Characterization of diamond-like nanocomposite thin films grown by plasma enhanced chemical vapor deposition
TL;DR: In this article, a-C:H and a-Si:O networks of diamond-like nanocomposite (DLN) thin films were analyzed by atomic force microscopy.
Abstract: Diamond-like nanocomposite (DLN) thin films, comprising the networks of a-C:H and a-Si:O were deposited on pyrex glass or silicon substrate using gas precursors (e.g., hexamethyldisilane, hexamethyldisiloxane, hexamethyldisilazane, or their different combinations) mixed with argon gas, by plasma enhanced chemical vapor deposition technique. Surface morphology of DLN films was analyzed by atomic force microscopy. High-resolution transmission electron microscopic result shows that the films contain nanoparticles within the amorphous structure. Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and x-ray photoelectron spectroscopy (XPS) were used to determine the structural change within the DLN films. The hardness and friction coefficient of the films were measured by nanoindentation and scratch test techniques, respectively. FTIR and XPS studies show the presence of CC, CH, SiC, and SiH bonds in the a-C:H and a-Si:O networks. Using Raman spectroscopy, we also found that the hardness of the DLN films varies with the intensity ratio ID/IG. Finally, we observed that the DLN films has a better performance compared to DLC, when it comes to properties like high hardness, high modulus of elasticity, low surface roughness and low friction coefficient. These characteristics are the critical components in microelectromechanical systems (MEMS) and emerging nanoelectromechanical systems (NEMS).
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TL;DR: In this paper, the role of magnetic field on the structural, morphological, mechanical properties and deposition rate of diamond-like carbon (DLC) thin films has been studied.
Abstract: Diamond-like carbon (DLC) thin films were grown on Si-(100) substrates by a magnetically-assisted pulsed laser deposition (PLD) technique. The role of magnetic field on the structural, morphological, mechanical properties and deposition rate of DLC thin films has been studied. The obtained films were characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM) and nanoindentation techniques. It was found that the diamond-like character, thickness and deposition rate of the DLC films increase in the presence of magnetic field. The films deposited under magnetic field exhibit a denser microstructure and smoother surface with lower surface roughness. Meanwhile, the mechanical properties of the magnetically processed DLC thin films experience an improvement, relative to the conventionally processed ones. It seems that the DLC films deposited under magnetic field can be better candidate for hard and wear resistance coating applications.
102 citations
Cites background from "Characterization of diamond-like na..."
...This behavior is attributed to the enhanced sp bonding in structure [3,35–39]....
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...Diamond-like carbon (DLC) thin films have attracted much interest due to their unique properties such as high hardness, low friction, good wear resistance, optical transparency and high chemical inertness [1–4]....
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TL;DR: In this paper, the structural, hydrophobicity, mechanical, and morphological properties of the diamond-like carbon (DLC) thin films were investigated by Raman spectroscopy, X-ray photoelectron spectrography (XPS), nanoindentation, water contact angle (CA) measurement, atomic force microscopy (AFM), and they were attributed to structural changes during deposition based on the sub-plantation model and stress induced mechanism.
Abstract: Diamond-like carbon (DLC) thin films were deposited by pulsed laser deposition (PLD) on Si-(1 0 0) substrates in the substrate temperature range of room temperature (RT) to 300 °C. The structural, hydrophobicity, mechanical, and morphological properties of the DLC films were investigated by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), nanoindentation, water contact angle (CA) measurement, atomic force microscopy (AFM). It was found that the DLC films deposited at RT were purely amorphous in structure with high sp 3 bonding and had very smooth surfaces. Raman and XPS results indicated a structural transition from amorphous to nano-crystalline graphitic nature, structural ordering of DLC films, and decrease of the sp 3 content with increasing substrate temperature. Degradation of the surface morphology and enhancement of the surface roughness with the substrate temperature were observed by AFM. It was also found that the mechanical properties such as nanohardness, elastic modulus, plastic index parameter, and elastic recovery decreased with the increasing substrate temperature. The CA measurements indicated that the hydrophobicity of DLC films increased with the substrate temperature and was sensitive not only to sp 2 /sp 3 ratio, but also to the ordering of sp 2 clusters. The observed hydrophobicity, mechanical and morphological properties were attributed to structural changes during deposition based on the sub-plantation model and stress induced mechanism.
51 citations
TL;DR: In this paper, the current situation on SiOx containing diamond like carbon (diamond like nanocomposite) films is reviewed and discussed, and a survey of different potential and industrial applications of diamond-like nanocompositionite films is presented.
Abstract: The present article reviews current situation on SiOx containing diamond like carbon (diamond like nanocomposite) films. The overview of different deposition methods and reagents used is presented; chemical composition of different diamond like nanocomposite films is described. Different models of structure of diamond like nanocomposite films are considered. Mechanical, optical, electrical properties as well as surface energy of diamond like nanocomposite films produced by different methods are reviewed and discussed. The survey of different potential and industrial applications of diamond like nanocomposite films is presented.http://dx.doi.org/10.5755/j01.ms.17.4.770
47 citations
Cites background from "Characterization of diamond-like na..."
...The C–H and Si–O stretching vibrations observed in spectra confirms that films are mainly comprised of the interpenetrating a-C:H and a-Si:O networks [9, 47]....
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...Si-H stretching vibrations at 2320 cm [10] observed in FTIR spectra were explained by the idea that some Si atoms are surrounded by some organic environment rather than being incorporated in a SiOx network [9]....
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TL;DR: In this paper, the authors reported the operando and self-healing formation of DLC films at sliding contact surfaces by the addition of synthetic magnesium silicon hydroxide (MSH) nanoparticles to base oil.
Abstract: The paper reports the operando and self-healing formation of DLC films at sliding contact surfaces by the addition of synthetic magnesium silicon hydroxide (MSH) nanoparticles to base oil. The formation of such films leads to a reduction of the coefficient of friction by nearly an order of magnitude and substantially reduces wear losses. The ultralow friction layer characterized by transmission electron microscope (TEM), electron energy loss spectroscopy (EELS), and Raman spectroscopy consists of amorphous DLC containing SiOx that forms in a continuous and self-repairing manner during operation. This environmentally benign and simple approach offers promise for significant advances in lubrication and reduced energy losses in engines and other mechanical systems.
46 citations
TL;DR: In this article, a-C:H:Si:O was mounted on the exterior of the International Space Station (MISSE) via the Materials International Space station (MISCSE) mission 7b.
Abstract: Harsh environments pose materials durability challenges across the automotive, aerospace, and manufacturing sectors, and beyond. While amorphous carbon materials have been used as coatings in many environmentally-demanding applications owing to their unique mechanical, electrical, and optical properties, their limited thermal stability and high reactivity in oxidizing environments have impeded their use in many technologies. Silicon- and oxygen-containing hydrogenated amorphous carbon (a-C:H:Si:O) films are promising for several applications because of their higher thermal stability and lower residual stress compared to hydrogenated amorphous carbon (a-C:H). However, an understanding of their superior thermo-oxidative stability compared to a-C:H is lacking, as it has been inhibited by the intrinsic challenge of characterizing an amorphous, multi-component material. Here, we show that introducing silicon and oxygen in a-C:H slightly enhances the thermal stability in vacuum, but tremendously increases the thermo-oxidative stability and the resistance to degradation upon exposure to the harsh conditions of low Earth orbit (LEO). The latter is demonstrated by having mounted samples of a-C:H:Si:O on the exterior of the International Space Station via the Materials International Space Station (MISSE) mission 7b. Exposing lightly-doped a-C:H:Si:O to elevated temperatures under aerobic conditions or to LEO causes carbon volatilization in the near-surface region, producing a silica surface layer that protects the underlying carbon from further removal. These findings provide a novel physically-based understanding of the superior stability of a-C:H:Si:O in harsh environments compared to a-C:H.
41 citations
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TL;DR: In this paper, the authors used a Berkovich indenter to determine hardness and elastic modulus from indentation load-displacement data, and showed that the curve of the curve is not linear, even in the initial stages of the unloading process.
Abstract: The indentation load-displacement behavior of six materials tested with a Berkovich indenter has been carefully documented to establish an improved method for determining hardness and elastic modulus from indentation load-displacement data. The materials included fused silica, soda–lime glass, and single crystals of aluminum, tungsten, quartz, and sapphire. It is shown that the load–displacement curves during unloading in these materials are not linear, even in the initial stages, thereby suggesting that the flat punch approximation used so often in the analysis of unloading data is not entirely adequate. An analysis technique is presented that accounts for the curvature in the unloading data and provides a physically justifiable procedure for determining the depth which should be used in conjunction with the indenter shape function to establish the contact area at peak load. The hardnesses and elastic moduli of the six materials are computed using the analysis procedure and compared with values determined by independent means to assess the accuracy of the method. The results show that with good technique, moduli can be measured to within 5%.
22,557 citations
TL;DR: Raman spectra are reported from single crystals of graphite and other graphite materials as mentioned in this paper, and the Raman intensity of this band is inversely proportional to the crystallite size and is caused by a breakdown of the k-selection rule.
Abstract: Raman spectra are reported from single crystals of graphite and other graphite materials. Single crystals of graphite show one single line at 1575 cm−1. For the other materials like stress‐annealed pyrolitic graphite, commercial graphites, activated charcoal, lampblack, and vitreous carbon another line is detected at 1355 cm−1. The Raman intensity of this band is inversely proportional to the crystallite size and is caused by a breakdown of the k‐selection rule. The intensity of this band allows an estimate of the crystallite size in the surface layer of any carbon sample. Two in‐plane force constants are calculated from the frequencies.
9,373 citations
TL;DR: In this article, the authors review the current understanding of the mechanics governing elastic-plastic indentation as they pertain to load and depth-sensing indentation testing of monolithic materials and provide an update of how they now implement the method to make the most accurate mechanical property measurements.
Abstract: The method we introduced in 1992 for measuring hardness and elastic modulus by instrumented indentation techniques has widely been adopted and used in the characterization of small-scale mechanical behavior. Since its original development, the method has undergone numerous refinements and changes brought about by improvements to testing equipment and techniques as well as from advances in our understanding of the mechanics of elastic–plastic contact. Here, we review our current understanding of the mechanics governing elastic–plastic indentation as they pertain to load and depth-sensing indentation testing of monolithic materials and provide an update of how we now implement the method to make the most accurate mechanical property measurements. The limitations of the method are also discussed.
6,616 citations
Book•
01 Jan 1971
TL;DR: In this article, the authors present an overview of the main components of optical atomic spectrometers and their application in the field of surface characterization by Spectroscopy and Microscopy.
Abstract: Introduction. Section I: Measurement Basics. Electrical Components and Circuits. Operational Amplifiers in Chemical Instrumentation. Digital Electronics and Microcomputers. Signals and Noise. Section II: Atomic Spectroscopy. An Introduction to Spectrometric Methods. Components of Optical Instruments. An Introduction to Optical Atomic Spectrometry. Atomic Absorption and Atomic Fluorescence Spectrometry. Atomic Emission Spectrometry. Atomic Mass Spectrometry. Atomic X-Ray Spectrometry. Section III: Molecular Spectroscopy. An Introduction to Ultraviolet/Visible Molecular Absorption Spectrometry. Applications of Ultraviolet/Visible Molecular Absorption Spectrometry. Molecular Luminescence Spectrometry. An Introduction to Infrared Spectrometry Applications of Infrared Spectrometry. Raman Spectroscopy. Nuclear Magnetic Resonance Spectroscopy. Molecular Mass Spectrometry. Surface Characterisation by Spectroscopy and Microscopy. Section IV: Electroanalytical Chemistry. Introduction to Electroanalytical Chemistry. Potentiometry. Coulometry. Voltammetry. Section V: Separation Methods. An Introduction to Chromatographic Separations. Gas Chromatography. High-Performance Liquid Chromatography. Supercritical Fluid Chromatography and Extraction. Capillary Electrophoresis and Capillary Electrochromatography. Section VI: Miscellaneous Methods. Thermal Methods. Radiochemical Methods. Automated Methods of Analysis. Appendices.
3,325 citations
TL;DR: In this article, the Raman spectra of carbon films were analyzed via a best fit to computer-generated line shapes, used to simulate the $D$ and $G$ lines.
Abstract: Carbon films were prepared by ion-beam as well as rf-discharge deposition, and annealed at temperatures up to 950\ifmmode^\circ\else\textdegree\fi{}C. Raman spectra of these films, in the range 1000-1800 ${\mathrm{cm}}^{\ensuremath{-}1}$, were analyzed via a best fit to computer-generated line shapes, used to simulate the $D$ and $G$ lines. Our results are given in terms of the $\frac{I(D)}{I(G)}$ intensity ratio, line position, and linewidth as a function of anneal temperature. The $\frac{I(D)}{I(G)}$ ratio for the rf-discharge-deposited films shows a maximum, and there is a suggestion of similar behavior for the ion-beam-deposited films. This maximum indicates that crystallite growth is promoted by higher anneal temperatures. As suggested by comparison with theory, the down-shifted $G$ line position of 1536 ${\mathrm{cm}}^{\ensuremath{-}1}$ in the as-deposited films indicates the presence of bond-angle disorder. The similarly, down-shifted $D$ line position of \ensuremath{\sim}1283 ${\mathrm{cm}}^{\ensuremath{-}1}$ indicates that the as-deposited films may contain some fourfold-coordinated bonds as well as disorder. The shift of the $D$ and $G$ lines to asymptotes of 1353 and 1598 ${\mathrm{cm}}^{\ensuremath{-}1}$, respectively, as anneal temperature increases, indicates that the crystallites are dominated by threefold over fourfold coordination. The linewidths of both lines decrease in width with increasing anneal temperature. This is also consistent with the removal of bond-angle disorder and the increasing dominance of crystallites as annealing proceeds to higher temperatures.
1,011 citations