Nickel Films Research Articles

Elimination Voltammetry with Linear Scan (ELSV) Study of Methanol Electro-Oxidation on Galvanostatically Deposited Ni

Elimination voltammetry with linear scan (EVLS) is an analysis method that allows the decomposition of the measured current into its capacitive, diffusional, and kinetic contributions. This method was applied to study the electro-oxidation of methanol on nickel films deposited galvanostatically on gold. This analysis suggests a strong dependence of the NiOOH formation and methanol oxidation on the scan rate. According to the EVLS deconvolution, at high scan rates (> 100 mV s−1), the oxidation of Ni(OH)2 to NiOOH has a remarkable resemblance to a reaction that proceeds in an adsorbed state. Decreasing the scan rate results in qualitative changes of the particular currents, implying the occurrence of electrochemical processes that require a larger time scale (>0.5 s), like the formation of the water intercalated γ-NiOOH. For the methanol electro-oxidation process, the main contribution comes from the kinetic current; however, increasing the scan rate reveals a parallel diffusional process related to the oxygen evolution.

24]Crown-8-modified carbon nanotubes for templating metal deposition and active materials for pseudocapacitors

A uniform nickel film could be coated on crown ether-modified carbon nanotubes (c-CNTs) by electroless deposition.

Nickel thin film preparation and its characterization as catalyst for HWC-in plasma-PECVD-growth graphene

Nickel thin film, aimed at catalyst layer for HWC-in plasma-PECVD-growth of graphene, has been deposited on SiO2 glass of microscope slide by thermal evaporation method. The thickness of the as-deposited Ni films was not uniform ranging from 200 nm to 700 nm as revealed from cross sectional SEM image. To reduce the film thickness and improve the crystal quality of the films, the samples were annealed in the furnace with three different temperatures, T = 400 °C, 500 °C, and 600 °C, for three hours. SEM images of the post-treatment indicated that the film thickness decreased to about 100–200 nm after annealed at 500 °C for 3 h. Increasing the annealing temperature to 600 °C leads the nickel atoms out of the substrate so that it leaves the substrate without nickel thin film anymore. The disappearing of the Nickel film after annealing at temperature 600 °C was confirmed by EDS spectrum examination which showed that there was no nickel element in the sample. Due to the loss of nickel thin film after annealing at 600 °C, we set the annealing temperature at 500 °C and optimized duration of annealing. It was found that after annealing for 4 h the obtained thickness of thin film was averagely 44 ± 6 nm with some spread piles on the film. Increasing annealing duration to 5 h lead to increasing the thickness of thin film nickel to be 66 ± 14 nm which seems contradict with our expectation. However, the tens order magnitude of thin film thickness obtained is the expected result for graphene growth.

Statistical analysis of electrodeposited nickel coating to S275JR grade mild steel

In recent trends the electrodeposition process are very important of the soft material as well as hard material to avoid the corrosion resistance. For this research, S275JR mild steel specimens are considered as a base material for the coating A thin film Nickel coatings are made on the S275JR mild steel with the concentration of electrodepositing route. Due to this electrodeposition work modified the surface structure, improves the mechanical properties and turned to high corrosion resistance in nature. Three process parameters are considered for this work namely: voltage rate, stirring speed and time. The response values of micro hardness and mass of deposition are analyzed by L9 orthogonal array effectively. Enhanced micro hardness and mass of deposition of S275JR mild steel is obtained by the influence of two major parameters such as time period and the stirring speed. Rank order and delta values are point out the parameters precedence. ANOVA statistical approaches informed the process factors role and contribution effectively.

Sensing chiral magnetic noise via quantum impurity relaxometry

We present a theory for quantum impurity relaxometry of magnons in thin films, exhibiting quantitative agreement with recent experiments without needing arbitrary scale factors used in theoretical models thus far. Our theory reveals that chiral coupling between prototypical spin>1/2 quantum impurities and magnons plays a central role in determining impurity relaxation, which is further corroborated by our experiments on nickel films interfaced with nitrogen-vacancy centers. Along with advancing magnonics and understanding decoherence in hybrid quantum platforms with magnets, the ability of a quantum impurity spin to sense chiral magnetic noise presents an opportunity to probe chiral phenomena in condensed matter.

Single particle tunneling spectrum of superconducting Nd1-xSrxNiO2 thin films

The pairing mechanism in cuprates remains as one of the most challenging issues in condensed matter physics. Recently, superconductivity was discovered in thin films of the infinite-layer nickelate Nd1-xSrxNiO2 (x = 0.12–0.25) which is believed to have the similar 3d9 orbital electrons as that in cuprates. Here we report single-particle tunneling measurements on the superconducting nickelate thin films. We find predominantly two types of tunneling spectra, one shows a V-shape feature which can be fitted well by a d-wave gap function with gap maximum of about 3.9 meV, another one exhibits a full gap of about 2.35 meV. Some spectra demonstrate mixed contributions of these two components. Combining with theoretical calculations, we attribute the d-wave gap to the pairing potential of the {mathrm{Ni - }}3d_{x^2 - y^2} orbital. Several possible reasons are given for explaining the full gap feature. Our results indicate both similarities and distinctions between the newly found Ni-based superconductors and cuprates.

Direct Graphene Synthesis on Lithium Niobate Substrate by Carbon Ion Implantation

A dozen-micron-scale 4-7 layers of graphene was synthesized directly on Lithium Niobate (LiNbO3, LN) by carbon implantation in nickel covered LiNbO3 film. The 1.52E16 ions·cm-2 carbon ions of 80KeV were implanted to the nickel film with the implantation depth of 100nm, which is close to the interface between the nickel film and LiNbO3. The implanted carbon atoms dissolved in nickel at an elevated temperature and diffused towards to the interface between nickel film and LiNbO3 during annealing. After the nickel film fell off, the graphene material was found by Raman spectroscopy and confirmed by the Atomic Force Microscope (AFM) topographic image. Implantation combined with patterned metal film suggests the possibility to engineer two-dimensional graphene with special confinement. It also provides a valuable and novel way for integrating graphene-wafer structure for other available substrate wafer in microelectronics and photonics devices.

LARGE VALUES OF THE TRANSVERSE M UES OF THE TRANSVERSE MAGNETIC RESISTANCEOF SINGLE CRYSTAL NICKEL FILMS

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

Study of physical properties of chemical bath deposited nickel oxide thin films

Abstract Being the p-type metal oxide semiconductor, nickel oxide (NiO) has gained lots of interest due to its interesting properties towards various applications. Here, the emphasis has been studying the force of attraction between the contact points of deposited thin film and its substrate using adhesion measurements. Initially the chemical bath deposited nickel (Ni) films on glass substrates were synthesized and further oxidized in air at 300 °C for 2 h to get the NiO thin films. The structural and morphological studies of Ni and NiO films were undertaken using XRD and SEM respectively. The crystal structure of NiO was confirmed with (1 1 1), (2 0 0), (2 2 0) peaks. The flakes like surface morphology was observed. The oxidized thin films showed higher adhesion than the metal thin films. The effect of deposition time on adhesion was also studied.

Role of substrate on film thickness, structural, compositional and magnetic properties of CoNi alloy thin films by low temperature electrodeposition technique

Impressment of Cobalt and Nickel based alloys in industries for the last few years attracted many researchers due to its significant features of physical, chemical and magnetic properties. The present work focused the structural, compositional, morphological and magnetic properties of Cobalt Nickel alloy thin film growth by one of the chemical methods. Thin films of Cobalt Nickel have been deposited on various substrates by means of low cost galvanostatic electrodeposition technique. Structural investigation showed that the deposited films have face centred cubic structure with orientation of crystallites along (111) plane. The structural parameters such as crystallite size, rms microstrain, dislocation density and stacking fault probability are estimated for the deposited films. Morphological features along with film composition showed that the deposited films have smooth surface with stoichiometry. Magnetic properties such as coercivity, remanence, retentivity was estimated and the results are reported.

Nondestructive Femtosecond Laser Lithography of Ni Nanocavities by Controlled Thermo-Mechanical Spallation at the Nanoscale.

We present a new approach to femtosecond direct laser writing lithography to pattern nanocavities in ferromagnetic thin films. To demonstrate the concept, we irradiated 300 nm thin nickel films by single intense femtosecond laser pulses through glass substrate. Using a fluence above the ablation threshold, the process is destructive, leading to the formation of an ablation crater. By progressively lowering the laser fluence, the formation of closed spallation cavities below the ablation threshold is achieved. Systematic studies by the electron and optical interferometric microscopies, supported by molecular dynamics simulations, enabled us to gain an understanding of the thermo-mechanical spallation mechanism at the solid-molten interface. We achieved the fabrication of periodic arrangements of closed spallation nanocavities. Due to their topology, closed magnetic nanocavities can support unique couplings of multiple excitations (magnetic, optical, acoustic, spintronic). Thereby, they offer a unique physics playground for emerging fields in magnetism, magneto-photonic, and magneto-acoustic applications.

Structural and optoelectronic properties of epitaxial Ni-substituted Cr2O3 thin films for p-type TCO applications

Transparent and conducting epitaxial thin films of pristine chromium oxide (Cr2O3) and nickel (Ni) substituted Cr2O3 were deposited on the sapphire substrates using pulsed laser deposition (PLD) technique. Co-precipitation method was used to prepare targets of Cr2O3 nanomaterials with varying Ni content (i.e. x = 0, 0.03, 0.05 and 0.1). In-plane diffraction (i.e. ϕ-scan) measurements confirmed that all thin films were epitaxially grown on sapphire substrates. X-ray diffraction (XRD) patterns illustrated that all thin films orienting along (006) plane only and crystallize in the rhombohedral structure of Cr2O3, and structure remains unchanged with Ni-substitution. Consequently, Cr cations were replaced by Ni counter-cations in Cr2O3 structure, which lead to the delocalization of holes and improve mobility. Moreover, an increase in Ni-content also leads to upsurge in the carrier concentration. Hence, both factors contributed to the improvement in Ni-substituted Cr2O3 thin films' conductivity and retained the p-type character as well. UV–Vis spectra demonstrated that pristine Cr2O3 thin film acquired an optical band gap energy of 3.64 eV, decreasing to 3.48 eV with Ni-substitution. Furthermore, optical transmittance spectra illustrated the average transparency of 77–81% for as-deposited thin films in the visible region. Therefore, this material can render a wide variety of applications in the field of optoelectronics.

Development of a portable electroanalytical method using nickel modified screen-printed carbon electrode for ethinylestradiol determination in organic fertilizers

Urine and struvite are organic fertilizers that have all nutritional requirements for the growth of a plant. However, these fertilizers may contain some emerging organic contaminants, such as ethinylestradiol, which is one of the most common hormones found in aquatic environments and can cause several changes in living organisms. Thus, the present study developed a fast, sensitive, inexpensive, and portable method for determining ethinylestradiol in urine and struvite, using square wave voltammetry (SWV) and screen-printed carbon electrodes modified with electrodeposited nickel film (SPCE-Ni). The electrodeposition of the nickel film on the screen-printed electrode was performed by cyclic voltammetry and optimized using complete factorial design 23 and central composite design. The parameters optimized for SPCE-Ni were: number of cycles (1000); scan rate (5 V s−1) and Ni2+ concentration (9.4 mmol L−1). The operational parameters of the SWV for ethinylestradiol analysis were also optimized by experimental designs and obtained the following optimal values: step potential (10 mV), modulation amplitude (40 mV), and frequency (20 Hz). The method used 0.1 mol L−1 BR buffer (pH 8.0) as support electrolyte and presented a limit of detection of 0.052 µmol L−1 (R2 = 0.996). Ethinylestradiol recovery test in struvite, human urine, synthetic urine, and pharmaceutical tablets ranged from 93.9% to 107.5%, indicating that there is no matrix effect. Furthermore, an interference test was performed with several drugs did not show any significant changes in the ethinylestradiol analytical signal, guaranteeing a greater precision of the method. These results reinforce the possibility of applying the proposed method in loco with a practical and fast way, without the need to use significant amounts of sample.

Observation of ion acceleration in nanosecond laser generated plasma on a nickel thin film under rear ablation geometry.

In this article we report acceleration observed for the ions produced in a 50-nm-thick nickel film coated on a quartz substrate, under nanosecond laser ablation, in the rear ablation geometry. A detailed study with varying background pressure and laser energy is done. Spectroscopic study including spectroscopic time of flight (STOF) measurements of ionic and other neutral transitions from the plasma has been undertaken. The STOF spectra recorded for ionic transition clearly show an enhancement in the velocity of the slow component as the background pressure increases. In addition, a large asymmetric spectral broadening in the 712.22-nm neutral line is observed, which increases with background pressure. While these observations have similarity to some of the reported studies on the acceleration of ionic species through double-layer formation, the electric fields calculated from the measured acceleration appear to be anomalously higher, and a double-layer concept seems to be inadequate. Moreover, the large asymmetry observed in the neutral line profile is indicative of microelectric fields present inside the laser produced plasma plume, which may play a role in the continuous acceleration of the ions. Interestingly, this asymmetry in spectral broadening exhibits temporal and spatial dependence, which indicates that significant electric field is present in the plasma plume even for longer duration and larger distance from the target. These spectroscopic observations of acceleration have also been complemented by triple Langmuir probe measurements. To the best of our information, such observations regarding large ion acceleration for the rather low laser intensities as used in this experiment have not been reported in literature so far.

Direct Electroless Deposition of Nickel onto Silicon Nitride Ceramic: A Novel Approach for Copper Metallization of Micro‐/Nano‐fabricated Devices

Current surface modification chemistry of silicon nitride (Si3N4) in the fabrication of micro/nano systems (MEMS/NEMS) mainly relies on multistep chemical processes, essentially consisting of a surface pretreatment and a challenging silanization procedure. Although direct modification of Si3N4 surface has rarely been reported in the literature, here a simple surface functionalization strategy using diazonium chemistry in open air and at room temperature, which provides a practical solution to directly attach aminophenyl groups to pristine silicon nitride without altering its intrinsic properties, is described. These strongly grafted amine‐terminated groups are easily activated to become nuclei for initializing electroless nickel plating (autocatalytic nickel deposition). This electroless nickel plating of silicon nitride while avoiding the multiplicity and complexity of the process steps is ideal for its integration into a typical MEMS/NEMS process flow. In a possible integration scheme, due to its suitable properties, this nickel film serves as a conducting seed layer for the electrolytic deposition of copper to fill the microdevices, thereby avoids the use of typically employed expensive vacuum processes.

Transfer-Free Layered Graphene on Silica via Segregation through a Nickel Film for Electronic Applications

Transfer-free graphene growth via annealing-induced carbon segregation was investigated on a series of carbon/metal/silica layered samples prepared by sequential deposition of Ni from evaporation o...

Annealing Temperature on Contact Properties between Nickel Film and Hydrogen-Terminated Single Crystal Diamond

Ohmic contact of nickel on hydrogen-terminated single-crystal diamond film was investigated with an annealing temperature ranging from room temperature to 750 °C in hydrogen atmosphere. Nickel film was deposited on a hydrogen-terminated single-crystal diamond surface with gold film in order to protect it from oxidation. Contact properties between nickel and hydrogen-terminated single crystal diamond were measured by a circular transmission line model. The lowest specific contact resistivity was 7.82 × 10−5 Ω cm2 at annealing temperature of 750 °C, indicating good ohmic contact, which reveals improved thermal stability by increasing temperature.

Superior Durability of Dissimilar Material Joint between Steel and Thermoplastic Resin with Roughened Electrodeposited Nickel Interlayer

The durability of the dissimilar material joint between a steel coated with a roughened nickel plating‐film and a thermoplastic resin is assessed. The roughened nickel film is fabricated by electrodeposition using carbon nanotubes (CNTs) as the roughening agent and a polyphenylenesulfide (PPS) resin as the thermoplastic resin. The plated steel and PPS resin are joined by injection molding without adhesive. The bonding strength is determined by a tensile lap shear strength test during the durability tests that includes a high‐temperature and high‐humidity test (85 ± 2 °C, 85 ± 2% relative humidity; 0–2000 h) and a thermal shock test (−50 °C–150 °C; 0–1000 cycles). During the high‐temperature and high‐humidity test, the bonding samples maintain their initial bonding strength (>40 MPa) even after 2000 h. By contrast, during the thermal shock test, although the bonding strength gradually decreases with increasing number of cycles, it remains above 20 MPa even after 1000 cycles. The mechanism of the deterioration of the bonding strength during the thermal shock test is analyzed in detail. The present joining method, which uses a roughened plating film as an interlayer, offers a way to achieve not only high initial bonding strength but also bonding durability for dissimilar material joining between steels and resins.

Effect of electrodeposition potential and time for nickel film generation from ionic liquid electrolytes for asymmetric supercapacitor production

The electrochemical performance of nickel-based modified electrodes deposited on stainless steel from ionic liquid was studied in the positive potential regions of alkaline solution to combine with graphite in the negative potential regions for asymmetric supercapacitor applications. Nickel-based electrodes were electroplated, separately, from an ionic liquid solution containing Ni2+ ions and an aqueous solution (Watts solution). The films obtained from the non-aqueous solutions (ionic liquid) were more stable and had better electrochemical performance than those from Watts solutions. The electrochemical performance, including capacitance, power and stability of electrodes were optimized depending on the deposition conditions, specifically, the electrolyte, deposition potential and deposition times. The performance of electrode may be regulated by altering material structure via the deposition conditions. The rate limiting reaction of nickel electrodes deposited from the ionic liquids was not dependent on deposition potentials and time. It was noted to be the mixture of surface and diffusional control mechanisms. As nickel-based coatings electrodeposited from ionic liquid had high surface area, they may be more suitable for energy storage electrodes than the electrodes obtained from Watts solution. The highest specific capacitance of the prepared nickel electrodes was found to be 1690 F g−1 for the electrode electrodeposited from ionic liquid by the application of -0.7 V for 300 s. Ion transfer reactions between nickel electrodes of porous nanostructures and alkaline electrolyte were fast as a direct result of the greater surface areas.

Control of hydrogen absorption by nickel films obtained upon magnetic spraying of zirconium alloy using the thermoEMF method

Nickel films formed on the surface of zirconium alloys are often used to protect materials against hydrogen penetration. Hydrogen adsorption on nickel is faster since the latter actively interacts with hydrogen, oxidizes and forms a protective film. The goal of the study is to develop a method providing control of hydrogen absorption by nickel films during vacuum-magnetron sputtering and hydrogenation via measuring thermoEMF. Zirconium alloy E110 was saturated from the gas phase with hydrogen at a temperature of 350°C and a pressure of 2 atm. A specialized Rainbow Spectrum unit was used for coating. It is shown that a nickel film present on the surface significantly affects the hydrogen penetration into the alloy. A coating with a thickness of more than 2 μm deposited by magnetron sputtering on the surface of a zirconium alloy with 1% Nb, almost completely protects the alloy against hydrogen penetration. The magnitude of thermoemf depends on the hydrogen concentration in the zirconium alloy and film thickness. An analysis of the hysteresis width of the thermoEMF temperature loop and a method for determining the effective activation energy of the conductivity of a hydrogenated material coated with a nickel film are presented. The results of the study can be used in assessing the hydrogen concentration and, hence, corrosion protection of the material.