Characterization of nanocomposite a-C:H/Ag thin films synthesized by a hybrid deposition process (original) (raw)
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Optical properties of a-C:H thin films modified by Ti and Ag
Nanostructured Thin Films IX, 2016
Structure and optical properties of amorphous diamond-like carbon (a-C: H) thin films modified with Ag, Ti and Ag + Ti metal impurities are studied. The films were prepared by ion-plasma magnetron sputtering of combined polycrystalline graphite and metal target in the mixture of Ar and CH4 gases. AFM, SEM and TEM methods show that a-C:H<Ag+Ti> films are heterogeneous, nanostructured and characterized by the presence of silver nanoclusters on the surface sized ~ 60 nm and both Ti and Ag nanoclusters with a mean size ~ (2 ÷ 3) nm in the bulk of films. It was found that in a-C:H<Ag+Ti> films as well as in a-C:H films plasma resonance absorption due to excitation of surface plasmons in silver nanoclusters in the visible region of spectrum takes place. Intensity of the resonance absorption in the a-C:H<Ag+Ti> films increases with increase in concentration of silver. The results are important for produce of nanomaterials with nonlinear optical properties based on the amorphous diamond-like carbon films containing metal nanoclusters.
Diamond and Related Materials, 2013
Silver containing diamond like carbon Multiwavelength (UV-VIS-NIR) Raman spectroscopy X-ray diffractometry (XRD) In the present study structure of silver containing diamond like carbon (DLC:Ag) films deposited by reactive magnetron sputtering was investigated by X-ray diffractometry (XRD) and multiwavelength Raman spectroscopy. In the case of the DLC:Ag films containing low amount of silver, crystalline silver oxide prevails over silver. While at higher Ag atomic concentrations formation of the silver crystallites of the different orientations was observed. Surface enhanced Raman scattering (SERS) effect was detected for high Ag content in the films. For UV excited Raman spectra sp 3 bonded carbon related Raman scattering T peak at~1060 cm −1 was detected only for the films with the highest amount of silver (34.3 at.%). The dependence of the Raman scattering spectra parameters such as position of the G peak, G peak full width at half maximum (FWHM(G)), D/G peak area ratio on Ag atomic concentration in DLC:Ag film as well as Raman scattering spectra excitation wavelength were studied. The dependence on Ag amount in film was more pronounced in the case of the Raman scattering spectra excited by higher wavelength laser beam, while in the case of the spectra excited by 325 nm and 442 nm laser beams only weak dependence (or no dependence) was observed. Overall tendency of the decrease of the dispersion of the G peak with the increase of Ag atomic concentration was found. Thus sp 3 /sp 2 bond ratio in DLC:Ag film decreased with the increase of Ag atomic concentration in the films.
Effect of Ar/CH4 Mixture Ratio on Properties of Ag/C:H Nanocomposite Prepared by DC Sputtering
Advances in Materials Science and Engineering, 2013
Ag/C:H films were deposited by DC sputtering method on Si substrates with different Ar/CH4gas mixture ratios. Effect of Ar/CH4gas mixture ratios was investigated on optical and structural properties of Ag/C:H films by FTIR spectroscopy analysis, X-Ray diffractometry (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM), respectively. In order to evaluate the effect of gas flow ratio on the optical and structural properties of Ag/C:H films, Ar/CH4gas ratio was changed by keeping the Ar flow rate constant while varying the CH4gas flow rate (2, 5, and 10 SCCM). From FTIR analysis it was observed that increase in the Ar/CH4gas ratio results in decreasing the sputtered Ag nanoparticles and increasing of C–H bonds. Also from XRD pattern it was found that intensity of Ag crystalline plane and average grain size decrease by adding CH4to working gas admixture. From SEM and AFM micrographs, size of the grains also became smaller on the surface of the films, which will l...
Structuring of DLC:Ag nanocomposite thin films employing plasma chemical etching and ion sputtering
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2014
We analyze structuring effects of diamond like carbon based silver nanocomposite (DLC:Ag) thin films by CF 4 /O 2 plasma chemical etching and Ar + sputtering. DLC:Ag films were deposited employing unbalanced reactive magnetron sputtering of silver target with Ar + in C 2 H 2 gas atmosphere. Films with different silver content (0.6-12.9 at.%) were analyzed. The films (as deposited and exposed to plasma chemical etching) were characterized employing scanning electron microscopy and energy dispersive X-ray analysis (SEM/ EDS), optical microscopy, ultraviolet-visible light (UV-VIS) spectroscopy and Fourier transform infrared (FTIR) spectroscopy. After deposition, the films were plasma chemically etched in CF 4 /O 2 mixture plasma for 2-6 min. It is shown that optical properties of thin films and silver nano particle size distribution can be tailored during deposition changing the magnetron current and C 2 H 2 /Ar ratio or during following plasma chemical etching. The plasma etching enabled to reveal the silver filler particle size distribution and to control silver content on the surface that was found to be dependent on Ostwald ripening process of silver nano-clusters. Employing contact lithography and 4 lm period mask in photoresist or aluminum the films were patterned employing CF 4 /O 2 mixture plasma chemical etching, direct Ar + sputtering or combined etching processes. It is shown that different processing recipes result in different final grating structures. Selective carbon etching in CF 4 /O 2 gas mixture with photoresist mask revealed micrometer range lines of silver nanoparticles, while Ar + sputtering and combined processing employing aluminum mask resulted in nanocomposite material (DLC:Ag) micropatterns.
Elsevier B.V., 2018
Atomic force microscopy (AFM) images give valuable information about surface roughness of thin films based on the results of power spectral density (PSD) through the fast Fourier transform (FFT) algorithms. In the present work, AFM data are studied for silver and gold nanoparticles (Ag NPs a-C: H and Au NPs a-C: H) embedded in amorphous hydrogenated carbon films and co-deposited on glass substrate via of RF-Sputtering and RF-Plasma Enhanced Chemical Vapor Deposition methods. Here, the working gas is acetylene and the targets are Ag and Au. While time and power are constant, the only variable parameter in this study is initial pressure. In addition, the crystalline structure of Ag NPs a-C: H and Au NPs a-C: H are studied using X-ray diffraction (XRD). UV–visible spectrophotometry will also investigate optical properties and localized surface plasmon resonance (LSPR) of samples. © 2017 The Authors
Synthesis of Ag-doped hydrogenated carbon thin films by a hybrid PVD–PECVD deposition process
Bulletin of Materials Science, 2014
Silver-doped hydrogenated amorphous carbon (Ag-DLC) films were deposited on Si substrates using a hybrid plasma vapour deposition-plasma enhanced chemical vapour deposition (PVD-PECVD) process combining Ag target magnetron sputtering and PECVD in an ArCH 4 plasma. Processing parameters (working pressure, CH 4 /Ar ratio and magnetron current) were varied to obtain good deposition rate and a wide variety of Ag films. Structure and bonding environment of the films were obtained from transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS) and Fourier transform infrared (FTIR) spectroscopy studies. Variation of processing parameters was found to produce Ag-doped amorphous carbon or diamond-like carbon (DLC) films with a range of characteristics with CH 4 /Ar ratio exercising a dominant effect. It was pointed out that Ag concentration and deposition rate of the film increased with the increase in d.c. magnetron current. At higher Ar concentration in plasma, Ag content increased whereas deposition rate of the film decreased. FTIR study showed that the films contained a significant amount of hydrogen and, as a result of an increase in the Ag content in the hydrogenated DLC film, sp 2 bond content also increased. The TEM cross sectional studies revealed that crystalline Ag particles were formed with a size in the range of 2-4 nm throughout an amorphous DLC matrix.
Thin Solid Films, 2007
Ag-incorporated diamond-like carbon films were prepared on Si(100) wafers using a hybrid deposition system composed of an end-Hall-type hydrocarbon ion gun and a silver DC magnetron sputter source. The Ag concentration in the films was controlled by changing the fraction of Ar in the Ar and benzene reaction gas. The chemical composition, microstructure, atomic bond structure, and mechanical properties were investigated for Ag concentrations ranging from 0 to 9.7 at.%. When the Ag concentration was 0.1 at.%, the Ag atoms were fully dissolved in the amorphous carbon matrix without forming any second phase. Amorphous and crystalline silver particles appeared when the Ag concentration was 1.7 and N 6.8at.%, respectively. It was found that the hardness was not sensitive to the Ag concentration in this concentration range. On the other hand, the residual compressive stress was strongly dependent on the chemical state of the incorporated Ag atoms. The mechanical properties are discussed in terms of the changes in the microstructure and atomic bond structure induced by Ag incorporation.
Nanotechnology, 2012
Structural properties of SiO x C y -Ag nanocomposite thin films prepared by a dual process PVD-PECVD in the same reactor have been investigated. The experimental results have demonstrated the influence of a PECVD process carried out at room temperature for the growth of a dielectric matrix on the size and the distribution density of Ag nanoparticles (NPs) deposited beforehand by magnetron sputtering. The plasma during the growth of the encapsulation SiO x C y layer caused a diffusion of silver from NPs through the SiO x C y matrix associated with a decrease in the average size of nanoparticles and an increase of their distribution density. Silver diffusion is blocked at a barrier interface to form a buried layer of individual Ag NPs which, for instance, can find plasmonic applications. Silver also diffuses toward the outer surface inducing antibacterial properties. In both cases initial Ag NPs act as reservoirs for multifunctional properties of advanced nanostructured films.
Nanomaterials
This study aimed to develop hydrogenated amorphous carbon thin films with embedded metallic nanoparticles (a-C:H:Me) of controlled size and concentration. Towards this end, a novel hybrid deposition system is presented that uses a combination of Plasma Enhanced Chemical Vapor Deposition (PECVD) and Physical Vapor Deposition (PVD) technologies. The a-C:H matrix was deposited through the acceleration of carbon ions generated through a radio-frequency (RF) plasma source by cracking methane, whereas metallic nanoparticles were generated and deposited using terminated gas condensation (TGC) technology. The resulting material was a hydrogenated amorphous carbon film with controlled physical properties and evenly dispersed metallic nanoparticles (here Ag or Ti). The physical, chemical, morphological and mechanical characteristics of the films were investigated through X-ray reflectivity (XRR), Raman spectroscopy, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM) and nanoscratch testing. The resulting amorphous carbon metal nanocomposite films (a-C:H:Ag and a-C:H:Ti) exhibited enhanced nanoscratch resistance (up to +50%) and low values of friction coefficient (<0.05), properties desirable for protective coatings and/or solid lubricant applications. The ability to form nanocomposite structures with tunable coating performance by potentially controlling the carbon bonding, hydrogen content, and the type/size/percent of metallic nanoparticles opens new avenues for a broad range of applications in which mechanical, physical, biological and/or combinatorial properties are required.
Fluence Enhanced Optical Response of Ag Implanted Amorphous Carbon Thin Films
C, 2019
Silver nanoparticles (NPs) are known to exhibit strong interaction with light photons because their surface conduction electrons undergo collective oscillations once photo-excited at specific wavelengths; the so-called surface plasmon resonance (SPR). Their incorporation into carbon-based material is shown to greatly influence the overall optical response of the matrix due to aggregation. In this paper, we studied the optical response of silver-irradiated amorphous carbon films due to varying fluence of 25 keV Ag ions in the range 2.5–3.4 × 1016 ions/cm2. Raman spectroscopy provided an insight into the microstructural details of the Ag:a-C nanocomposites such that access to bond characteristics of the films is enabled by directly linking the Raman information with sp2/sp3 configurations. Atomic force microscopy (AFM) analysis show significant increase in particle grain size and surface roughness of the films with increasing fluence while transmission electron microscopy (TEM) confir...