Zr Films Research Articles

Zr-based conversion film fabricated on cold rolled steel by separately providing zirconium and fluorine ions: Performance and mechanism study

Controlling the concentrations of Zr4+ and F− in traditional Zirconium (Zr)-based film-formation solution is challenging due to their dependence on the hydrolytic equilibrium of H2ZrF6. In this study, Zr-based films were prepared on cold rolled steel surface through the film-formation solution prepared by mixing Zr(NO3)4 and different amount of HF. The electrochemical results demonstrated that the Zr-based film prepared by Zr(NO3)4 and HF exhibited superior corrosion resistance compared to H2ZrF6. Under optimal film formation conditions, the protective efficiency of the prepared film reached 74.4 % which was higher than that of film fabricated in H2ZrF6. The electrochemical results concurrently demonstrated the self-reinforcing anti-corrosion performance of the prepared films. Scanning electron microscopy revealed that the Zr film, prepared in Zr(NO3)4 and HF, exhibited excellent corrosion resistance attributed to its high film density. The X-ray photoelectron spectroscopy and energy dispersive spectroscopic results indicated the presence of a fluoride layer on the surface of the Zr film. The F− ions can chelate with the corrosion products and selectively deposit onto the damaged areas of the film, thereby effectively contributing to the repair of the film layer. The results of density functional theory calculations demonstrated that Zr4+ readily forms Zr(OH)4 rather than ZrF62−. The present study offers an enhanced approach for regulating the properties of films prepared via H2ZrF6 by separately providing zirconium and fluorine ions.

Microstructural evolution in a one-directional phase transforming ultrahigh temperature ceramic laminate composite

A metal-ceramic multilayer composite composed of Zr and ZrC films was magnetron sputter deposited and annealed at 1325 °C to demonstrate its ability to phase transform into a single phase, substoichiometric ultrahigh temperature ceramic carbide. The pre-annealed laminate microstructure comprised columnar grains for both the Zr and ZrC layers, common to thin film deposition. Upon annealing, the diffusion of carbon facilitated the precipitation of multiple equiaxed carbide grains that consumed the former Zr layers. As this carbon diffused from ZrC, it resulted in the carbide undergoing a lattice contraction where the elastic strains facilitated a decohesion between the carbide grain boundaries. This decohesion is shown to be mitigated by increasing the ratio of the initial ZrC layer-to-Zr layer thicknesses. Finally, oxygen, found to be a minor impurity in the ethylene hydrocarbon gas used to reactively deposit ZrC, facilitated irregular zirconia precipitation within the evolving microstructure during the anneal.

Synthesis and Characterization of a Zirconium (Zr) Thin Film on Si(100) via Pulsed Laser Deposition

Zirconium (Zr) thin films were deposited on silicon using pulsed laser deposition (PLD) with two laser wavelengths (1064 nm and 532 nm) and varying substrate temperatures (25 °C, 300 °C, and 500 °C) and laser fluences (0.25, 0.5, 1.0 J/cm2). Results indicate that smoother films were obtained with 1064 nm and surface roughness increased with higher fluences. Optimal crystalline films were obtained at 300 °C. XRD, SEM, and AFM analysis revealed distinct patterns and peaks related to laser parameters. The growth mechanisms of a Zr film were computed based on a well-known continuum model of thin film growth. Our simulations agree with experimental observations. The study highlights crucial factors affecting Zr thin film deposition and provides insights for optimizing PLD parameters to achieve high-quality films.

Analysis of Hazy Ga- and Zr-Co-Doped Zinc Oxide Films Prepared with Atmospheric Pressure Plasma Jet Systems.

Co-doped ZnO thin films have attracted much attention in the field of transparent conductive oxides (TCOs) in solar cells, displays, and other transparent electronics. Unlike conventional single-doped ZnO, co-doped ZnO utilizes two different dopant elements, offering enhanced electrical properties and more controllable optical properties, including transmittance and haze; however, most previous studies focused on the electrical properties, with less attention paid to obtaining high haze using co-doping. Here, we prepare high-haze Ga- and Zr-co-doped ZnO (GZO:Zr or ZGZO) using atmospheric pressure plasma jet (APPJ) systems. We conduct a detailed analysis to examine the interplay between Zr concentrations and film properties. UV-Vis spectroscopy shows a remarkable haze factor increase of 7.19% to 34.8% (+384%) for the films prepared with 2 at% Zr and 8 at% Ga precursor concentrations. EDS analysis reveals Zr accumulation on larger and smaller particles, while SIMS links particle abundance to impurity uptake and altered electrical properties. XPS identifies Zr mainly as ZrO2 because of lattice stress from Zr doping, forming clusters at lattice boundaries and corroborating the SEM findings. Our work presents a new way to fabricate Ga- and Zr-co-doped ZnO for applications that require low electrical resistivity, high visible transparency, and high haze.

Blade Test in Atmospheric-Pressure Ar Gas to Characterize Bonded Interface Fabricated Using Atomic Diffusion Bonding

A blade test was applied in atmospheric-pressure Ar gas for wafers bonded using atomic diffusion bonding processing. We assessed the variation of the values of surface free energy at the bonded interface γ calculated, for convenience, from the debonding length. For interfaces bonded using thin Zr and Ti films, γ measured in Ar maintained the initial value γ0(Ar) in the initial region of observation time t and started decreasing as t increased further. Results indicate that γ0(Ar) corresponds to the value without water stress corrosion effects. The initial value of γ measured in air with a higher blade insertion-speed was almost equal to γ0(Ar). Result obtained for wafers bonded using Al2O3 films were almost identical to those obtained using metal films. However, γ for wafers bonded using ZrO2 films did not maintain their initial values. They decreased gradually as t increased, even in Ar, suggesting high water stress corrosion effects.

Origin of morphotropic phase boundary in thin-film Hf0.5Zr0.5O2 on the TiN electrode

Our study aims to clarify the morphotropic phase boundary observed in Zr-doped hafnia systems. We utilize density-functional-theory calculations to examine various structural phases of (Hf,Zr)O2 thin films on TiN electrodes. We account for Zr composition, film thickness, and temperature to model the free energy of (Hf,Zr)O2 on TiN electrodes. Our assessment of the thermodynamic stability of each structural phase in terms of surface and interface energies under the substrate strain allows us to determine that the substrate strain and temperature significantly reduce the energy differences between different phases. Our findings lead to the energy reversal between tetragonal and orthorhombic phases when the film thickness increases. Based on our results, we propose that the formation of a high-temperature tetragonal phase, arising from the rapid thermal or annealing processes, is crucial to the appearance of the morphotropic phase boundary in Hf0.5Zr0.5O2. Understanding the origin of the morphotropic phase boundary can have significant implications for device applications.

Structural Properties of He-Irradiated Zr/Nb Multilayer Investigated by Grazing Incidence X-ray Diffraction

Zr/Nb nanoscale multilayers are regarded as one of the important candidate materials used in next-generation reactors. Understanding structural evolution induced by ion bombardment is crucial for the evaluation of lifetime performance. Magnetron sputter-deposited Zr/Nb multilayers with a periodicity of 7 nm were subjected to 300 keV He ion irradiation with three different fluences at room temperature. The depth-resolved strain and damage profiles in the Zr/Nb multilayers were investigated by grazing incidence X-ray diffraction. The tensile strain was found in the deposited Zr/Nb films. After He ion irradiation, the intensity of diffraction peaks increased. The change in diffraction peaks depends on He fluence and incident angle. Irradiation-induced pre-existing defect annealing was observed and the ability to recover the microstructure was more significant in the Zr films compared to the Nb films. Furthermore, the efficiency of defect annealing depends on the concentration of pre-existing defects and He fluence. When the He fluence exceeds the one for pre-existing defect annealing, residual defects will be formed, such as 1/3<12¯10> and 1/3<11¯00> dislocation loops in the Zr films and 1/2<111> dislocation loops in the Nb films. Finally, introducing deposited defects and interfaces can improve the radiation resistance of Zr/Nb nanoscale multilayers. These findings can be extended to other multilayers in order to develop candidate materials for fusion and fission systems with high radiation resistance.

Tuning electronic properties in tin-assisted n-type ε-Ga2O3:Zr thin films via PLD for p-n heterojunction

The orthorhombic ε-Ga2O3 has received attention due to its ultra-wide bandgap (4.9 eV), high lattice symmetry and unique theoretically spontaneous polarization, etc. Controlled carrier concentration of ε-Ga2O3 is essential for device fabrication. In this work, we successfully deposited tin-assisted n-type Zr-doped ε-Ga2O3 on epi-GaN/sapphire substrate using PLD with tunable carrier concentration merely by adjusting growth parameters of oxygen partial pressure and laser pulses, without further post-sputter annealing process. Furthermore, Sn element was a surfactant to stabilize epsilon phase rather than provide electrons as donors, while Zr acted as a shallow donor to generate carriers. The results show that the growth window of orthorhombic ε-Ga2O3:Zr is oxygen pressure between 0.005-0.03 mbar and laser pulses between 3000-8000. Both the oxygen pressure and laser pulses affect the Zr component in n-type ε-Ga2O3 thin films. The optimal deposition conditions of ε-Ga2O3:Zr thin films are as follows: 0.012 mbar oxygen pressure and 7000 laser pulses, where the ε-Ga2O3:Zr films have a minimum resistivity 2.4 Ω·cm, a carrier concentration of 1.6×1017 cm−3, and the mobility of 17.4 cm2V−1s−1. In this paper, the n-type ε-Ga2O3 thin film was deposited on p-GaN substrate and p-GaN/n-Ga2O3 heterojunction diodes were fabricated. This device exhibited a rectification ratio of 104-105, turn-on voltage of 2.05–2.3 V, and high breakdown voltage of −954 V.

Mechanical and Anticorrosive Properties of TiNbTa and TiNbTaZr Films on Ti-6Al-4V Alloy

In this study, TiNbTa and TiNbTaZr films were utilized as protective coatings on a Ti-6Al-4V alloy to inhibit corrosive attacks from NaCl aqueous solution and simulated body fluid. The structural and mechanical properties of multicomponent TiNbTa(Zr) films were investigated. The corrosion resistance of the TiNbTa(Zr)-film-modified Ti-6Al-4V alloy was evaluated using potentiodynamic polarization tests in a NaCl aqueous solution. The results indicate that the TiNbTa(Zr) films with high Ti and Zr contents exhibited inferior corrosive resistance related to the films with high Ta and Nb contents. Moreover, the TiNbTa(Zr)-coated Ti-6Al-4V plates were immersed in Ringer’s solution for eight weeks; this solution was widely used as a simulated body fluid. The formation of surficial oxide layers above the TiNbTa(Zr) films was examined using transmission electron microscopy and X-ray photoelectron spectroscopy, which prevented the elution of Al and V from the Ti-6Al-4V alloy. Ti33Nb19Ta21Zr27, Ti15Nb68Ta8Zr9, and Ti8Nb8Ta79Zr5 films are suggested as preferential candidates for TiNbTa(Zr)/Ti-6Al-4V assemblies applied as biocompatible materials.

Thin Zr Film Deposition Using a Refractory Anode Vacuum Arc Plasma Source

Thin Zr films were deposited using a vacuum arc with a refractory graphite anode and a water-cooled Zr cathode. The deposition rate was obtained from the film thickness, measured by profilometry, and time of exposure to the arc plasma. The deposition rate increased with the arc current, gap distance, and arcing time before substrate exposure to Zr plasma. The measured deposition rate reached <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.9 ~\mu \text{m}$ </tex-math></inline-formula> /min for an arc current of 225 A for time before substrate exposure of 90 s and the rate tends to about <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1 ~\mu \text{m}$ </tex-math></inline-formula> /min with further this time.

Sample Preparation and Experimental Design for In Situ Multi-Beam Transmission Electron Microscopy Irradiation Experiments.

There is a need to understand materials exposed to overlapping extreme environments such as high temperature, radiation, or mechanical stress. When these stressors are combined there may be synergistic effects that enable unique microstructural evolution mechanisms to activate. Understanding of these mechanisms is necessary for the input and refinement of predictive models and critical for engineering of next generation materials. The basic physics and underlying mechanisms require advanced tools to be investigated. The in situ ion irradiation transmission electron microscope (I³TEM) is designed to explore these principles. To quantitatively probe the complex dynamic interactions in materials, careful preparation of samples and consideration of experimental design is required. Particular handling or preparation of samples can easily introduce damage or features that obfuscate the measurements. There is no one correct way to prepare a sample; however, many mistakes can be made. The most common errors and things to consider are highlighted within. The I³TEM has many adjustable variables and a large potential experimental space, therefore it is best to design experiments with a specific scientific question or questions in mind. Experiments have been performed on large number of sample geometries, material classes, and with many irradiation conditions. The following are a subset of examples that demonstrate unique in situ capabilities utilizing the I3TEM. Au nanoparticles prepared by drop casting have been used to investigate the effects of single ion strikes. Au thin films have been used in studies on the effects of multibeam irradiation on microstructure evolution. Zr films have been exposed to irradiation and mechanical tension to examine creep. Ag nanopillars were subjected to simultaneous high temperature, mechanical compression, and ion irradiation to study irradiation induced creep as well. These results impact fields including: structural materials, nuclear energy, energy storage, catalysis, and microelectronics in space environments.

Three-dimensional in situ imaging of single-grain growth in polycrystalline In2O3:Zr films

Strain and interactions at grain boundaries during solid-phase crystallization are known to play a significant role in the functional properties of polycrystalline materials. However, elucidating three-dimensional nanoscale grain morphology, kinetics, and strain under realistic conditions is challenging. Here, we image a single-grain growth during the amorphous-to-polycrystalline transition in technologically relevant transparent conductive oxide film of In2O3:Zr with in situ Bragg coherent X-ray diffraction imaging and transmission electron microscopy. We find that the Johnson-Mehl-Avrami-Kolmogorov theory, which describes the average kinetics of polycrystalline films growth, can be applied to the single grains as well. The quantitative analysis stems directly from imaging results. We elucidate the interface-controlled nature of the single-grain growth in thin films and reveal the surface strains which may be a driving force for anisotropic crystallization rates. Our results bring in situ imaging with coherent X-rays towards understanding and controlling the crystallization processes of transparent conductive oxides and other polycrystalline materials at the nanoscale.

Ultralight flexible perovskite solar cells

Ultrathin (thickness less than 10 μm) and ultralight flexible perovskite solar cells (FPSCs) have attracted extensive research enthusiasm as power sources for specific potential lightweight applications, such as drones, blimps, weather balloons and avionics. Currently, there is still a certain gap between the power conversion efficiency (PCE) of ultrathin FPSCs and common FPSCs. This study demonstrates ultrathin FPSCs on 3-μm-thick parylene-C substrates via a flip-over transferring process. The Zr, Ti and Ga-doped indium oxide (ITGZO) film is employed as the bottom transparent electrode of ultrathin inverted FPSCs with a remarkable PCE of 20.2%, which is comparable to that based on common FPSCs. Devices on glasses and parylene-F (i.e., parylene-VT4) substrates were also constructed to verify the advantages of parylene-C. Furthermore, an excellent power-per-weight of 30.3 W g−1 is achieved attributed to remarkable PCE and ultrathin-ultralight substrates, demonstrating the great promise of fabricating efficient, ultrathin and ultralight solar cells with parylene-C films.

Synthesis and Mechanical Properties of sub 5‐μm PolyUiO‐66 Thin Films on Gold Surfaces

AbstractMetal‐organic framework (MOF) thin films currently lack the mechanical stability needed for electronic device applications. Polymer‐based metal‐organic frameworks (polyMOFs) have been suggested to provide mechanical advantages over MOFs, however, the mechanical properties of polyMOFs have not yet been characterized. In this work, we developed a method to synthesize continuous sub‐5 μm polyUiO‐66(Zr) films on Au substrates, which allowed us to undertake initial mechanical property investigations. Comparisons between polyUiO‐66 and UiO‐66 thin films determined polyUiO‐66 thin films exhibit a lower modulus but similar hardness to UiO‐66 thin films. The initial mechanical characterization indicates that further development is needed to leverage the mechanical property advantages of polyMOFs over MOFs. Additionally, the demonstration in this work of a continuous surface‐supported polyUiO‐66 thin film enables utilization of this emerging class of polyMOF materials in sensors and devices applications.

High haze Ga and Zr co-doped zinc oxide transparent electrodes for photovoltaic applications

Creating textured front electrodes to improve optical path length is promising to enhance the power conversion efficiency of solar cells. Deposition of transparent conductive oxides with textured surfaces usually requires additional processing steps, such as etching and coating nanoparticles. However, this makes the process complicated and inefficient. We demonstrate a one-step fabrication process to deposit high haze gallium and zirconium co-doped zinc oxides (GZO:Zr) prepared by atmospheric pressure plasma jets. GZO:Zr (2 at%) films achieve a low resistivity (7.88 × 10–4 Ω cm), a high haze (34.8%), and a great FoM (8.22 × 10−3 Ω−1). The haze factor increases from 7.19% to 34.8% (+384%) when 2% Zr is doped into GZO films. Such an enhancement of haze is attributed to the increased surface roughness and deterioration of crystallinity. AFM results show that roughness increases from 18.4 to 122 nm after 2% Zr is doped. SEM images show that spherical particles appeared on the film surface when Zr was doped into GZO films. Unlike conventional methods, our method produces hazy transparent electrodes in one step without changing any operational parameters and is suitable for industrial-scale mass production. Our findings pave the way for new applications of co-doping in transparent conductive oxides.

Effect of nanostructuring on picosecond acoustics in a Zr film

Using the picosecond ultrasonic technique, we studied the effect of the formation of nanocrystallites on the surface of a metal transducer film. We found that the velocity of sound and the elastic constant are enhanced due to the nanocrystalline structures. The acoustic echo’s shape, resulting from the reflection of the acoustic pulse at the surface, is modified, and an echo with an asymmetric bipolar shape is obtained. The shape of the acoustic echo can be explained, taking into account the formation of nanocrystallites at the film’s surface.

Control of Magnetic Properties of Barium Ferrite Thin Films With Unusual Valence Fe

Thin films of BaFe1-xMxO3 (M = Hf, Zr, and Ce; 0.0 ≤ x ≤ 0.75) were fabricated using pulsed laser deposition and their magnetic properties were investigated. X-ray diffraction analysis indicated that oxygen-deficient BaFeOx (x &amp;lt; 3.0) with a monoclinic structure was formed when the deposition was conducted using a non-substituted target (x = 0.0). The as-grown BaFeOx films were converted into fully oxidized BaFeO3 with a perovskite structure by low-temperature oxidation in an ozone atmosphere. In contrast, the as-deposited films of Hf, Zr, and Ce-substituted films exhibited a perovskite structure, and their crystallinity did not change after low-temperature ozone annealing. The magnetic transition temperature Tc of the BaFeO3 film was 115 K, whereas the substituted BaFeO3 films showed ferromagnetic behavior even at 300 K. These results can be attributed to the weakening of the antiferromagnetic super-exchange coupling among Fe ions owing to the lattice expansion in the substituted BaFeO3. In addition, the magnetization of the films was found to increase with the decreasing ionic ratio of Fe4+/Fe3+, suggesting that the inherent carrier-induced ferromagnetic interaction is dominant in the films.

Highly conductive and adhesive ternary Cu–Cr–Zr alloy electrode for flexible optoelectronic applications

In this study, high-performance ternary Cu-0.13 wt% Cr-0.04 wt% Zr (Cu–Cr–Zr) alloy films on flexible polyimide (PI) substrate were investigated for the metallization of flexible thin-film transistor. The optimized Cu–Cr–Zr film was endowed excellent electrical resistivity (21.7 mΩ μm) and adhesion strength (5 B). The results showed that the sputtering rate increased with the increase of the sputtering power and pressure, and the adhesion strength tended to increase while the resistivity decreased with the rise of annealing temperature. X-ray diffraction (XRD) analysis showed that the copper grain size increased significantly as the rise of annealing temperature, which indicates the attenuation of the grain boundary scattering and accounts for the decrease of the resistivity. Compared with the glass substrate, lower resistance was achieved on PI substrate, which is related to the surface morphology . The smoothness and adhesion of the Cu–Cr–Zr film were improved more distinctly on the PI substrate can be attributed to more low interfacial energy sites of PI. Further mechanical bending test demonstrated that the robust Cu–Cr–Zr film has good stability and durability without significant deterioration after 50 k times bending. • Discusses changes in the properties of Cu–Cr–Zr thin film under different conditions. • The conductivity, smoothness and adhesion of film areexcellent on the PI substrate. • Obtained the conditions for the optimal resistivity and adhesion strength. • Analyze the micro mechanism of the thin film performance change in depth.

Metastable structures in magnetron sputtered W–Zr thin-film alloys

Binary W–Zr thin-film alloys with different metastable structures were prepared by dc magnetron co-sputtering of W and Zr targets in argon atmosphere on unheated and unbiased substrates. The effect of the elemental composition on the formation of different structures and phases was studied in a very wide range of 3–99 at.% Zr. The microstructure and properties of the films were related to the individual metastable structures prepared. We found that W-rich films with an α-W(Zr) solid solution structure can be prepared in much wider range of the elemental composition (up to 24 at.% Zr) than indicated in the equilibrium W–Zr phase diagram. These films exhibited an enhanced hardness (up to 16.1 GPa) and a reduced residual stress (down to −0.05 GPa). Amorphous W–Zr films with a very low surface roughness (down to 0.4 nm) and metallic glass features were prepared with the Zr content between 33 and 83 at.%. The hardness of these films gradually decreased with increasing Zr content due to reducing average bond energy. All films were in the compressive state in contrast to the crystalline ones. The structure of crystalline Zr-rich films with higher than 88 at.% Zr was predominantly dual-phased exhibiting a gradual transition from a metastable β-Zr(W) solid solution (86–96 at.% Zr) through a metastable ω-Zr(W) solid solution (94–100 at.% Zr) to the thermodynamically stable α-Zr phase (99–100 at.% Zr) with increasing Zr (decreasing W) content. We also observed the formation of dual-phase glassy-crystalline structures in the transition zones between fully crystalline and glassy films.

Activation of Zr, ZrVHf and TiZrV Non-Evaporative Getters Characterized by In Situ Synchrotron Radiation Photoemission Spectroscopy

The activation process of Zr, ZrVHf and TiZrV non-evaporative getter (NEG) thin films, prepared by direct current magnetron sputtering, is investigated by in situ synchrotron radiation photoemission spectroscopy. The activation temperatures of Zr and ZrVHf films are found to be 300 °C and 200 °C, respectively, and the activation temperature of TiZrV film is 120 °C—the lowest activation temperature reported on TiZrV. As the heating temperature increases, the transformation of metal-C bond follows the orders of V–C, Ti–C, Zr–C, Hf–C. It is found that the order of reduction difficulty of the same element oxides, that is, Zr oxide and V oxide in different films follows Zr film &gt; ZrVHf film &gt; TiZrV film. The order of difficulty in the reduction of oxides in the same alloy NEG films follows HfO2 &gt; ZrO2 &gt; TiO2 &gt; V2O5. We propose that the above phenomena can be explained by interstitial diffusion, grain boundary diffusion of residual gas atoms and grain boundary precipitation of V and Ti in the solid solution of the NEG films.