Nickel Thin Films Research Articles

Influence of electrosynthesis methods in the electrocatalytical and morphological properties of cobalt and nickel hexacyanoferrate films

Prussian Blue analogues (PBA) based on Cobalt and Nickel thin films were assembled by two distinct methodologies using direct electroprecipitation on the substrate and metallic nanoparticle surface modification. The modified electrodes were characterized by several techniques such as Infrared Reflection-Absorption and Electrochemical Impedance Spectroscopies, Scanning Electron and Atomic Force Microscopies, and Electrochemical methods. The electrocatalytical properties of the films were also evaluated and the rate constants for thiosulfate oxidation were obtained and discussed. The results pointed out that the metallic nanoparticle approach has presented higher electrocatalytic effect, suggesting this methodology towards the construction of high performance electrochemical based devices such as sensors, biosensors, fuel cells and others.

Nickel doped molybdenum oxide thin film counter electrodes as a low-cost replacement for platinum in dye sensitized solar cells

Replacement of expensive platinum counter electrodes has been primarily focusing research on Dye-Sensitized Solar Cells. Here, we present a facile solution-processed thin-film nickel doped molybdenum oxide counter electrode as a cheap alternative of Platinum. The most motivation of doping nickel in molybdenum oxide was to explore the synergic effect produced due to hypo-hyper electronic d orbital coupling between the pair. These results show the shift of valence band energy level upwards to properly align with electrolyte redox potential for facilitating hole transport. We found that optimized 10 mol. % Ni doping yielded the maximum efficiency of the fabricated solar cells.

Plasma-Enhanced Atomic Layer Deposition of Nickel Nanotubes with Low Resistivity and Coherent Magnetization Dynamics for 3D Spintronics.

We report plasma-enhanced atomic layer deposition (ALD) to prepare conformal nickel thin films and nanotubes using nickelocene as a precursor, water as the oxidant agent, and an in-cycle plasma-enhanced reduction step with hydrogen. The optimized ALD pulse sequence, combined with a post-processing annealing treatment, allowed us to prepare 30 nm-thick metallic Ni layers with a resistivity of 8 μΩ cm at room temperature and good conformality both on the planar substrates and nanotemplates. Thus, we fabricated several micrometers-long nickel nanotubes with diameters ranging from 120 to 330 nm. We report the correlation between ALD growth and functional properties of individual Ni nanotubes characterized in terms of magnetotransport and the confinement of spin-wave modes. The findings offer novel perspectives for Ni-based spintronics and magnonic devices operated in the GHz frequency regime with 3D device architectures.

Laser-Induced Tar-Mediated Sintering of Metals and Refractory Carbides in Air.

Refractory metals and their carbides possess extraordinary chemical and temperature resilience and exceptional mechanical strength. Yet, they are notoriously difficult to employ in additive manufacturing, due to the high temperatures needed for processing. State of the art approaches to manufacture these materials generally require either a high-energy laser or electron beam as well as ventilation to protect the metal powder from combustion. Here, we present a versatile manufacturing process that utilizes tar as both a light absorber and antioxidant binder to sinter thin films of aluminum, copper, nickel, molybdenum, and tungsten powder using a low power (<2W) CO2 laser in air. Films of sintered Al/Cu/Ni metals have sheet resistances of ∼10-1 ohm/sq, while laser-sintered Mo/W-tar thin films form carbide phases. Several devices are demonstrated, including laser-sintered porous copper with a stable response to large strain (3.0) after 150 cycles, and a laserprocessed Mo/MoC(1-x) filament that reaches T ∼1000 °C in open air at 12 V. These results show that tar-mediated laser sintering represents a possible low energy, cost-effective route for engineering refractory materials and one that can easily be extended to additive manufacturing processes.

Direct Color Printing with an Electron Beam.

The direct patterning of colors using the bombardment of a focused beam of electrons onto a thin-film stack consisting of poly(methyl methacrylate) coated with a thin nickel film is demonstrated. This direct electron-beam color printing approach creates variations in the height of a Fabry-Perot (FP) cavity, resulting directly in a color print without the need for prepatterned substrates, distinct from some direct laser writing methods. Notably, the resolution of the color prints is defined by the electron beam. Height measurements with ∼5 nm accuracy through color image analysis of an electron-beam-patterned FP cavity were carried out. This technique also introduces a reflectance-based measurement of the point exposure function of a focused electron beam, aiding in rapid proximity effect corrections. In addition, the grayscale lithographic nature of this process was used to produce blazed gratings and could enable the fabrication of other 2.5D nanostructures with precise height control.

The study of magnetic resistance on thin single-crystal nickel films

In this work the anisotropy of the transverse magnetoresistance of single-crystal nickel films was studied. The measurements were carried out on samples whose surface plane coincided with the [001] plane. Studies of magnetoresistance in a single-crystal nickel film showed the influence of tensile stresses acting on it from the side of magnesium oxide. The modification of the anisotropy of the magnetoconductivity of the film on the substrate as compared with the free sample is apparently associated with a change in the shape of the Fermi surface of the carriers.

Evaluation of a Manufacturable in-Situ Thin Film RTD Temperature Sensor for Lithium-Ion Batteries

As an in-situ temperature sensor for Li-Ion batteries, RTD’s (Resistance Temperature Detector) have a simple linear response to temperature and can accurately sense from -40 °C through thermal runaway initiation. An economical manufacturing method using a high-volume real-to-real flexible substrate is used that can combine the tab and sensors or produce sensor packages where either type integrate into a pouch cell in a similar way to the electrode tabs.Commercial 4.84 Ahr Li-ion NMC/graphite pouch cells were constructed incorporating a prototype thin film Nickel based RTD integrated tab at the center of the jelly-roll. This unified approach greatly simplifies the methods of construction avoiding the effects of around 2%1 strain due to the charge/discharge cycle. Much of the capital cost associated with adding new components to the manufacturing of Li-ion batteries are also avoided. Owing to the method of construction, the RTD has little to no impact on battery energy density which is very important to the competitive landscape.Experimental in-operando results illustrating the importance of sensor location are presented such as the case shown in Figure 1. More utilitarian and more extreme cases are also investigated comparing the in-situ vs ex-situ temperature responses to situations such as external short-circuit as well as normal operation modes. Progress on long term cycling will also be presented showing stability of sensor and any effects on battery performance.Incorporation of additional sensors are also discussed such as reference electrodes. In a recent review2 cathode materials such as LiFePO4 make a more suitable long term pseudo-reference electrode material than the much more difficult to handle Li metal alloys. A sensor package of the type described here allows for simple addition of a pseudo-reference electrode utilizing cathode material. 1 Drew Joseph Pereira et al. Meet. Abstr. 2019;MA2019-02:428 2 Rinaldo Raccichini et al. Batteries 2019, 5, 12 Figure 1

Investigations on sputter deposited lithium nickel manganese oxide thin film cathodes for micro battery applications

Abstract Lithium manganese oxide thin films have been deposited on nickel (Ni) and platinum (Pt) coated stainless steel substrates at room temperature using powder target by Radio Frequency (rf) reactive magnetron sputtering. The samples are exposed to heat treatment at 500 °C to form crystalline phase. Nickel and platinum thin film coatings have been carried out using direct current (DC) sputtering. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and electrochemical characterizations have been carried out. XPS spectra indicate the presence of all elements present in the powder target. A discharge capacity of 54 µAh µm−1 cm−2 and 48 µAh µm−1 cm−2 has been obtained from charge discharge studies in the potential range 2.0 to 4.4 V for the thin film samples deposited on Ni and Pt coated SS substrates correspondingly Charge discharge cycles are conducted up to 40 cycles.

Generation and Imaging of Magnetoacoustic Waves over Millimeter Distances.

Using hybrid piezoelectric-magnetic systems we have generated large amplitude magnetization waves mediated by magnetoelasticity with up to 25degrees variation in the magnetization orientation. We present direct imaging and quantification of both standing and propagating acoustomagnetic waves with different wavelengths, over large distances up to several millimeters in a nickel thin film.

Kinetics of nickel particle formation on silicon substrate with a buffer layer of niobium nitride

The size, form and distribution function of catalyst particles define the quality of synthesized arrays of carbon nanotubes. In this work, we study the kinetics of catalyst particle formation from the thin nickel film (9 nm) deposited on the silicon substrate (SiO2/Si) with a buffer layer of niobium nitride at the temperature of 880 °C. In the experiment, we have obtained the time dependences of the average radius, average height and concentration of nickel particles. The experimental data are satisfactorily described by simulations based on the wetting transition theory. Comparison of the simulation results and experimental data allows us to estimate the effective interaction potential between the nickel film and buffer layer of niobium nitride. Besides, we have estimated the viscosity of the nickel confirming an undercooled liquid state of the nanosized nickel film at the temperature of 880 °C.

Fabrication and characterization of nickel thin film as resistance temperature detector

In practical applications, thin film resistance temperature detectors (RTD) are often used in the environments that the attached substrates cannot stand high temperature. Therefore, it is necessary to prepare thin film RTDs by a low temperature process. In this study, the fabrication of nickel (Ni) thin film RTDs at low temperatures is investigated by direct-current (DC) magnetron sputtering. It is found that the dense and uniform Ni thin film can be prepared even at room temperature. The effects of sputter pressure and power on thin film microscopic morphology and structure are also investigated. The Ni thin film RTDs prepared at room temperature exhibit a value of temperature coefficient of resistance (TCR) about 3000 ppm/°C and excellent repeatability under cycling temperatures.

Black silicon quality control by conditions of nickel-assisted etching of crystalline silicon surfaces in photovoltaic devices

Here we present a study of the nickel-assisted etching applied to form uniform black silicon layers on crystalline silicon substrates. We related the parameters used for technological process control (etchant, nickel thickness) to parameters of the obtained surface and explain the correlation using the etching model responsible for etching of the silicon covered by a thin nickel film. The increase in the thickness of the metal catalyst did not suppress the etching completely but allowed one to tune the roughness of the silicon surface. The rate of the electrochemical etching was additionally changed by adaptation of the proportion of components in the complex etchant. Depending on the intentionally selected conditions, the duration of the optimized process was from 3 to 10 min. The lowest optical reflection commonly accepted as the black silicon surface was obtained for the mixture with a low amount of the active etchant component. It was demonstrated that the method is acceptable to improve the characteristics of a photovoltaic cell.

Structural and optical proprieties of [M(8-HQ)2(H2O)2] {M = Ni(II), Co(II)} thin films deposed by chemical bath deposition method

The objective of this study was the deposition of thin films of 8-hydroxyquinolin (8-HQ) Cobalt(II) and Nickel(II) complexes onto glass substrates using the chemical bath deposition (CBD) method. The deposition experiments were carried out under the effect of some physicochemical factors such as solution temperature (25 °C–55 °C), medium pH (1–6), metal: ligand molar stoichiometric ratio (1:1–1:3), and immersion time (in the range 10–60 min). The obtained thin films were characterized using many analytical methods (UV-Vis spectrophotometry, infrared spectrophotometry, optical microscopy, scanning electron microscopy, and X-ray diffraction). The study of the optical properties of the obtained thin films showed that the complexes [Ni(8-HQ)2(H2O)2] and [Co(8-HQ)2(H2O)2] have strong absorbance in UV area corresponding to a π-π* or n-π* electronic transition between the HOMO and the LUMO with a gap’s energy in the range 4.1 and 4.4 eV. In the light of the optical measurements, [Ni(8-HQ)2(H2O)2] and [Co(8-HQ)2(H2O)2] complexes can be considered as semiconductors.

Facile and Eco-Friendly Method for Fabrication of Superhydrophobic Surface on Copper Metal

A superhydrophobic nickel film was successfully fabricated on copper surface by galvanostatic deposition in presence of palmitic acid as a superhydrophobic material and eggshell extract as additive. The electrodeposition process in presence of eggshell extract exhibits potential oscillations with 180° antiphase shape. The surface morphology of the as-prepared nickel film was examined by scanning electron microscope (SEM), the results show that, in absence of eggshell extract the formed nickel film shows a smooth shape while in presence of eggshell extract the formed nickel film exhibits micro-nano structure with pine cone shape. The EDX results confirm the deposition of thin film of nickel on copper surface modified by low surface energy palmitic acid and the eggshell extract. The wettability of the deposited films indicates that, the as-prepared nickel film in presence of eggshell extract (NiC) exhibits superhydrophobicity with contact angle of 162° and sliding angle of 3o. The formed superhydrophobic film in presence of eggshell extract exhibits superhydrophobicity even after 200 abrasion, reflecting excellent mechanical resistance. In acidic, neutral, and basic environments the prepared superhydrophobic film display strong chemical stability. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicate that the formed superhydrophobic surface exhibits high corrosion resistance behavior.

Electrical, Transport, and Optical Properties of Multifunctional Graphitic Films Synthesized on Dielectric Surfaces by Nickel Nanolayer-Assisted Pyrolysis

We demonstrate that predepositing a nanometrically thin nickel film on a dielectric surface is sufficient to transform an amorphous pyrolyzed photoresist film (PPF) into a graphitic film (GRF) enriched with nickel particles. The GRF shows 3 orders of magnitude higher carrier mobility than the amorphous PPF, whereas its electrical conductivity doubles after etching away the nickel remains. The pronounced 2D peak in the Raman spectrum, almost dispersionless absorbance in the spectral range of 750-2000 nm, and the saturable absorption coefficient indicate that GRF possesses a graphene-like band structure. The proposed cost-efficient and scalable synthesis route opens avenues toward fabrication of micron size patterned graphitic structures of any shape directly on a dielectric substrate. Having graphene-like transport and electrical properties at 20 times higher absorbance than the single-layer graphene, GRF is attractive for fabrication of fast modulators for optical radiation, bolometers, and other photonics and optoelectronic devices that require enhanced optical absorption.

Facile and scalable fabrication of nanostructured nickel thin film electrodes for electrochemical detection of formaldehyde.

Fluorine doped tin oxide (FTO) substrates were deposited with thin metallic nickel films, having distinguishable surface morphologies, via a rapid, facile, and scalable approach i.e., aerosol assisted chemical vapor deposition (AACVD). The growth patterns of the nickel deposits were studied, showing a coalescing behavior as a function of the deposition time in a hierarchical fashion. These studies were followed by electrochemical measurements to design an efficient sensor for formaldehyde detection. The electrochemical responses were correlated with the surface characteristics of the films, whereas the optimized parameters were subjected to the evaluation of sensing performances. The developed sensor demonstrated a detection limit of 8.3 × 10-6 M and a sensitivity of 0.18 A M-1 within a linear range of 0-6.5 mM. Further, the sensor showed a response time of less than 5 s, selectivity against similar concentrations of methanol and formaldehyde, and recovery of ∼102% in a spiked fruit juice sample. Finally, the commercial viability of the fabrication procedure is tested using batch production analysis, and the high reproducibility of the data shows a promising future in mass production. It is envisaged that such low-cost fabrication procedures can be converted into many useful applications in the future.

Influence of annealing temperature on corrosion inhibition of Cu coated with Ni in NaCl solution

Copper substrates were coated with a 100 nm nickel thin film and post-annealed with a 300 sccm flow of nitrogen at different temperatures. The formation of nickel nitride is confirmed by x-ray diffraction analyses. Atomic force microscopy (AFM) results showed morphological changes by variation of the annealing temperature which is explained on the basis of physical processes (e.g., diffusion, penetration depth). The electrochemical behavior of the samples in 0.6 M NaCl solution was investigated by means of electrochemical impedance spectroscopy and polarization measurements. EIS data were confirmed by Kramers-Kronig transformations and by the fitting of these data with equivalent electrical circuits. Results showed that the 473 K sample has the highest corrosion inhibition efficiency (). This can be due to the large grain size, hence a lower number of grain boundaries and the lowest surface roughness and porosity of this sample.

Laser-Based Fabrication of Microstructures on Nickel Thin Films and Its Applications in On-Chip Thin Film Inductors

This work reports on the fabrication of microbump structures on nickel (Ni) films by single-pulse, localized laser irradiation. Conditions for the reproducible formation of such microstructures have been identified in terms of laser-irradiation and film parameters after systematic studies involving a relevant parameter space. Ni films deposited by vacuum evaporation were found to be better suited for reproducible laser microstructuring because they lack the typical cracks and voids morphology of sputtered films. The continuous and smooth nature of the evaporated films facilitated a radially symmetric heat flow propagation upon laser irradiation, which then resulted in a complex combination of thermal expansion, deformation, and other processes leading to a high yield of microstructures. An improvement in the inductance and the quality factor of on-chip spiral inductors, incorporating such laser-microstructured ferromagnetic nickel thin films was observed, which demonstrates the potential of such a laser-based method for fabrication or fine tuning of various micro-/nano-electric/electronic sensor and other components and systems.

Crystal structure and diffraction pattern of Ni thin film

The crystal structure of Nickel (Ni) thin film has fascinated the material science research groups. An area in which Ni has found applications is the usage of thin films, which are essential in modern technologies and their optimization is the focus of continued growing research. Its application in thin films promotes the fabrication of nanostructured materials. The structural parameters are calculated by crystal visualization and molecular visualization and functional program, diamond software. The table of angles and the powder diffraction pattern of nickel (Ni) is main focus of this research work.

Fabrication of Nickel Coating on a Stainless Steel Mesh for Supercapacitor Applications

A stainless steel mesh current collector was coated by one-step electrochemical method for supercapacitor applications. As stainless steel mesh has a high surface area, accessibility of ions may be achieved easier than bulk stainless steel. Thin nickel films were synthesized in an aqueous solution electrolyte medium by a three-electrodes electrochemical configuration system under room temperature conditions by applying the potential of -1.5 V for 150, 300 and 600 seconds. The electrochemical capacitive characterization of the prepared nickel films was investigated in 1 M KOH electrolyte solution. The surface morphology of the prepared electrodes was examined. Microstructures of nickel coatings obtained on stainless steel wire surface were similar to tree peels. Therefore, electrodes with high surface area were obtained in the electrodeposition of nickel from pyrophosphate medium. The ion and electron transfer rates between the nickel-coated stainless steel mesh and the alkaline electrolyte were increased. Nickel coated steel mesh having a redox reaction at positive potential between +0.2 V and +0.6 V could be used as cathode electrodes. The nickel/stainless steel mesh electrode has a specific capacity of 1090 F g-1 at the scan rate of 5 mV s-1. As the electroactivity of stainless steel in KOH electrolyte was increased with nickel film, nickel-based coatings on stainless steel mesh surface in aqueous solution can be used as cathode electrodes in supercapacitor applications.