Figure 5 - available from: Journal of Materials Science: Materials in Electronics
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In this work a series of RuO2 thin films were
synthesized through sol–gel spin coating processes and
their structural and electrical properties are studied. The (1
1 0), (1 0 1), (2 0 0), and (2 1 1) characteristic peaks of
RuO2 phase are identified from the annealed RuO2 films
X-ray diffraction profiles. Through the Atomic Force
Microscopy, the su...
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A pure and (Fe-Ni) doped tin oxide thin films were formed on glass substrates by sol-gel dip coating method. Some characterization techniques are used as X-ray diffraction (XRD), UV-vis spectroscopy and atomic force microscopy (AFM) to study the effect of method conditions and dopants on the structural, morphological, and optical properties of thin...
Citations
... This fact gives a clear advantage for RuO 2 as electrodes for the capacitors in DRAM over the currently integrated TiN (∼4.2 eV) and even metallic Ru. 1 In addition, it has been used as a positive electrode material for lithium ion batteries, 24,25 and thin RuO 2 films act as excellent barriers against O 2 diffusion. 26 RuO 2 thin films have been grown for various purposes using techniques such as direct deposition by magnetron sputtering 27,28 or reactive sputtering of Ru. 29 The other commonly employed techniques are pulsed laser deposition, 30,31 electrodeposition from aqueous solution 32 or cyclic voltammetry, 33 sol−gel spin coating method, 34 metal organic chemical vapor deposition, 35,36 chemical vapor deposition (CVD), 37,38 pulsed-CVD, 39 and atomic layer deposition (ALD). 40 −50 Among those techniques to prepare RuO 2 thin films, ALD offers uniform and conformal growth over three-dimensional substrates without compromising the precise control over thickness and composition. ...
Atomic layer deposition (ALD) of ruthenium dioxide (RuO2) thin films using metalorganic precursors and O-2 can be challenging because the O-2 dose needs to be precisely tuned and significant nucleation delays are often observed. Here, we present a low-temperature ALD process for RuO2 combining the inorganic precursor ruthenium tetroxide (RuO4) with alcohols. The process exhibits immediate linear growth at 1 angstrom/cycle when methanol is used as a reactant at deposition temperatures in the range of 60-120 degrees C. When other alcohols are used, the growth per cycle increases with an increasing number of carbon atoms in the alcohol chain. Based on X-ray photoelectron spectroscopy (XPS) and conventional X-ray diffraction, the deposited material is thought to be amorphous RuO2. Interestingly, pair distribution function (PDF) analysis shows that a structural order exists up to 2-3 nm. Modeling of the PDF suggests the presence of Ru nanocrystallites within a predominantly amorphous RuO2 matrix. Thermal annealing to 420 degrees C in an inert atmosphere crystallizes the films into rutile RuO2. The films are conductive, as is evident from a resistivity value of 230 mu Omega.cm for a 20 nm film grown with methanol, and the resistivity decreased to 120 mu Omega.cm after crystallization. Finally, based on in situ mass spectrometry, in situ infrared spectroscopy, and in vacuo XPS studies, an ALD reaction mechanism is proposed, involving partial reduction of the RuO2 surface by the alcohol followed by reoxidation of the surface by RuO4 and concomitant deposition of RuO2.
... Thin films of ruthenium oxide have been grown by adopting different techniques, such as reactive sputtering [18], electrodeposition [19] (even under pulsed modality [20,21]), electro-spray deposition [22], as well as powder-to-electrode [23]. Other common routes include thermal decomposition of sol-gel [24,25] of hydroalcoholic solutions containing salt precursors [1,26] where the surface coating is generally conducted by drop or dip casting. ...
Ruthenium oxide (RuOx) thin films were spin coated by thermal decomposition of alcoholic solutions of RuCl3 on titanium foils and subsequently annealed at 400 °C. The effect of spin coating parameters, such as spinning speed, volume, and molar concentration of the precursor as well as the number of deposits, on the morphology and electrochemical performance of the electrodes was investigated. The films were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX), cyclic voltammetry (CV) with and without chloride, and linear sweep voltammetry (LSV). The prepared materials were also compared to drop cast films and spin-coated films obtained by adopting low-temperature intermediate treatments. The results indicate that even dispersion of the oxide layer was always achieved. By tuning the spin coating parameters, it was possible to obtain different electrochemical responses. The most influential parameter is the number of deposits, while the concentration of the precursor salt and the rotation speed were less relevant, under the adopted conditions.
... The graphite with an energy gap close to 0 eV and a work function of about 4.2−5.2 eV [43] can form with RuO2, with an energy gap equal to 2.6−2.9 eV, as mentioned above, and the work function of about 5.2 eV [44], a junction similar to the neutral contact with a barrier height not higher than 2.9 eV. The barrier can be easily overcome by the photon energy of the light used. ...
Abstract: Plasma-enhanced chemical vapor deposition (PECVD) was used to produce new
Ru-based thin catalytic films. The surface molecular structure of the films was examined by X-ray photoelectron spectroscopy (XPS). To determine the electro- and photoelectrochemical properties, the oxygen evolution reaction (OER) process was investigated by linear sweep voltammetry (LSV) at pH = 13.6. It was found that Ru atoms were mainly in the metallic state (Ru0) in the as-deposited films, whereas after the electrochemical stabilization, higher oxidation states, mainly Ru+4 (RuO2),
were formed. The stabilized films exhibited high catalytic activity in OER—for the electrochemical process, the onset and η10 overpotentials were approx. 220 and 350 mV, respectively, while for the photoelectrochemical process, the pure photocurrent density of about 160 mA/cm2 mg was achieved at 1.6 V (vs. reversible hydrogen electrode (RHE)). The plasma-deposited RuOX catalyst appears to be an interesting candidate for photoanode material for photoelectrochemical (PEC) water splitting.
... RuO 2 is one of the most used metal oxides due to easy synthesis, high theoretical capacitance (C sp = 1358 F/g) [124], rapid charge/discharge processes, long life cycle [125,126], and high gravimetric capacity [127]. RuO 2 ·xH 2 O has been synthesized by vapor-phase deposition from RuO 4 [128][129][130]. ...
In this review article, we have presented for the first time the new applications of supercapacitor technologies and working principles of the family of RuO2–carbon-based nanofiller-reinforced conducting polymer nanocomposites. Our review focuses on pseudocapacitors and symmetric and asymmetric supercapacitors. Over the last years, the supercapacitors as a new technology in energy storage systems have attracted more and more attention. They have some unique characteristics such as fast charge/discharge capability, high energy and power densities, and long stability. However, the need for economic, compatible, and easy synthesis materials for supercapacitors have led to the development of RuO2–carbon-based nanofiller-reinforced conducting polymer nanocomposites with RuO2. Therefore, the aim of this manuscript was to review RuO2–carbon-based nanofiller-reinforced conducting polymer nanocomposites with RuO2 over the last 17 years.
... Because of various morphologies obtained, values in the range 40-3600 μΩcm were reported for the electrical resistivity of RuO 2 thin films [27][28][29][30][31][32][33][34][35]. The large variations in the electrical resistivity of RuO 2 thin films have been mainly correlated to the film morphology rather than to the chemical composition variations. ...
The present paper reports on an experimental investigation of the structural, electrical and optical properties of Ru rich Ru 1-x Ti x O 2 thin films. Rutile single-phase Ru 1-x Ti x O 2 thin films have been deposited by reactive hybrid High-power impulse magnetron sputtering (HiPIMS) and direct current magnetron sputtering (DCMS) at a substrate temperature of 250 °C. The HiPIMS source was applied to the Ru target while the DCMS source was connected to the Ti target in order to vary the Ti content in the films. The films are well crystallized and compact with randomly orientated nanocrystallites. The optical properties have been investigated by ellipsometric measurements in the optical energy range from 1.3 eV to 3.3 eV, while the electrical resistivity has been measured in the Van der Paw configuration at room temperature. The electrical resistivity increases gradually from 70 μΩcm for pure RuO 2 to about 243 μΩcm for Ru 1-x Ti x O 2 films with x = 0.13. The optical properties are correlated with the Ti doping. The refractive index n changes from a strong dispersion relationship to a moderate one with increasing Ti content.
... The SnSe exists as a layered compound with an orthorhombic crystal and has the arrangement of atoms in the crystal lattice similar to a severely distorted NaCl structure [12]. Because of their interesting physical properties and device applications a variety of techniques has been used for the deposition of SnSe films, such as chemical bath deposition [13], sol-gel method [14], vacuum evaporation, chemical vapor deposition, electrodeposition [15,16] and solvothermal routes [15]. The selection of synthesis mechanism is very crucial in controlling the properties of developed nanomaterials. ...
SnSe thin films have been prepared by chemical bath deposition method at different substrate temperature. The influence of deposition temperature on structural, optical and electrical properties of polycrystalline SnSe films have been investigated using X-ray diffraction, optical absorbance and conductivity measurements. The X-ray diffraction study reveals the orthorhombic structure of the SnSe films oriented along the (111) direction. The structural parameters such as lattice spacing, crystallite size, strain, number of crystallites per unit area and dislocation density have been evaluated. Optical absorbance measurement indicates the existence of direct allowed band gap in the range 1.50–1.91 eV. The dark conductivity (σd) and photoconductivity (σph) measurement in the temperature range (278–385 K), indicates that the conduction in these materials is through an activation process having one activation energy. σd and σph values decrease with the decrease of crystallite size. The value of photosensitivity, carrier life time and trap depth have also been calculated.
While efficient for electrochemical hydrogen evolution reaction (HER), Pt is limited by its cost and rarity. Traditional Pt catalysts and Pt single-atom (aPt) catalysts (Pt-SACs) face challenges in maintaining kinetically favorable HER pathways (Volmer–Tafel) at ultralow Pt loadings. Herein, carbon-promoted aPts were deposited on RuO2 without the addition of reductants. aPts confined on carbon-supported RuO2 nanorods (aPt/RuO2NR/Carbon) promoted “inter-aPts” Tafel. aPt/RuO2NR/Carbon is the Pt-SAC that retained underpotentially deposited H; additionally, its HER onset overpotential was “negative”. The aPt/RuO2NR/Carbon exhibited 260-fold higher Pt mass activity (imPt)/turnover frequency (TOF) (522.7 A mg–1/528.4 s–1) than that of commercial Pt/C (1.9 A mg–1/1.9 s–1). In an ultralow Pt loading (0.19 μg cm–2), the HER rate-determining step maintained Volmer–Tafel and the Pt utilization efficiency was 100.3%.
Ruthenium oxide has long been considered as an excellent pseudocapacitive electrode material with high specific capacitance and high energy density, but suffers from poor electrochemical stability. In this work, the capacitive performance and electrochemical stability of RuO2 are significantly enhanced by applying hybrid RuO2 materials, which are prepared by precipitation reaction using RuCl3 in the presence of polyhydroxy organic molecules. RuO2 wrapped by sorbitol and tween is defined as RuO2@S+T, and by glucose and tween is defined as RuO2@G+T. It is shown that the specific capacitances of RuO2@S+T and RuO2@G+T at 1 A g⁻¹ are 1865.7 and 1792.0 F g⁻¹, much larger than the 602.6 F g⁻¹ of pristine RuO2. The improvement in electrochemical stability is also evident, with the capacitance retention of 93.9% and 90.2% for RuO2@S+T and RuO2@G+T, respectively, after 8000 charging-discharging cycles, which is much more stable than the 30.2% for pristine RuO2. This improvement can be attributed to the small size and uniform distribution of RuO2@S+T and RuO2@G+T nanoparticles that facilitate proton and electron transfer, as well as the surrounding organic molecules that can stabilize RuO2 structure and also facilitate proton transfer. The hybrid RuO2 material used in this work could be extended to design and invent stable electrode materials for high-performance supercapacitors.
Iridium Oxide (IrO2) is a metal oxide with a rutile crystalline structure, analogous to the TiO2
rutile polymorph. Unlike other oxides of transition metals, IrO2 shows a metallic type conductivity and
displays a lowsurfacework function. IrO2 is also characterized by a high chemical stability. These highly
desirable properties make IrO2 a rightful candidate for specific applications. Furthermore, IrO2 can
be synthesized in the form of a wide variety of nanostructures ranging from nanopowder, nanosheets,
nanotubes, nanorods, nanowires, and nanoporous thin films. IrO2 nanostructuration, which allows
its attractive intrinsic properties to be enhanced, can therefore be exploited according to the pursued
application. Indeed, IrO2 nanostructures have shown utility in fields that span from electrocatalysis,
electrochromic devices, sensors, fuel cell and supercapacitors. After a brief description of the IrO2
structure and properties, the present review will describe the main employed synthetic methodologies
that are followed to prepare selectively the various types of nanostructures, highlighting in each case the
advantages brought by the nanostructuration illustrating their performances and applications.
We demonstrate a facile and seedless wet chemical process to deposit RuO2 thin film on a glass slide. The process entails the use of dopamine and its oxidized form, polydopamine (PDA), as the reducing and chelating agent, as well as the adhesive agent bonding the RuO2 and glass slide. The formula starts with the oxidation of K2RuCl5 to prepare RuO4 solution, followed by its reduction by dopamine to form chelated RuO2 colloids for the deposition of amorphous RuO2 thin film containing 26.5 at% hydrous RuO2 and 73.5 at% RuO2. After a mild Ar annealing, the RuO2 thin film exhibits a rutile phase with (110) preferred orientation. Elemental analysis indicates incomplete pyrolysis of PDA. Results from X-ray absorption spectroscopy confirm the presence of RuO4 and its transformation to RuO2. Electrochemical analysis of the adsorbed dopamine molecules on an ITO substrate validates the oxidative behavior of dopamine. The bonding strength of RuO2 thin film is determined by a tape-peeling test in which both the as-deposited and annealed RuO2 thin films show robust adhesion to the glass substrate.
