反应磁控溅射法沉积的氟化类金刚石薄膜的结构分析

以高纯石墨作靶、Ar／CHF3作源气体采用射频反应磁控溅射法室温下制备了氟化类金刚石薄膜(F-DLC)。发现随着射频功率的增加,F-DLC薄膜拉曼光谱的D峰与G峰强度之比ID／IG加大,薄膜中芳香环式结构比例上升。红外吸收光谱则显示射频功率增加导致薄膜中的氟含量上升．氟原子与碳原子以及芳香环的耦合加强。控制射频功率可以有效调制薄膜中的氟含量以及芳香环结构的比例,F—DLC可能成为热稳定性较好的碳氟薄膜。     

FCVA法制备的超薄类金刚石薄膜的结构分析

用真空阴极过滤电弧(Filtered Cathode Vacuum Arc,FCVA)法制备厚度分别为50 nm,30 nm,10 nm,5 nm,2 nm的类金刚石(DLC)薄膜,利用拉曼光谱和电子能量损失谱研究了薄膜的结构,分析了硬度和内应力的变化趋势。结果表明,随着薄膜厚度的减小,可见光拉曼光谱高斯分解的G峰位置向低波数方向移动,D峰和G峰强度之比Id/Ig不断增大,G峰面积与D峰面积之比Ag/Ad减小;说明随着薄膜厚度的减小,DLC薄膜中的sp3键含量减少,有序化的sp2团簇增加。电子能量损失谱的结果也表明薄膜厚度的减小会引起薄膜中sp3键含量的减少。当薄膜的厚度由50 nm变为30 nm时,薄膜硬度由53.85 GPa减小为39.64 GPa,内应力由4.63 GPa降低为3.47 GPa,随着厚度降低,薄膜的硬度和内应力呈下降趋势。     

掺氮类金刚石薄膜的显微结构和光谱学研究

本文利用射频磁控溅射法,以高纯N2、Ar混合气体为溅射气体,用高纯石墨靶在Si（100）基片上制备出掺氮的类金刚石薄膜（DIE：N）。拉曼光谱（Raman）测试表明该薄膜仍然是类金刚石结构,对其进行拟合后得两个特征峰,分别是在1342．9cm^-1的D峰和1555．3cm^-1的G峰,ID／IG=0．45;X射线光电子能谱（XPS）表明薄膜含氮量为24％,XPS光谱的C1s和N1s的芯能级证实了薄膜中的碳氮进行了化合,形成了C-N、C=N、C≡N,说明薄膜中形成了非晶碳氮结构;傅里叶变换红外透射光谱（FTIR）也表明了薄膜中碳氮进行了化合;扫描电子显微镜（SEM）结果表明,实验所制备的薄膜表面均匀、致密、光滑,从横截面图像观察,薄膜与衬底结合紧密,薄膜的厚度大约为150nm。     

YBCO外延薄膜的 afterglow plasma溅射生长

Y1Ba2Cu3O7-δ（YBCO)高温超导薄膜溅射生长所遇到的主要问题是负氧离子的反溅射效应。采用afterglow plasma溅射生长YBCO薄膜，有效地抑制了负氧离子的反溅射效应，从而生长出了超导性质优导的YBCO单晶薄膜，薄膜的临界电流密度Jc(77K,10GHz)＝206μΩ，薄膜（005）峰摇摆曲线半高宽（FWHM）为0．12^0。     

高质量ZnO薄膜的退火性质研究

在LP－MOCVD中，我们利用Zn(C2H5)2作Zn源，CO2作氧源，在（0002）蓝宝石衬底上成功制备出皮c轴取向高度一致的ZnO薄膜，并对其进行500℃-800℃四个不同温度的退火。利用XRD、吸收谱、光致发光谱和AFM等手段研究了退火对ZnO晶体质量和光学性质的影响。退火后，（0002）ZnO的XRD衍射峰强度显著增强，c轴晶格常数变小，同时（0002）ZnOX射红衍射峰半高宽不断减小表明晶粒逐渐增大，这与AFM观察结果较一致。由透射谱拟合得到的光学带隙退火后变小，PL谱的带边发射则加强，并出现红移，蓝带发光被有效抑制，表明ZnO薄膜的质量得到提高。     

PVDF-PMMA聚合物薄膜电解质的制备和性能研究

将聚偏氟乙烯（PVDF）和聚甲基丙烯酸甲酯（PMMA）溶于N-N-二甲基甲酰胺（DMF）中，加入丙三醇作造孔剂，使用两种不同方法制得聚合物薄膜，再将薄膜浸泡于I2／KI的液态电解质中吸液，制得聚合物薄膜电解质。用四探针法测量其电导率，对比两种方法制得的聚合物薄膜的扫描电镜图片，从微观结构分析其电导率的差异。由分析可知制膜方法不同导致薄膜微观结构不同，也导致薄膜性能的差异。     

La2/3Sr1/3MnO3/ZnO混合物薄膜的磁电阻和伏安特性研究

利用脉冲激光沉积的方法在Si（100）氧化成SiO₂的基片上制备了(La_2/3Sr_1/3MnO₃)_x/(ZnO)_1-x混合物薄膜,研究了薄膜的磁电阻和伏安特性. X射线衍射分析表明,除了衬底SiO₂的衍射峰以外,分别出现了La_2/3Sr_1/3MnO₃（101）的衍射峰和ZnO（002）的衍射峰,且它们形成了两相共存体系. 实验表明：x=0.3的混合物薄膜表现为半导体导电特性,而x=0.4的样品则出现了典型的金属绝缘相变. 所制备的样品表现出了低场磁电阻效应和非线性伏安特性. 在0.7T磁场的作用下,x=0.3的样品在温度为60K时取得的最大磁电阻值为28.8%. 通过对伏安关系拟合表明,在La_2/3Sr_1/3MnO₃和ZnO颗粒之间存在一定的耗尽层,且产生了界面缺陷态.     

LLDPE／LDPE薄膜老化程度的表征方法

将一种农用LLDPE（线性低密度聚乙烯）/LDPE（低密度聚乙烯）薄膜进行加速和自然老化，对羰基含量、熔点和高温剪切模量以及老化时间的关系进行了研究。从老化薄膜IR（红外光谱）图上可以得到两种羰基指数-I1和I2。可以用I1和I2来表征LLDPE/LDPE薄膜的老化程度。本文还对人工老化和自然老化的相互关系进行了研究，加速老化1小时相当于自然老化10.73小时。     

FCVA制备超薄类金刚石薄膜的拉曼光谱分析

采用FCVA方法制备厚度分别为50nm、30nm、10nm、5nm、2nm的DLC薄膜,利用可见光拉曼光谱分析薄膜的G峰位置、Id/g和Ag/Ad,发现随着薄膜厚度的减小,Id/Ig不断增大,AgAd减小,G峰位置向低波数方向移动.紫外拉曼光谱分析结果表明,薄膜厚度减薄会减小It/Lg使T峰位置向高波数方向移动.结合两种不同波长的拉曼光谱进行分析,G峰偏移量随薄膜厚度减小呈下降趋势;随薄膜厚度的减小,FCVA法制备的类金刚石薄膜中的sp3键含量减少,同时有序化的sp2团簇增加.EELS结果也证实,薄膜厚度的减小会减少薄膜中sp3键的含量.对于50nm和30nm的非晶碳膜,拉曼光谱分析的结果与薄膜硬度和内应力实际测试结果存在一致的对应关系.     

钛掺入对Cu/Si（100）及Cu/SiO2薄膜体系热稳定性的影响

利用简易合金靶材在Si（100）和SiO2基底上磁控溅射制备了Cu（1.42%Ti）薄膜。研究了少量钛对Cu/Si（100）和Cu/SiO2薄膜体系在573-773 K退火前后的微观组织结构以及界面反应的影响。X射线衍射分析表明,溅射态Cu（Ti）薄膜均呈现Cu（111）和Cu（200）衍射峰,而钛显著增强铜薄膜的（111）织构。对于退火态的Cu（Ti）/Si薄膜体系,由于少量钛在薄膜/基底界面处的存在,起到净化界面作用,促使Cu3Si的形成,从而降低了薄膜体系的热稳定性。但对于Cu（Ti）/SiO2薄膜体系,在773 K退火后,仍然呈现出良好的热稳定性。薄膜截面的结构形貌以及界面处俄歇谱的分析结果都充分证实了上述结果。     

射频输入功率对DLC∶F∶Si薄膜结构和附着特性的调制机理

以SiC陶瓷靶为靶材,Ar和CHF_3为源气体,采用反应磁控溅射法在双面抛光的316L不锈钢基片上制备出了系列Si和F共掺杂的DLC∶F∶Si薄膜。研究了射频输入功率对薄膜的附着力、硬度和表面接触角的影响。结果表明,选取适当的输入功率(180W左右)可以制备出附着力达11N的DLC∶F∶Si薄膜。通过拉曼和红外光谱分析以及样品粗糙度分析,作者提出了输入功率对DLC∶F∶Si薄膜结构和特性调制的机理,即输入功率直接影响SiC靶的溅射产额、空间Ar~+的能量以及CHF_3的分解程度,继而影响空间Si、C、-CF、-CF_2,特别是F~*等基团的能量和浓度,调制薄膜中F含量以及Si-C键含量和C网络的关联度。Si-C、C=C键的增加有助于薄膜附着力的明显改善,F含量的减少则会导致薄膜的疏水性能有所下降。     

介质阻挡放电化学气相沉积法制备DLC薄膜研究

采用介质阻挡化学气相沉积法(DBD CVD)在Si及石英衬底上、室温下成功的沉积出光滑、致密、均匀、膜基结合较好的类金刚石(DLC)薄膜,并考察了电源电压对类金刚石薄膜结构及性能的影响。拉曼光谱(Raman)、扫描电子显微镜(SEM)、原子力显微镜(AFM)、紫外可见光谱(UV Vis)、高阻仪等测试及分析结果显示DBD CVD 法适于制备高质量硬质DLC薄膜。对DBD放电做了理论分析,结果与工艺研究的结论相符合。     

Wettability control by DLC coated nanowire topography

Here we have developed a convenient method to fabricate wettability controllable surfaces that can be applied to various nanostructured surfaces with complex shapes for different industrial needs. Diamond-like carbon (DLC) films were synthesized on titanium substrate with a nanowire structured surface using plasma immersion ion implantation and deposition (PIII&D). The nanostructure of the DLC films was characterized by field emission scanning electron microscopy and found to grow in a rippling layer-by-layer manner. Raman spectroscopy was used to investigate the different bonding presented in the DLC films. To determine the wettability of the samples, water contact angles were measured and found to vary in the range of 50°-141°. The results indicated that it was critical to construct a proper surface topography for high hydrophobicity, while suitable I(D)/I(G) and sp2/sp3 ratios of the DLC films had a minor contribution. Superhydrophobicity could be achieved by further CF? implantation on suitably structured DLC films and was attributed to the existence of fluorine. In order to maintain the nanostructure during CF? implantation, it was favorable to pre-deposit an appropriate carbon content on the nanostructure, as a nanostructure with low carbon content would be deformed during CF? implantation due to local accumulation of surface charge and the following discharge resulting from the low conductivity.     

Investigation of diamond-like carbon/silicon heterojunctions deposited by pulsed Nd:YAG laser

Diamond-like carbon (DLC) films were deposited on p-type silicon (Si-100) substrates by using a pulsed Nd:YAG laser for the ablation of a pyrolytic graphite target at a background pressure of 10⁻⁶ Torr. For a fixed distance of 3 cm between the target and substrate, samples of DLC/Si heterojunction were prepared for two different laser wavelengths of 355 nm and 1064 nm. All DLC films showed typical D and G bands in their Raman spectra. DLC films were also deposited on glass substrates for resistivity measurement by four-point probe. The electrical properties for DLC/Si heterojunctions were analyzed current-voltage measurement at room temperature in the dark and also under illumination. The dependencies of the electrical characteristics on the depositing parameters were discussed.     

Improvement of adhesion of DLC coating on nitinol substrate by hybrid ion beam deposition technique

Diamond-like carbon (DLC) films were prepared for a protective coating on nitinol substrate by hybrid ion beam deposition technique with an acetelene as a source of hydrocarbon ions. An amorphous silicon (a-Si) interlayer was deposited on the substrates to ensure better adhesion of the DLC films followed by Ar ion beam treatment. The film thickness increased with increase in ion gun anode voltage. The residual stresses in the DLC films decreased with increase in ion gun anode voltage and film thickness, while the stress values were independent of the radio frequency (RF) bias voltage. The adhesion of the DLC film was improved by surface treatment with argon ion beam for longer time and by increasing the thickness of a-Si interlayer.     

The influence of fluorine doping on the optical properties of diamond-like carbon thin films

Optical properties of fluorine doped diamond-like carbon (F:DLC) films deposited by the direct current plasma enhanced chemical vapor deposition (PECVD) technique were studied in detail. Surface morphologies of the F:DLC films were studied by an atomic force microscope, which indicated surface roughness increased with increase in at.% of F in the films. The chemical binding was investigated by X-ray photoelectron spectroscopic studies. Fourier transformed infrared spectroscopic studies depicted the presence of CF_x (x = 1,2,3) and CH_n (n = 1,2) bonding within the F:DLC films. Optical transparency and the optical band gap decreased with the fluorine incorporation in the DLC film. Optical band gap calculated from the transmittance spectra decreased from 2.60 to 1.95 eV with a variation of 0-14.8 at.% of F concentration in the diamond-like carbon films. Urbach parameter determined from the band tail of the transmittance spectra showed that it increased with the doping concentration.     

Deposition of Ti/C nano-composite DLC films by magnetron DC sputtering with dual targets

Deposition of Ti/C nano-composite DLC films by magnetron DC sputtering was examined using dual targets of titanium and carbon, in order to in order to investigate the effects of Ti/C nano-composite structure on its mechanical properties such as hardness or physical properties such as electrical resistivity. The deposition of DLC films or Ti/C nano-composite DLC films was respectively carried out in the atmosphere of argon at the pressure of 0.4 Pa by sputtering of only the carbon target or by co-sputtering of both the carbon one and the titanium one. The DLC film obtained in this study looked semitransparent and dark brown, while the Ti/C nano-composite DLC one looked metallic and light gray. According to Raman spectroscopy, a typical spectrum for DLC was detected for the metal-like titanium containing composite DLC films even though it's intensity was rather small. And it was found that the G band slightly shifted to higher wave numbers and the shoulder D band was enhanced, compared to the spectrum for the DLC films. Furthermore, based on both the indentation hardness and the electrical resistivity of the obtained films, it was assumed that the miniaturization of titanium phase might bring the increase in hardness.     

Microstructure and property evolution of Cr-DLC films with different Cr content deposited by a hybrid beam technique

Cr-containing diamond-like carbon (Cr-DLC) films was deposited on silicon wafers by a hybrid beams system, which consists of a DC magnetron sputtering and a linear ion source. The chromium content in the films was adjusted by varying the fraction of Ar in the Ar and CH₄ gas mixture. The composition, microstructure, surface morphology, mechanical properties and tribological behavior of the films were investigated by XPS, TEM, AFM, SEM, nano-indentation and tribological tester as a function of Cr content. It is shown that, as the Cr content increased from 1.49 to 40.11 at.%, the Cr-DLC films transfer from amorphous DLC with dispersed metallic-like Cr to composite DLC with carbide phases embedding in the DLC matrix, and the film surface morphology also evolve from flat surface into rough surface with larger hillocks. The amorphous Cr-DLC films exhibit a low friction coefficient and wear rate as pure DLC, while the composite Cr-DLC films show a higher friction coefficient and wear rate, although they possess a relatively high hardness.     

Evaluation of microstructures and mechanical properties of diamond like carbon films deposited by filtered cathodic arc plasma

Diamond-like carbon (DLC) films were deposited by a cathodic arc plasma evaporation (CAPD) process, using a mechanical shield filter combined with a magnetic filter with enhanced arc structure at substrate-bias voltage ranging from − 50 to − 300 V. The film characteristics were investigated using Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and high-resolution transmission electron microscopy (HRTEM). The mechanical properties were investigated by using a nanoindentation tester, scratch test and ball on disc wear test. The Raman spectra of the films showed that the wavenumber ranging from 900 to 1800 cm^− 1 could be deconvoluted into 1140 cm^− 1, D band and G band. The bias caused a significant effect on the sp³ content which was increased with the decreasing of I_D/I_G ratio. The XPS spectra data of the films which were etched by H⁺ plasma indicated the sp³ content are higher than those of the as-deposited DLC films. This implied that there is a sp²-rich layer present on the surface of the as-deposited DLC films. The nanoindentation hardness increased as the maximum load increased. A 380 nm thick and well adhered DLC film was successfully deposited on WC-Co substrate above a Ti interlayer. The adhesion critical load of the DLC films was about 33 N. The results of the wear tests demonstrated that the friction coefficient of the DLC films was between 0.12 and 0.2.     

CVD of hard DLC films in a radio frequency inductively coupled plasma source

Chemical vapor deposition (CVD) of hard diamond-like carbon (DLC) films on silicon (100) substrates from methane was successfully carried out using a radio frequency (r.f.) inductively coupled plasma source (ICPS). Different deposition parameters such as bias voltage, r.f. power, gas flow and pressure were involved. The structures of the films were characterized by Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The hardness of the DLC films was measured by a Knoop microhardness tester. The surface morphology of the films was characterized by atomic force microscope (AFM) and the surface roughness (R_a) was derived from the AFM data. The films are smooth with roughness less than 1.007 nm. Raman spectra shows that the films have typical diamond-like characteristics with a D line peak at 1331 cm⁻¹ and a G line peak at 1544 cm⁻¹, and the low intensity ratio of I_D/I_G indicate that the DLC films have a high ratio of sp³ to sp² bonding, which is also in accordance with the results of FTIR spectra. The films hardness can reach approximately 42 GPa at a comparatively low substrate bias voltage, which is much greater than that of DLC films deposited in a conventional r.f. capacitively coupled parallel-plate system. It is suggested that the high plasma density and the suitable deposition environment (such as the amount and ratio of hydrocarbon radicals to atomic or ionic hydrogen) obtained in the ICPS are important for depositing hard and high quality DLC films.