Influence of flow rate on different properties of diamond-like nanocomposite thin films grown by PECVD
TL;DR: In this paper, a diamond-like nanocomposite (DLN) thin films were deposited on pyrex glass substrate using different flow rate of haxamethyldisiloxane (HMDSO) based liquid precursor with nitrogen gas as a glow discharged decomposition by plasma enhanced chemical vapor deposition (PECVD) technique.
Abstract: Diamond-like nanocomposite (DLN) thin films were deposited on pyrex glass substrate using different flow rate of haxamethyldisiloxane (HMDSO) based liquid precursor with nitrogen gas as a glow discharged decomposition by plasma enhanced chemical vapor deposition (PECVD) technique. The significant influence of different precursor flow rates on refractive index and thickness of the DLN films was measured by using spectroscopic filmatrics and DEKTAK profilometer. Optical transparency of the DLN thin films was analyzed by UV-VIS-NIR spectrometer. FTIR spectroscopy, provides the information about shifted bonds like SiC2, Si-C, Si-O, C-C, Si-H, C-H, N-H, and O-H with different precursor flow rate. We have estimated the hardness of the DLN films from Raman spectroscopy using Gaussian deconvolution method and tried to investigate the correlation between hardness, refractive index and thickness of the films with different precursor flow rates. The composition and surface morphology of the DLN films were investigat...
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Journal Article•
TL;DR: In this paper, the authors show that the optical gap is 2.5% and the band gap is 1: 1:1/3/4% for optical and band gap.
Abstract: CH $_{4}$ 와 H $_{2}$ 의 혼합가스에 미량의 질소와 산소를 첨가하여 rf-플라즈마 CVD법으로 DLC막을 합성하였다. 이 때 챔버내 압력은 430mtorr, 기판에 인가된 전력은 80W였으며, H $_{2}$ 와 CH $_{4}$ 의 비율은 1:1이었다. 이 시편들에 대해 가시광선 영역과 자외선 영역에서의 투과도를 비교하였으며, 결합구조의 변화를 알아보기 위하여 FTIR 분석을 실시하였다. 질소의 경우 첨가량이 6.3%에서 17.4%으로 증가됨에 따라 전체적인 투과도값이 증가하였으며, FRIR 분석결과 wavenumber 3500 $cm^{-1}$ /의 위치에 N-H stretching band가 나타나고 2300 $cm^{-1}$ /에는 nitrile의 피크가 나타났다. 이 피크들의 존재는 질소의 첨가에 의하여 interlink를 감소시킴으로써 막의 잔류응력을 현저히 감소시킬 수 있음을 의미한다. 2% $O_{2}$ 를 첨가한 경우 막의 투과도는 질소를 첨가한 경우보다 월등히 더 향상되었다. 질소첨가량을 증가시킴에 따라 optical band gap또한 증가되는 경향을 보였으며, 2% $O_{2}$ 를 첨가하였을 때 막의 optical band gap은 0.5까지 감소하였다.
37 citations
TL;DR: In this article, the authors reported the formation of very hard (35.8 GPa) hydrogenated diamond-like carbon film at a self-bias of −100 V using simple radio frequency-plasma enhanced chemical vapor deposition process.
Abstract: By creating nanostructures and controlling the hydrogen content and sp3/sp2 bonding ratio, we report the formation of very hard (35.8 GPa) hydrogenated diamond-like carbon film at a self-bias of −100 V using simple radio frequency-plasma enhanced chemical vapor deposition process. When the self-bias is varied and modifications such as incorporation of nitrogen and Ag interlayer are executed, the mechanical properties of such films, however, got altered that are correlated well with the structural changes investigated using various spectroscopic and microscopic techniques.
34 citations
TL;DR: In this article, the structural properties of the diamond-like carbon (DLC) thin films were examined using a variety of spectroscopic and microscopic techniques, such as Fourier Transform Infrared spectroscopy, X-ray Photoelectron Spectroscopy and Atomic Force Microscopy, which showed that high quality DLC films with higher hardness can be deposited by monitoring and controlling the process parameters of the plasma.
Abstract: Mixed Ar–C2H2 plasma was characterized by VI probe for estimating the actual consumed power (CP) in the plasma and its effect on diamond-like carbon (DLC) thin films deposited at different CPs in the range 16–85 W. The structural properties of the films were examined using variety of spectroscopic and microscopic techniques, such as Fourier Transform Infrared spectroscopy, X-ray Photoelectron Spectroscopy, Micro-Raman Spectroscopy and Atomic Force Microscopy. The film deposited at 36 W CP showed the formation of nano-structure, creation of optimum sp3/sp2 bonding ratio and excellent nano-mechanical properties with the maximum hardness of ∼28.2 GPa. However, the nano-mechanical properties of the films got altered with the variation of CP, which is attributed to the changes seen in the structural properties. These findings show that high quality DLC films with higher hardness can be deposited by monitoring and controlling the process parameters of the plasma.
21 citations
TL;DR: A series of a-C:H:SiOx films was deposited on polished silicon and glass substrates by plasma-assisted chemical vapor deposition combined with pulsed bipolar substrate bias from mixtures of argon and polyphenylmethylsiloxane vapors as discussed by the authors.
Abstract: A series of a-C:H:SiOx films was deposited on polished silicon and glass substrates by plasma-assisted chemical vapor deposition combined with pulsed bipolar substrate bias from mixtures of argon and polyphenylmethylsiloxane vapors. Different Ar pressures and substrate bias voltages were applied for the synthesis of a-C:H:SiOx films having different mechanical properties. Detailed characterization of the mechanical properties of a-C:H:SiOx films was made using the nanoindentation. Hardness and elastic modulus were used for the evaluation of the endurance capability (H/E) and resistance to plastic deformation (H3/E2). The structural properties of the deposited films were analyzed by Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. It was shown that the Ar pressure and substrate bias variation can change the film properties and the growth rate and these changes are not linear. So, depending upon application, deposition conditions are to be optimized. In all of the examined coatings, increase of Ar pressure and amplitude of negative pulse of substrate bias lead to improvement in mechanical properties. According to the results of FTIR and Raman spectroscopy; this improvement is due to an increase in the sp3 bonded carbon content and decrease of hydrogen content in the films.
19 citations
TL;DR: In this article, a-C:H:SiOx films were synthesized on silicon and glass substrates by plasma-assisted chemical vapor deposition combined with pulsed bipolar substrate bias from mixtures of argon and polyphenylmethylsiloxane vapor.
Abstract: In this paper the a-C:H:SiOx films were synthesized on silicon (100) and glass substrates by plasma-assisted chemical vapor deposition combined with pulsed bipolar substrate bias from mixtures of argon and polyphenylmethylsiloxane vapor. The process of a-C:H:SiOx films formation was investigated by controlling processing conditions such as amplitude of negative pulse of substrate bias and the distance between the substrate and plasma generator. Physico-mechanical characteristics of a-C:H:SiOx films were studied by the nanoindentation technique, atomic force microscopy, Fourier transform infrared and Raman spectroscopy. The contact angle and surface free energy were determined by the sessile drop method using couple liquids (water and glycerin). It was found that the films' properties are interrelated with the density of the ion current on the substrate, which was measured using a guarded planar probe. The obtained results show that film prepared at the smaller substrate/plasma generator distance and optimal substrate biasing has a higher content of sp3 bonded carbon and, accordingly, has higher hardness, Young's modulus and resistance to plastic deformation. At the same time the a-C:H:SiOx films show large hydrophobicity with a contact angle for water of about 91° and small total surface free energy of about 17.9 mN/m.
10 citations
References
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TL;DR: In this paper, the authors describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of diamond-like carbon.
Abstract: Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications as protective coatings in areas, such as magnetic storage disks, optical windows and micro-electromechanical devices (MEMs).
5,400 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: It is shown how to use resonant Raman spectroscopy to determine structure and composition of carbon films with and without nitrogen, and the assignment of the peaks at 1150 and 1480 cm−1 often observed in nanodiamond.
Abstract: Raman spectroscopy is a standard characterization technique for any carbon system. Here we review the Raman spectra of amorphous, nanostructured, diamond-like carbon and nanodiamond. We show how to use resonant Raman spectroscopy to determine structure and composition of carbon films with and without nitrogen. The measured spectra change with varying excitation energy. By visible and ultraviolet excitation measurements, the G peak dispersion can be derived and correlated with key parameters, such as density, sp(3) content, elastic constants and chemical composition. We then discuss the assignment of the peaks at 1150 and 1480 cm(-1) often observed in nanodiamond. We review the resonant Raman, isotope substitution and annealing experiments, which lead to the assignment of these peaks to trans-polyacetylene.
2,172 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
TL;DR: In this article, the authors compare the Raman spectra and other macroscopic properties of nearly one hundred amorphous carbon films deposited at five research laboratories by a total of five different methods in search of correlations useful for both process control and basic understanding of these materials.
Abstract: We compare the Raman spectra and other macroscopic properties of nearly one hundred amorphous carbon films deposited at five research laboratories by a total of five different methods in search of correlations useful for both process control and basic understanding of the structure of these materials. For the full range of carbon‐hydrogen alloys, including so‐called ‘‘amorphous diamond,’’ hydrogenated ‘‘diamondlike’’ carbon, and plasma‐polymers, a simple parametrization of the Raman spectrum in the usual 1000 cm−1 to 2000 cm−1 range can be used as a reliable predictor of hydrogenation and other properties (e.g., optical gap, hardness). Raman features in the 200 cm−1 to 1000 cm−1 range, a spectral region not usually reported for carbon films, may also be used as an indicator of hydrogenation. These growth method independent correlations greatly enhance the utility of Raman spectroscopy as a non‐destructive characterization and process control tool.
915 citations