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Industrial thin-film composite (TFC) membranes achieve superior gas separation properties from high-performance selective layer materials, while the success of membrane technology relies on high-performance gutter layers to achieve production scalability and low-cost manufacturing. However, the current literature predominantly focuses on the design of polymer architectures to obtain high permeability and selectivity, while the art of fabricating gutter layers is usually safeguarded by industrial manufacturers and appears lackluster to academic researchers. This is the first report aiming to provide a comprehensive and critical review of state-of-the-art gutter layer materials and their design and modification to enable TFC membranes with superior separation performance. We first elucidate the importance of the gutter layer on membrane performance through modeling and experimental results. Then various gutter layer materials used to obtain high-performance composite membranes are critically reviewed, and the strategies to improve their compatibility with the selective layer are highlighted, such as oxygen plasma treatment, polydopamine deposition, and surface grafting. Finally, we present the opportunities of the gutter layer design for practical applications. [ABSTRACT FROM AUTHOR]

In this study, Cobalt (Co) doped Copper Oxide (CuO) films at different concentrations were deposited on glass substrates, using the Chemical Bath Deposition (CBD) method. The films were characterized by Field Emission Scanning Electron Microscopy (FESEM), X-Ray Diffraction (XRD), Ultra Violet-Visible Spectroscopy (UV-Vis.) and two-point contact method. The FESEM images showed that nanoplates formed increased in size and voids on the films surface decreased with increasing Co concentration. The XRD patterns revealed an increase in crystallite size with increasing (from 14.40 to 18.60 nm) Co concentration and no secondary phase was formed. The Energy-dispersive X-ray spectroscopy (EDS) spectra showed the presence of Co in the film composition with increasing concentration. The results of UV-Vis. spectroscopy showed that band gap values could be changed with Co doping and thus the CuO band gap could be adjusted with the Co doping. The temperature-dependent current-voltage measurement results obtained with the two-point contact method showed that activation energy levels increased (from 0.134 to 0.232 eV) with increasing Co concentration. It was also observed that the conductivity increased with increasing temperature. [ABSTRACT FROM AUTHOR]

In this research, MgF2 and SiO2 thin films were prepared by the magnetron sputtering method on glass and ITO substrates. The crystal structure, morphology, and antireflection performance of the coatings were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and ultraviolet spectrophotometry (UV-vis) techniques, respectively. Furthermore, by utilizing both experimental characterization and optical film design tools, the best experimental parameters for every coating were identified. FESEM images confirmed proper growth of the layers on the substrates. EDAX analysis revealed that the manufactured layer consisted of Magnesium fluoride and silica. The study of optical properties demonstrated that the average transmission in the 400-1000 nanometer range exceeded 99%, indicating good agreement with theoretical results. Furthermore, the use of ITO as the substrate reduced the bandgap. [ABSTRACT FROM AUTHOR]

Thin films have received great attention in recent years because of their extensive applications in various fields of science and technology. The studies of the electrical properties of semiconducting thin films have been primarily provoked by attractive micro-electronic device applications. Bismuth Telluride (Bi2Te3) is the most widely used material among the various V-VI compounds. In this study, thin films of Bi2Te3 were fabricated onto different substrates (i.e., glass and silica) by using thermal evaporation technique. Their structural, morphological, optical, and electrical properties were investigated using X-ray diffraction (XRD), Field Emission-Scanning Electron Microscopy (FE-SEM), Photoluminescence (PL) spectroscopy, and Source meter instrument, respectively. XRD analysis showed that the films were crystalline in nature. FESEM images showed that the films have a homogenous and compact grain surface. The optical band gap was about 2 eV for both types of film. The I-V characteristics of thin films were analysed at temperatures ranging from 30 °C to 100 °C. It was found that the film fabricated onto silica substrates showed large electrical conductivity as compared to the others. Also, the increment in electrical conductivity was observed with the temperature indicating that the prepared films have a negative temperature coefficient of resistance. [ABSTRACT FROM AUTHOR]

Cuprous (Cu2O) and cupric (CuO) oxide thin films have been deposited by radio frequency magnetron sputtering with two different oxygen partial pressures. The as-deposited copper oxide films were subjected to post-annealing at 300 °C for 30 min to improve the microstructural, morphological, and optical properties of thin films. Optical absorption studies revealed the existence of a large number of subgap states inside CuO films than Cu2O films. Cu2O and CuO thin film transistors (TFTs) were fabricated in an inverted staggered structure by using a post-annealed channel layer. The field effect mobility values of Cu2O and CuO TFTs were 5.20 × 10−4 cm2 V−1 s−1 and 2.33 × 10−4 cm2 V−1 s−1, respectively. The poor values of subthreshold swing, threshold voltage, and field effect mobility of the TFTs were due to the charge trap density at the copper oxide/dielectric interface as well as defect induced trap states originated from the oxygen vacancies inside the bulk copper oxide. In order to study the distribution of the trap states in the Cu2O and CuO active layer, the temperature dependent transfer characteristics of transistors in the temperature range between 310 K and 340 K were studied. The observed subgap states were found to be decreasing exponentially inside the bandgap, with CuO TFT showing higher subgap states than Cu2O TFT. The high-density hole trap states in the CuO channel are one of the plausible reasons for the lower mobility in CuO TFT than in Cu2O TFT. The origin of these subgap states was attributed to the impurities or oxygen vacancies present in the CuO channel layer. [ABSTRACT FROM AUTHOR]

The work investigated in this paper focused on the fabrication of WO3 films by the spray pyrolysis technique, and different analyses were made to find optimized samples for studying properties suitable for the application of gas sensing. The substrate temperature is the most important parameter among other spray parameters for the synthesis of thin films hence WO3 thin films were deposited on glass substrates by maintaining the substrate temperature at 350 °C, 450 °C, 550 °C, and 650 °C using compressed air as a carrier gas. The influence of the substrate temperature on the structural, morphological, compositional, and optical properties of the WO3 thin films has been justified using XRD data. Good and enhanced crystallinity is observed for the film deposited at a substrate temperature of 550 °C. The nonconventional properties were studied by different investigations and confirmed by past research work. The manipulation of surface morphology with the different deposition temperatures is monitored. Only the characteristic peaks of W and O are present in the fabricated WO3 thin films. The optical activity of about 70 to 80 % of the selected sample in the visible region (300 to 1200 nm) is found. The selective absorption activity of light in the ultraviolet region and visible region is checked. The obtained IR bands confirmed the inter bridge stretching and bending modes of W-O and O-W-O. A high response towards ammonia compared to other test gases is exhibited. The repeatability of WO3 towards NH3 over three periodic sensing cycles, response, and recovery time has also been discussed. From all the characteristic studies, it has been suggested that the fabricated WO3 thin films have been used in the health care field to detect the toxic NH3 gas. [ABSTRACT FROM AUTHOR]

This report describes the fabrication, characterization, and transfer of ultra-compact thin-film magnetless Faraday rotators to silicon photonic substrates. Thin films of magnetization latching bismuth-substituted rare-earth iron garnets were produced from commercially available materials by mechanical lapping, dice polishing, and crystal-ion-slicing. Eleven-lm-thick films were shown to retain the 45° Faraday rotation of the bulk material to within 2° at 1.55 lm wavelength without repoling. Anti-reflection coated films evince 0:09 dB insertion loses and better than -20 dB extinction ratios. Lower extinction ratios than the bulk are ascribed to multimode propagation. Significantly larger extinction ratios are predicted for single-mode waveguides. Faraday rotation, extinction ratios, and insertion loss tests on He-ion implanted slab waveguides of the same material yielded similar results. The work culminated with bond alignment and transfer of 7 μm-thick crystal-ion-sliced 50×480 μm² films onto silicon photonic substrates. [ABSTRACT FROM AUTHOR]

Copper zinc tin sulfide (CZTS) thin films with different doping ratios of Cadmium (Cd) were successfully fabricated using the sol-gel method by dip-coating technique. The surface morphology, the crystal structure properties as well the optical properties of undoped CZTS thin film and Cd- doped CZTS thin films were investigated using scanning electron microscopy (SEM), x-ray diffraction (XRD), and UV-Vis spectrophotometer. SEM micrographs demonstrated that the size and morphology of the particles improve due to increasing the Cd concentration in CZTS thin films. In addition, the XRD patterns exhibited the crystalline nature for CZTS thin films with kesterite crystal structure and showed improvement in some crystal structure properties such as crystal size and volume of unit cell with the incorporation of Cd into CZTS thin films. Moreover, optical bandgap energy Eg, in addition to several optoelectronic parameters such as refractive index (n), extinction coefficient (k), dispersion energy, high-frequency dielectric constant, density of state, Plasma frequency, and relaxation time have been estimated. Remarkably, the bandgap energy of CZTS thin films ranges from 1.594 eV to 1.529 eV depending on the Cd content; it increases with increases the concentration of Cd into CZTS thin films. [ABSTRACT FROM AUTHOR]

While the process of metal induced crystallization (MIC) is widely used in the fabrication of thin film electronic devices, its application to the field of thermoelectrics is fairly new. Especially, its implementation in the field of the classic thermoelectric material SiGe could lead to a low cost approach by combining the benefits of low thermal budget, self-doping, and thin film and sputter deposition compatibility. In this work, samples consisting of SiGe/Al multilayers deposited on aluminum oxide based substrates have been prepared. Special emphasis was put on the ratio of Al to SiGe and the resulting changes in transport properties during annealing. On one hand, a certain amount of Al is needed to ensure a complete MIC process for the SiGe, but on the other hand, an excess of Al results in a metallic system with low thermoelectric efficiency. In-situ characterization during annealing of the samples was carried out via x-ray diffraction, electrical resistivity, and Seebeck measurements. [ABSTRACT FROM AUTHOR]

Gallium Oxide (Ga2O3) for solar‐blind photodetectors (PDs) has drawing increasing research interest in recent years because of its natural wide bandgap. However, the traditional material growth methods are always complicated and the corresponding PD performance is also not good enough. In this work, amorphous Ga2O3 (a‐Ga2O3) thin film grown by mist chemical deposition applied as solar blind deep ultraviolet phototransistors (PTs) is investigated for the first time, to solve the problem of high cost and time‐consuming by traditional methods. Bottom‐gate a‐Ga2O3 three terminal thin film transistors (TFTs) are fabricated to boost their ultraviolet (UV) photodetection properties. Under the 254 nm UV illumination, the a‐Ga2O3 PTs demonstrates a very high responsivity of 2300 AW−1, external quantum efficiency of 1.12 × 106% and detectivity of 1.87 × 1014 Jones. Such field‐effect PTs with the ultrahigh performance address a significant step toward the feasibility and practicability of Ga2O3 PDs in the future applications. [ABSTRACT FROM AUTHOR]

The remarkable camouflage capabilities of cephalopods have inspired many to develop dynamic optical materials which exploit certain design principles and/or material properties from cephalopod dermal cells. Here, the angle-dependent optical properties of various single-layer reflectin thin-films on Si wafers are characterized within the UV–Vis–NIR regions. Following this, initial efforts to design, fabricate, and optically characterize a bio-inspired reflectin-based multilayer reflector is described, which was found to conserve the optical properties of single layer films but exhibit reduced angle-dependent visible reflectivity. Finally, we report the integration of phytochrome visible light-induced isomerism into reflectin-based films, which was found to subtly modulate reflectin thin-film reflectivity. [ABSTRACT FROM AUTHOR]

The ongoing miniaturization of electronic devices has boosted the development of new post-silicon two-dimensional (2D) semiconductors, such as transition metal dichalcogenides, one of the most prominent materials being molybdenum disulfide (MoS2). A major obstacle for the industrial production of MoS2-based devices lies in the growth techniques. These must ensure the reliable fabrication of MoS2 with tailored 2D properties to allow for the typical direct bandgap of 1.9 eV, while maintaining large-area growth and device compatibility. In this work, we used a versatile and industrially scalable MoS2 growth method based on ionized jet deposition and annealing at 250 °C, through which a 3D stable and scalable material exhibiting excellent electronic and optical properties of 2D MoS2 is synthesized. The thickness-related limit, i.e., the desired optical and electronic properties being limited to 2D single/few-layered MoS2, was overcome in the thin film through the formation of encapsulated highly crystalline 2D MoS2 nanosheets exhibiting a bandgap of 1.9 eV and sharp optical emission. The newly synthesized 2D-in-3D MoS2 structure will facilitate device compatibility of 2D materials and confer superior optoelectronic device function. [ABSTRACT FROM AUTHOR]

As the advantageous properties of nanoparticles (NPs) often emerge only when appropriate coupling and exchange phenomena between the NPs can take place, the control of the inter-particle distance, regular ordering, and location of the nanoparticles onto solid supports is a critical issue. A robust method to control the spatial organization of NPs onto solid supports, based on the use of self-assembling di-block copolymers (BCPs) as structure-guiding material, is reported. Two different polystyrene-b-poly(methyl methacrylate) (PSb- PMMA) BCPs, characterized by a different PS volume fraction, were used as matrices for the fabrication of nanocomposite thin films with cylindrical and lamellar morphologies controlled at the nanoscale. Selective inclusion of surface functionalized gold (Au) and zinc oxide (ZnO) NPs of appropriate size in the PS nanodomains was achieved from dispersions of the BCPs and NPs in a common solvent. The orientation of the BCPs cylinder and lamellar nanodomains in spin-coated thin films was controlled by solvent and thermal annealing protocols, coupled with techniques of surface neutralization. [ABSTRACT FROM AUTHOR]

In this paper, thin film AlGaInP LED chips with a 50 μm thick composite metal substrate (Copper-Invar-Copper; CIC) were obtained by the wet etching process. The pattern of the substrate was done by the backside of the AlGaInP LED/CIC. There was no delamination or cracking phenomenon of the LED epilayer which often occurs by laser or mechanical dicing. The chip area was 1140 μm × 1140 μm and the channel length was 360 μm. The structure of the CIC substrate was a sandwich structure and consisted of Cu as the top and bottom layers, with a thickness of 10 μm, respectively. The middle layer was Invar with a 30% to 70% ratio of Ni and Fe and a total thickness of 30 μm. The chip pattern was successfully obtained by the wet etching process. Concerning the device performance after etching, high-performance LED/CIC chips were obtained. They had a low leakage current, high output power and a low red shift phenomenon as operated at a high injected current. After the development and fabrication of the copper-based composite substrate for N-side up thin-film AlGaInP LED/CIC chips could be diced by wet etching. The superiority of wet etching process for the AlGaInP LED/CIC chips is over that of chips obtained by mechanical or laser dicing. [ABSTRACT FROM AUTHOR]

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Nickel ditelluride (NiTe2), a recently discovered Type-II Dirac semimetal with topological Dirac fermions near the Fermi energy, is expected to exhibit strong thickness-mediated electronic tunability and intrinsic two-gap superconductivity in the single-layer limit. Realizing such intriguing phenomena requires the fabrication of ultrathin NiTe2 films and an understanding of the underlying physics that is still under debate. By conducting experimental band mappings of ultrathin films prepared with molecular beam epitaxy, we reveal spectroscopic evidence for the dimensionality crossover of single-crystalline ultrathin NiTe2 films as a function of film thickness. As the film thickness increases from one to five layers, the gap in the conical topological surface states closes. Comparisons of experimental to first-principles results also highlight difficulties in fabricating atomically smooth single-layer NiTe2 films. Our results not only provide further impetus for studying emergent phenomena in NiTe2 but also underscore the limitations of fabricating NiTe2 films for device applications. [ABSTRACT FROM AUTHOR]

In a world focused on the development of cybersecurity, many densely populated areas and transportation hubs are still susceptible to terrorist attacks via improvised explosive devices (IEDs). These devices frequently employ a combination of peroxide based explosives as well as nitramines, nitrates, and nitroaromatics. Detection of these explosives can be challenging due to varying chemical composition and the extremely low vapor pressures exhibited by some explosive compounds. No electronic trace detection system currently exists that is capable of continuously monitoring both peroxide based explosives and certain nitrogen based explosives, or their precursors, in the vapor phase. Recently, we developed a thermodynamic sensor that can detect a multitude of explosives in the vapor phase at the parts-per-trillion (ppt) level. The sensors rely on the catalytic decomposition of the explosive and specific oxidation–reduction reactions between the energetic molecule and metal oxide catalyst; i.e. the heat effects associated with catalytic decomposition and redox reactions between the decomposition products and catalyst are measured. Improved sensor response and selectivity were achieved by fabricating free-standing, ultrathin film (1 µm thick) microheater sensors for this purpose. The fabrication method used here relies on the interdiffusion mechanics between a copper (Cu) adhesion layer and the palladium (Pd) microheater sensor. A detailed description of the fabrication process to produce a free-standing 1 µm thick sensor is presented. [ABSTRACT FROM AUTHOR]

In pulsed laser deposited YBa2Cu3O7-x thin films containing 5mol. % Ba2YNbO6 pinning additions, we show that a growth rate of 1 nm/s (10 Hz laser repetition rate with an instant rate ~0.1 nm/pulse) gives remarkably strong c-axis correlated pinning which is associated with the presence of Ba2YNbO6 nanocolumns. This is different to the behaviour of other well-studied pinning additions where only random nanoparticles of the pinning phase are present at high growth rates and is an important finding for industrial fabrication of coated conductors where fast growth is required. [ABSTRACT FROM AUTHOR]

N-type bismuth telluride (Bi2Te3) thin films were prepared on an aluminum nitride (AlN)-coated stainless steel foil substrate to obtain optimal thermoelectric performance. The thermal co-evaporation method was adopted so that we could vary the thin film composition, enabling us to investigate the relationship between the film composition, microstructure, crystal preferred orientation and thermoelectric properties. The influence of the substrate temperature was also investigated by synthesizing two sets of thin film samples; in one set the substrate was kept at room temperature (RT) while in the other set the substrate was maintained at a high temperature, of 300 °C, during deposition. The samples deposited at RT were amorphous in the as-deposited state and therefore were annealed at 280 °C to promote crystallization and phase development. The electrical resistivity and Seebeck coefficient were measured and the results were interpreted. Both the transport properties and crystal structure were observed to be strongly affected by non-stoichiometry and the choice of substrate temperature. We observed columnar microstructures with hexagonal grains and a multi-oriented crystal structure for the thin films deposited at high substrate temperatures, whereas highly (00 l) textured thin films with columns consisting of in-plane layers were fabricated from the stoichiometric annealed thin film samples originally synthesized at RT. Special emphasis was placed on examining the nature of tellurium (Te) atom based structural defects and their influence on thin film properties. We report maximum power factor (PF) of 1.35 mW/m K2 for near-stoichiometric film deposited at high substrate temperature, which was the highest among all studied cases. [ABSTRACT FROM AUTHOR]

This report focuses on fabrication, characterization, and fundamental optical, structural and thermal properties of PVA/calcium aluminum doped zirconate (CaAl2ZrO6) nanocomposites (NCs) films. The PVA-NCs with different amounts viz., 2, 4, 6 and 8 wt% of calcium aluminum zirconate (CaAl2ZrO6) have been fabricated using solvent casting technique. The NC films structural and morphology have been investigated by X-ray diffraction, FTIR and scanning electron microscopy. TEM result indicates that the size of nanoparticles (NPs) lies in the range 10-23nm. Thermal studies have been evaluated by differential scanning calorimetry (DSC). The optical properties of NCs has been investigated by UV-vis spectroscopy, where the optical study reveals an increased refractive index from 1.22 to 2.23 at a wave length of 300 nm, where as the band gap energy (Eg) is reduced from 5.01 to 3.32 eV for PVA to PVA/8wt% CaAl2ZrO6, respectively. The dielectric studies, optical conductivity measurements and Urbach energy analysis also supports the dopant dependent optical property, tuning of PVA/CaAl2ZrO6 NC films to enable effective material property engineering to suit specified application requirements. [ABSTRACT FROM AUTHOR]

Abstract Reduced graphene oxide (rGO) thin films were prepared by one-step electrostatic spray deposition (ESD) technique with a precursor solution of graphene oxide in mixed alcohol solvent. The deposited rGO films showed decreasing thicknesses ranging from approximately 340 nm–120 nm as substrate temperature increased from 150 °C to 275 °C. Raman spectroscopy indicated lowest intensity ratio of D to G band (I D /I G) of the rGO films at substrate temperature of 275 °C. Highest carbon per oxygen (C/O) ratio was also obtained at substrate temperature of 275 °C. The ESD technique was used for film deposition on an area of 5 × 5 cm2, while an acetone gas sensor based on single layer rGO film was fabricated by one-step ESD technique. Results indicated the possibility of controlling thickness components in the rGO film, and the capability of large-area production by this scalable ESD method. Highlights • The rGO thin film can be prepared by one-step electrostatic spray deposition technique. • The reduction of graphene oxide changed by substrate temperature heating. • Large-area reduced graphene oxide thin films can be prepared by our technique. [ABSTRACT FROM AUTHOR]

Abstract Compared to the single-scale planar anodic aluminum oxide (AAO) film, the multi-scale hierarchical AAO structures can have a better performance due to the larger surface area. The conventional multi-scale AAO structure on a micro-pattern surface was fabricated using time-consuming lithography and etching process at high cost. In this article, the 3D porous AAO films with nanopores of 35–45 nm in diameter have been achieved on the surface of silica micro beads of 2 μm in diameter. The superimposed nano-micro structure was fabricated using hybrid-pulse anodizing the sputtered Al film on beads with a period of negative potential to dissipate Joule heating at room temperature. The 3D AAO-on-beads structure provides a large-surface-area substrate for enhancing the sputtered TiO 2 photocatalysis. The photocatalysis on the superimposed nano-micro structures can exhibit a high performance with the MB concentration of 30% after 15 h photo-degradation. Highlights • The multi-scale AAO structure with a larger specific surface area may have a better performance. • Conventional multi-scale AAO used a high-cost time-consuming lithography and etching process. • Here, 3D porous AAO films with 35–45 nm pores were achieved on the silica micro beads of 2 μm. • The TiO 2 film was sputtered and annealed on the 3D porous AAO for photocatalytic test. • The nano-micro structure exhibits a high photocatalysis with MB of 30% after 15 h photo-degradation. [ABSTRACT FROM AUTHOR]

A typical oxygen permeation hollow fiber membrane fabricated by phase inversion‐based extrusion process demonstrates heterogeneous porous microstructures, in which the surface layer with relatively low porosity is used as a separation layer after sintering. It is usually not convenient to control the thickness of separation layer. And a high sintering temperature is needed to densify the separation layer, which in turn could destroy the desired porous microstructures in other portion. This paper studies a novel process to fabricate multilayer asymmetric hollow fiber membrane with a rational design using 67 vol. % Gd0.2Ce0.8O2−δ−33 vol. % La0.6Sr0.4Co0.2Fe0.8O3−δ (GDC‐LSCF) as a model material system. The phase inversion‐based extrusion process in open literature is employed to fabricate a hollow fiber substrate featuring radially well‐aligned microchannels open at the inner surface. Built upon the hollow fiber substrate, a thin dense separation layer and porous surface catalyst layer at shell side are then fabricated through dip‐coating and sintering process alternatively. The oxygen permeation flux of the fabricated hollow fiber membrane reaches 2.68 mL/cm2/min at 900°C under Ar/air gradient, the highest performance of the membranes with GDC‐LSCF material system in open literature. The innovative fabrication process is able to readily control the thickness of functional layers while decreasing sintering temperatures. [ABSTRACT FROM AUTHOR]

Highlights • Earth-abundant and non-toxicity quaternary chalcogenide Cu 2 SrSnS 4 is prepared by a facial ball-milling method and its formation process is revealed. • Suitable bandgap and relative long carrier lifetime of the Cu 2 SrSnS 4 film have been discovered. • The potential of the Cu 2 SrSnS 4 film for photoelectric conversion application is explored. Abstract Earth-abundant and non-toxicity quaternary chalcogenide Cu 2 SrSnS 4 is prepared by a facial ball-milling method. Its formation is revealed to be from the reaction between Cu 2 SnS 3 and SrS at 600 °C. The bandgap of the prepared Cu 2 SrSnS 4 film is speculated around 1.78 eV according to absorption test. The carrier lifetime of the prepared Cu 2 SrSnS 4 film is about 2.06 ns. The photocurrent density of the Cu 2 SrSnS 4 film is about 150 μA cm−2 at −670 mV bias vs Ag/AgCl electrode and it repeats after 10 cycles of 1000 s. Its notable generation of photocurrent and photoelectrochemical stability indicates its potential for photoelectric conversion application. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract The expansion of the use of polymeric membranes in gas separation requires the development of membranes based on new polymers with improved properties and their assessment under real operating conditions. In particular, the fabrication of ultrathin films of high performance polymers that can be used as the selective layer in composite membranes will allow large reductions in the amount of the expensive polymer used and, hence, the cost of membrane fabrication. In this contribution, two polymers of intrinsic microporosity (PIMs) with very different chain configurations (two-dimensional, 2D, chains or conventional contorted three-dimensional, 3D, conformation) have been compared in their ability to form ultrathin films, showing the relevance of polymer design to obtain compact and defect-free films. Monolayers of the 2D polymer PIM-TMN-Trip can be efficiently deposited onto poly[1-(trimethylsilyl)-1-propyne] (PTMSP) to obtain composite membranes with a CO 2 /N 2 selectivity similar to that of the corresponding thick membranes of the same PIM using only a small fraction of the selective polymer (less than 0.1%). [ABSTRACT FROM AUTHOR]

Abstract Highly oriented Bi 2-x Sb x Te 3 (x = 0, 0.7, 1.1, 1.5, 2) ternary nanocrystalline films were fabricated using vacuum thermal evaporation method. Microstructures and morphologies indicate that Bi 2-x Sb x Te 3 films have pure rhombohedral phase with well-ordered nanopillars array. Bi, Sb and Te atoms uniformly distributed throughtout films with no precipitation. Electrical conductivity of Bi 2-x Sb x Te 3 films transforms from n-type to p-type when x > 1.1. Metal-insulator transition was observed due to the incorporation of Sb in Bi 2 Te 3. Bi 2-x Sb x Te 3 film with x = 1.5 exhibits optimized electrical properties with maximum electrical conductivity σ of 2.95 × 105 S m−1 at T = 300 K, which is approximately ten times higher than that of the undoped Bi 2 Te 3 film, and three times higher than previous report for Bi 0.5 Sb 1.5 Te 3 films and bulk materials. The maximum power factor PF of Bi 0.5 Sb 1.5 Te 3 nanopillars array film is about 3.83 μW cm−1 K−2 at T = 475 K. Highly oriented (Bi,Sb) 2 Te 3 nanocrystalline films with tuned electronic transport properties have potentials in thermoelectric devices. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • A cheap aromatic precursor was designed to synthesize single-layer NG sheet. • The precursor with heteroatom and planar-structure can facilitate NG growth. • Doping concentrations can be controlled by the growth temperature. • Synthetic strategy has universality for preparing heteroatom doped graphene. Abstract A cheap aromatic precursor (1,10-phenanthroline) with heteroatom and planar-structure was designed to synthesize large-scale, continuous and mostly single-layer nitrogen-doped graphene (NG) films by one-step chemical vapor deposition method. The NG sheets can be obtained even at 600 °C. The results indicated that the content and type of doped N are intensely relied on the growth temperature. Our fabrication approach provides an economic synthetic route and potentially promotes the practical application of graphene-based materials. [ABSTRACT FROM AUTHOR]

For the design of magnetostrictive MEMS devices, finite-element modeling (FEM), the determination of the magnetostrictive coefficient, and application examples were examined in this paper. The magnetostrictive coefficients are usually calculated by measuring the bending deflection of the cantilever on which magnetostrictive materials are deposited. In most of the research on the magnetostrictive deposited substrate for the derivation of structural formulas, it is commonly assumed that the flexural rigidities of magnetostrictive materials are negligible because magnetostrictive films are much thinner than substrate materials. In this paper, the effect of magnetostrictive thin film’s elastic energy on the magnetostrictive coefficient is investigated. A self-coded and developed finite-element program for magnetostrictive actuators is formulated, where magnetic properties are considered as nonlinear, and elastic properties are assumed as linear. As a result, it is potentially shown that magnetostrictive thin-film micropatterned actuators would be accommodated for targeted actuating behavior through an FEM capability for evaluation and selective micropatterning technique for fabrication. [ABSTRACT FROM AUTHOR]

Abstract Porous membranes and thin films containing poly-lactic acid (PLA), carvacrol (CRV) and graphene nanoplatelets (GNP) were fabricated by electrospinning and solvent casting at different formulations. The systems were characterized from a mechanical, morphological, calorimetric and spectroscopic point of view. CRV release as a function of time was studied and a mathematical model was used to fit and interpret the data in order to investigate the release mechanism. The results indicate that the incorporation of GNP generally determined a simultaneous strengthening, stiffening and toughening effect, while preserving a good ductility. Furthermore, integrating GNP allowed tuning the amount and kinetics of CRV release, and proved to reduce the initial burst release effect. [ABSTRACT FROM AUTHOR]

Abstract A photodetector based on Mg/ZnSnP 2 /Sn structure was fabricated on p-type silicon (100) to operate in the wavelength range of 450–850 nm. The observed current-voltage characteristics showed roll-over like features which was successfully modeled considering two Schottky junction diodes connected back to back. The device showed strong photo-response in both the forward and reverse bias configuration and the current-voltage curve shifted to the fourth quadrant under illumination. The barrier height and the ideality factor of the two Schottky diodes were evaluated using numerical simulation. The maximum values of responsivity, photosensitivity and detectivity were found to be 22.76 mA W−1, 57.00 cm2W‐1 and 6.34 × 1010 cm Hz1/2 W−1 in the forward bias and 3.48 mA W−1, 48.22 cm2 W−1 and 2.25 × 1010 cm Hz1/2 W−1 in the reverse bias, respectively at illumination of wavelength 850 nm. The photodetector showed a fast response time of 47 μs and multiple recovery times of 725 μs, 1.2 ms and 1.3 ms respectively. The existence of traps within the ZnSnP 2 thin films was responsible for extending the time of recovery in comparison to time of response. Graphical abstract fx1 Highlights • Mg/ZnSnP 2 /Sn based photodetector successfully fabricated for the first time. • This device is sensitive to 450–850 nm spectral region. • Double diode model with Lambert W transformation is implemented to fit I-V curve. • Rapid response time of 47 μs has been reported for this device. • Trap assisted multiple recovery time of 725 μs, 1.2 ms and 1.3 ms are obtained. [ABSTRACT FROM AUTHOR]

Abstract Metal nano-particles (NPs) have been successfully synthesized by the reduction of Ag@Cu 2 O with the aid of surfactant PVP and excessive reducer ascorbic acid in ambient conditions. The composition and structures of the NPs were characterized by scanning and tunnelling microscopies (SEM and TEM). The synthesized nano-particles were employed as solar absorber in thin film organic photovoltaic (OPV) with the view to exploit the effect of local surface plasmon resonance (LSPR) of the metals. As a consequence, substantial improvement on the major solar cell parameters were measured by the incorporation of Ag@Cu NPs in the P3HT:PCBM based photo-active medium. The power conversion efficiency of the solar cell increased by 103% compared to those devices fabricated without metal nano-particles. The observed balanced charge transport, in the current experiment, is attributed to presence of metal nano-particles in OPV devices which are responsible for near field enhanced photons scattering in the medium. Highlights • Efficient charge carrier collection was possible using metal-nanocomposite in solar absorber. • Core-shell type silver:zinc (Ag:Cu) nanocomposite was synthesized by co-reduction methods. • Ag:Cu nanocomposite in photoactive layer has improved device performance by 103%. [ABSTRACT FROM AUTHOR]

Abstract Tungsten disulfide (WS 2) is a promising material for potential applications in next-generation 2D-electronics. However, for such applications large-area films will be required. Fabrication techniques involving exfoliation give films of high crystal quality but suffer from the problem of extremely small size of the films which makes it very challenging to realize real devices for industrial applications. In this study, we are reporting the growth of large area two-dimensional (2 D) films of WS 2 using pulsed laser deposition technique. A polycrystalline WS 2 target was ablated using a pulsed KrF excimer laser (wavelength: 248 nm; pulse width: 25 ns). The ablated material was deposited over a c-axis aligned single crystal sapphire substrate maintained at 500 °C in an ambient vacuum of 10−5 Torr. Thickness of the resulting films was controlled by controlling the number of incident laser pulses. Detailed characterization of the films was carried out using several state-of-the-art techniques including atomic force microscopy, Raman spectroscopy, and ultraviolet–visible spectroscopy. Relationship between the number of monolayers in the WS 2 films and the spacing between the A 1g (Γ) and E 2g 1 (Γ) Raman peaks (Δf) was determined. Effect of post annealing on the optical properties of the films was also investigated. Highlights • 2D WS 2 films were grown over sapphire substrate using pulsed laser deposition. • Raman spectra suggested peak shifts as number of monolayer varies. • UV–Vis spectrograph proved high transparency of 2D WS 2 films. • Film quality showed improvement after annealing. [ABSTRACT FROM AUTHOR]

Abstract: CMOS and SOI technology compatible structures and devices are currently intensively investigated by many research groups, since various effects observed in such structures can be relatively easy implemented in electronic devices thereby expanding their functionality. The most promising is the research and development of spintronic devices, which will allow using both electron charge and spin degrees of freedom for transmission, storage and processing of information. In this work we report the fabrication process of 3-terminal (3-T) ferromagnet/silicon devices of two types. First is the planar Fe3Si/Si 3-T structure with 5 μm gap between closest ferromagnetic electrodes. Second is silicon nanowire back-gate transistor with Fe film source and drain synthesized on SOI substrate. Transport and magnetotransport properties of both devices are investigated. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • The Pd/W 2 N nanoball like structure was grown on porous silicon (PSi) substrates by reactive DC sputtering technique. • Hydrogen gas sensing properties of Pd/W 2 N/PSi nanoballs sensor were studied in detail at room temperature. • The Pd/W 2 N/PSi nanoballs sensor exhibits the fast response/recovery towards (5–500) ppm H 2 gas. Abstract Here, we reported the hydrogen sensing performance of the palladium modified tungsten nitride (Pd/W 2 N) nanoballs (NBs) grown on the porous silicon (PSi) substrate via reactive DC magnetron sputtering. The reversible change in resistance was observed during hydrogenation and dehydrogenation process at room temperature. Hydrogen gas sensing performances together with the sensing mechanism of the proposed Pd/W 2 N/PSi NBs sensor under low sensing range (5–500 ppm) were discussed in detail. Moreover, the prime requirements of the device including stability, reproducibility and selectivity measurements were also studied at room temperature. The observed excellent sensing performance is attributed to the enhanced surface area of the proposed sensor. [ABSTRACT FROM AUTHOR]

Acoustophoresis, the movement of particles with sound, has evolved as a promising handling tool for micrometer-sized particles. Recent developments in thin film deposition technologies have enabled the reproducible fabrication of thin film piezoelectric materials for miniaturized ultrasound transducers. In this study, we combine both technologies and present the first implementation of a thin film Pb(Zr,Ti)O3 (PZT) transducer as actuation source for bulk acoustic wave (BAW) acoustophoresis. The design and fabrication process was developed for thin film BAW (TFBAW) devices. High-quality piezoelectric layers were produced using Solmates SMP-800 pulsed laser deposition (PLD) equipment which enables wafer-level batch fabrication. Results from simulations and experiments enabled the characterization of different designs and the prediction of the pressure field inside the TFBAW device. Moreover, the acoustic streaming field was analyzed to determine critical particle diameters for acoustophoresis. Operation conditions were identified for the acoustophoretic unit operations particle concentration and sorting. The TFBAW device was able to generate a high acoustic pressure amplitude of 0.55 MPa at a low peak input voltage of 0.5 V. Overall, this study demonstrates that TFBAW devices have the potential of a miniaturized, predictable and reproducible acoustic particle manipulation at a low voltage for lab-on-a-chip applications. [ABSTRACT FROM AUTHOR]

Abstract In this study, Cu 2 ZnSnS 4 (CZTS) thin films were fabricated by periodically sequential depositions of metallic precursors by magnetron sputtering followed by sulfurization. The element compositions, crystal structures, and surface morphologies of the single-period precursor (Zn/Sn/Cu) and four-period precursor (Zn/Sn/Cu/Zn/Sn/Cu/Zn/Sn/Cu/Zn/Sn/Cu) during the sulfurization process were investigated. The experimental results showed that in the initial stage of sulfurization, the single-period precursor had a more efficient reaction with sulfur vapor below 300 °C because of its thicker metal layers. During the process of sulfurization, the CZTS phase first formed in the four-period film at 400 °C, owing to the wide distribution of the internal layer in the periodic thin film. With a further increase in temperature, the crystallinity of CZTS was enhanced and the secondary phases were reduced. A CZTS phase with Cu-poor and Zn-rich composition was confirmed in both thin films after complete sulfurization. The CZTS thin film with a four-period precursor showed a better degree of crystallization, and a single phase of CZTS was obtained more easily than in the single-period thin film. Therefore, using a periodic structure can promote the sulfurization reaction of Cu-Zn-Sn precursors and enhance the properties of CZTS thin films. [ABSTRACT FROM AUTHOR]

Abstract Transparent conducting electrodes have been systematically developed for optoelectronic devices and applications in industry through materials exploration and manufacturing process optimization. The nanostructural, optical and electrical properties were correlated with the embedded Ag interlayer thickness for the first time, for α-IGZO/Ag/α-IGZO trilayer electrodes fabricated using DC magnetron sputter deposition. Optimizing the Ag interlayer thickness at 14 nm achieves a maximum Haacke figure of merit (FOM) of 7.3 × 10−3 Ω−1, at least two orders of magnitude greater than that of the single IGZO film, with X-ray diffraction patterns indicating a crystalline phase that is also retained for thicker layers. Electrical and surface topography measurements confirm a uniform, continuous Ag interlayer film with bulk metallic behavior and resistivity as low as 6 × 10−5 Ω cm. Experimentally-calibrated finite-element modeling and ray tracing simulations unravel in the multilayer films, backscattering and transmission effects from random surface roughness, as well as phonon- or ionized impurity-scattering mediated free carrier absorption plus surface/interface scattering and interference effects. Moreover, film thickness-sensitive tuning of the optical bandgap between 2.98 and 3.14 eV was demonstrated, yielding a maximum bandgap and Haacke FOM at the optimized Ag interlayer thickness, and with many-body interactions outcompeting the Burstein-Moss effect above this thickness. [ABSTRACT FROM AUTHOR]

Abstract We report the synthesis of monolayered g-C 3 N 4 from bulk g-C 3 N 4 via ultrasonication where the monolayered g-C 3 N 4 dispersions remained stable for nearly two months due to effective production of ultra-small-sized layered g-C 3 N 4. A g-C 3 N 4 thin film was fabricated with the utilization of as-prepared dispersion. The fabrication method involved spin coating the dispersion followed by drying at low temperatures of ∼150 °C. The photoelectrochemical performance obtained via this research is comparable with those via other methods of deposition, reaching the value of 1.4 μA cm−2 at 1.23 V (vs. RHE). The g-C 3 N 4 maintained its intrinsic n-type properties and was activated under positive applied bias with minimum amount of dark current. The selection of pure methanol as disperser not only yielded excellent spreadability of the dispersion on substrate but also quickened the drying time. The developed method in this research provided an effective framework for a surpassingly facile and quick fabrication of monolayered g-C 3 N 4 photoelectrodes. Highlights • G-C 3 N 4 thin films were fabricated by spin-coating technique. • 2D G-C 3 N 4 was prepared by liquid exfoliation in methanol. • Quenched N H bonds were observed for 2D g-C 3 N 4 compared with bulk g-C 3 N 4. • 2D G-C 3 N 4 resulted in more uniform thin films compared with bulk g-C 3 N 4. • The photocurrent of 1.4 μAcm−2 at 1.23 V (vs. RHE) were achieved for 2D g-C 3 N 4. [ABSTRACT FROM AUTHOR]

In this study, the industrial inspection of optical thin film on touch screen panels was demonstrated using line field spectral domain optical coherence tomography. The conventional Fourier domain optical coherence tomography system requires a single scanner for two-dimensional cross-sectional images and two scanners for volumetric images. Our developed line field spectral domain optical coherence tomography has the advantage of needing only a single scanner for volumetric images, while two-dimensional cross-sectional images are obtained by the parallel acquisition of an illuminated line on a sample using an area camera. Further, the image acquisition speed was enhanced by implementing a high speed camera (340 frames per seconds) with improved quantum efficiency at near infrared region enabling two-fold frame rate. Cross-sectional and volumetric images were acquired to detect the internal sublayer defects in the optical thin films, which are difficult to observe using visual or machine vision-based inspection methods. The developed pseudo code for defect identification in optical thin films was well-utilized here for the defect inspection. The system characterization is demonstrated using United State Air Force (USAF) resolution target. The results indicate the possible application of the proposed system in touch screen panel inspection for the quality assurance of products at the consumer end. [ABSTRACT FROM AUTHOR]

Highlights • We demonstrate a smart sensor that is capable of performing simultaneous sensing and actuation using a single device. • The microbeam is uniformly functionalized with metal organic frameworks (MOFs) to enhance the sensitivity and selectivity of the proposed sensor. • The proposed technique can be extended to simultaneously measure multiple physical stimuli using a higher number of modes of a single resonator. Abstract Smart sensing systems suffer complexity requiring interface circuits, microcontrollers, switches, and actuators to detect and sense, process the signal and take a decision, and trigger an action upon demand. This increases the device footprint and boosts significantly the power required to actuate the system. Here, we present a hybrid sensor and switch device, which is capable of accurately measuring gas concentration and perform switching when the concentration exceeds specific (safe) threshold. The device is based on a clamped-clamped microbeam coated with metal-organic frameworks (MOFs). Using the electrostatic harmonic voltage, we employ dynamic multi-modal actuation in which the microbeam is simultaneously excited at the first mode of vibration, near the pull-in band, and at the third mode. We demonstrate experimentally the effectiveness of this technique in measuring the concentration of water vapor and achieving switching when the concentration exceeds a threshold value. In contrast to the first mode operation, we show that monitoring the third mode enhances sensitivity, improves accuracy, and lowers the sensor sensitivity to noise. [ABSTRACT FROM AUTHOR]

The MoS 2 /GO hybrid composite thin film is prepared by a facile solution mixing process. To reduce the composite film spin-coated on a SiO 2 (300 nm)/Si substrate, thermal annealing at 600 °C for 1 h in a N 2 atmosphere is used. The thermally reduced GO (rGO) composite film is subjected to line patterning through a soft lithographic patterning method, and the patterned MoS 2 /rGO composite thin film is re-transferred onto a PET film from the Si substrate. The patterned MoS 2 /rGO composite thin film has a thickness of about 10 nm and the transmittance of the patterned MoS 2 /rGO composite thin film on the PET substrate is 93%. The NO 2 gas sensor device is fabricated and its basic characteristics are systematically investigated. The patterned MoS 2 /rGO composite thin film gas sensor has a sensitivity at least four times higher than the pure rGO thin film gas sensor. In addition, the characteristics of the sensor device are also maintained at a bending radius of 14 mm. This transparent and flexible patterned MoS 2 /rGO composite thin film can be used as a highly sensitive gas sensor that will detect a concentration as low as 0.15 ppm of harmful gases such as NO 2 . [ABSTRACT FROM AUTHOR]

Abstract Organic-inorganic perovskite solar cells (PSCs) are among the most attractive and efficient emerging thin film photovoltaic technologies. The perovskite films have been fabricated by lots of deposition methods, including one-step/two-step spin coating, thermal evaporation and vapor assisted processes. However, the laboratory-based fabrication methods are not well matched with large area manufacture for actual use. Spray coating deposition technique is being explored to prepare perovskite films to break the bottleneck plaguing large scale production. Herein, a comprehensive study is conducted in fabricating perovskite films by air-brush spraying method. The spraying process is classified into three stages, namely, 1) atomization process, 2) droplet flight and 3) film deposition. Each of them is discussed in detail from principles to parameters. Integrating the three aspects above, high quality perovskite films comparable to spin coated films are obtained. A best power conversion efficiency (PCE) of 16.68% is achieved for planar structure PSCs, which is prominent among the PSCs fabricated by spraying method. In addition, devices with spraying method show excellent optical and electrical properties. The principles we discuss here could be applied in the actual condition for mass production. Graphical abstract Image 1 Highlights • Spray coating method is explored to prepare perovskite films for large scale production. • The spraying process is discussed from principles to parameters. • The devices with spraying method show excellent optical and electrical properties. [ABSTRACT FROM AUTHOR]

The paper deals with development of the high-frequency welding technology in manufacture of thin-walled spirally- welded pipes by adding activators to the weld zone and applying the pressure to improve the strength characteristics of welded joint metal. Investigations are based on scientific principles of theoretical fundamentals of welding, materials science and problems of metal strength. A specifics of the welding technology considered is the fact that during heating of edges to be joined by high frequency currents the activators, having lower melting temperatures, transition to the liquid state, bind surface contaminations and transport them to the surface at pressure applying. Edges of the cleaned metal are joined as a result of running of diffusion processes at temperatures close to base metal melting temperatures. In principle, the process of joining at the final stage proceeds with the weld metal being in the solid phase. The obtained weld width does not exceed 4-8 μm. Weld metal consists of the base metal being welded, enriched in activator elements. Near-weld zone structure is close to that of the base metal. Thin-walled spirally-welded pipes can be produced with a high quality of welded joint at a high welding speed. [ABSTRACT FROM AUTHOR]

In the second generation thin film solar cell, Copper Zinc Tin Selenium (CZTSe) thin film is considered as the quintessential absorber layer in solar cell as its constituents are earth abundant and non-toxic, making it environmental friendly. Many fabrication methods have been employed to fabricate the films like Thermal evaporation method, pulsed layer deposition, RF-DC Sputtering, etc. The authors have monitored the aspects that highly influence the band gap of CZTSe thin films during the deposition process. This paper recapitulate the parameters that affect the band gap of CZTSe thin film as an absorber layer like substrate temperature, annealing temperature, and order of precursors. [ABSTRACT FROM AUTHOR]

Abstract: A facile approach to the fabrication of bioinspired hierarchical functional structures by using honeycomb films with controllable micropores as templates is described here. Taking advantage of the breath figure method, honeycomb films with manipulable micropores can be conveniently fabricated by modulating the experimental conditions such as duration of the moist gas flow, temperature, and stretching of the film, which further serve as templates to induce the assembly of subsequently introduced silica nanoparticles for the construction of hierarchical functional structures in a controlled fashion. The resultant hierarchical functional structures not only present a viewing angle independent property, but also exhibit improved hydrophobicity and unique wetting behaviors depending on the morphologies of their building units. It is believed that the work will provide plenty of inspiration for the fabrication of novel high‐performance optical devices for display, as well as functionalized surfaces for waterproof and self‐cleaning. [ABSTRACT FROM AUTHOR]

Anodic aluminum oxide (AAO) layers with nano-sized pores have been used as shadow masks for the fabrication of two-dimensional (2D) metal nanodot arrays (NDAs). However, the localized surface plasmon resonance (LSPR) of size-controlled NDAs fabricated using AAO masks has not been much studied. In this study, we report on the improved preparation method and utilization of an ultrathin AAO mask for the fabrication of 2D plasmonic metal NDAs. The greatest challenge in preparing an AAO mask is to control the pore diameter and to make it reproducible. AAO masks with size-controlled pores were reproducibly prepared using a two-step chemical wet etching method. Ag NDAs with different dot diameters (42, 60, and 80 nm) and Ag, Cu, and Au NDAs with dot a diameter of 80 ± 5 nm were fabricated on indium tin oxide glass substrates using AAO masks. The wavelengths corresponding to LSPR of 2D metal NDAs were investigated using ultraviolet–visible spectroscopy. Our results show that AAO masks with tunable pores can be used as shadow masks for the fabrication of 2D plasmonic NDAs. [ABSTRACT FROM AUTHOR]

We present the design, analysis, fabrication, and measurement of an ultrathin cross-polarization converter in the transmission mode with near unity conversion efficiency. The converter is constructed of a periodic array of the dielectric substrate sandwiched with simply artificial structures, in which the top layer and bottom layer are connected by metallic vias. The proposed polarizer can convert the linearly polarized incident electromagnetic wave to its orthogonal counterpart in the transmission mode. The conversion mechanism is explained by both equivalent circuit model and full-wave simulations. The simulation and measured results have a good agreement in the entire frequency range. Such a scheme of the ultrathin cross-polarization converter has simple geometry and can be used in microwave communications, remote sensing, and imaging. [ABSTRACT FROM AUTHOR]