Sn Films Research Articles

Comments on: “Low temperature engineering feasibility of high reflective Ag–Sn films from experimental and thermodynamic views” [Mater. Phys. Chem. 254 (2020) 123490]

In this communication, some aspects of a paper published recently by Gao et al. Mater. Phys. Chem. 254 (2020) 123490 (here Gao et al. (2020) [4] are discussed. In this paper, some erroneous interpretation and citation of previously published work and false considerations concerning the phase formation in Ag–Sn thin layers are outlined.

Regulating Sn Metal Growth Towards Highly Reversible Anode in Aqueous Acidic Batteries

Safe and cost-effective aqueous acidic batteries (AABs) offer substantial promise for renewable energy storage, as it have the potential to achieve greater energy and power density by utilizing non-metal hydrate protons as charge carriers.1 However, most of traditional aqueous anode electrodes (Zn, Fe, etc.) have incompatibility with AABs due to the instability in acid, resulting in the quite limited choice of anode materials in acidic environment.In prior research, we successfully demonstrated that Sn metal can serve as a highly suitable anode material for AABs.2 This is attributed to its comparatively high overpotential for the hydrogen evolution reaction (HER), substantial theoretical capacity (451.6 mAh g−1), and negative redox potential (−0.14 V vs. SHE).3 The critical issue is that Sn tends to form polyhedral particles during the electro-deposition due to the small difference in surface energy between different planes.4 Along with the increase of capacity, the polyhedron Sn particles may become detach and fragment, ultimately leading to the formation of inactive, or dead Sn, which significantly impacts the cycling stability of Sn anode and even cause severe HER.We will present our efforts of developing reversible Sn anode for AABs by regulating Sn metal growth. Our first work applies interfacial alloying regulation to achieve smaller grain size and more uniform Sn deposition by higher propensity for nucleation and Sn migration energy barrier, thus increased the anode reversibility. The following work successfully selected a HER-inert crystal plane and achieved its preferential growth used cationic surfactants electrolyte additive. A dense and compact Sn film is obtained by adjusting the adsorbed species on the Sn surface, and no dead Sn was observed after cycling. Based on these regulated Sn metal anodes, we demonstrated several Sn-based AABs (MnO2//Sn, PbO2//Sn, etc.), with promising performance on output voltages, specific energy densities, kinetics, and lifespans. References X. Wu, J. J. Hong, W. Shin, L. Ma, T. Liu, X. Bi, Y. Yuan, Y. Qi, T. W. Surta, W. Huang, J. Neuefeind, T. Wu, P. A. Greaney, J. Lu, X. Ji. Nat. Energy 2019, 4, 123-130.H. Zhang, D. Xu, F. Yang, J. Xie, Q. Liu, D. Liu, M. Zhang, X. Lu, Y. S. Meng. Joule 2023, 7, 971-985.W. Zhou, S. Ding, D. Zhao, D. Chao. Joule 2023, 7, 1099-1110.Y. Yao, Z. Wang, Z. Li, and Y. Lu. Adv. Mater. 2021, 33, 2008095.

Laser transmission welding of Polyphenylsulfone resin using Sn film absorbent: Weld formation control and mechanical properties enhancement

Polyphenylsulfone resin (PPSU), holding significance across various domains, was successfully welded by the laser transmission welding (LTW). In order to optimize the morphology and mechanical properties of the weld seam, the Sn film was chosen as an intermediate layer and the mechanism governing the formation control and mechanical performance was unveiled. Without the addition of Sn film, weld formation was subpar, marked by defects such as bubbles occurring in the weld seam, particularly under moderate power conditions. After introducing Sn film as a metal absorbent, the molten pool pores were stabilized and the temperature distribution was optimized during LTW process, which promoted the welding process stability and facilitated the mixing and agitation of the molten pool. The Energy-dispersive X-ray Spectroscopy (EDS) and X-ray Photoelectron Spectroscopy (XPS) were conducted on cross-sections of the weld seam. Analysis revealed the formation of newly forged metallic bonds (SnC) between the metal and the PPSU, which were instrumental in bolstering the shear strength of the weld seam. After using the Sn as intermediate layer, the shear strength of welding joints increased from 23.21 MPa to 29.14 MPa. At optimal intermediate-layer thickness, the shear fracture exhibited predominantly a plastic tearing micro-pit morphology instead of brittle fracture rock pattern.

High quality heavy Sn doping β‑Ga2O3 film with high mobility grown by time division transport Metal Organic Chemical Vapor Deposition

High-quality heavily Sn doped homoepitaxial β-Ga2O3 films with high mobility were deposited on (100) Ga2O3 substrates using long-distance time division transport method by Metal Organic Chemical Vapor Deposition. The structure, composition, Raman, and electrical properties of the films with different Sn source flow rates were investigated in detail. The room temperature carrier mobility of 139.89 cm2/(V·s) is attained at a RT donor concentration of 2.78×1019 cm-3, with a peak mobility of 444.9 cm2/(V·s) at 114 K. This RT mobility is currently the highest at the same doping concentration level. Furthermore, combined with the analysis of the first-principles calculation results, it is revealed that time dependent transport technology is beneficial to modulating the substitution mode of Sn replacing GaII more often. The conclusions of this study are significant to broaden the potential application of ultrawide bandgap gallium oxide in high-power microwave and power electronics devices.

Tin Gallium Oxide Epilayers on Different Substrates: Optical and Compositional Analysis

Electron beam techniques have been used to analyze the impact of substrate choice and growth parameters on the compositional and optical properties of tin gallium oxide [(SnxGa1−x)2O3] thin films grown by plasma‐assisted molecular beam epitaxy. Sn incorporation and film quality are found to be highly dependent on growth temperature and substrate material (silicon, sapphire, and bulk Ga2O3) with alloy concentrations varying up to an x value of 0.11. Room temperature cathodoluminescence spectra show the Sn alloying suppressing UV (3.3–3.0 eV), enhancing blue (2.8–2.4 eV), and generating green (2.4–2.0 eV) emission, indicative of the introduction of a high density of gallium vacancies (VGa) and subsequent VGa–Sn complexes. This behavior was further analyzed by mapping composition and luminescence across a cross section. Compared to Ga2O3, the spectral bands show a clear redshift due to bandgap reduction, confirmed by optical transmission measurements. The results show promise that the bandgap of gallium oxide can successfully be reduced through Sn alloying and used for bandgap engineering within UV optoelectronic devices.

Sputtering deposition of dense and low-resistive amorphous In2O3: Sn films under ZONE-T conditions of Thornton's structural diagram

We have fabricated smooth-surfaced amorphous In2O3:Sn (a-ITO) films at a high temperature of 550 °C, far above the typical crystallization threshold of 150 °C for ITO films. This achievement has been made possible by intentionally introducing N2 into the sputtering atmosphere, which maintains a low N atom incorporation of only a few atomic percent within the films. Positioned within ZONE-T of the Thornton diagram (higher-temperature region characterized by high film density), our method allows the preparation of films with superior film density about 6.96 g/cm3, substantially exceeding the density of 6.58 g/cm3 for conventional a-ITO films fabricated under ZONE-1 (low-temperature region) and approaching the bulk crystal density of In2O3 at 7.12 g/cm3. The films also feature a high carrier density of 5 × 1020 cm−3 and a remarkably low resistivity of 3.5 × 10−4 Ω cm, comparable to those of polycrystalline films. The analysis via vacuum-ultraviolet absorption spectroscopy on N and O atom densities in the plasma suggests that amorphization is primarily caused not by N atoms incorporated in the films but by those temporally adsorbed on the film surface, inhibiting crystal nucleation before eventually desorbing. Our findings will pave the way not only for broader applications of a-ITO films but also for the design of other amorphous materials at temperatures beyond their crystallization points.

A combined theoretical and experimental study on vertically aligned ZnO and ZnO: Sn

Vertically aligned ZnO and Sn (5, 10 v/v%) doped ZnO microrods were produced using chemical bath deposition technique on ZnO seed layers fabricated on glass substrates by spin coating method. The thickness of the seed layer is 365 nm and the length of the ZnO and ZnO:Sn rods are in the range of 1–5 μm. The length of the rods decreases with increasing Sn concentration. The structural, morphological, elemental compound, electrical and optical properties of ZnO and ZnO:Sn films were investigated using x-ray powder diffraction, field emission scanning electron microscopy, energy-dispersive x-ray spectroscopy, two probe method and UV–Vis absorption spectroscopy, respectively. The electronic structure of ZnO and Sn doped ZnO is calculated depending Density Functional Theory thanks to the WIEN2k program. Based on experimental and theoretical calculations, the band gap energy decreases with increasing Sn concentration. The band gap energy of seed layer, pure ZnO, Sn (5%) and Sn (10%) doped ZnO films was estimated as 3.27 eV, 3.18 eV, 3.14 eV and 3.12 eV, respectively. The band gap energy of Sn (1 atom) and Sn (2 atom) doped ZnO calculated theoretically was found as 0.392 eV and 0.245 eV, respectively. The Fermi Energy shifting towards the conduction band was observed upon Sn doping. Sn (5%) doped ZnO film shows the highest electrical conductivity although its band gap energy is higher than that of Sn (10%). The highest conductivity is attributed to the lowest dislocation density and less oxygen vacancies in the structure.

Influence of Laser Energy on the Structural and Optical Properties of Sn Nanoparticles produced with Laser-Induced Plasma

This study aimed to investigate the structure and optical properties of Sn nanostructures. Thin tin (Sn) films were deposited on glass substrates using the pulsed laser deposition method. Nd:YAG laser with fundamental wavelengths of 532 nm and 1064 nm was used to create Sn nanostructures with varying energies of 400 mJ to 700 mJ and the same frequency of 6 Hz. The tin powder was compressed into a disc with a one-centimetre diameter to serve as a sample. The X-ray diffraction (XRD) pattern showed a crystalline structure with several Sn nanostructures peaks at various energies (400–700 mJ). The results revealed a crystalline size of 65.90 nm and 86.55 nm at 700 mJ, while the size was 40.19 nm and 17.19 at 400 mJ for the given wavelengths (532nm and 1064 nm), respectively. The appearance of Sn nanostructures and the aggregation of, particularly in the form of cauliflower, were revealed in Field emission scanning electron microscopy (FE-SEM) images. The results of the dispersive energy X-ray spectroscopy (EDS) analysis showed that various amounts of tin, carbon, and oxygen were present. Additionally, the optical characteristics were investigated of each film using absorbance spectra, which covered a range of wavelengths from 190 to 1100 nm. As the laser power increased, the band gap energy values in the optical properties decreased, falling into the ranges of 3.06 to 1.65 eV and 3.22 to 1.82 eV at 1064nm and 532nm, respectively.

The role of coalescence and ballistic growth on in-situ electrical conduction of cluster-assembled nanostructured Sn films

The electrical conduction of nanostructured Sn films assembled via Supersonic Cluster Beam Deposition is studied in-situ during film growth. The kinetic energy of Sn nanoparticles, in combination with low melting point of Sn, promotes coalescence phenomena, enabling the investigation of their impact on film morphology and on percolation threshold. A percolation threshold occurring at thicknesses much larger than the dimensions of Sn nanoparticles suggests that coalescence leads to the growth of disconnected, island-like structures. The deposition rate is found to influence coalescence dynamics during the early stages of film growth, allowing for the tuning of film microstructure from a more compact, island-like morphology to a more porous structure. The percolation threshold shifts accordingly from 24 nm to 3 nm film thickness. Upon completion of the percolation phase, film resistivity settles at values 2–3 orders of magnitude larger than that of bulk Sn, attributed to the nanogranular nature of cluster-assembled films. During the “3D conduction” phase, resistivity exhibits an increasing trend with thickness following a power law with an exponent value of 0.76–0.78. This behavior is attributed to the decrease in the density of interconnections between particles in the topmost layer during film growth, consistent with expectations in ballistic growth processes.

Epitaxial twin coupled microstructure in GeSn films prepared by remote plasma enhanced chemical vapor deposition

Growth of GeSn films directly on Si substrates is desirable for integrated photonics applications since the absence of an intervening buffer layer simplifies device fabrication. Here, we analyze the microstructure of two GeSn films grown directly on (001) Si by remote plasma-enhanced chemical vapor deposition (RPECVD): a 1000 nm thick film containing 3% Sn and a 600 nm thick, 10% Sn film. Both samples consist of an epitaxial layer with nano twins below a composite layer containing nanocrystalline and amorphous. The epilayer has uniform composition, while the nanocrystalline material has higher levels of Sn than the surrounding amorphous matrix. These two layers are separated by an interface with a distinct, hilly morphology. The transition between the two layers is facilitated by formation of densely populated (111)-coupled nano twins. The 10% Sn sample exhibits a significantly thinner epilayer than the one with 3% Sn. The in-plane lattice mismatch between GeSn and Si induces a quasi-periodic misfit dislocation network along the interface. Film growth initiates at the interface through formation of an atomic-scale interlayer with reduced Sn content, followed by the higher Sn content epitaxial layer. A corrugated surface containing a high density of twins with elevated levels of Sn at the peaks begins forming at a critical thickness. Subsequent epitaxial breakdown at the peaks produces a composite containing high levels of Sn nanocrystalline embedded in lower level of Sn amorphous. The observed microstructure and film evolution provide valuable insight into the growth mechanism that can be used to tune the RPECVD process for improved film quality.

Selective separation of Y and Nd with similar electrochemical properties by pulsed electrolysis on Sn electrode

Selective separation of Y and Nd from LiCl-KCl melt was systematically investigated on W and Sn electrodes by various electrochemical methods. The electrochemical properties of Y and Nd on W and Sn film electrodes were firstly analyzed and compared by cycle voltammetry (CV), square wave voltammetry (SWV), reverse chronopotentiometry (RCP), etc. The results indicate that the deposition potentials of Y and Nd on W electrode are very close, while the deposition potential difference could reach 0.15 V on Sn film electrode. The selective separation of Y and Nd was conducted by potentiostatic electrolysis (PE) on W electrode assisted by Sn(II), and the product is composed of Sn and NdSn3 phases. In addition, the electrochemical properties and kinetic parameter of Y and Nd on liquid Sn electrode were also studied. The results prove that Nd has a more positive deposition potential, larger exchange current density and smaller reaction activation energy than Y, illustrating that Nd is more easily extracted on liquid Sn electrode. Thus, PE and potentiostatic electrolysis + pulse potential electrolysis (PE + PPE) were used to separate Y and Nd on liquid Sn electrode. The results show that the application of PPE effectively reduced the extraction efficiency of Y from 16.75 ± 1.50 % to 8.36 ± 1.13 %, and increased the separation factor β from 4.98 ± 0.46 to 9.64 ± 0.58.

Intermediate tin oxide in stable core-shell structures by room temperature oxidation of cluster-assembled nanostructured Sn films

Room temperature oxidation of cluster-assembled nanostructured Sn films obtained by supersonic cluster beam deposition was investigated. Sn clusters smaller than about 10 nm are observed to be fully oxidized while in larger ones, as well as in Sn islands formed by clusters coalescence, completion of Cabrera-Mott process is prevented resulting in partial oxidation. Core-shell structures are therefore obtained, with shell thickness of about 4 nm. Core is composed by highly ordered, tetragonal β-tin, with micro-strain of 0.16 %, while shell is composed of tin oxides, where similar quantity of both Sn oxidation states Sn2+ and Sn4+ are observed, according to XPS. The presence in the samples of metallic tin, SnO, and SnO2 is confirmed by valence band photoelectron spectrum, whose components show edges at 0, 0.6, and 3.2 eV from Fermi level, respectively. Raman spectroscopy highlights the presence of Sn3O4 (short version of Sn2+2O2Sn4+O2), which confirms the spontaneous formation of this intermediate oxide. It is therefore proposed that an oxidation gradient Sn-SnO-Sn3O4-SnO2 characterizes core-shell system resulting from room temperature Cabrera-Mott oxidation of cluster-assembled nanostructured films.

Investigation of Sn-doped WO3 thin films: One-step deposition by hydrothermal technique, characterization, and photoluminescence study

Thin film technology is significant in technological progress and modern research because it allows for the production of optoelectronic devices with improved characteristics. Because of its superior chromatic efficiency, tungsten oxide (WO3) is one of the best candidates for energy-saving applications. In this study, undoped and tin (Sn)-doped WO3 films were grown on top of WO3 seed layers directly by a facile hydrothermal route at a temperature as low as 110∘C for 24[Formula: see text]h. The seed layers were also deposited on top of glass substrates using spray pyrolysis. The results of tin doping on the structural, optical, and morphological characteristics of the WO3:Sn films were studied. X-ray diffraction patterns show that peak intensities increase significantly by adding Sn and the films’ crystallinity was improved by rising Sn content. In the visible region, the average optical transmittance is around 13% and the optical bandgap changes from 2.61[Formula: see text]eV to 2.81[Formula: see text]eV, by increasing the dopant amount. Finally, the room temperature photoluminescence of samples shows intense green light emissions. The results of this research can be beneficial for the fabrication and performance optimization of electrical and optical devices such as gas sensors, electrochromic devices, and photosensors.

Fabrication and characterization of thin [formula omitted]Sn films for heavy-ion nuclear reaction measurements

The fabrication of thin isotopically enriched 120,124Sn targets have been presented. The thin film targets prepared have been used in nuclear physics experiments to apprehend the heavy-ion fusion and multi-nucleon transfer reaction dynamics around the Coulomb barrier. Vacuum evaporation viz. resistive heating technique has been used for the fabrication of the targets with varying areal densities in the range of 50–250 μg/cm2 backed with a carbon layer of ≈20μg/cm2 using a nominal amount of 30 mg isotopically enriched material. The fabricated targets have been characterized using multiple advanced techniques viz. Energy Dispersive X-ray Spectroscopy (EDS), Scanning Electron Microscopy (SEM), and X-ray Diffractometry (XRD). The thickness of the targets has been measured using Rutherford Back-scattering Spectrometry (RBS). The isotopic contamination levels have been ascertained with an in-beam experiment using Heavy Ion Reaction Analyzer at IUAC, New Delhi.

Thermal annealing of DC sputtered Nb3Sn and V3Si thin films for superconducting radio-frequency cavities

Nb 3 Sn and V3Si thin films are promising candidates for the next generation of superconducting radio-frequency (SRF) cavities. However, sputtered films often suffer from stoichiometry and strain issues. This exploratory study investigates the structural and chemical effects of thermal annealing, both in−situ and post-sputtering, on DC-sputtered Nb3Sn and V3Si films with varying thicknesses, deposited on Nb or Cu substrates. Building upon our initial studies [Howard et al., Proceedings of the SRF’21, East Lansing, MI (JACoW, 2021), p. 82.], we provide fundamental insights into recrystallization, phase changes, and the issues of stoichiometry and strain. Through annealing at 950 °C, we have successfully enabled the recrystallization of 100 nm thin Nb3Sn films on Nb substrates, yielding stoichiometric and strain-free grains. For 2 μm thick films, elevated annealing temperatures led to the removal of internal strain and a slight increase in grain size. Moreover, annealing enabled a phase transformation from an unstable to a stable structure in V3Si films, while we observed significant Sn loss in 2 μm thick Nb3Sn films after high-temperature annealing. Similarly, annealing films atop Cu substrates resulted in notable Sn and Si loss due to the generation of Cu–Sn and Cu–Si phases, followed by evaporation. These results encourage us to refine our process to obtain high-quality sputtered films for SRF use.

Synthesis of Nanocrystalline CdS:Sn Film and Study on Its Optical, Structural, and Electrical Characteristics

Synthesis of Nanocrystalline CdS:Sn Film and Study on Its Optical, Structural, and Electrical Characteristics

Role of a capping layer on the crystalline structure of Sn thin films grown at cryogenic temperatures on InSb substrates

Metal deposition with cryogenic cooling is a common technique in the condensed matter community for producing ultra-thin epitaxial superconducting layers on semiconductors. However, a significant challenge arises when these films return to room temperature, as they tend to undergo dewetting. This issue can be mitigated by capping the films with an amorphous layer. In this study, we investigate the influence of different in situ fabricated caps on the structural characteristics of Sn thin films deposited at 80 K on InSb substrates. Regardless of the type of capping, we consistently observe that the films remain smooth upon returning to room temperature and exhibit epitaxy on InSb in the cubic Sn (α-Sn) phase. Notably, we identify a correlation between alumina capping using an electron beam evaporator and an increased presence of tetragonal Sn (β-Sn) grains. This suggests that heating from the alumina source may induce a partial phase transition in the Sn layer. The existence of the β-Sn phase induces superconducting behavior of the films by percolation effect. This study highlights the potential for tailoring the structural properties of cryogenic Sn thin films through in situ capping. This development opens avenues for precise control in the production of superconducting Sn films, facilitating their integration into quantum computing platforms.

Room-temperature gas sensing properties of Zn, Sn and Cu-doped TiO2 films

Room-temperature gas sensing properties of Zn, Sn and Cu-doped TiO2 films

Prediction by a hybrid machine learning model for high-mobility amorphous In2O3: Sn films fabricated by RF plasma sputtering deposition using a nitrogen-mediated amorphization method

In this study, we developed a hybrid machine learning technique by combining appropriate classification and regression models to address challenges in producing high-mobility amorphous In2O3:Sn (a-ITO) films, which were fabricated by radio-frequency magnetron sputtering with a nitrogen-mediated amorphization method. To overcome this challenge, this hybrid model that was consisted of a support vector machine as a classification model and a gradient boosting regression tree as a regression model predicted the boundary conditions of crystallinity and experimental conditions with high mobility for a-ITO films. Based on this model, we were able to identify the boundary conditions between amorphous and crystalline crystallinity and thin film deposition conditions that resulted in a-ITO films with 27% higher mobility near the boundary than previous research results. Thus, this prediction model identified key parameters and optimal sputtering conditions necessary for producing high-mobility a-ITO films. The identification of such boundary conditions through machine learning is crucial in the exploration of thin film properties and enables the development of high-throughput experimental designs.

Imidazolium ionic liquids as neat lubricant for electroplating Sn on Cu substrate under sliding electrical contact at high temperatures up to 80 °C

Three kinds of imidazolium ionic liquids (IILs) with different fluorine-containing anions, i.e. imidazolium tetrafluoroborate (LB108), imidazolium hexafluorophosphate (LP108), imidazolium methyltributylammomiumbis ((trifluoromethyl)sulfonyl)imide ([HEMIM]NTf2), are selected as neat lubricant for electroplating Sn on Cu substrate under sliding electrical contact at room temperature (25 °C) and elevated temperatures (40 °C and 80 °C). All the IILs effectively reduce friction coefficient (0.28 for LB108 and LP108, 0.4 for [HEMIM]NTf2) and prevent Sn film from rapidly worn out and severe adhesive wear at 25 °C. However, at high temperatures, only LB108 well lubricate Sn-on-Sn contact up to 80 °C. It is found that, at 80 °C, the microstructure and chemical composition of the worn surface and the subsurface of the electroplating Sn are markedly modified due to two aspects: (1) temperature related phenomena (i.e. thermal diffusion of Cu to Sn film and even to SnO2 layer, as well as formation of intermetallic phase Cu6Sn5) and (2) interaction of the worn surface and IILs (i.e. adsorption, tribochemical interaction of the worn surface and the anion species, and diffusion of N species in Sn film). The interaction of the worn surface and the anion species of IILs plays an important role in wear reduction of electroplating Sn at 80 °C.