Fe纳米颗粒嵌埋对类金刚石薄膜结构及电学性能的影响

采用脉冲激光气相沉积方法制备了不同Fe嵌埋浓度的Fe: DLC多层纳米复合薄膜。用X射线光电子能谱仪(XPS)对薄膜的组成成分进行分析。利用透射电子显微镜（TEM）、拉曼光谱、电流-电压曲线研究Fe纳米颗粒嵌埋对薄膜的微观结构及电学性能的影响。XPS和TEM表明,Fe纳米颗粒周期性地均匀地嵌埋在碳薄膜中。拉曼光谱表明薄膜中的C为典型的类金刚石结构,Fe纳米颗粒促进芳香环式结构的形成,薄膜结构的有序度提高。电流 电压曲线表明,Fe纳米颗粒的嵌埋导致薄膜的室温电导率增加。     

氦压对类金刚石薄膜结构和光学性质的影响

使用脉冲激光沉积技术在不同氦压下制备了系列无氢类金刚石薄膜,测量了样品的Raman光谱、光吸收光谱和光致发光光谱,采用原子力显微镜测试了薄膜的表面形貌,研究了薄膜的微结构和光学性质与制备条件的依赖关系. 结果表明,该薄膜是由sp2和sp3杂化碳原子组成的非晶碳膜. 薄膜的光学带隙在1.45～1.78 eV. 薄膜的发光在可见光区呈宽带结构,氦压能够对类金刚石薄膜的结构和光学性质产生较大影响. 当氦压从0.05 Pa升高至15 Pa时,sp2团簇变大,带尾态增多,从而导致薄膜的发光增强,光学带隙变窄,发光峰位红移. AFM 形貌表明随着氦压的升高,薄膜的表面由致密光滑变得粗糙,并且许多大小不均匀的球状颗粒出现在薄膜表面.     

射频功率对类金刚石薄膜结构和性能的影响

利用直流-射频-等离子体增强化学气相沉积技术在单晶硅表面制备了类金刚石薄膜，采用原子力显微镜、Raman光谱、x射线光电子能谱、红外光谱和纳米压痕仪考察了射频功率对类金刚石薄膜表面形貌、微观结构、硬度和弹性模量的影响.结果表明，制备的薄膜具有典型的含H类金刚石结构特征，薄膜致密均匀，表面粗糙度很小.随着射频功率的升高，薄膜中成键H的含量逐渐降低，而薄膜的sp3³含量、硬度以及弹性模量先升高， 后降低，并在射频功率为100W时达到最大. 关键词： 等离子增强化学气相沉积 类金刚石薄膜 射频功率 结构和性     

射频功率对类金刚石薄膜性能的影响

在不同射频功率条件下,实验研究了射频等离子体化学气相沉积类金刚石薄膜的金刚石相分数、光学常数和硬度。利用Raman光谱仪、椭圆偏振仪、数字式显微硬度计分别测试了不同条件下单层类金刚石薄膜的金刚石相分数、光学常数和硬度。实验表明,随着功率的增加,金刚石相的相对分数减少,薄膜的折射率先减小再增加然后减小,射频功率大于910 W时,沉积速率急剧增大。而薄膜的硬度先增加后减小,在射频功率为860 W处获得最大值。     

射频功率对类金刚石薄膜性能的影响

在不同射频功率条件下,实验研究了射频等离子体化学气相沉积类金刚石薄膜的金刚石相分数、光学常数和硬度。利用Raman光谱仪、椭圆偏振仪、数字式显微硬度计分别测试了不同条件下单层类金刚石薄膜的金刚石相分数、光学常数和硬度。实验表明,随着功率的增加,金刚石相的相对分数减少,薄膜的折射率先减小再增加然后减小,射频功率大于910 W时,沉积速率急剧增大。而薄膜的硬度先增加后减小,在射频功率为860 W处获得最大值。     

脉冲激光制备类金刚石薄膜及原位激光等离子体发射光谱

用ＹＡＧ脉冲激光轰击真空室内的石墨靶,可以形成包含碳素的激光等离子体,并在硅或石英衬氏上淀积形成某种类型的碳膜。用光学多道分析仪原位测量了激光等离子体的发射光谱,给出反应空间可能存在的反应基团有碳原子、碳离子、碳分子等,用拉曼光谱研究了薄膜的结构,证明所形成的薄膜为类金刚石膜,并得出碳原子和碳离子与薄膜的类金刚石结构有关。制备过程中,氢的参与有利于薄膜中金刚石成分的形成。空间分辨的原位激光等离子体发射光谱表明,在反应空间存在薄膜形成的最佳位置。     

衬底温度对类金刚石薄膜力学性能的影响

 采用脉冲激光沉积方法在不同衬底温度下制备了最高硬度与弹性模量分别达45 GPa和290 GPa,且表面十分光滑的类金刚石薄膜。在相对湿度为80%的条件下,薄膜最低的摩擦系数与磨损率分别为0.045与5.74×10^-10 mm³·N^-1·m^-1。实验结果表明,硬度与弹性模量随衬底温度升高而降低,摩擦系数与磨损率随衬底温度升高而增大。拉曼光谱表明:在室温下制备的薄膜为典型类金刚石结构,sp³含量高达76.8%,而随温度升高,薄膜结构逐渐经无定形碳结构向纳米晶石墨结构方向发展,sp³含量也随之降低,力学性能变差。     

电化学方法制备ZnO纳米颗粒掺杂类金刚石薄膜及其场发射性能研究

采用液相电化学沉积技术制备了ZnO纳米颗粒掺杂的类金刚石(DLC)薄膜, 研究了ZnO纳米颗粒掺杂对DLC薄膜场发射性能的影响. 利用X射线光电子能谱、透射电子显微镜、Raman光谱以及原子力显微镜分别对薄膜的化学组成、 微观结构和表面形貌进行了表征. 结果表明: 薄膜中的ZnO纳米颗粒具有纤锌矿结构, 其含量随着电解液中Zn源的增加而增加. ZnO纳米颗粒掺杂增强了DLC薄膜的石墨化和表面粗糙度. 场发射测试表明, ZnO纳米颗粒掺杂能提高DLC薄膜的场发射性能, 其中Zn与Zn+C的原子比为10.3%的样品在外加电场强度为20.7 V/μm时电流密度达到了1 mA/cm². 薄膜场发射性能的提高归因于ZnO掺杂引起的表面粗糙度和DLC薄膜石墨化程度的增加.     

利用脉冲激基分子激光制备大尺寸类金刚石薄膜及其均匀性分析

利用脉冲激光沉积结合计算机辅助衬底扫描技术制备了尺寸为70×66mm、均匀性为±5%的类金刚石薄膜,薄膜显微硬度最高为27GPa,薄膜结合强度达到20000转;在制备大尺寸薄膜的过程中,衬底扫描速度越慢,薄膜的均匀性越好;在应用传统清洗等方法的基础上,认为增大镀膜粒子的能量对于提高薄膜和衬底的结合强度是非常重要的.     

宽波段的类金刚石薄膜光学窗口

 介绍了实用化宽波段光学镀膜窗口的研制过程，研制的光学窗口实现了从可见至远红外波段使用同一光学器件工作的目标，主要波段透过率在70%以上。该产品膜层均匀性优于95%，可以抵抗潮热、温度变化等恶劣环境,可耐受高功率的红外激光辐射，通过了GJB2485—95《光学膜层通用规范》和Q/AF20087—2003《宽波段军用光学镀膜窗口规范》的标准检测。     

退火对B掺杂纳米金刚石薄膜微结构和电化学性能的影响

采用热丝化学气相沉积法制备B掺杂纳米金刚石薄膜,并对薄膜进行真空退火处理,系统研究了不同退火温度对B掺杂纳米金刚石薄膜的微结构和电化学性能的影响.结果表明,当退火温度升高到800 ℃后,薄膜的Raman谱图中由未退火时在1157,1346,1470,1555 cm^-1处的4个峰转变为只有D峰和G峰,说明晶界上的氢大量解吸附量减少,并且D峰和G峰的积分强度比I_D/I_G值变为最小,即sp²相团簇     

掺硅类金刚石膜的制备与力学性能研究

用脉冲电弧离子镀技术,通过调整掺硅石墨靶和纯石墨靶的数量,制备了一系列不同硅含量的类金刚石薄膜样品.研究发现：当硅含量达6.7at.%时,类金刚石薄膜的应力从4.5GPa降低到3.1GPa,薄膜的硬度还保持在3600Hv,和没有掺杂的类金刚石薄膜的硬度相比,基本保持不变;当硅含量小于6.7at.％时薄膜的摩擦系数相对于未掺杂的类金刚石薄膜也保持不变,为0.15.当薄膜中硅含量继续增加时,薄膜中C—Si键的含量增多,导致薄膜硬度和应力都有较大幅度地减小、摩擦系数增大、磨损性能也变差了. 关键词： 类金刚石膜 掺硅 应力 硬度     

The protective properties of ultra-thin diamond like carbon films for high density magnetic storage devices

With the increase of magnetic storage density, the thickness of the protective diamond like carbon (DLC) film on the surfaces of head and disk is required as thin as possible. In this paper, the structure, mechanical properties and corrosion and oxidation resistance of ultra-thin DLC films are investigated. The ultra-thin DLC films were deposited by using filtered cathodic vacuum arc (FCVA) technique. The exact thickness of the ultra-thin DLC film was determined by high resolution transmission electron microscope (HRTEM). Raman analysis indicates that the ultra-thin DLC film presents ta-C structure with high sp³ fraction. In the wear test, a diamond tip was used to simulate a single-asperity contact with the film surface and the wear marks were produced on the film surface. The wear depths decrease with film thickness increasing. If the film thickness was 1.4 nm or above, the wear depth was much lower than that of Si substrate. This indicates that the ultra-thin DLC film with thickness of 1.4 nm shows excellent wear resistance. Corrosion tests in water and oxidation tests in air were carried out to investigate the diffusion barrier effect of the ultra-thin DLC films. The results show that the DLC film with thickness of 1.4 nm provides adequate coverage on the substrate and has good corrosion and oxidation resistance.     

退火温度对硼掺杂纳米金刚石薄膜微结构和p型导电性能的影响

采用热丝化学气相沉积法制备硼掺杂纳米金刚石 (BDND) 薄膜, 并对薄膜进行真空退火处理, 系统研究退火温度对BDND薄膜微结构和电学性能的影响. Hall效应测试结果表明掺B浓度为5000 ppm (NHB) 的样品的电阻率较掺B浓度为500 ppm (NLB) 的样品的低, 载流子浓度高, Hall迁移率下降. 1000 ℃退火后, NLB和NHB 样品的迁移率分别为53.3和39.3 cm²·V^-1·s^-1, 薄膜的迁移率较未退火样品提高, 电阻率降低. 高分辨透射电镜、紫外和可见光拉曼光谱测试结果表明, NLB样品的金刚石相含量较NHB样品高, 高的硼掺杂浓度使薄膜中的金刚石晶粒产生较大的晶格畸变. 经1000 ℃退火后, NLB和NHB薄膜中纳米金刚石相含量较未退火时增大, 说明薄膜中部分非晶碳转变为金刚石相, 为晶界上B扩散到纳米金刚石晶粒中提供了机会, 使得纳米金刚石晶粒中B浓度提高, 增强纳米金刚石晶粒的导电能力, 提高薄膜电学性能. 1000 ℃退火能够恢复纳米金刚石晶粒的晶格完整性, 减小由掺杂引起的内应力, 从而提高薄膜的电学性能. 可见光Raman光谱测试结果表明, 1000℃退火后, Raman谱图中反式聚乙炔 (TPA) 的1140 cm^-1峰消失, 此时薄膜电学性能较好, 说明TPA减少有利于提高薄膜的电学性能. 退火后金刚石相含量的增大、金刚石晶粒的完整性提高及TPA含量的大量减少有利于提高薄膜的电学性能. 关键词： 硼掺杂纳米金刚石薄膜 退火 微结构 电学性能     

Laser energy density, structure and properties of pulsed-laser deposited zinc oxide films

Zinc oxide thin films were deposited on soda lime glass substrates by pulsed laser deposition in an oxygen-reactive atmosphere at 20 Pa and a constant substrate temperature at 300 °C. A pulsed KrF excimer laser, operated at 248 nm with pulse duration 10 ns, was used to ablate the ceramic zinc oxide target. The structure, the optical and electrical properties of the as-deposited films were studied in dependence of the laser energy density in the 1.2-2.8 J/cm² range, with the aid of X-ray Diffraction, Atomic Force Microscope, Transmission Spectroscopy techniques, and the Van der Pauw method, respectively. The results indicated that the structural and optical properties of the zinc oxide films were improved by increasing the laser energy density of the ablating laser. The surface roughness of the zinc oxide film increased with the decrease of laser energy density and both the optical bang gap and the electrical resistivity of the film were significantly affected by the laser energy density.     

The microstructure, mechanical and friction properties of protective diamond like carbon films on magnesium alloy

Protective hard coatings deposited on magnesium alloys are believed to be effective for overcoming their poor wear properties. In this work, diamond-like carbon (DLC) films as hard protective films were deposited on AZ91 magnesium alloy by arc ion plating under negative pulse bias voltages ranging from 0 to −200 V. The microstructure, composition and mechanical properties of the DLC films were analyzed by scanning electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy and nanoindentation. The tribological behavior of uncoated and coated AZ91 magnesium alloy was investigated using a ball-on-disk tribotester. The results show that the negative pulse bias voltage used for film deposition has a significant effect on the sp³ carbon content and mechanical properties of the deposited DLC films. A maximum sp³ content of 33.3% was obtained at −100 V, resulting in a high hardness of 28.6 GPa and elastic modulus of 300.0 GPa. The DLC films showed very good adhesion to the AZ91 magnesium alloy with no observable cracks and delamination even during friction testing. Compared with the uncoated AZ91 magnesium alloy, the magnesium alloy coated with DLC films exhibits a low friction coefficient and a narrow, shallow wear track. The wear resistance and surface hardness of AZ91 magnesium alloy can be significantly improved by coating a layer of DLC protective film due to its high hardness and low friction coefficient.     

退火时间对硼掺杂纳米金刚石薄膜微结构和电化学性能的影响

采用高分辨透射电镜、紫外和可见光Raman光谱及循环伏安法研究了1000 ℃下退火不同时间的硼掺杂纳米金刚石薄膜的微结构和电化学性能. 结果表明,随退火时间的延长,薄膜中纳米金刚石晶粒尺寸逐渐减小.当退火时间为0.5 h时, 金刚石晶粒尺寸由未退火样品的约15 nm减小为约8 nm, 金刚石相含量增加;当退火时间为2.0 h时,金刚石晶粒减小为2—3 nm, 此时晶界增多,金刚石相含量减少;退火时间为2.5 h时纳米金刚石晶粒尺寸和金刚石相含量又略有上升.晶粒尺寸和金刚石相含量的变化表明薄膜在退火过程中发生了金刚石和非晶碳相的相互转变.可见光Raman光谱测试结果表明,不同退火时间下, G峰位置变化趋势与I_D/I_G值变化一致,说明薄膜内sp²碳团簇较大时, 非晶石墨相的有序化程度较高.退火0.5, 1.0, 1.5和2.0 h时, 电极表面进行准可逆电化学反应,而未退火和退火时间为2.5 h时电极表面进行不可逆电化学反应.退火有利于提高薄膜电极的传质效率, 退火0.5 h时薄膜电极的传质效率最高,催化氧化性能最好.较小的晶粒尺寸、 较高的金刚石相含量以及纳米金刚石晶粒的均匀分布有利于提高电极表面反应的可逆性和催化氧化性能.     

Magnetic/non-magnetic nanoparticles films with peculiar properties produced by ultrashort pulsed laser deposition

Films of magnetic nanoparticles uniformly mixed with non-magnetic nanoparticles have been produced by ultrashort pulsed laser deposition. These films present innovative characteristics with respect to their counterparts produced by standard techniques, as for example nanosecond laser ablation or sputtering, due to the peculiar shape and preferential distribution of their constituent nanoparticles. In the present investigation, the difficult coalescence among the deposited nanoparticles, specific characteristic of the ultrashort pulsed laser deposition, is particularly stressed for what concerns its effect on the collective magnetic behaviour. In particular, we observed that, even for a significant fraction of magnetic particles, the films exhibit an unusual high remanent magnetization, together with relatively low values of saturation and coercive fields, showing a strong squareness of the hysteresis loops. In perspective, these nanogranular films appear very promising for potential application as permanent magnets and in magnetic recording.     

金属Fe薄膜的PLD制备及其非线性光学性质研究

采用脉冲激光沉积（PLD）技术在MgO基片上制备了金属Fe薄膜.利用原子力显微镜研究了不同制备温度对薄膜表面形貌的影响.x射线衍射分析表明沉积温度大于500℃时，Fe薄膜在MgO基片上有很好的结晶性，并有单一取向.通过z扫描方法测量了超薄Fe膜的光学非线性，得到了Fe薄膜的非线性折射率n₂＝709×10^-5cm²/ kW，非线性吸收系数 β＝-552×10^-3cm/W. 关键词： Fe薄膜 非线性 脉冲激光沉积