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• Growth of methyl ammonium tin iodide (MASnI3) perovskite thin films. • Plasma enhanced chemical vapour deposition technique is used for MASnI3 thin film deposition. • Single step vacuum based approach for MASnI3 perovskite thin film growth. • Formation of MASnI3/Si heterojunctions. • Applications of MASnI3/silicon heterojunction as photodetector. In the present work, lead free methyl ammonium tin iodide (CH 3 NH 3 SnI 3 or MASnI 3) perovskite thin films have been deposited via single step plasma enhanced chemical vapour deposition (PECVD) technique. In our earlier work, we reported lead based methyl ammonium lead iodide (CH 3 NH 3 PbI 3 or MAPbI 3) perovskite thin film deposition in 2-step, using sputtering technique for the PbI 2 thin films and PECVD technique for CH 3 NH 3 I (MAI) thin films. Similarly, CH 3 NH 3 SnI 3 perovskite thin films are deposited in this work using PECVD technique in single step. Lead is substituted with tin due to its toxic behaviour, environmental and health related issues. CH 3 NH 3 SnI 3 perovskite is doped n-type via changing the molar ratio of SnI 2 and CH 3 NH 3 I. SnI 2 /CH 3 NH 3 I ratio is changed from 0.33 to 2 to study the n-type doping of CH 3 NH 3 SnI 3 perovskite. Deposited CH 3 NH 3 SnI 3 perovskite thin films are deposited over p-type silicon wafer to make n-type doped n-CH 3 NH 3 SnI 3 /p-Si heterojunction photodiode. [ABSTRACT FROM AUTHOR]

Thin Sn films on Ag(111) grown at different Sn coverage and substrate temperature were characterized with low-energy electron diffraction and x-ray photoelectron spectra. The results show that surface alloying of Sn atoms on Ag(111) occurs at a temperature as low as 96 K, indicating a strong tendency to form a surface alloy between Sn and Ag. During the alloying, Sn atoms substitute Ag atoms in random locations, resulting in a disordered Sn/Ag(111) surface. The alloy surface becomes completely ordered with a (√3 × √3) R30° reconstruction (the √3 phase) only when it is annealed above 453 K, but annealing at 403 K converts all Sn atoms on Ag(111) into the alloy state; the surface coverage of Sn is no more than 1/3 monolayer with excess Sn diffusing into the Ag(111) substrate. These observations indicate that the √3 phase with the Sn-Ag surface alloy is the only ordered phase obtainable on Sn/Ag(111) once the Sn-Ag surface alloy is formed. It is consequently impracticable to grow non-alloy ordered phases, such as stanene, on Ag(111) epitaxially at a temperature above 96 K, showing evident discrepancies with the conclusions of the previous computational study. • Sn/Ag(111) thin films grown at different conditions are studied. • Sn-Ag alloying on Ag(111) occurs at a temperature as low as 96 K. • Annealing above 403 K converts all Sn atoms into alloy states. • Sn/Ag(111) has a completely ordered √3 phase only when annealed above 453 K. • Non-alloy ordered phases do not exist on Ag(111) when Sn is deposited above 96 K. [ABSTRACT FROM AUTHOR]

Abstract Tin monosulfide (SnS) thin films were deposited on both soda lime glass (SLG) and Mo-coated SLG substrates by radio-frequency (RF) sputtering at a substrate temperature (T s) from room temperature (RT) to 420 ° C. The structural and optical properties were investigated by performing the scanning electron microscopy, electron dispersive spectroscopy, atomic force microscopy, X-ray diffraction, micro-Raman, and ultraviolet-visible-near infrared spectroscopy measurements. For T s greater than RT showed the well-defined grain features with increased grain sizes. At 350 ° C , the films showed the [S/Sn] ratio close to the stoichiometric SnS. The X-ray diffraction studies unveiled the orthorhombic crystal structure of SnS with the (111) preferred orientation for all the T s. The Raman analysis confirmed the single phase of SnS without any secondary phases. The optical properties revealed a direct energy bandgap of SnS was around 1.2–1.4 eV and the bandgap decreased with increasing T s. We fabricated the SnS/CdS heterojunction solar cell with the SnS grown at 350 ° C. The device with a structure of SLG/Mo/SnS/CdS/i-ZnO/ITO/Ni/Ag exhibited the power conversion efficiency of 0.35% with an open-circuit voltage of 0.143 V, short-circuit current density of 6.7 mA·cm−2, and fill factor of 40.3%. Highlights • The SnS thin films showed the well-defined grain features with increasing T s. • Films deposited at 350 ° C showed the [S/Sn] ratio close to stoichiometric SnS. • All films exhibited the orthorhombic crystal phase of SnS without any secondary phases. • The optical bandgap was decreased from 1.37 to 1.24 eV with increasing T s. • The solar cell showed the PCE of 0.35% for the SnS grown at 350 ° C. [ABSTRACT FROM AUTHOR]

Abstract As has recently been shown experimentally, adatoms from group 14 exhibit distinct growth characteristics on Ru(0001) at submonolayer coverages. In particular, Pb and Sn atoms agglomerate in dense islands of the c (2 × 4) or c (2 × 8) symmetry with local coverage of 1/2 monolayer (ML), respectively, already for much lower deposition doses, whereas Ge atoms self-assemble in the dilute 21 × 21 structure with adatom density of 1/7 ML. To trace the observed differences, we employed ab-initio density-functional-theory simulations and followed the early stages of growth of Pb, Sn, and Ge on Ru(0001) in a systematic manner by examining the potential energy surfaces for successive adsorption of up to several atoms of each element within a large surface unit cell. This way the effective lateral interactions between adatoms were recognized in the low-coverage regime, and their most favorable dimer and trimer configurations were identified. Interpreting them as initial building blocks of the adsorbate structure enabled us to clarify the tendency of various considered elements towards formation of a dense or dilute ordered overlayer on Ru(0001) at low nominal coverages. Highlights • Successive adsorption of Pb, Sn and Ge atoms on Ru(0001) investigated by DFT. • Effective lateral interactions between adatoms recognized in low-coverage regime. • Initial building blocks of ordered overlayers identified for various adsorbates. • Formation of dense (Pb, Sn) or dilute (Ge) overlayers at low depositions clarified. [ABSTRACT FROM AUTHOR]

Abstract Tin (II) sulfide (SnS) films were prepared using physical vapor deposition coupled with glancing angle deposition technique at zero and high oblique incident vapor angles (α = 65° and 85°). The resulting films were all nanostructured with thin nano-sheets. The thickness of the nano-sheets increased upon deposition angle increment due to shadowing and re-emission effects. In order to investigate substrate-induced changes, the films were deposited on glass, indium tin oxide, and fluorinated tin oxide substrates. The X-ray diffraction analysis indicated that the thin films coated at different incident angles and substrates were crystallized in single phase with orthorhombic structure while a change of the growth orientation observed in the samples prepared at α = 65° and 85°. In addition, the presence of Sn 2 S 3 phase in some samples was also detected. The top and cross-sectional images of the samples, obtained by field emission scanning electron microscopy, confirmed considerable changes in the structure and morphology of individual nano-plates as which was a function of the incident deposition angle and substrate type. Atomic force microscopy analysis confirmed that the substrate type and deposition angle have an effect on the apparent average surface roughness and porosity. The optical band-gaps of the samples prepared at α ≥ 65° were higher than those prepared at α = 0°. In near-IR spectral range, significant changes in the refractive index of all the samples deposited at α = 85° were observed. Highlights • SnS films were prepared on different substrates using GLAD technique. • Substrates-induced changes investigation was systematically carried out. • The FESEM images showed dramatic changes in the morphology of the samples. • At α =85°, the layers showed a considerable change in optical parameters. [ABSTRACT FROM AUTHOR]

Incorporation of varying amounts of graphene oxide (GO) into conventional Sn coating electrodeposited over mild steel resulted in significant changes in the corrosion resistance performance of the coatings. An aspect of “optimum” GO amount for best corrosion resistance for the Sn-GO composite coatings was explored. All the Sn-GO coatings exhibited compact and crack free morphology. Incorporation of GO facilitated growth along the low index planes and supressed it along the high index planes. Corrosion behaviour of the coatings was examined through potentiodynamic polarisation and electrochemical impedance spectroscopy methods. It was observed that with the addition of GO, the corrosion rate initially decreased to a minimum value and then, upon continued addition of GO, it increased to a value that was even higher than the pure Sn coating. In the case of lower GO amounts, the textured growth coupled with impermeability of GO increased the corrosion resistance whereas, at higher GO concentrations, the galvanic coupling between GO and Sn dominated, leading to lowering of the corrosion resistance. [ABSTRACT FROM AUTHOR]

The initial reaction between Pt and molten Sn has been studied by dipping tests of 1 and 2 s. It was found that both PtSn and PtSn 4 formed in the first second of contact. PtSn formed 7 nm (1 s) and 20 nm (2 s) thick layers on top of the Pt substrate but PtSn 4 formed scattered particles in the liquid Sn. No orientation relationship was found between Pt and PtSn. PtSn nucleates heterogeneously on Pt by its larger energy of formation than PtSn 4 and PtSn 4 nucleates in liquid Sn by the very low solubility of Pt in molten Sn. [ABSTRACT FROM AUTHOR]

We have fabricated Cu 2 ZnSnSe 4 (CZTSe) solar cells with different absorber layer thickness. Absorber layers with different thicknesses were fabricated by changing the thickness of e-beam evaporated Sn/Zn/Cu precursor stacks and then selenization in a rapid thermal processing system. Scanning electron microscopy revealed that by increasing the thickness the morphology of CZTSe films improves substantially and energy dispersive spectrometry measurements showed that the Cu to Sn ratio increased with increasing the film thickness, despite a similar Cu to Sn ratio in the starting layers. A longer minority carrier lifetime and higher open circuit voltage were achieved for solar cells with thicker absorber layers. A maximum conversion efficiency of 7.8% (without anti reflection coating) was achieved for a solar cell with 1.7 μm thickness in which a low doping density of the order of 10 15 cm − 3 was measured, leading to a wide space charge region of about 300 nm. [ABSTRACT FROM AUTHOR]

Highly (001)-oriented pure PbZrO 3 (PZO) films and Sn-substituted PZO films are deposited on (001)-LaNiO 3 buffered SiO 2 /Si substrates by RF magnetron sputtering. Different Sn-substituted PbZrO 3 films (PbZr 1-x Sn x O 3 , x = 0%, 3%, 5%, 10%) with orthorhombic anti-ferroelectric phase are fabricated. The effects of Sn substitution on structure and energy performance have been investigated in detail. The switching electric fields are enlarged and energy loss is lowered by Sn substitution. Recoverable energy density (Wr) of 14.8 ± 0.2 J/cm 3 and energy efficiency (η) of 71.2 ± 0.5% at 900 kV/cm are obtained in 5% Sn-substituted PZO film (~ 360 nm). Furthermore, with thicker thickness of ~ 650 nm, Wr and η can be further improved. The Sn-substituted PZO film is believed to be an improved material for applications in energy storage systems and 5% Sn-substituted PZO film exhibits the highest Wr and η in this work. [ABSTRACT FROM AUTHOR]

In the current article, we studied the effect of substrate temperature on the morphological and electrical behavior of sulfosalt material Sn 4 Sb 6 S 13 deposited by vacuum thermal evaporation procedure on glass substrate heated at various temperatures in the range of 30–200 °C. X-ray diffraction patterns indicate that Sn 4 Sb 6 S 13 thin films crystallized in monoclinic structure according to a preferential direction 6 ¯ 11 and the average grain size increases by increasing substrate temperature. Atomic force microscopy was used to characterize the surface morphology of the layers. Electrical and dielectric properties have been investigated by ac impedance spectroscopy over a wide range of temperature up to 400 °C starting from room temperature in the frequency range 5 Hz–13 MHz. The complex impedance plots display a single semicircle that highlights the influences of grain on the films. Impedance analyses showed that the resistance decreased by increasing the temperature. In addition, the analysis of conductivity shows that the conduction mechanism was thermally activated and was assured by hopping between localized states. [ABSTRACT FROM AUTHOR]

• Database of direct current magnetron sputtered TiN coatings was compiled. • Machine learning algorithms were trained to predict coating hardness. • Data filtering and imputing improved performance of machine learning algorithms. • The most important descriptors for predicting coating hardness were determined. • Trained algorithm was applied for the inverse problem of coating deposition. Modern vacuum ion-plasma technology makes it possible to obtain coatings of various compositions and properties on the surface of metals. Titanium nitride ion-plasma coatings are the most widely used in industry and can significantly improve the mechanical and tribological characteristics of the tribocontacts. The synthesis of coating depends on many parameters and often an optimized set of parameters from a one coater cannot be directly transferred to another. In this work we have compiled a database of reactive direct current magnetron sputtered TiN coatings based on a wide range of reports available in literature. Machine learning algorithms were trained on the database entries from independent authors to establish a relationship between coating hardness and experimental deposition settings. We address the necessary steps for its training: filtration, imputing and feature selection. The algorithm was then applied to the coating inverse design problem and predicted optimal synthesis parameters for given hardness. [ABSTRACT FROM AUTHOR]

Micrometer-scale Sn particles are produced by plasma treating Sn films from 50 nm to 2000 nm on silicon oxide substrates. Plasma treatment is conducted using an inductively coupled plasma source. Behaviors of spinodal dewetting as well as hole nucleation and growth are observed when analyzing the average particle size with its initial film thickness and monitoring the morphological evolution of the dewetting film. A range of RF powers are evaluated to observe changes in particle size and size distribution. When increasing the RF power of the plasma treatment, the particle size and size distribution decreases, while the number of particles per area increases. With the help of the dewetting results on smooth substrates, an attempt is made to produce an array of Sn particles using a templated substrate to imitate the Sn solder bumps used in semiconductor packaging. [ABSTRACT FROM AUTHOR]

Single and binary two-dimensional (2D) films of Pb and Sn on Al(111) at room temperature were investigated using low-energy electron diffraction (LEED) and scanning tunneling microscopy. The 2D Pb and Sn films form a (√ 31 × √ 31)-Pb structure with close-packed six-fold symmetry and a (“2” × √ 3)-Sn structure with square-like fourfold symmetry, respectively. The 2D bimetallic Pb-Sn films only exhibit (√ 31 × √ 31)-Pb and/or (“2” × √ 3)-Sn LEED patterns in any compositional ratio of Pb to Sn. Sub-monolayer Sn deposition on the 2D Pb film reveals (“2” × √ 3)-Sn LEED pattern, indicating the preferential formation of the 2D Sn film. These results indicate that monolayer Pb and Sn films are immiscible on Al(111). [ABSTRACT FROM AUTHOR]

The fabrication of optically smooth thin Sn films by vacuum or electrodeposition techniques is usually challenging. Little has been published on how to address this challenge mainly because very few applications require such smooth Sn surfaces. The excitation of surface plasmon polaritons on Sn surfaces by prism-based methods represents a case that requires very smooth surfaces and has motivated this work. It is shown that the deposition rate and the substrate temperature of a vacuum evaporation method can be optimized to obtain very smooth Sn films and this is supported by direct imaging evidence from atomic force microscopy and scanning electron microscopy. [ABSTRACT FROM AUTHOR]

The role of NaF treatment in the production of SnS thin films and solar cells was investigated. The grain size of SnS films containing Na was large (about 500 nm) compared to that of SnS films prepared by conventional sulfurization (typically 250 nm). The carrier concentration of SnS increased from 5 × 10 16 to 2 × 10 17 cm − 3 by Na diffusion into the SnS film, and Na acted as an acceptor. Moreover, the NaF layer exhibited a capping effect during high-temperature sulfurization at 500 °C and suppressed the re-evaporation of SnS. The short-current density tended to increase from 1.1 to 8.8 mA/cm 2 with increasing thickness of the deposited NaF layer from 0 to 200 nm, because of the larger grain size and carrier concentration of SnS. [ABSTRACT FROM AUTHOR]

The epitaxial growth of a Ge 1 − x Sn x layer was examined using metal-organic chemical vapor deposition (MOCVD) with two types of Ge precursors; tetra-ethyl-germane (TEGe) and tertiary-butyl-germane (TBGe); and the Sn precursor tri-butyl-vinyl-tin (TBVSn). Though the growth of a Ge 1 − x Sn x layer on a Ge(001) substrate by MOCVD has been reported, a high-Sn-content Ge 1 − x Sn x layer and the exploration of MO material combinations for Ge 1 − x Sn x growth have not been reported. Therefore, the epitaxial growth of a Ge 1 − x Sn x layer on Ge(001) and Si(001) substrates was examined using these precursors. The Ge 1 − x Sn x layers were pseudomorphically grown on a Ge(001) substrate, while the Ge 1 − x Sn x layer with a high degree of strain relaxation was obtained on a Si(001) substrate. Additionally, it was found that the two Ge precursors have different growth temperature ranges, where the TBGe could realize a higher growth rate at a lower growth temperature than the TEGe. The Ge 1 − x Sn x layers grown using a combination of TBGe and TBVSn exhibited a higher crystalline quality and a smoother surface compared with the Ge 1 − x Sn x layer prepared by low-temperature molecular beam epitaxy. In this study, a Ge 1 − x Sn x epitaxial layer with a Sn content as high as 5.1% on a Ge(001) substrate was achieved by MOCVD at 300 °C. [ABSTRACT FROM AUTHOR]

• Si 20 Te 80-x Sn x (1 ≤ x ≤ 5) bulk glasses and thin films are prepared. • Prepared thin film samples exhibited smooth memory type of switching behaviour. • The electrical switching fields and energy bandgap decreased with Sn dopant. • Raman peaks are ascribed to crystalline Te and the vibrational modes of Sn lattice. • Scanning electron microscopy studies reveal morphological changes in the switched region. In this work, the electrical switching, optical and structural properties of Sn doped Si-Te glasses and thin films are studied. The Si 20 Te 80-x Sn x (1 ≤ x ≤ 5) glasses and thin-film samples are prepared using melt quenching and flash evaporation techniques respectively. All prepared bulk and thin-film samples exhibited smooth memory type of switching behaviour. Thicknesses of the thin film samples are found to be in the range of 92-111 nm. The electrical switching fields and energy bandgap of Si 20 Te 80-x Sn x (1 ≤ x ≤ 5) thin films have decreased as the concentration of Sn dopant is increased. Micro-Raman investigation on as-quenched Si 20 Te 80-x Sn x glasses is performed to study the structural network and its progression with composition. The reported Raman peaks are attributed to crystalline Te and the vibrational modes of Sn lattice. Scanning Electron Microscopy studies on switched and unswitched regions of Si 20 Te 80-x Sn x (1 ≤ x ≤ 5) glasses reveal the formation of a crystalline channel that acts as a conduction path between the two electrodes in the switched region. [ABSTRACT FROM AUTHOR]

• Silicon nanowires (NWs) grown on various substrates via Vapor–Liquid–Solid method. • Best crystallized SiNWs obtained using tin catalyst on silicon germanium substrate. • Morphology and crystalline nature strongly depend on the junction substrate-catalyst. • Substrate surface energy affects growth by regulating catalyst repartition. The plasma-assisted Vapor-Liquid-Solid technique has been used to grow Silicon nanowires (SiNWs) on different substrates coated with 1 nm of tin and indium, to study the impact of the surface energy of the substrates on the morphology and structure of the NWs. The characteristics of the prepared Si NWs were analyzed by field emission scanning electron microscopy, X-ray diffraction (XRD) and Raman spectroscopy. The morphological characteristics differ in the density, diameter and length of the synthesized SiNWs. The mean diameters of these SiNWs range from 36 to 51 nm at the bottom and from 15 nm to 34 nm at the tip, while their average length varies from 0.2 μm up to 0.54 μm depending on the substrate and catalyst. The presence of strong peaks in all XRD patterns indicates that the as-grown SiNWs are highly crystalline. The XRD and Raman characteristics of the Sn and In catalyzed SiNWs formed on different substrates show that the crystalline grain size is influenced by the substrate nature and catalyst material, which can be related to the substrate surface energy. In particular shorter NWs with improved crystallinity (larger grain size) are obtained when using Sn as a catalyst on an amorphous silicon-germanium (a-SiGe) substrates, while the small grains were obtained on the same substrate when indium was used as a catalyst. [ABSTRACT FROM AUTHOR]

Aluminum matrix composites reinforced with carbon fibers (CF/Al-MMC) are promising materials for lightweight applications. So far the application has been hindered by a lack of wettability of carbon fibers by aluminum alloys and detrimental reactions like aluminum carbide (Al 4 C 3 ) formation. Protective coatings prepared by chemical vapor deposition (CVD) could be a suitable way to overcome these problems. In this work carbon fiber based 3D-textile preforms were coated with titanium nitride (TiN). Coating thickness, homogeneity, layer structure and composition were determined. Furthermore oxidation resistance and tensile strength of coated fibers were investigated. The wettability by molten aluminum combined with an interface analysis is examined on TiN-coated graphite substrates. Finally the quality of MMC parts prepared by gas pressure infiltration (GPI) method is evaluated. The CVD process was performed with a gas mixture of TiCl 4 , N 2 and H 2 . A homogeneous coating was achieved at moderate deposition temperatures in the range from 800° to 850 °C and by proper adjustment of further process parameters as TiCl 4 concentration and total pressure. A very thin TiN layer with a thickness between 30 nm and 35 nm improves the oxidation resistance and results in a moderate decrease of the tensile strength. TiN improves the wettability and acts as a protective coating. However because of the long infiltration time in the GPI process, interface reactions occur. SEM investigations of TiN coated 3D-textile preforms infiltrated with AlSi 9 Cu 3 alloy (226D) show a completely dense composite with a strong reduction of the Al 4 C 3 formation. TiN offers a good protective effect if the contact time with the melt is not too long. [ABSTRACT FROM AUTHOR]

Nonvolatile memory devices were fabricated utilizing Ga and Sn co-doped ZnO (GZTO) films formed by using a solution process method. X-ray diffraction patterns showed that the crystallinity of the annealed GZTO films was an amorphous phase. X-ray photoelectron spectroscopy spectra of the GZTO films depicted Zn O, Ga O, and Sn O bonds. Current–voltage measurements on the Al/GZTO/indium-tin-oxide (ITO) devices at 300 K showed bipolar resistive switching behaviors. The resistances at both the low resistance state (LRS) and high resistance state (HRS) measured at 0.5 V for the devices maintain almost constant without any damage and breakdown above 130 s, indicative of the memory stability of the devices. A difference in the resistance between the HRS and the LRS was more than 1 order of the magnitude. The conduction mechanisms of the HRS in the set process for the Al/GZTO/ITO devices were dominated by a space-charge-limited current model. [ABSTRACT FROM AUTHOR]

Transparent conductive zinc oxide co-doped with tin and aluminum (TAZO) thin films were prepared via sol–gel dip-coating process. Non-toxic ethanol was used in this study instead of 2-methoxyethanol used in conventional work. Dip-coating was repeated several times to obtain relatively thick films consisting of six layers. The films were then annealed at 500 °C for 1 h in air or in vacuum and not subsequently as employed in other studies. The X-ray diffraction patterns indicated that all the samples revealed a single phase of hexagonal ZnO polycrystalline structure with a main peak of (002). The optical band gap and resistivity of the TAZO films were in the ranges of 3.28 to 3.32 eV and 0.52 to 575.25 Ω cm, respectively. The 1.0 at.% Sn, 1.0 at.% Al co-doped ZnO thin film annealed in vacuum was found to have a better photoelectrochemical performance with photocurrent density of about 0.28 mA/cm 2 at a bias of 0.5 V vs. SCE under a 300 W Xe lamp illumination with the intensity of 100 mW/cm 2 . Compared to the same dopant concentration but annealed in air (~ 0.05 mA/cm 2 bias 0.5 V vs. SCE), the photocurrent density of the film annealed in vacuum was 5 times higher than the film annealed in air. Through electrochemical measurements, we found that the dopant concentration of Sn plays an important role in TAZO that affected photocurrent density, stability of water splitting and anti-corrosion. [ABSTRACT FROM AUTHOR]

A wafer-curvature method has been developed to subject thin films, deposited on (Si) substrates, to well defined and controllable loads in a contact-free manner. To this end, a custom-made glass pan (i.e. a roof-less cylinder with a connection piece for vacuum tubes) connected to a needle valve, a vacuum pump and a pressure gauge has been used as an experimental setup. By fixing the coated Si wafer on top of the glass cylinder and evacuating the glass cylinder to a defined low-pressure, a state of stress is imposed in the thin film due to bending of the wafer. It has been shown that the (initial) stress state of a film and its change, due to its bending with the help of the wafer-curvature method, can be analyzed accurately close to the wafer center by application of one of two independent X-ray diffraction techniques: i) conventional X-ray diffraction stress analysis (i.e. application of the well known sin 2 ψ -method) to reflections originating from the film and ii) determination of the radii of curvature by rocking curve measurements utilizing reflections originating from the substrate . The validation of this stress-imposition method has been carried out with a tungsten film of 500 nm thickness, since tungsten is known to be (practically) intrinsically elastically isotropic. Further, the method has been applied to an electro-deposited, potentially whiskering, aging Sn film of 3 μm thickness where a combination of both stress-measurement techniques is essential for the determination of initial and (by wafer bending) imposed stresses. The results of the aging experiment of the Sn film under load have been discussed with respect to the current whisker-growth model. [ABSTRACT FROM AUTHOR]

Abstract: Ultrafine Sn nanoparticles (NPs) (diameter<10nm) exhibiting a remarkable depression in their melting point were synthesized at room temperature by a modified polyol process. For the synthesis, low-grade Sn(II) 2-ethylhexanoate and sodium borohydride were used as the precursor and reducing agent in a diethylene glycol medium. Further, polyvinyl pyrrolidone was used as a capping agent during the synthesis. The synthesized crystalline Sn NPs showed an average diameter of 7.98nm and an extremely low melting point of 128°C. To test the applicability of the synthesized ultrafine Sn NPs to practical systems, an Ag-based composite ink containing the Sn NPs was prepared. The ink was easily sintered through local liquid-phase sintering by melting of the ultrafine Sn NPs added as a metal binder. Therefore, despite the low-temperature (170°C) sintering with a short duration (~15min), the composite ink exhibited excellent sheet resistance. [Copyright &y& Elsevier]

Abstract: We report on the effects of Ar ion beam treatment on the electrical, optical, and mechanical properties of flexible Sn-doped In2O3 (ITO) films grown on colorless polyimide (CPI) by roll-to-roll (R2R) sputtering. Effective Ar ion beam treatment on ITO films led to the reduction of sheet resistance without degradation of optical transmittance of ITO films even though they were prepared at room temperature. In addition, Ar ion beam treatment resulted in crystallization of the R2R-sputtered ITO films without intentional substrate heating. At optimized conditions, the Ar ion beam treated ITO film showed a sheet resistance of 54.6Ω/square and an optical transmittance of 80.1%. A flexible organic solar cell (FOSC) fabricated with the Ar ion beam treated ITO film exhibited a power conversion efficiency (PCE) of 3.137%, which was higher than that of a FOSC made with untreated ITO film. This indicates that the in-situ Ar ion treatment is a promising method for fabrication of crystalline ITO films on flexible substrates without intentional substrate heating in a R2R sputtering process. [Copyright &y& Elsevier]

Abstract: We investigated the position of Sn atoms in Ge1−xSnx film grown at a low temperature by using the Extended X-ray Absorption Fine Structure (EXAFS) method. Vacancies had been expected to be introduced near the growing surface vicinity of a Sn atom and located at a split-vacancy position due to the binding nature between a Sn atom and a vacancy, which was predicted by the calculation for a bulk model in the literature. However, the EXAFS showed that almost all Sn atoms were located at the substitutional position and did not form a split-vacancy. [Copyright &y& Elsevier]

Abstract: In this study, we have examined the formation of uniaxially strained Ge microstructures with embedded Ge1− x Sn x epitaxial layers and the microscopic local strain structure in Ge and Ge1− x Sn x using synchrotron X-ray microdiffraction and the finite element method. We achieved local heteroepitaxial growth of Ge0.947Sn0.053 layers on the Ge recess regions. Microdiffraction measurements reveal that an average uniaxial compressive strain of 0.19% is induced in Ge locally with Ge1− x Sn x stressors. In addition, we found that the Sn precipitation near the Ge1− x Sn x /Ge(001) interface occurs after post-deposition annealing at 500°C without the introduction of dislocation. It is considered that the local Sn precipitation occurs preferentially due to the larger residual stresses near the Ge1− x Sn x /Ge interface. [Copyright &y& Elsevier]

Abstract: We have investigated the substrate orientation dependence of the crystallinity and strain relaxation behavior of Ge and Ge1− x Sn x layers epitaxially grown on Ge(001), (110), and (111) substrates. The strain relaxation in Ge1− x Sn x layers on Ge(110) and (111) occurs from a strain value smaller than that on Ge(001). We obtained the critical strain energy of a Ge1− x Sn x layer regardless of Ge substrate orientation. As a result, we achieved the epitaxial growth of pseudomorphic Ge1− x Sn x layers with high substitutional Sn contents of 8.5% and 6.7% on Ge(110) and (111) substrates, respectively. [Copyright &y& Elsevier]

The search for materials with thermoelectric parameters capable of operating at high temperatures continues to be of great interest; n-type metal oxides are promising candidates. Here, two series of thin (~100nm) indium oxide films doped by tin (from 0 to 50at.%) were deposited by spray pyrolysis at 350°C and 450°C. Characterization of the films was performed using X-ray diffraction, scanning electron microscopy and atomic force microscopy. Thermoelectric properties, i.e., the conductivity and the Seebeck coefficient, were then studied over a temperature range of 20–450°C. It was shown that these parameters as well as their nanostructure were strongly dependent on the Sn content and deposition temperature. Specifically, the conductivity had maxima near 5% and 20% for films deposited at 350°C and 450°C, respectively. The power factor (PF) as a function of Sn content also demonstrated non-monotonous behavior with two maxima; for films deposited at 350°C these maxima were again observed near 5% and 20% of Sn content. The maximal PF value equaled to 4.7mW/(m·K2) at a temperature of 450°C was observed at 5at.% Sn. This result is one of the best ever obtained for metal oxides in a given temperature range. The optimal films were characterized by a cubic-like crystallite nanostructure with {400} surface faceting. A model explaining such high parameters was subsequently proposed. We also determined the effect of ambient humidity on the thermoelectric properties of nanostructured In2O3:Sn films at an operating temperature range below 400°C, which is caused by the change of surface conductivity under the influence of water vapor. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes an investigation of low-temperature diffusion in thin films of Sn/Cu, Cu/Mn and Sn/Cu/Mn. The combination of Rutherford backscattering spectroscopy, grazing incidence X-ray diffraction and Auger electron spectroscopy has been used to provide information about the concentration distribution of components and the depth of the various phases and interfaces. The results show that processes that occur on a free surface of thin films can stimulate diffusion of elements in the bulk. It is shown that the element with higher affinity to oxygen tends to move to the surface in order to oxidize and that this oxidation process provides a driving force for further diffusion. Introduction of a third layer to a bilayer system may lead to changes in the surface topography caused by the reactive diffusion between upper layers and it causes the development of fast, ‘short-circuit’ diffusion paths and so increases the diffusion of elements from the bottom to the top. Reactive diffusion between Sn and Cu in the top layers leads to significant changes at the surface with features of the size of 10 to 20nm appearing. These changes provide shortcuts for the diffusion of Mn atoms from the bottom layer to the free surface. As a consequence of these processes, the sequence of layers of different elements in thin-film structures alters diffusion and results in different sample properties. [Copyright &y& Elsevier]

Solution-processed thin film transistors (TFTs) using a magnesium zinc tin oxide (MZTO, Ma–Zn–Sn–O) channel layer were fabricated and bias-stress stability during device operation was evaluated. The cause of the bias-stress instability was investigated through comparison with zinc tin oxide (ZTO, Zn–Sn–O) TFTs. The MZTO layers had a significantly lower oxygen vacancy concentration than the ZTO layer, which affected the electrical characteristics as well as bias-stress stability of MZTO TFTs. When 2mol% Mg was added, a more stable transistor was attained, showing a typical semiconductor behavior with a saturation mobility of 0.27cm2/V·s, on/off ratio of 3.3×106, off-current of 5.3×10−12A, and threshold voltage of 5.4V. [ABSTRACT FROM AUTHOR]