Glass Thin Films Research Articles

Electrochemical Characterization of a Drawn Thin-Film Mixed Oxy-Sulfide Glassy Electrolyte Material for Solid-State Battery Applications

Solid-state batteries are a promising avenue for next-generation lithium-ion batteries due to their enabling of the lithium metal anode, while simultaneously removing the flammable organic electrolyte. Glassy materials are particularly interesting as solid-state electrolytes due to their intrinsic lack of grain boundaries, their low temperature forming capabilities, and their highly tunable chemistries. Much work has been done to study the electrochemical properties of glasses in the Li2S – SiS2 – LixMOy phase space, and several compositions have shown high ionic conductivities (~ 10-3 S/cm), large electrochemical stability windows (0-5 V vs. Li/Li+), and good glass forming ability. These glasses, however, have not been well studied at thicknesses that are viable for commercialization of solid electrolytes (< 100 μm). Utilizing a glass working method known as the redraw process, a rectangular preform of glass can be reheated and drawn from ~ 5 mm in thickness to thin films of less than 100 μm. The electrochemical behavior of thin-film glasses in the Li2S – SiS2 – LiPO3 phase space created through the glass redraw process are studied utilizing electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic symmetric cell cycling. These results show that thin-film glassy solid electrolytes made through the glass redraw method are a viable new research direction for generation of highly conducting thin-film solid-state electrolytes.

Large Area, High Resolution Mapping of Approximate Rotational Symmetries in a Pd77.5Cu6Si16.5 Metallic Glass Thin Film

Densely spaced four-dimensional scanning transmission electron microscopy (4D STEM) analyzed using correlation symmetry coefficients enables large area mapping of approximate rotational symmetries in amorphous materials. Here, we report the effects of Poisson noise, limited electron counts, probe coherence, reciprocal space sampling, and the probe-sample interaction volume on 4D STEM symmetry mapping experiments. These results lead to an experiment parameter envelope for high quality, high confidence 4D STEM symmetry mapping. We also establish a direct link between the symmetry coefficients and approximate rotational symmetries of nearest-neighbor atomic clusters using electron diffraction simulations from atomic models of a metallic glass. Experiments on a Pd77.5Cu6Si16.5 metallic glass thin film demonstrate the ability to image the types, sizes, volume fractions, and spatial correlations amongst local rotationally symmetry regions in the glass.

Silver deposition on titanium oxide thin glass films for efficient visible light-induced photocatalytic removal of diphenhydramine and venlafaxine

Silver deposition on titanium oxide thin glass films for efficient visible light-induced photocatalytic removal of diphenhydramine and venlafaxine

Effect of structural heterogeneity on work-hardening behavior of metallic glass thin film

In this study, three kinds of atomic disordered Cu50Zr50 metallic glass thin films (MGTFs) with different structural heterogeneities are prepared by controlling the substrate temperature in magnetron sputtering, i.e., controlling the thermal history. A work-hardening behavior is observed in the MGTFs by cyclic nanoindentation. The spatial distribution of structural heterogeneities, and the correlation length of the viscoelasticity of heterogeneity in three MGTFs with different thermal histories demonstrate the effect of thermal history on the viscoelasticity of three MGTFs. The activation volume of heterogeneity controlling the initiation of shear band during local deformation correlates the correlation length of viscoelastic heterogeneity, which is used to elucidate the relationship between the structural heterogeneity and the work-hardening behavior. The results show that the increase of the substrate temperature causes the viscosity of structural heterogeneity to be increased, which means the reduction of viscoelastic heterogeneity correlation length. In this case, the activation volume of heterogeneity in the MGTF is decreased, which leads the formation of shear band to be difficult.

The manufacture and study of the microstructure, mechanical properties, and corrosion behavior of Fe31Cr15Mo14C10B10Si5Ti15 metallic glass thin film, prepared by the magnetic sputtering method

Fe31Cr15Mo14C10B10Si5Ti15, as an iron-based TFMG, was provided on a substrate made of 304 SUS and a Si wafer by the magnetic sputtering method at a sputtering power of 147 W. The microstructure, mechanical properties like nanohardness, adhesion strength, and toughness, and corrosion behavior of the metallic glass thin films were examined. The results indicated the formation of an amorphous thin film having a thickness of 753 nm, a nanohardness of 17 GPa, and a satisfactory adhesion value HF1-HF2. Moreover, the fracture toughness of the TFMG was obtained to be equal to 6.14 MPa.m 1/2. The decrease of corrosion current density to 3.09×10–6 A/cm2 and the increase of its polarization resistance to 14,903 Ω.cm2 compared to the substrate showed the high corrosion resistance of the thin film.

Design and characterization of Ge/SeO2 heterojunctions as tunneling thin film transistors

Herein stacked layers of germanium and selenium oxide are employed to fabricate heterojunction devices that can perform as a multifunctional thin film transistors (TFT). The stacked layers of Ge and SeO2 are coated onto ultrasonically cleaned glass and Ag thin film substrates using thermal deposition technique under a vacuum pressure of 1.5×10−4 mbar. The stacked layers are structurally, morphologically, optically and electrically characterized. It is observed that while amorphous germanium films exhibit two energy band gaps of values of 3.56 and 0.78 eV, amorphous SeO2 show one band gap of 3.70 eV. The conduction and valence band offsets at the Ge/SeO2 interfaces are 2.24 eV and 0.68 eV, respectively. Optically, the coating of SeO2 onto Ge films enhanced the light absorbability of SeO2 by ~ 50 times (at 2.38 eV) and ~17 times (at 1.71 eV) in the visible and infrared ranges of light, respectively. Formation of Ge/SeO2 is associated with a redshift and blue shift in the values of the energy band gaps of SeO2 and Ge, respectively. In addition, the current-voltage characteristic curve analyses have shown that Ag/Ge/SeO2/Ag TFTs is of tunneling type showing an estimated peak to valley current ratios of 2.0. The TFT displayed additional functionalities presented by PMOS characteristics, microwave resonators, negative capacitance sources and multiband band stop filters. The features of the devices nominate them for use in microwave technology as band stop filters of notch frequencies of 1.10 and 1.53 GHz.

Biomimetic macroscopic hierarchical moire gratings.

Large-scale hierarchical macroscopic moire gratings resembling the surface structure of Peruvian lily flower petals are fabricated on azobenzene molecular glass thin films using a Lloyd's mirror interferometer. It is shown that nanostructured linear and crossed moire gratings can be made with pitch values reaching a few millimeters. Also, using atomic force microscopy, scanning electron microscopy, optical microscopy, and surface profilometry techniques, it is shown that the obtained moire gratings have two-fold or three-fold hierarchical structures fabricated using a simple all optical technique.

Effect of hybridization in PdAlY-(Ni/Au/Ir) metallic glasses thin films on electrical resistivity

Thin film metallic glasses (MGs) are promising materials for electronic applications. While the transport properties of MGs are composition dependent, the influence of hybridization on the resistivity has not been investigated systematically. We implement a correlative experimental and computational approach utilizing thin film deposition, electrical resistivity measurements, synchrotron X-ray diffraction and ab initio calculations to explore the relationship between the fraction of hybridized bonds present in PdAlY-M glasses with M=Ir,Au,Ni, where the electrical behavior is dominated by d-electrons. The strong bonds hybridization in PdAlY-Ir yields a high resistivity of 175 µΩm, while the weakly hybridized bonds in PdAlY-M MGs (M = Au, Ni) result in lower resistivities of 114 and 92 µΩm, respectively. We propose that an increase in the amount of anti-bonding states close to the Fermi level yields an increased room temperature resistivity.

Residual stress of glass and crystalline oxide thin films responding to humidity

Here, we demonstrate that oxide thin film devices could be affected by humidity in their in-plane stress and in substrate curvature. We prepared silica glass and ceria crystalline thin films on Si(100) wafers by the sol-gel method. Both films had “tensile” in-plane residual stress. We cycled the relative humidity between ca. 20% and 80% in the square wave and monitored the substrate curvature in situ, from which in-plane stress was calculated. The increase and decrease in humidity resulted in a decrease and an increase in tensile stress, respectively. In situ ellipsometric measurements during humidity cycles showed that both thickness and refractive index increase and decrease on the increase and decrease in humidity, respectively. This guarantees that the volume expansion and shrinkage caused by water molecule adsorption/absorption and desorption, respectively, are the origins of the response of the stress to humidity. Responding to the change in humidity, thicker silica glass films with low porosities of 1%–3% showed more sluggish change in stress, suggesting absorption/desorption of water via diffusion in siloxane network in such dense films. Silica glass films with a larger porosity showed more quick response to humidity, indicating adsorption/desorption on the pore wall as the primary cause of the response. “Compressive” stress in a silica glass film with ca. 1% porosity exhibited very slight response in stress to humidity, which was attributed to the hard diffusion of water in compressed siloxane network.

Growth and characterization of (glass, Ag)/SeO2 thin films

Herein, thin films of SeO2 coated onto glass and Ag thin film substrates are studied and characterized. The films which are prepared by a vacuum evaporation technique, displayed Ag-metal induced crystallization process. The grown films are composed of tetragonal structure of SeO2 as major phase and orthorhombic β−Ag2Se as minor phase. The optical studies showed that the films exhibit an energy band gap of 3.69 eV. In addition, the analyses of the dielectric dispersion spectra indicated the nonlinear character of dielectric response. The SeO2 films response to oscillatory electromagnetic field is accompanied with drift mobility values in the range of 5.02–12.06 cm2/Vs. Moreover, polycrystalline SeO2 films coated onto Ag substrates are found appropriate for use as negative capacitance (NC) sources in the frequency domain of 0.41–1.80 GHz. Accompany with the NC effect, negative conductance (NG) effect was observed near 0.410 GHz and near 1.53 GHz.

A new toxic-free Ti40Zr10Co36Pd14 metallic glass with good biocompatibility and surface behaviour comparable to Ti-6Al-4V

In this study, a new toxic-free Ti40Zr10Co36Pd14 amorphous alloy with a critical casting size of 5 mm diameter and 20 mm long has been synthesised through copper-mold casting process. The Ti40Zr10Co36Pd14 bulk metallic glass (BMG) rod has further formed into thin films through the filtered cathodic vacuum arc (FCVA) deposition process. To assess the biocompatibility and the surface behaviour of the synthesised Ti40Zr10Co36Pd14 BMG, the metallic glass (MG) thin films are fabricated on the glass substrate and cultured using murine osteoblast cells (MC3T3-E1) and human osteoblast-like cells (SaOS-2). Various characterisation techniques has been utilised to evaluate the surface properties and the cultured cells behaviour of the deposited thin films. The synthesised Ti40Zr10Co36Pd14 composition shows good biocompatibility similar to the routinely used Ti-6Al-4V. The osteoblast cells proliferate very well on the Ti40Zr10Co36Pd14 MGs and exhibit similar levels of alkaline phosphatase enzymatic activity to those of the controls and the Ti-6Al-4V material. The MC3T3-E1 cells adhered and spread faster on the alumina particle blasted Ti40Zr10Co36Pd14 and Ti-6Al-4V surfaces with osteoblast-like shapes. These results suggest that Ti40Zr10Co36Pd14 BMG is biocompatible and could support osteoblast differentiation. Thus, the new alloy can be used as a candidate material for potential biomedical application.

The ac conduction mechanism and dielectric relaxation behavior of amorphous Te81Ge15Bi4 chalcogenide glass thin films

Various chalcogenide amorphous films of Te81Ge15Bi4 in the range (143–721 nm) were synthesized using the thermal evaporation technique. The ac electrical conductivity {sigma }_{ac}left(omega right) and dielectric measurements were examined for the studied films over the temperature and frequency ranges of (303–393 K) and (100 Hz–1 MHz), respectively. The obtained results of ac conductivity {sigma }_{ac}left(omega right) are temperature dependent and follow the relation {sigma }_{ac}left(omega right)propto {omega }^{s}, where the frequency exponent s decrements with temperature through the examined range. These results of {sigma }_{ac}left(omega right) and s are explained based on the correlated barrier hopping CBH model. Values of ac activation energy Delta {E}_{sigma }left(omega right) show thickness independence and decrease from 0.270 to 0.144 eV as the frequency increases. The estimated maximum barrier height {W}_{M} values decrement with temperature in the considered frequency range. The density of localized states near the Fermi level Nleft({E}_{F}right) increases with increasing temperature and frequency. The dielectric constant {varepsilon }_{1}(omega ) and loss {varepsilon }_{2}(omega ) were found to increment with temperature and decrement with frequency. The obtained results indicate that {sigma }_{ac}left(omega right), Nleft({E}_{F}right), {varepsilon }_{1}left(omega right) and {varepsilon }_{2}left(omega right) are enhanced by decreasing the thickness of the film sample in the investigated ranges of temperature and frequency. The real {M}_{1}(omega ) and imaginary {M}_{2}(omega ) parts of the electric modulus were studied for the films under test, and the value of the activation energy for relaxation Delta {E}_{r} (0.143 ± 0.002 eV) is thickness independent in the investigated range.

Structural, optical, and electrical properties via two simple routes for the synthesis of multi-phase potassium antimony oxide thin films

Multi-phase ternary oxide glass thin films of potassium antimony oxide were synthesized via dip coating (DC) and spray pyrolysis (SP) methods. The growth of thin film was conducted on a non-conductive borosilicate glass substrate. Surface morphology was investigated and showed different characteristics. X-ray diffraction (XRD) analysis revealed the peaks corresponded to the monoclinic KSb3O5 and K2Sb4O11 phases. The structural parameter analysis shows that the lower values of micro strain (ε), dislocation density (δ), and stacking fault probability (SF) with higher number (N) of particle in the multi-phase thin film for the spray pyrolysis method confirm slightly larger crystallite size, less crystal imperfection, and less structural disorder. The lower average transmission, absorption, and extinction coefficients resulted to higher refractive index, permittivity, and electrical susceptibility for the sample synthesized by a spray pyrolysis method. In addition, the average energy band gap values (Eg) of 3.57 and 3.60 eV were obtained for the dip coating and spray pyrolysis methods, respectively. However, the lower Rs (14.69 × 107 Ω/sq.) with higher σh (85.09 S/cm) and the FOM(H-HR) (0.183 Ω-1) of the multi-phase K–Sb–O thin film for the dip coating method were obtained may be due to more interconnections generated at the interface and there are less residual on the surface of thin film.

Solution chemistry back-contact FTO/hematite interface engineering for efficient photocatalytic water oxidation

This work describes a simple yet powerful scalable solution chemistry strategy to create back-contact rich interfaces between substrates such as commercial transparent conducting fluorine-doped tin oxide coated glass (FTO) and photoactive thin films such as hematite for low-cost water oxidation reaction. High-resolution electron microscopy (SEM, TEM, STEM), atomic force microscopy (AFM), elemental chemical mapping (EELS, EDS) and photoelectrochemical (PEC) investigations reveal that the mechanical stress, lattice mismatch, electron energy barrier, and voids between FTO and hematite at the back-contact interface as well as short-circuit and detrimental reaction between FTO and the electrolyte can be alleviated by engineering the chemical composition of the precursor solutions, thus increasing the overall efficiency of these low-cost photoanodes for water oxidation reaction for a clean and sustainable generation of hydrogen from PEC water-splitting. These findings are of significant importance to improve the charge collection efficiency by minimizing electron-hole recombination observed at back-contact interfaces and grain boundaries in mesoporous electrodes, thus improving the overall efficiency and scalability of low-cost PEC water splitting devices. To minimize photogenerated carrier losses and improve overall PEC efficiency, the back-contact FTO-photocatalyst interface is engineered using a simple and scalable solution chemistry process.

Study of optical properties of photo annealed solution based As2S3 chalcogenide glass thin films

Chalcogenide glasses have wide range of applications in Mid- IR region due to its attractive optical properties. In this paper, we study the influence of UV light on the optical properties of solution based A2S3 chalcogenide thin films by examining transmission spectraand further we compare optical properties of photo annealed solution based thin films with the optical properties of thermally deposited As2S3 thin film annealed at 150°C for one hour. Illumination removes the excess amount of solvent which results in high refractive index, lower absorption coefficient and optical band gap ranging from 2.32 eV to 2.27eV.

Ag Surface and Bulk Segregations in Sputtered ZrCuAlNi Metallic Glass Thin Films.

We report on the formation of Ag-containing ZrCuAlNi thin film metallic glass (nano)composites by a hybrid direct-current magnetron sputtering and high-power pulsed magnetron sputtering process. The effects of Ag content, substrate temperature and substrate bias potential on the phase formation and morphology of the nanocomposites were investigated. While applying a substrate bias potential did not strongly affect the morphological evolution of the films, the Ag content dictated the size and distribution of Ag surface segregations. The films deposited at low temperatures were characterized by strong surface segregations, formed by coalescence and Ostwald ripening, while the volume of the films remained featureless. At higher deposition temperature, elongated Ag segregations were observed in the bulk and a continuous Ag layer was formed at the surface as a result of thermally enhanced surface diffusion. While microstructural observations have allowed identifying both surface and bulk segregations, an indirect method for detecting the presence of Ag segregations is proposed, by measuring the electrical resistivity of the films.

Confinement Effects on the Spatially Inhomogeneous Dynamics in Metallic Glass Films.

This work develops the elastically collective nonlinear Langevin equation theory to investigate, for the first time, the glassy dynamics in capped metallic glass thin films. Finite-size effects on the spatial gradient of structural relaxation time and glass transition temperature (Tg) are calculated at different temperatures and vitrification criteria. Molecular dynamics is significantly slowed down near rough solid surfaces, and the dynamics at location far from the interfaces is sped up. In thick films, the mobility gradient normalized by the bulk value obeys the double-exponential form since interference effects between two surfaces are weak. Reducing the film thickness induces a strong dynamic coupling between two surfaces and flattens the relaxation gradient. The normalized gradient of the glass transition temperature is independent of vitrification time scale criterion and can be fitted by a superposition function as the films are not ultrathin. The local fragility is found to remain unchanged with location. This finding suggests that one can use Angell plots of bulk relaxation time and the Tg spatial gradient to characterize glassy dynamics in metallic glass films. Our computational results agree well with experimental data and simulation.

The effect of ZnO – TiO2 synthesis analysis using sol-gel method on calcination temperature of thin film as an alternative energy materials

The manufacture of solar cells from ZnO – TiO2 is synthesized at 400°C, 500°C, and 600°C. This research was carried out by synthesizing ZnO, TiO2, and ZnO + TiO2 with the sol-gel method and was ground using a stirrer at 80°C, 200 rpm for 30 minutes. In this study, the thin-film glass used was Select Micro Slides, which measures 76 x 26 mm of 1.0/1.2 mm thick. The synthetic mixture used is 98% ethanol. Before testing, materials synthesis resulted from 2x2 mm coated thin glass was furnished for 1 hour with the calcination temperature of 400°C, 500°C, and 600°C. The results or the characterization performed on ZnO with a temperature of 400°C, has a peak point: 50 - 20. The graph described that there are two pairs of the same peak point, namely: 27 and 20. TiO2 with a temperature of 500oC has a peak point of 300 - 20, and 20. And ZnO + TiO2 with a temperature of 600°C has a peak point of 340 - 4. The temperature of crystal size varied; ZnO at a temperature of 400°C has a crystal size of 792.0585 AO or 79.205 nm, TiO2 at a temperature of 500oC has a crystal size 492.10489 AO or 49.21 nm, and ZnO + TiO2 at a temperature of 600°C has a crystallite size of 453 440 Ao or 45.34 nm. The result of the synthesis was different from the XRD characterization, wavelength, and crystal size. ZnO and TiO2 can influence various characteristics such as; increasing peak point, wavelength, crystal size, and other effects that can provide heat or electrical energy.

Slow coarsening of ultra-confined phase-separated glass thin films

Diffusion-driven coarsening of droplets is a classical subject in statistical physics, yet coarsening kinetics in confined systems have received little attention. We report here on the coarsening of droplets in thin (50–200 nm) films of phase-separated barium borosilicate glasses. In this ultra-confined geometry where at most one droplet is observed within the film thickness, droplets grow like a power-law of time with an exponent about 0.17 significantly smaller than that of the one of Ostwald ripening (1/3) characteristic of bulk coarsening. We complement these experimental results with two-dimensional Cahn–Hilliard numerical simulations of diffusion, where a wider range of parameters can be varied. In simulations, we recover a slow coarsening behavior in ultra-confined geometry. We explain the anomalous scaling exponent of simulations by ultraconfined geometry, which imposes a different scaling with time of the radius of a droplet and the distance between droplets. In the experimental system, diffusive transport also becomes less efficient with time compared to the bulk case with an additional change of geometry compared to simulations. Flattening of droplets with time is indeed observed, which we attribute to strong variations of the diffusion coefficient with the local matrix composition. We finally propose a simple model assuming a spatial localization of the diffusion paths to account for this effect.

Highly Elastic and Corrosion-Resistive Metallic Glass Thin Films for Flexible Encapsulation.

Ternary CuZrTi metallic glass thin films synthesized by sputtering are suggested as highly flexible and corrosion-resistant encapsulation materials. Unlike nanocrystalline Cu and binary CuZr metallic glass thin films, the ternary CuZrTi metallic glass thin films retain amorphous structure and do not oxidize even after 1000 h in an accelerated harsh environment at 85 °C with 85% relative humidity. The encapsulation performance of 260 nm thick ternary CuZrTi metallic glass is maintained even after 1000 bending cycles at a 3% tensile strain, corresponding to 70% of the elastic deformation limit, according to the results of a uniaxial tensile test. Because of the enhanced mechanical flexibility and reliability of the ternary CuZrTi metallic glass thin films, they have been applied to flexible organic solar cells as an encapsulation material.