefficient. • Seebeck coefficient retained the p to n type transition in the second heating cycle. • A Seebeck coefficient as high as −227 μV/K was achievable for CoSb 3 thin films. • CoSb 3 skutterudite thin films achieved a sound maximum power factor of 4 mW/m.K2. [ABSTRACT FROM AUTHOR]

The recent steady improvements in the performance of the nascent hybrid perovskite photovoltaic devices have led to power conversion efficiencies that rival the best‐performing established photovoltaic technologies. However, to scale these laboratory demonstrations to photovoltaic module‐scale production will require development of scalable deposition methods for perovskite thin films. Every record result for perovskite photovoltaics so far was achieved via spin‐coating, a technique that is popular in research laboratories for thin‐film coating over relatively small device areas, but not considered to be a method that could be used to scale up the manufacturing of perovskite photovoltaics. Significantly larger thin‐film areas are needed for future commercial photovoltaic products. Hence, some researchers have focused their efforts on perovskite deposition techniques that can be considered as scalable for mass production and have achieved notable results even on large areas. Here, we present an overview of the solution‐based and vapor‐based deposition processes; we explain their influence on the molecular crystal growth behavior of perovskite thin films and discuss the morphology as well as other material quality characteristics. By presenting a comprehensive comparison of the deposition techniques and the corresponding performance parameters for different device sizes, we intent to guide the growing research community through the methods that might enable mass production of perovskite solar products. [ABSTRACT FROM AUTHOR]

Abstract We have measured magnetic damping in polycrystalline Co 25 Fe 75 films adjacent to various nonmagnetic materials (Ti, Cu, Au, NiO) serving as buffer and/or cover layers. It was shown that it is crucial to use a proper buffer layer to achieve low damping in the Co 25 Fe 75 layer. We found that even an ultrathin Cu buffer layer is sufficient to reduce the total damping when inserted between the substrate and the Co 25 Fe 75 layer. The damping measured in the in-plane configuration reduces almost threefold (to α t o t < 0.003). Moreover, the Co 25 Fe 75 films with a Cu buffer layer possess low inhomogeneous linewidth broadening, in contrast to those with Au or Ti buffer layers. Using spin pumping into a dielectric antiferromagnetic capping layer (NiO), we determined that the effective spin mixing conductance is 4.8 × 1019 m−2. This value is large compared to those of Pt, Pd, and Au. Highlights • Intrinsic magnetization damping of Co 25 Fe 75 films is low and is equal to 0.0005. • Low magnetization damping (less than 0.003) of Co 25 Fe 75 films was obtained only for Cu buffer layer. • Even ultrathin Cu buffer layer (approx. 0.25 nm) is sufficient to lower the damping. • NiO dielectric layer has high spin mixing conductance in comparison to Au, Pt, Pd. [ABSTRACT FROM AUTHOR]

Abstract The structural, optical spectroscopic ellipsometry and morphological properties of nanocrystalline Hg 1-x Mn x O (0 ≤ x ≤ 0.2) oxide diluted magnetic semiconductor thin films synthesized by electron beam deposition technique have been investigated by means of X-ray diffraction (XRD), spectroscopic ellipsometry (SE) and atomic force microscopy (AFM) techniques. All the deposited films crystallize in the form of a hexagonal crystal structure. The integration between X-ray and atomic force microscopy data shows a very good agreement for the nanosize nature of the deposited films. For the surface roughness, good matching between the results of SE and AFM measurements was observed. In the spectral range 200–1200 nm, the real part (ε 1) and imaginary part (ε 2) of the dielectric constant of nanocrystalline Hg 1-x Mn x O films have been extracted from SE measurements. At fixed energy value, the ε 1, consequently the refractive index is found to decrease with increasing Mn2+ dopant. In contrary, the energy gap (E g) of the deposited films determined from the ε 2 is found to increase as the Mn2+ concentration increases. The variation of both the ε 1 and E g as a function of Mn2+ concentration is understood based on Lorentz-Lorenz relation and sp-d exchange interaction, respectively. The results reported here show that Mn-doped HgO nanocrystalline films could be employed in the fabrication of nanoscale optical and magneto-optical devices. [ABSTRACT FROM AUTHOR]

Abstract A facile stacking technology must be developed for various types of polymer semiconductors through a continuous solution process for successful commercial applications of organic electronics. In this study, we report a strategic method of stacking different polymer semiconductors from the same processing solvent in a non-destructive manner using vapor-phase iodine. We utilize the concept of reversible doping mechanism of iodine; interstitial iodine ions in the polymer backbone significantly reduce the solubility of entire films and such an immobilized phase can be quickly recovered to the initial phase via a simple vacuum treatment. Thus, a polymer–polymer p-n planar heterojunction (PHJ) can be realized using the same solvent without compromising the inherent electrical/optical characteristics of the polymer semiconductor. Detailed photophysical and morphological analyses on the doping and dedoping of polymeric semiconductors with iodine are discussed. As a target application of such iodine-mediated non-destructive stacking technology, a thin-film near-infrared(NIR)-selective polymeric photodiode, which can fully reflect the genuine advantages of a well-defined PHJ, is demonstrated. We successfully demonstrate a visible-blind and narrow-band NIR-selective photodiode with a high peak detectivity of 1.50 × 1011 Jones. Graphical abstract Image 1 Highlights • We suggest a facile and non-destructive multilayer stacking strategy of polymer semiconductors based on iodine doping/dedoping methods. • As using iodine-mediated multilayer stacking method, we demonstrate a thin-film, visible-blind and NIR-selective polymeric photodiode. • Our visible-blind and NIR-selective photodiode show a high peak detectivity of 1.50 × 1011 Jones. [ABSTRACT FROM AUTHOR]

Abstract The device stability and toxic-solvent-free processing are indispensable development to industrialize organometal halide perovskite solar cells. In this work, the conventional top surface of vapor prepared 3D-MAPbI 3 was replaced by 2D-(BA) 2 (MA) n‐1 Pb n I 3n+1 perovskite platelet via molecular substitution from MA (CH 3 NH) to BA (C 4 H 9 NH 2). Our fully vapor process fabricated a 3D-2D perovskite heterojunction for solar cell application, realizing the power conversion efficiency as high as 16.50% and the average one as 15.40%. Furthermore, unencapsulated devices can sustain their 81% efficiency after 30 days under 55% RH, and also 74% efficiency after 30 days under 80 °C heat stress. Stability of humidity resistance arises from the reduced n value of 2D perovskite caused by the surface reaction of moisture, and the improvement of thermal stability comes from the buffering of MA molecules release. Meanwhile, the fabrication of large scale device with high efficiency is also demonstrated in our experiment. Graphical abstract Image 1 Highlights • 3D-2D heterojunction perovskite solar cells were fabricated by vapor deposition. • 3D-2D device shows champion PCE of 16.50% and the stability has been greatly improved compare with 3D device. • The stability mechanism for 2D perovskite layer to protect 3D perovskite is explained. • The potential of scale up fabrication is demonstrated. [ABSTRACT FROM AUTHOR]

Abstract BaSn 0.15 Ti 0.85 O 3 /Ba 0.6 Sr 0.4 TiO 3 /BaZr 0.2 Ti 0.8 O 3 multilayer, BaSn 0.15 Ti 0.85 O 3 /Ba 0.6 Sr 0.4 TiO 3 and Ba 0.6 Sr 0.4 TiO 3 /BaZr 0.2 Ti 0.8 O 3 bilayer composite thin films are deliberately grown on Pt-Si substrates by pulsed laser deposition. The multilayers exhibit preferential growth along the (1 1 0) direction and reveal prominently enhanced dielectric tunable performance compared to the previous reported single-layer dielectric tunable thin films, the BaSn 0.15 Ti 0.85 O 3 /Ba 0.6 Sr 0.4 TiO 3 and Ba 0.6 Sr 0.4 TiO 3 /BaZr 0.2 Ti 0.8 O 3 bilayers at room temperature. For the multilayers, a large tunability of 71.3% under bias electric field of 400 kV/cm is achieved, while the dielectric loss is 0.0063 and the leak current density is ∼1.0 × 10−10 A/cm2 at 300 kV/cm. Calculation of figure of merit (FoM) shows a large value of 113. Such outstanding properties have suggested that BaSn 0.15 Ti 0.85 O 3 /Ba 0.6 Sr 0.4 TiO 3 /BaZr 0.2 Ti 0.8 O 3 multilayer composite thin films are excellent candidates for electrically steerable applications. Highlights • (1 1 0)–textured multilayers with enhanced tunable performance were prepared. • Dielectric tunable performance of multilayers is enhanced by the interface. • The heterolayers show a high FoM value (∼115). • A low loss tangent of 0.0063 is obtained for the multilayer thin films. [ABSTRACT FROM AUTHOR]

Amorphous Ge15Te80–xIn5Agx ($6\le {x} \le24$) thin films prepared in sandwich geometry exhibit memory switching behavior unlike the bulk sample that has shown both threshold switching for less current (1–2 mA) and memory switching for current greater than 2 mA. As anticipated, the threshold voltage of Ge15Te80–xIn5Agx($6\le {x} \le24$) thin films is found to be lower as contrast to those of bulk counterparts. The compositional dependence of amorphous system shows an extensive plateau in the range of $\textsf {6} \le {x} \le \textsf {12}$ which literally stands for the intermediate phase after which there is a drastic increase in the threshold field. Shifted rigidity percolation threshold has also been confirmed from the compositional dependence of threshold field of amorphous Ge15Te80–xIn5Agx thin films. In addition, the optical bandgap of a-Ge15Te80–xIn5Agx thin-film sample has been reckoned considering absorption spectra, and the compositional dependence has been described based on average bond energy of the system. [ABSTRACT FROM AUTHOR]

Abstract Magnesium doped GaN powders were obtained by nitridation of a Ga-Mg liquid metallic solution in a chemical vapor deposition system during two hours at 1000 °C. Photoluminescence spectrum, obtained at room temperature of the Mg doped GaN powders, showed an emission band with a maximum energy of 2.9 eV (427.5 nm), which is characteristic of Mg doped GaN. Raman spectra agree with the incorporation of Mg as dopant in the GaN powders, showing a shoulder at 669.98 cm−1 and a slight shift to low frequency of the vibration mode A 1 (TO) with respect to undoped GaN powders. X-ray diffraction patterns suggested that the crystalline structure of the GaN powders was not affected by the incorporation of Mg into the lattice. Finally, scanning electronic microscope images showed that the surface morphology of the Mg doped GaN powders was composed of hexagonal platelets, which could be due to the magnesium diffusion in the gallium before the nitridation process takes place. Highlights • Mg doped GaN powders were obtained by nitridation of a Ga-Mg liquid metallic. • PL spectrum showed an emission band with a maximum energy of 2.9 eV (427.5 nm). • Raman spectrum agrees with the incorporation of Mg as dopant in the GaN powders. • Crystalline structure of GaN powders was not affected by the incorporation of Mg. • The surface morphology of Mg doped GaN powders is formed by hexagonal platelets. [ABSTRACT FROM AUTHOR]

Abstract Vertically-standing, few-layer MoS 2 flakes were uniformly and conformally grown on closely-packed TiO 2 nanowire substrates using metal-organic chemical vapor deposition. The TiO 2 /MoS 2 heterostructures exhibited remarkably improved photoelectrochemical (PEC) performance and long-term stability owing to enhanced photogenerated electron–hole separation and transfer properties across the heterojunction. Due to the built-in heterojunction potential, the onset potential of TiO 2 /MoS 2 heterostructures was cathodic-shifted to −0.3 V, thereby resulting in maximum PEC reactivity at approximately zero potential. In contrast, MoS 2 flakes on fluorine-doped tin oxide substrates exhibited an onset potential of approximately 0.3 V. Furthermore, PEC performance was critically affected by the size of the vertically-standing MoS 2 flakes, indicating that controlled conformal growth of MoS 2 flakes on appropriate nanostructures is essential to exploit these nanostructures as efficient, non-toxic, inexpensive, and earth-abundant PEC electrodes. Graphical abstract Image 1 Highlights ● Conformal growth of few-layer MoS 2 flakes on closely-packed TiO 2 nanowires via MOCVD. ● Manipulation of size and vertically-standing configuration of MoS 2 flakes. ● Efficient and long-term stable photoelectrochemical activity of TiO 2 /MoS 2 flakes. [ABSTRACT FROM AUTHOR]

Abstract Advanced material engineering gave rise to cutting-edge characteristics of sustainable separation by fabrication of high permeable and gas selective membranes. A developed fabrication process of ultrathin polymers with controlled microporosity helps understanding pore size dependent transport and performance of thin membranes with constant pore number from continuum to free-molecular to solution-diffusion regimes. Fabrication of polymer layers with controlled pore size was realized by stage-wise physical vapor deposition of dimethylsiloxane oligomers onto porous alumina support. Single process step forms high permeable porous films of 13 nm in thickness. Further deposition allows fabrication of up to 120 nm nanopore-free uniform layers with defined gas selectivity. Permeances as high as 1300 GPU through gas-selective, uniform dense films results in gas concentration polarization and apparent selectivity loss, so far only observed for porous materials. Our fabrication process enabled observation of two unseen separation regimes in the transport physics transition from (nano) channel flow to solution diffusion supported by mathematical model derived for transport through ultra-thin membranes. Highlights • Selective and highly permeable polymer nanofilms with controlled porosity. • Capturing of transitions from channel flow to solution-diffusion mechanism. • Theoretical models of permeance-selectivity dependency on fine pore sizes. • Understanding of the role of gas concentration polarization in ultrathin membranes. [ABSTRACT FROM AUTHOR]

Abstract Carbon nanofibers (CNFs) are used as active materials for electrodes in various energy devices, such as lithium ion secondary batteries, supercapacitors, and fuel cells. Recent studies have shown that nanoscale coatings on carbon nanotubes increase the output and lifespan of these devices owing to the improvement of their mechanical and chemical properties. Among various coating methods, atomic layer deposition (ALD) can adjust the thickness of the coating layer conformally without any directional growth. Therefore, ALD can coat particles with high aspect ratios, such as CNFs, even at nanometer levels of thickness. In this work, we grew two different morphologies of a SnO 2 layer on CNF. We used two types of ALD equipment: flow-type ALD (static ALD), and fluidized bed reactor-type ALD (dynamic ALD). Static ALD could form a discontinuous SnO 2 , while a uniform SnO 2 layer was formed by pre-inserting a layer of Al 2 O 3. On the other hand, dynamic ALD formed a uniform SnO 2 layer without pre-insertion of an Al 2 O 3 layer. X-ray photoelectron spectroscopy analysis revealed that both Sn4+ and Sn2+ were present in SnO 2 on the CNF deposited by static ALD, probably due to the formation of an interfacial layer between the SnO 2 and CNF. When the dynamic ALD method was used, only Sn4+ was present in the SnO 2 on CNF. Cyclic voltammetry analysis was performed to characterize the electrochemical properties of the SnO 2 -coated CNF as an electrode on a direct methanol fuel cell. It was revealed that the discontinuous SnO 2 on CNF deposited by static ALD showed the highest current efficiency as well as enhanced electrocatalytic stability. [ABSTRACT FROM AUTHOR]

Bottom-gate InSnZnO (ITZO) thin-film transistors (TFTs) with back channels modified by a self-assembled monolayer (SAM) as a passivation layer are proposed. The SAMs are prepared by a vapor-phase deposition method based on three types of triethoxysilane with three different alkyl chain lengths. Vapor-phase reactions are much less sensitive to variations in humidity and reagent purity, are more practical than the solution-phase method, and generate more reproducible results. After the SAMs are treated, a densely packed and highly hydrophobic interface is formed on the top of the devices, and the electrical performance of the ITZO TFTs is greatly improved, especially with the SAM with a chain length of 18 carbon atoms. More importantly, it is also found that SAMs with a long alkyl chain length are beneficial for bias stress stability. [ABSTRACT FROM AUTHOR]

Growth of monolayer WS2 of domain size beyond few microns is a challenge even today; and it is still restricted to traditional exfoliation techniques, with no control over the dimension. Here, we present the synthesis of mono- to few layer WS2 film of centimeter2 size on graphene-oxide (GO) coated Si/SiO2 substrate using the chemical vapor deposition CVD technique. Although the individual size of WS2 crystallites is found smaller, the joining of grain boundaries due to sp2-bonded carbon nanostructures (~3–6 nm) in GO to reduced graphene-oxide (RGO) transformed film, facilitates the expansion of domain size in continuous fashion resulting in full coverage of the substrate. Another factor, equally important for expanding the domain boundary, is surface roughness of RGO film. This is confirmed by conducting WS2 growth on Si wafer marked with few scratches on polished surface. Interestingly, WS2 growth was observed in and around the rough surface irrespective of whether polished or unpolished. More the roughness is, better the yield in crystalline WS2 flakes. Raman mapping ascertains the uniform mono-to-few layer growth over the entire substrate, and it is reaffirmed by photoluminescence, AFM and HRTEM. This study may open up a new approach for growth of large area WS2 film for device application. We have also demonstrated the potential of the developed film for photodetector application, where the cycling response of the detector is highly repetitive with negligible drift.

Among the various methods for the preparation of nanoparticles, a sparking process at atmospheric pressure is of interest because it is a simple method for producing nanoparticles ranging from a few nanometer-sized particles to agglomerated film structures. In this research, we studied the effects of metal electrode properties on nanoparticle sizes. The experiments were carried out by applying a high voltage to different metal sparkling tips. The transfer of energies from positive ions and electron bombardments induced the melting and vaporization of electrode metals. Based on this research, we have developed a model to describe the formation of a nanoparticle film on the substrate, placed under the sparking gap, and the nanostructure produced by metal vapor on the sparking electrodes. The model provides a realistic tool that can be used for the design of a large-scale coating and the application of nanoparticles developed by this process for the filtration of PM2.5 mask fabric by air.

The objective of this article is to provide an overview on the current development of micro- and nanoporous fiber processing and manufacturing technologies. Various methods for making micro- and nanoporous fibers including co-electrospinning, melt spinning, dry jet-wet quenching spinning, vapor deposition, template assisted deposition, electrochemical oxidization, and hydrothermal oxidization are presented. Comparison is made in terms of advantages and disadvantages of different routes for porous fiber processing. Characterization of the pore size, porosity, and specific area is introduced as well. Applications of porous fibers in various fields are discussed. The emphasis is put on their uses for energy storage components and devices including rechargeable batteries and supercapacitors.

[Display omitted] • Vapor deposition of ceramics occurred during atmospheric plasma spraying. • Nanoscale clusters were constructed by vapor deposition on the coating surface. • Backside deposition was designed to demonstrate the occurrence of vapor deposition. • The porous agglomerated powder resulted in gas–liquid-solid co-deposition. • Nanostructures exhibited wettability transitions under vacuum and UV-O 3 treatment. The construction of nanostructures on the coating surface by vapor deposition of CeO 2 was realized during atmospheric plasma spraying (APS). The backside deposition method was specially designed to demonstrate the occurrence of vapor deposition and to collect pure vapor-deposited nanostructures for performance development. The effects of high-temperature and high-speed deposition conditions, the intrinsic high vapor pressure of CeO 2 , and the agglomerated porous feature of the powder on the formation of vapor phase were discussed and the deposition mechanism was revealed. The study developed the reversible wettability of vapor-deposited nanostructures under vacuum and UV-O 3 alternate treatment. [ABSTRACT FROM AUTHOR]

The physical, electronic and optical properties of Barium halides have been investigated by both experimental and theoretical approaches. The First Principle electronic structure and optical properties were calculated by DFT formalism using Full Potential Linearized Augmented Plane Wave plus local orbitals (FP-LAPW + lo) implementing different appropriate exchange-correlation functionals in WIEN2k code at various applied volumetric pressure up to 50 GPa. All the properties of these halides were analyzed and compared using their cation-anion radii ratio and ionicity. Except BaF 2 , the other three halides show ionic to covalent transformation at 50 GPa applied pressure. Both experimental and theoretical results compare reasonably well. The scintillation efficiency of these three halides was found to be directly proportional to their ionicity or band gap. • Study of physical, electronic and optical properties of Barium halides by experimental and theoretical approaches. • All the properties of the halides were analyzed and compared using their cation-anion radii ratio and ionicity. • The direct type band gap of the three halides decrease with pressure at least till 50 GPa. • Observed ionic to covalent transformation at 50 GPa applied pressure. • Experimental and theoretical results match reasonably well. [ABSTRACT FROM AUTHOR]

Current–voltage characteristics of indium-embedded indium oxide thin films (600–850 Å), with Ag electrodes approximately 1000 Å thick, prepared by reactive evaporation of pure metallic indium in partial air pressure have been studied for substrate temperatures between 50 and 125°C. The optical properties of these films have also been investigated as a function of metallic indium concentration and substrate temperature. I–V characteristics of all the samples are non-ohmic, independent of metallic indium concentration. The conductivity of the films increases but the optical transmission decreases with increasing metallic indium concentration. Metallic indium concentration was found to be an important parameter affecting the film properties. Furthermore, two possible conduction mechanisms are proposed.

Multi-metal interconnection is a crucial technology for the development of large-scale integrated circuits (ICs). However, organic semiconductors are not robust enough to be compatible with conventional lithography-and-etching-based via-forming methods. Thus, an alternative metal interconnect method is required for successful organic IC implementation. In-situ patterning of a dielectric polymer through a shadow mask while depositing in vapor phase possibly addresses the issues in both solvent susceptibility and process complexity. Here we report multi-stage organic logic circuits with a multi-level metal interconnection scheme based on patterned interlayer dielectrics via vapor phase deposition. We implement an exclusive OR circuit composed of four 2-input NAND gates and three-level metal interconnections to demonstrate the potential of the proposed solvent-free metal interconnection scheme. [ABSTRACT FROM AUTHOR]

Superhard boron-rich boron carbide coatings were deposited on silicon substrates by microwave plasma chemical vapor deposition (MPCVD) under controlled conditions, which led to either a disordered or crystalline structure, as measured by X-ray diffraction. The control of either disordered or crystalline structures was achieved solely by the choice of the sample being placed either directly on top of the sample holder or within an inset of the sample holder, respectively. The carbon content in the B-C bonded disordered and crystalline coatings was 6.1 at.% and 4.5 at.%, respectively, as measured by X-ray photoelectron spectroscopy. X-ray diffraction analysis of the crystalline coating provided a good match with a B50C2-type structure in which two carbon atoms replaced boron in the α-tetragonal B52 structure, or in which the carbon atoms occupied different interstitial sites. Density functional theory predictions were used to evaluate the dynamical stability of the potential B50C2 structural forms and were consistent with the measurements. The measured nanoindentation hardness of the coatings was as high as 64 GPa, well above the 40 GPa threshold for superhardness.

Uniform optoelectronic quality of metal halide perovskite (MHP) films is critical for scalable production in large-area applications, such as photovoltaics and displays. While vapor-based MHP film deposition is advantageous for this purpose, achieving film uniformity can be challenging due to uneven temperature distribution and precursor concentration over the substrate. Here, we propose optimized substrate orientations for the vapor-based fabrication of homogeneous MAPbI 3 thin films, involving a PbI 2 primary layer deposition and subsequent conversion using vaporized methylammonium iodide (MAI). Leveraging computational fluid dynamics (CFD) simulations, we confirm that vertical positioning during the PbI 2 layer growth yields a uniform film with a narrow temperature distribution and minimal boundary layer thickness. However, during the subsequent conversion step, horizontal substrate positioning results in spatially more uniform MAPbI 3 thickness and grain size compared to the vertical placement due to enhanced MAI intercalation. From this optimized substrate positioning, we observe substantial optical homogeneity across the substrate on a centimeter scale, along with uniform and enhanced optoelectronic device performance within photodetector arrays. Our results offer a potential path toward the scalable production of highly uniform perovskite films.

Mesoporous g-C 3 N 4 consisting of hollow nanospheres (MCNHN) was prepared via a facile vapor-deposition method. It demonstrated an excellent visible-light photocatalytic H 2 evolution activity of 22.3 times greater than bulk g-C 3 N 4 . The special hollow nanosphere structure, increased specific surface area and modified crystalline enabled MCNHN to realize stronger light harvest and better photoinduced electron-hole separation, which leaded to highly improved photocatalytic performance. The proposed method and setup are easy to be established, and have the potential for preparing nanoscale g-C 3 N 4 with other tailored nanostructures. [ABSTRACT FROM AUTHOR]

Based on their natural degradation in the human body, magnesium-based alloys are attractive for temporary implants such as cardiovascular stents and bone fixation devices. Unfortunately, rapid degradation of magnesium-based alloys in the physiological environment is a major obstacle limiting wider application. Herein, the WE43 Mg alloy deposited with tantalum nitride films by reactive magnetron sputtering shows enhanced corrosion resistance. The modified WE43 exhibits a 95-fold decrease in the corrosion current density and 100-fold initial increase in the charge transfer resistance in simulated body fluids (SBF). The ion concentration and pH of the soaking solution show that corrosion of the modified WE43 is remarkably retarded during a long-term immersion in SBF for 30 days. The corrosion propagation mechanism of the untreated and modified WE43 during long-term immersion in SBF is investigated. [ABSTRACT FROM AUTHOR]

Metal oxide has been the focus of research for decades. In this work, besides the trigonal-structure Al 2 O 3 nanotubes and orthorhombic-structure Al 2 O 3 nanosheets, novel Mg-Al-O/Al 2 O 3 heterostructure nanowires were successfully synthesized at high temperature. The structural characteristics of these oxides were investigated based on electron microscopy and group theory analysis. More importantly, it was found that incorporating the orthorhombic-structure Al 2 O 3 could effectively modulate the occurrence of monoclinic domains and thus the related properties of Mg-Al-O/Al 2 O 3 heterostructures. This work provides a reference for understanding and modulating the complex structures with multiple domain variants in Mg-Al-O oxides. [ABSTRACT FROM AUTHOR]

Considerable interest has been motivated in the study of oil-water separation by developing new materials and technologies. Here, we demonstrated a simple and effective method to separate oil-water mixtures using the prepared stainless steel meshes by vapor deposition of liquid state polydimethylsiloxane (PDMS). By changing the heating temperature, underoil superhydrophobic stainless steel meshes and underwater superoleophobic stainless steel meshes can be alternatively achieved. The former is used for heavy oil-water mixtures separation after oil prewetting, while the latter is utilized to separate light oil-water mixtures after water prewetting. As a result, a variety of light or heavy oil-water mixtures could be separated with the efficiency above 99.0%. The separation efficiency maintains high even after 60 separation cycles. In addition, these two types of meshes still take effects under severe environmental situation when they are employed to separate oils from strong acidic, alkaline, salt aqueous solutions, and hot or ice water. [ABSTRACT FROM AUTHOR]

Co-doping with two elements has recently attracted attention as a novel approach for tailoring the semiconductor-metal transition (SMT) characteristics of vanadium dioxide (VO 2 ). Here, we investigate the influence of titanium/yttrium (Ti/Y) co-doping on the microstructure and SMT characteristics of VO 2 thin films. At low Y concentration, Ti/Y co-doped VO 2 thin films exhibit a monoclinic structure similar to VO 2 but characterized by a smaller grain size, whereas, the VO 2 (B) phase appears as the Y concentration is increased. Interestingly, even a complete amorphization of the film is obtained for co-doped VO 2 thin films. The strong dependence of the microstructure upon the co-doping level is ascribed to the conjugated influence from the simultaneous adjustment of V V chains and V O bonds due to the existence of Ti 4+ and Y 3+ ions in VO 2 lattice, respectively. As a result, the SMT feature of VO 2 thin films is strongly limited or even fully disappears. [ABSTRACT FROM AUTHOR]

In this article, we tried to induce siloxane to form microtubes through the way of self-assembly on the surface of polyester fabric and make the fabric super-hydrophobic. After the polyester fabric coated by silicon microtubes, the modified fabric obtained super-hydrophobicity due to the same property of silicon microtubes. We used the ethyl trichlorosilane to deposit the siloxaneon the surface of the polyester fabrics in the nitrogen condition by vapor deposition method. The structures and properties of modified polyester fabrics were characterized by scanning electron microscopy (SEM), Energy Dispersive Spectrometer (EDS), Fourier transform infrared spectrum (FTIR), Thermogravimetric analysis (TG) and oil/water separation testing. The results showed the silicon microtubes had been formed and the Si takes a high mass proportion in the sample, proving the siloxane had been successfully grown on the surface further. Oil/water separation experiment and water contact angle measurement proved that the modified fabric had high super-hydrophobicity and it’s important for application in various environment. [ABSTRACT FROM AUTHOR]

A novel structure of yttria stabilized zirconia coatings was developed in this study by a newly laminar plasma spraying technology in atmospheric environment. The unique microstructures of coatings showed the multi-island protrusions feature at the top surface, quasi-columnar structures along the cross-section distributed as a certain interval and hybrid droplet/vapor deposited structures at the fracture surface. The distributions of particle velocity and surface temperature along the axial direction of long laminar plasma jet were investigated and compared with other plasma spraying methods. The effects of different microstructures to thermal conductivities comparing with other current plasma spray methods were also demonstrated. [ABSTRACT FROM AUTHOR]

The BaSn 0.15 Ti 0.85 O 3 (BTS) thin films are prepared on Pt-Si substrates with thickness ranging from ~ 60 nm to ~ 380 nm by radio frequency magnetron sputtering. The effects of thickness on microstructure, surface morphologies and dielectric properties of thin films are investigated. The thickness dependence of dielectric constant is explained based on the series capacitor model that the BTS thin film is consisted by a BTS bulk layer and an interfacial layer (dead layer) between the BTS and bottom electrode. The thin films with thickness of 260 nm give the largest figure of merit of 76.9@100 kHz, while the tunability and leakage current density are 64.6% and 7.46 × 10 −7 A/cm 2 at 400 kV/cm, respectively. [ABSTRACT FROM AUTHOR]

Cu2FeSnS4 (CFTS) was synthesized by direct fusion of high-purity elemental copper, iron, tin and sulfur. CFTS thin films were deposited on glass substrates heated by single source vacuum thermal evaporation, after which the obtained samples were annealed under a sulfur atmosphere in a sealed quartz tube at 400°C for 1 h in order to optimize the CFTS stannite phase. The substrate temperature was varied from room temperature to 200°C. The formation of a stannite structure with (112), (200) and (004) planes in the powder and thin films was confirmed using x-ray diffraction measurements and the crystallites were found to have a preferred orientation along the (112) direction. Optical measurements analysis showed that after the sulfurization process the layers have a relatively high absorption coefficient close to 105 cm−1 in the visible spectrum. The films show a direct optical band gap in the range 1.30-1.63 eV for substrate temperature varied from room temperature to 200°C. All samples revealed p-type conductivity as determined by the hot probe method. [ABSTRACT FROM AUTHOR]

The dependence of the structure of (TiZrHf)N coatings deposited by reactive magnetron sputtering on different working pressures and their mechanical and electro-optical properties were investigated. The increased working pressure contributed to the decreased oxygen contamination. With increased working pressure, the compressive stress was transitioned to tensile one. Compressively stressed coatings consisted of tightly packed columns with a smooth surface. The tensile stressed coatings presented void network structure surrounding the columnar grains with a rough surface. Moreover, the grain size initially increased and subsequently decreased. Accordingly, the (TiZrHf)N coatings deposited at high working pressure were characterized with poor hardness, low electrical conductivity, and low light reflectivity due to the porous structure and high oxygen contamination. In addition, the coating color changed from bright gold to dark gray. In this study, the working pressure was proven a sensitive deposition parameter in controlling the microstructure, mechanical, and electro-optical properties of the coating. The wide structural variation in the (TiZrHf)N coatings allowed a diverse physical performance suitable for a broad range of applications. [ABSTRACT FROM AUTHOR]

ZrN/CrN multilayers have been produced by a cathodic arc technique (CA-PVD) using different depositions conditions. Microstructural and mechanical characterizations of the coatings were performed by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive spectroscopy (SEM with EDS), transmission electron microscopy (TEM), and Vickers microhardness tests. Variations in thermal transformation properties due to heating within the temperature range from 30 °C to 1400 °C were studied by differential scanning calorimetry (DSC) measurements. SEM and TEM observations showed that the coatings comprise a multilayered structure with nanometric grains. EDS spectra confirmed the formation of stoichiometric composition. Near-to-super stoichiometric nitrides can be suggested in certain specimens. Results of the XRD analysis revealed that the (200) and (111) planes for ZrN and Cr 2 N are the most intense. Calorimetric tests showed that below a certain annealing temperature no transformations were defined. 1180 °C was found to be the value where only one-stage state transformation, presented by endothermic or exothermic reactions, took place. The highest hardness (4685HV0.025) was obtained for the coating with Λ = 140 nm, P N  = 0.43 Pa, U S  = −70 V. [ABSTRACT FROM AUTHOR]

Mixed cation halide perovskite solar cells (PSCs), in a formula of ABX 3 where A is a mixture of formamidinium (FA) or cesium (Cs) cations, represent a promising new architecture to achieve largely improved stability and higher power conversion efficiency (PCE). While all these mixed-cation PSCs were synthesized via a solution method, we here propose and demonstrate a precisely tunable stack sequence physical-chemical vapor deposition (SS-PCVD) approach to prepare a mixed-cation absorber in CsBr-doped hybrid organic perovskite, which features a beneficial gradient bandgap profile to enable an improvement of PCE from 11.69% in pure FAPbI 3 to 18.22% in mixed-cation PSCs. Remarkably, an excellent stability in ambient exposure for 60 days has been achieved by a proper control of the CsBr cation incorporation and interface passivation. This new approach indicates a simple, precisely tunable and low cost fabrication strategy to implement high performance and scalable mixed-cation halide perovskite solar cells. [ABSTRACT FROM AUTHOR]

Two dimensional (2D) nanomaterials are promising fundamental building blocks for use in the next-generation semiconductor industry due to their unique geometry and excellent (opto)-electronic properties. However, large scale high quality fabrication of 2D nanomaterials remains challenging. Thus, the development of controllable fabrication methods for 2D materials is essential for their future practical application. In this review, we will discuss the importance of the space-confined vapor deposition strategy in the controllable fabrication of 2D materials and summarize recent progress in the utilization of this strategy for the synthesis of novel materials or structures. Using this method, various high quality ultrathin 2D materials, including large-area graphene and boron nitride, ReS2/ReSe2, HfS2, pyramid-structured multilayer MoS2, and the topological insulators Bi2Se3 and Bi2Te3, have been successfully obtained. Additionally, by utilizing van der Waals epitaxy growth substrates such as mica or other 2D materials, patterned growth of 2D nanomaterials can be easily achieved via a surface-induced growth mechanism. Finally, we provide a short prospect for future development of this strategy. [ABSTRACT FROM AUTHOR]

MoS 2 vertically standing nanosheets were prepared by metal-organic chemical vapor deposition using molybdenum hexacarbonyl (Mo(CO) 6 ) and 1,2-ethanedithiol (C 2 H 6 S 2 ) as precursors. The sulfur source was chosen as a less toxic alternative to the well-established hydrogen sulfide (H 2 S). These films were deposited between 500 and 800 °C resulting in different surface morphologies, from nanoparticles to vertically standing nanosheets. A highly (002) oriented 2H-MoS 2 film was obtained at 700 °C. The effect of the microstructure on the catalytic performance of hydrogen evolution reaction (HER) of the MoS 2 films was investigated. The Tafel slope varied from 68 to 94 mV/dec, showing that the microstructure of the films had an influence on their final electrochemical performance. Water contact angle analysis was used to study the surface wettability of the films, obtaining values from 60 to 121.2°. These results exhibited a quite consistent trend with the Tafel slope, indicating a significant effect of wettability and nanosheets edge exposure on the HER performance. [ABSTRACT FROM AUTHOR]

Possible existence of topologically protected surface in samarium hexaboride has created a strong need for investigations allowing to distinguish between properties coming from the surface states and those originating in the (remaining) bulk. Studies of SmB 6 thin films represent a favorable approach allowing well defined variations of the bulk volume that is not affected by surface states. Moreover, thin films are highly desirable for potential technology applications. However, the growth of SmB 6 thin films is accompanied by technology problems, which are typically associated with maintaining the correct stoichiometry of samarium and boron. Here we present feasibility study of SmB 6 thin film synthesis by pulsed laser deposition (PLD) from a single stoichiometric SmB 6 target. As proved by Rutherford Backscattering Spectrometry (RBS), we succeeded to obtain the same ratio of samarium and boron in the films as that in the target. Thin films revealing characteristic electrical properties of (crystalline) SmB 6 were successfully deposited on MgO, sapphire, and glass-ceramics substrates, when the substrates were kept at temperature of 600 °C during the deposition. Performed electrical resistance studies have revealed that bulk properties of the films are only slightly affected by the substrate. Our results indicate that PLD is a suitable method for complex and intensive research of SmB 6 and similar systems. [ABSTRACT FROM AUTHOR]

Pursuing novel new materials for fabricating efficient electrically pumped lasers is the emphasis of researchers for decades. Although organic semiconductors with high gain have been reported previously, a significant challenge remains in using them for electrically pumped lasers due to their low carrier mobility. Recently, hybrid halide perovskites have been reported to possess high carrier mobility and optical gain which allows them to be used for various optoelectronic applications. To explore the feasibility of using them as possible candidates for electrically pumped lasers, tin (Sn)‐based perovskite light‐emitting diodes (PeLEDs) with all‐inorganic heterostructure are fabricated by the vapor‐deposition process. The all‐inorganic hetero‐structured PeLEDs exhibited a maximum EQE of ≈0.34%, and withstood current density up to 915 A cm−2 with small emission zone of 0.01 mm2. In addition, by vacuum vapor deposition, extremely smooth and uniform cesium tin halide perovskite films with small grain size (≈60 nm) are obtained, in which low threshold (≈7 µJ cm−2) of their amplified spontaneous emission was presented. These characteristics demonstrate the great potential of using them as gain media for electrically pumped lasers. Lead‐free cesium tin halide perovskite films with extremely smooth and uniform film morphology are obtained via vapor deposition. All‐inorganic CsSnBr3 perovskite light‐emitting diodes were achieved with a maximum EQE of 0.34% at 6.1 V. In addition, low‐threshold amplified spontaneous emission from optically pumped CsSnX3 films, tunable by halogen substitution, is also demonstrated. These Sn‐based perovskite films with high film quality and high optical gain can also bear high current density up to 915 A cm−2, enabling them to be considered as promising candidates for electrically pumped lasers. [ABSTRACT FROM AUTHOR]

The hydrophobic organosilane coatings decorated with graphene oxide were prepared to hinder the water molecules and corrosive ions to the metal bases, and to retard the corrosion reactions. The trilaminar structure was composed of Fe-W amorphous alloy layer, silane cross-linked graphene oxide layer and hydrophobic organosilane layer, which were formed layer by layer via electroplating, electrophoresis and vapor deposition, respectively. The morphology of the composite coating was observed by scanning electron microscopy, the electrochemical behavior was analyzed with the electrochemical impedance spectroscopy and potentiodynamic polarization curves in 3.5 wt% NaCl solution. The results showed that the trilaminar structure composite coatings were successfully prepared, and they have excellent corrosion resistance property by a reduction of three orders of magnitude. The formation of Si O C covalent bonds based on X-ray photoelectron spectrometer analysis implied the improved binding force between silane and the graphene oxide sheets. The composite coatings also showed a well hydrophobic performance that the static water contact angle was achieved 141.7° by controlling the morphology of the electrodeposited Fe-W alloy layer. [ABSTRACT FROM AUTHOR]

Huge difference of surface energies between dielectric and metal provides an effective method to tune the structure and magnetic properties of films. Due to the difference of surface energies between SiO 2 and Fe, dopant of SiO 2 with 3.6% in atomic ratio in Fe film transforms the strip and column structure in the Fe films to equiaxed crystal formed by nanoparticles of the Fe-SiO 2 films. Zeeman energy of applying high magnetic field (HMF) during film growth increases Fe atomic aggregation and atomic diffusion of SiO 2 into the grain boundary. This leads to the improvement of the particle size with applying HMF during the film growth. These structural evolutions have a significant effect on the performance of the films. After the dopant of SiO 2 , the saturation magnetization M s of the Fe-SiO 2 film (324.6 kA/m) is 73.2% less than that of the Fe films. The coercivity H c decreases 204.0% to 788.04 A/m. However, the M s increases 44.3% and the H c increases 27.4% for the Fe-SiO 2 film with applying HMF during the film growth. [ABSTRACT FROM AUTHOR]

Zn-Mg alloys are strong candidates for the protective coating materials on steel products due to their excellent corrosion resistance compared to pure Zn. In previous research, sputtered Zn-Mg coatings with a high Mg content (above 27 at.%) exhibited a featureless amorphous structure that improved the corrosion resistance of the coatings. However, these Zn-Mg coatings showed a brittle fracture during deformation, resulting in a decrease in adhesion strength. Accordingly, in the present study, to improve the adhesion strength of Zn-Mg coating, the deposition temperature of the Zn-Mg coatings was controlled and the effects of the deposition temperature on the coating microstructure, corrosion resistance, and adhesion strength of the synthesized coatings were investigated. The results revealed that the deposition temperature significantly affected the microstructure as well as the coating properties. Zn-Mg coatings synthesized below 50 °C showed a featureless amorphous microstructure, while porous crystalline Zn-Mg coatings were synthesized above 100 °C. Even though the corrosion resistance of the Zn-Mg coatings decreased slightly as the deposition temperature increased, all of the Zn-Mg coated steel samples exhibited passivation behavior in the corrosion environment. As the deposition temperature of coating increased above 100 °C, the fracture and detachment phenomena of the Zn-Mg coatings during deformation decreased. These results revealed that the adhesion strength of Zn-Mg coating could be improved by controlling the deposition temperature. [ABSTRACT FROM AUTHOR]

In this paper, in order to improve the wettability and corrosion resistance of Ti-6Al-4V, titanium silicon nitride (TiSiN) films with different Si contents were deposited on this alloy using pulsed-DC plasma-assisted chemical vapor deposition (PACVD) method. The results indicated that the TiSiN films have a nanocomposite microstructure in which the TiN nanocrystallines are surrounded by an amorphous matrix of SiN x . With increasing Si content from 0 to 24.7 wt%, the film's water contact angle reduced from 82.2° to 47.5° due to the formation of a hybrid TiO 2 /SiO 2 surface oxide layer on the TiSiN film and also rising its surface roughness from 21 to 32 nm. The electrochemical studies in a simulated body fluid (SBF) at 37 °C showed that the TiSiN films due to the nanocomposite microstructure, formation of a hybrid SiO 2 /TiO 2 passive oxide layer and lower microstructural defects in comparison with TiN film can act as a more effective protective barrier layer against the corrosive liquid. In the electrochemical impedance spectroscopy (EIS) examinations, the TiSiN film with 12.1 wt% of Si represented the best corrosion resistance compared to the uncoated Ti-6Al-4V alloy and the other TiSiN films with 0, 6.3, 17.8 and 24.7 wt% of Si. [ABSTRACT FROM AUTHOR]