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1.
The structural properties and features of the chemical composition of SiO x N y /SiO2, SiO x N y /Si3N4, and SiN x /Si3N4 multilayer thin films with ultrathin (1–1.5 nm) barrier SiO2 or Si3N4 layers are studied. The films have been prepared by plasma chemical vapor deposition and have been annealed at a temperature of 1150°С for the formation of silicon nanocrystals in the SiO x N y or SiN x silicon-rich layers with a nominal thickness of 5 nm. The period of superlattices in the studied samples has been estimated by X-ray reflectivity. The phase composition of superlattices has been studied by X-ray electron spectroscopy using the decomposition of photoelectron spectra of the Si 2p, N 1s, and O 1s levels into components corresponding to different charge states of atoms.  相似文献   

2.
对用微波等离子体化学汽相沉积法沉积在Si基片上的CNx膜分别进行Raman散射、X射线光电子能谱、X射线衍射和扫描电子显微镜等技术的分析与测试. Raman散射的研究结果表明在CH4与N2的流量比低于1∶8时,CNx膜的散射谱中以非晶石墨峰的形式出现.当流量比为1∶8时,则表现为较尖锐的C≡N键(2190cm-1)的特征峰;从X射线光电子能谱的分析结果可以看出C,N成键的方式主要是C≡N键和C—N 关键词:  相似文献   

3.
Deposition of carbon materials from methane-hydrogen gas mixtures in a DC gas discharge is investigated. Parameters ensuring stable discharge conditions and synthesis of diamond and graphite-like films are determined. Optical emission spectroscopy is used to analyze the composition of the activated gas phase in the course of carbon film deposition. Synthesis of graphite-like carbon nanotubes and nanocrystallites is shown to correlate with the presence of C2 dimers in the plasma. A noncatalytic mechanism of synthesis of nanostructured graphite in a carbon-containing gas phase is proposed.  相似文献   

4.
Excimer laser ablation of highly oriented pyrolytic graphite (HOPG) was performed at atmospheric pressure in an N2 and in an air ambient. During the ablation, nanoparticles condensed from the material ejecta, and their size distribution was monitored in the gas phase by a Differential Mobility Analyzer (DMA) in combination with a Condensation Particle Counter (CPC). Size distributions obtained at different laser repetition rates revealed that the interaction between subsequent laser pulses and formed particles became significant above 15 Hz. This interaction resulted in laser heating, leading to considerable evaporation and a decrease in the size of the particles. X-ray photoelectron spectroscopy revealed that approximately 8% nitrogen was incorporated into the CNx particles generated in the N2 ambient, and that the nitrogen was mostly bonded to sp3-hybridized carbon. Monodisperse particles were also deposited and were analyzed by means of Raman spectroscopy to monitor size-induced effects. PACS 81.07.-b; 61.46.+w; 79.70.+q  相似文献   

5.
The aim of the present work was the improvement of titanium-aluminium nitride (TiAlN) coatings by the solid-solution hardening with carbon atoms leading to titanium-aluminium carbon-nitride (Ti,Al)CxN1-x coatings with varying carbon (x) and nitrogen contents. The request of low deposition temperatures necessary for the coating of heat sensitive materials like tool steels of high hardness and polymers was reached by the application of the room temperature pulsed laser deposition (PLD) technique. A Nd:YAG laser of 1064 nm wavelength operated at two different laser pulse energies was used in the ablation experiments of pure TiAl targets (50 at.% Al) in various C2H2-Ar gas mixtures. Different pulse energies of the laser resulted in changes of the ratio of Ti/Al atoms in the grown coatings. Furthermore, the results reveal a strong proportionality of the gas mixture to the C and N content of the coatings. In the coatings deposited at low C2H2 gas flows the XRD investigations showed crystalline phases with fcc TiN type lattices, whereas high acetylene flows during deposition resulted in the formation of fully amorphous coatings and carbon precipitation or cluster boundaries found in Raman investigations. PACS 81.15.Fg; 46.55.+d  相似文献   

6.
Amorphous carbon nitride (a-CNx) thin films have been synthesised by three different deposition techniques in an Ar/N2 gas mixture and have been deposited by varying the percentage of nitrogen gas in the mixture (i.e. the N2/Ar + N2 ratio) from 0 to 10%. The variation of the electrical conductivity and the gap values of the deposited films versus the N2/Ar + N2 ratio were investigated in relation with their local microstructure. Film composition was analysed using Raman spectroscopy and optical transmission experiments. The observed variation of electrical conductivity and optical properties are attributed to the changes in the atomic bonding structures, which were induced by N incorporation, increasing both the sp2 carbon content and their relative disorder. The low N content samples seem to be an interesting material to produce films with interesting properties for optoelectronic applications considering the facility to control the gas composition as a key parameter.  相似文献   

7.
Lei Zhao 《Applied Surface Science》2008,254(15):4620-4625
Nitrogen-doped titanium dioxide (TiO2−xNx) thin films have been prepared by pulse laser deposition on quartz glass substrates by ablated titanium dioxide (rutile) target in nitrogen atmosphere. The x value (nitrogen concentration) is 0.567 as determined by X-ray photoelectron spectroscopy measurements. UV-vis spectroscopy measurements revealed two characteristic deep levels located at 1.0 and 2.5 eV below the conduction band. The 1.0 eV level is attributable to the O vacancy state and the 2.5 eV level is introduced by N doping, which contributes to narrowing the band-gap by mixing with the O2p valence band. The enhanced degradation efficiency in a broad visible-light range was observed from the degradation of methylene blue and methylene orange by the TiO2−xNx film.  相似文献   

8.
Hydrogenated amorphous carbon nitride (a-C:N:H) films were synthesized from CH4/N2, C2H4/N2 and C2H2/N2 mixtures using dielectric barrier discharge (DBD) plasmas. Atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) were used to characterize the surface morphology, bonding structure, and composition of the a-C:N:H films. The influences of plasma parameters (discharge pressure in the range of 25-1000 Pa) and feed gases used on the composition and the structure of deposited films were systematically studied. The a-C:N:H films with the uniform surface structure were deposited by low-pressure DBD plasmas with various systems. Compared to the films deposited in C2H4/N2 and C2H2/N2 systems, the films deposited in the CH4/N2 system exhibit the relatively lower surface roughness and deposition rate. For all the films prepared in these three systems, increasing the discharge pressure leads to an increase in film surface roughness and deposition rate. Significant differences among the FTIR spectra of all deposited a-C:N:H films were also observed. Both FTIR and XPS spectra show that for all the films deposited in three different systems, increasing the N2 fraction leads to a decrease in the H content of deposited a-C:N:H films and an increase in the N content. The properties of deposited films may change from those of polymerlike to diamond-like when the discharge pressure is increased. Correlations between the film properties and growth processes are discussed in this study.  相似文献   

9.
采用直流-射频等离子增强化学汽相沉积技术制备a-C∶H(N)薄膜,用X射线光电子能谱研究了混合气体中N2含量对薄膜成分与结构的影响.a-C∶H(N)薄膜中含氮量可达9.09%.对a-C∶H(N)薄膜的C1s和N1s结合能谱的分析表明a-C∶H(N)薄膜的结构是由C3N4相镶嵌在sp2键结合的CNx基体中组成.其中C3N4相中N和C原子比接近4∶3,不随薄  相似文献   

10.
In this study, we report on the gas permeability of non-polymerized and polymerized fullerene films (thickness about 0.5 μm) grown on an organic polymer substrate, polycarbonatesyloxane (PCS), using a high vacuum deposition method. The photopolymerized C60 films were prepared by a simultaneous thin film deposition and UV-vis irradiation method which was reported previously [V.A. Karachevtsev, P.V. Mateichenko, N.Y. Nedbailo, A.V. Peschanskii, A.M. Plokhotnichenko, O.M. Vovk, E.N. Zubarev, A.M. Rao, Carbon 42 (2004) 2091]. Raman spectroscopy revealed that ∼90% of the C60 molecules are covalently linked to neighboring C60 molecules in the photopolymerized film after 20 h of film deposition/irradiation. Permeability of the resulting membranes consisting of polymer PCS base and fullerene films to the N2, O2, CH4, and He gases has been investigated. Our experiments revealed that the gas permeability properties are dependent on the age of the membrane. In particular, the aged membrane exhibited an enhanced permeability for O2 and He gases in comparison to N2 and CH4, respectively.  相似文献   

11.
This paper reports on the results of investigations into the temperature and spectral dependences of the magnetic circular dichroism in Dy1?xNix-Ni bilayer films prepared through thermal sputter deposition of components under ultrahigh vacuum. The distribution of the components over the layer thickness is examined by Auger spectroscopy. The nickel content x in Dy1?xNix layers varies from 0.005 to 0.06. It is shown that, in the temperature range 80–300 K, the contribution made to the magnetic circular dichroism by a Dy1?xNix layer in a bilayer film with a nickel content higher than the threshold value is approximately equal to the magnetic circular dichroism observed in an isolated Dy1?xNix film at temperatures below the temperature of the phase transition to a ferromagnetic state (~100 K). This phenomenon is explained by magnetic ordering in the Dy1?xNix layer of the bilayer film due to the combined effect of two factors, namely, the incorporation of nickel into a dysprosium layer and the presence of a continuous nickel sublayer in the film.  相似文献   

12.
Diamond-like carbon (DLC) films were deposited on polytetrafluoroethylene (PTFE) using radio frequency (RF) plasma-enhanced chemical vapour deposition (PE-CVD). Before the DLC coating, the PTFE substrate was modified with a N2 plasma pre-treatment to enhance the adhesive strength of the DLC to the substrate. The influences of the N2 plasma pre-treatment and process pressure on the gas permeation properties of these DLC-coated PTFE samples were investigated. In the Raman spectra, the G peak position shifted to a lower wave number with increasing process pressure. With scanning electron microscopy (SEM), a network of microcracks was observed on the surface of the DLC film without N2 plasma pre-treatment. The density of these cracks decreased with increasing process pressure. In the film subjected to a N2 plasma pre-treatment, no cracks were observed at any process pressure. In the gas barrier test, the gas permeation decreased drastically with increasing film thickness and saturated at a thickness of 0.2 μm. The DLC-coated PTFE with the N2 plasma pre-treatment exhibited a greater reduction in gas permeation than did the samples without pre-treatment. For both sample types, gas permeation decreased with increasing process pressure.  相似文献   

13.
Hydrogenated amorphous silicon carbide (a-Si1-xCx:H) films were deposited by RF plasma enhanced chemical vapor deposition (PECVD) and subsequently annealed in N2 atmosphere at different temperatures. Systematic investigations of the deposition temperature and annealing effect on the film's properties, including film thicknesses, optical bandgap, refractive indexes, absorption coefficient (α), chemical bond configurations, stoichiometry and crystalline structures, were performed using ellipsometry, FTIR absorbance spectroscopy, Raman spectroscopy, XPS, and XRD. All of the results indicate that the structural and optical properties of the a-Si1-xCx:H film can be effectively engineered by proper annealing conditions. Moreover, molecular vibrational level equation was introduced to explain the peak shift detected by FTIR and Raman spectroscopy.  相似文献   

14.
Amorphous carbon nitride (CNx) thin layer, formed by the keV N2+ irradiation of highly oriented pyrolytic graphite, has been investigated using X-ray photoelectron and raman spectroscopies, and time-of-flight secondary ion mass spectrometry. C1s X-ray photoelectron spectroscopy (XPS) peak separations indicate that C-N bonds form over and above the graphite fragmentation previously obtained on Ar+ irradiation. N1s XPS peak separations indicate three components. Their attributions, and the resultant CNx structure, are confirmed by angle-resolved XPS and TOF-SIMS analyses.  相似文献   

15.
《Current Applied Physics》2010,10(2):428-435
Plasma enhanced chemical vapor deposition of nitrogen-incorporated silicon oxycarbide thin films obtained from the gas mixture of TMOS (tetramethoxysilane), N2, and NH3 is studied. The effects of the TMOS to N2 pressure ratio on the properties of the film and the plasma are investigated. The deposited films are analyzed by in situ ellipsometry, ex situ Fourier transform infrared spectroscopy (FTIR), and by X-ray photoelectron spectroscopy (XPS). The plasma is characterized by using optical emission spectroscopy (OES). The mass spectra of the constituents in the plasma are obtained by quadrupole mass spectroscopy. The correlation between the film properties and the plasma characteristics is explained wherever possible. As the partial pressure of N2 is decreased, the refractive index begins to decrease, reaches a minimum, and then saturates. The FTIR absorption bands are observed from about 850 to 1000 cm−1 and from 1000 to 1250 cm−1, and can be attributed to the formation of a nitrogen-incorporated silicon oxycarbide thin film. The variation of the refractive index is discussed in relationship with the deposition rate, the OES spectra, the mass spectra of the plasma, the film composition obtained by XPS, and FTIR spectra.  相似文献   

16.
The effect of white and UV radiation on the phase composition of amorphous CN x films are studied by X-ray diffraction analysis and visible-range spectroscopy. The films have variable-range atomic order and consist of amorphous graphite clusters (30 Å) crystalline clusters (50–100 Å) of graphite, diamond, and carbon nitride phases; and intercluster medium with long-range (1–2 Å) atomic order. It is shown that irradiation of the films by white light facilitates the growth of fine graphite clusters. Irradiation by UV light suppresses the growth of the graphite and carbon nitride phases, favoring the growth of the diamond phase (1.5%). It is demonstrated that a change in the mesoscopic phase composition of the CN x films causes a change in the energy gap width in the visible range from E g = 0.75 eV for the films irradiated by white light to E g = 1.75 eV for those exposed to UV radiation.  相似文献   

17.
Amorphous carbon nitride thin films were deposited by pulsed laser deposition combined with a nitrogen rf radical beam source. A structural characterization of the deposited films was performed using X-ray photoelectron and Raman-scattering spectroscopy. The Raman spectra showed that the dominant hybridization state of carbon atoms in the deposited film is sp2. N 1s electron spectra were deconvoluted into three components, N bonded to pyridine-like N and/or N-sp3C (N1), substitutional N in graphite (N2), and N-O and/or N-N (N3). The proportion of N1 increased with increasing N/C atomic ratio in the film. The electrical conductivity at room temperature decreased and the Tauc optical band gap increased with increasing N/C atomic ratio. The temperature dependence of the electrical conductivity indicated that electronic conduction occurred by variable range hopping between electron localized states. The decrease in electrical conductivity with increasing N/C atomic ratio was caused by a strong electron localization due to the increased proportion of N1. PACS 81.05.Uw; 81-15.Fg; 73.61.Jc  相似文献   

18.
采用螺旋波等离子体化学气相沉积技术以N2/SiH4/H2为反应气体制备了镶嵌有纳米非晶硅颗粒的氢化氮化硅薄膜,通过改变N2流量实现了薄膜从红到蓝绿的可调谐光致发光.傅里叶红外透射和紫外-可见光吸收特性分析表明,所生长薄膜具有较高的氢含量,N2流量增加使氢的键合结构发生变化,非晶硅颗粒尺寸减小,所对应的薄膜的光学带隙逐渐增加和微观结构有序度减小.可调光致发光(PL)主要来源于纳米硅颗粒的量子限制效应发光,随N2流量增加,PL的谱线展宽并逐渐增强. 关键词: 傅里叶红外透射谱 光吸收谱 纳米硅粒子镶嵌薄膜 光致发光  相似文献   

19.
In this work, we investigated a carbon plasma plume produced by laser ablation of a graphite target in a nitrogen gas environment. The spatial distributions of C and N atoms were measured by time-resolved absorption spectroscopy. The spatial distributions of the relative densities of CN radicals, C2, and C3 molecules were measured using time-resolved emission spectroscopy. We determined that nitrogen gas produced an increase in carbon atom and molecule densities in the ablation plume. It was observed that the addition of RF plasma to the plume increased the CN radicals and C atom densities, and decreased the C2 and C3 molecule densities. The RF plasma changed the evolution of various fractional species of C, N, CN, C2, and C3 in the ablation plume. The chemical reactions with and without RF plasma were explained using the evolution and density of the fractional species of C, N, CN, C2, and C3in the plume. PACS 52.38.Mf; 42.62.Fi; 33.20.-t; 81.05.Uw  相似文献   

20.
Diamond-like carbon (DLC) films were deposited on polytetrafluoroethylene (PTFE) using a radiofrequency plasma chemical vapour deposition method. Prior to DLC coating, the PTFE substrates were modified with O2 and N2 plasma to enhance the adhesion strength of the DLC film to the substrate. The effect of the plasma pre-treatment on the chemical composition and the surface energy of the plasma pre-treated PTFE surface was investigated by X-ray photoelectron spectroscopy (XPS) and static water contact angle measurement, respectively. A pull-out test and a ball-on-disc test were carried out to evaluate the adhesion strength and the wear properties of the DLC-coated PTFE.In the N2 plasma pre-treatment, the XPS result indicated that defluorination and the nitrogen grafting occurred on the plasma pre-treated PTFE surface, and the water contact angle decreased with increasing the plasma pre-treatment time. In the O2 plasma pre-treatment, no grafting of the oxygen occurred, and the water contact angle slightly increased with the treatment time. In the pull-out test, the adhesion strength of the DLC film to the PTFE substrate was improved with the plasma pre-treatment to the PTFE substrate, and N2 plasma pre-treatment was more effective than the O2 plasma pre-treatment. In the ball-on-disc test, the DLC film with the N2 plasma pre-treatment showed good wear resistance, compared with that with O2 plasma pre-treatment.  相似文献   

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