掺硼四面体非晶碳膜的微观结构及光谱表征

分别采用过滤阴极真空电弧技术制备了不同含硼量四面体非晶碳(ta-C:B)膜, 并用X射线光电子能谱(XPS)、Raman光谱对薄膜的微观结构和化学键态进行了研究. XPS分析表明薄膜中B主要以石墨结构形式存在, 随着B含量的增加, sp³杂化碳的含量逐渐减小, Ta-C:B膜的Raman谱线在含硼量较高时, 其D峰和G峰向低频区偏移, 且G峰的半峰宽变窄, 表明B的引入促进了sp²杂化碳的团簇化, 减小了原子价键之间的变形, 从而降低了薄膜的内应力．     

脉冲磁过滤阴极弧等离子体制备四面体非晶碳膜

介绍了脉冲磁过滤阴极电弧法制备四面体非晶碳膜(tetrahedral amorphous carbon即ta-C),并对制得的薄膜表面形貌、硬度、电阻等进行了测试.结果表明,脉冲磁过滤阴极电弧法制备的ta-C膜有优良的性能.拉曼光谱分析显示,制得的薄膜为非晶结构,有明显的sp3结构特征,符合ta-C膜的特征峰.     

磁过滤阴极弧制备四面体非晶碳膜热稳定性研究

为研究磁过滤阴极弧制备的四面体非晶碳(tetrahedral amorphous carbon, ta-C)膜在自然环境中使用的热稳定性, 将ta-C膜在空气中退火3h, 退火温度分别为200、400和500℃. 用XPS和Raman谱对膜的微观结构进行表征. 结果表明, 在400及400℃以下退火, XPS谱C1_s峰和Raman谱都没有明显变化. 当退火温度为500℃时, C1_s峰峰形仍然没有变化; Raman峰I_D/I _G增大, G峰峰位未变, 峰的对称性变好. 分析显示膜中石墨颗粒长大, 但没有发生石墨化. 说明磁过滤阴极弧制备的ta-C膜因不含氢和结构致密而表现出良好的热稳定性. 另外, 在退火温度为500℃时, 样品边缘已经氧化挥发.     

膜厚对四面体非晶碳膜机械性能的影响

采用过滤阴极真空电弧技术以相同的工艺条件在p(100)单晶硅衬底上制备了不同厚度的四面体非晶碳薄膜,并利用表面轮廓仪测试薄膜的厚度和应力,利用纳米压入仪测试薄膜的硬度、杨氏模量和临界刮擦载荷.试验表明,在一定的扫描波形条件下,薄膜大约以0.7 nm/s的沉积速率稳定生长.随着膜厚的增加,薄膜的应力持续降低,当膜厚超过30nm时,应力将低于5GPa;当膜厚超过300nm时,硬度和杨氏模量分别将近70GPa和750GPa,已经十分接近体金刚石的性能指标.另外,随着膜厚增加所产生的应力变化,也导致了可见光拉曼光谱非对称宽峰的峰位逐渐向低频偏移.     

超薄四面体非晶碳膜的结构和性能

使用磁过滤阴极真空电弧(FCVA)技术制备不同厚度的超薄四面体非晶碳膜(ta-C)，研究了表征和测量超薄ta-C碳膜微观结构和性能的方法以及膜厚的影响。使用X射线衍射仪验证椭圆偏振光谱仪联用分光光度计表征膜厚度的可靠性并测量了膜密度；用拉曼谱分析薄膜的内在结构，验证用椭偏联用分光光度计表征sp³ C含量的可靠性；用Stoney^，s公式计算了薄膜的残余应力。结果表明，薄膜的厚度由7.6 nm增大到33.0 nm其沉积速率变化不大，为1.7±0.1 nm/min；根据椭偏联用分光光度计的表征结果，薄膜中sp³ C的含量逐渐减少，拓扑无序度降低，与拉曼谱的表征结果一致；厚度为7.6 nm的超薄ta-C碳膜中p³ C的含量最高；随着厚度的增大薄膜中的残余压应力从14 GPa降低到5 GPa；厚度为11.0 nm的薄膜主体层密度最大，为3070 kg/m³，致密性较好；厚度对薄ta-C碳膜表面粗糙度的影响较小。用椭偏和分光光度计测量超薄ta-C碳膜的厚度和表征显微结构是可行的，X射线反射法可用于测量超薄ta-C碳膜密度和表面粗糙度，但是对薄膜的质量要求较高。     

厚度对真空电弧制备传感器用非晶ta-C膜性能的影响

采用双弯曲磁过滤阴极真空电弧沉积方法在传感器用P型单晶硅上制备ta-C膜,并通过实验测试的手段研究厚度对其组织及性能的影响。研究结果表明:逐渐延长沉积时间后,沉积速率始终保持1.6 nm/min的稳定状态。分别运用椭偏仪和光度计测定ta-C膜的厚度结果基本一致,差值小于2 nm。随着膜厚的增加,sp³C比例发生了减小,原先的sp³结构逐渐转变为sp²结构。当膜厚增大后,ta-C膜内形成了更高比例的sp³C。当膜厚增大后,G峰发生了低位移动,此时膜内的sp³C比例发生了降低。当膜厚增大后,ta-C膜色散值和残余压应力发生了不断减小,表明膜获得了更小的拓扑无序度。不同厚度的涂层粗糙度基本接近,都在0.6 nm以内。膜表面呈现光滑的连续分布形态,粗糙度保持基本恒定。     

硼掺杂四面体非晶碳薄膜的光学特性研究

采用过滤阴极真空电弧技术制备了不同硼含量的掺杂四面体非晶碳薄膜(ta-C:B)。使用椭偏仪和紫外-可见光分度计测试了薄膜的折射率、消光系数、透过率和反射率。结果表明,硼含量小于2.13%时,硼含量增加,薄膜折射率缓慢增大;消光系数基本保持不变。当硼含量继续增加到3.51%和6.04%时,折射率分别迅速增加至2.65和2.71,相应的消光系数增大至0.092和0.154;而薄膜的光学带隙从2.29eV缓慢减小至1.97eV,后又迅速降至1.27eV。同时ta-C:B膜的透过率逐渐减小,反射率逐渐增大,表明硼的掺入降低了薄膜的透光性能。ta-C:B膜光学性能的变化,除了与sp3杂化碳的含量有关外,还取决于薄膜中sp2杂化碳的空间分布特点。     

电绝缘用ta-C薄膜的微观结构与电学特性

采用ta—C薄膜用于SOI结构中的绝缘层，在高温高功率器件中有很大的应用潜力。应用真空磁过滤弧源沉积(FAD)的方法制备了ta—C薄膜。通过AFM、non—RBS、IR、I—V、C—V等方法对薄膜的表面形貌、微观结构和电学性能进行了研究。研究表明，ta—C薄膜的sp^3键含量高达87％，且具有很高的表面光洁度(粗糙度低于0．5nm)及较好的电绝缘性能，击穿场强达到4．7MV／cm。     

不同厚度四面体非晶碳薄膜的高通量制备及表征

材料基因组工程能大幅度提高材料研发速度, 降低材料研发成本, 近年来受到广泛关注。本研究采用高通量制备工艺, 结合碳等离子体束流和基片位置的调控, 利用自主设计研制的45°双弯曲磁过滤阴极真空电弧设备, 沉积了厚度为4.7~183 nm的系列四面体非晶碳(ta-C)薄膜, 使用椭偏仪、原子力显微镜、拉曼光谱仪和X射线光电子能谱仪(XPS)表征了厚度对ta-C薄膜表面粗糙度、微结构和原子键态的影响。结果表明：通过碳等离子体束流和基片位置的调控, 实现了不同厚度ta-C薄膜的高通量制备。尽管膜厚不同, 所制备的ta-C薄膜均具有几乎不变的光滑表面(R_a=(0.38±0.02) nm)和色散值(Disp(G)), 说明不同厚度ta-C薄膜的sp³含量、sp²团簇尺寸保持相对稳定。XPS结果进一步证实ta-C薄膜的sp³相对含量均维持在(55±5)%。此外, 不同厚度ta-C薄膜的光学带隙E_opt均保持在(1.02±0.08)eV。相关结果为设计制备结构和光学性能可控的不同厚度ta-C薄膜提供了一种新思路。     

离子注入纯Fe表面微观结构研究

本文应用透射电镜（ＴＥＭ）等方法对纯Ｆｅ中注入Ｎｉ＋、Ｍｏ＋、Ｂ＋及Ｎｉ＋＋Ｍｏ＋＋Ｂ＋引起表面层微观结构变化进行了研究，同时对不同注入条件进行了计算机模拟计算。结果表明，离子注入后纯Ｆｅ表面层微观结构有明显变化，较高剂量离子注入可使表面晶粒细化，并能形成表面非晶层，注入Ｎｉ＋后，注入层内出现以Ｆｅ为主的ｈｃｐ碳化物，部分α－Ｆｅ转变为γ－Ｆｅ，并呈现微孪晶形貌     

Thickness dependent electronic structure of ultra-thin tetrahedral amorphous carbon (ta-C) films

Microstructural properties of ultrathin (1-10 nm) tetrahedral amorphous carbon (ta-C) films are investigated by Near Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy, X-ray Photoelectron Spectroscopy, Raman spectroscopy and Atomic Force Microscopy (AFM). The CK-edge NEXAFS spectra of 1 nm ta-C films provided evidence of surface defects (C―H bonds) which rapidly diminish with increasing film thickness. A critical thickness for stabilization of largely sp³ matrix structure distorted by sp² sites is observed via the change of π*C═C peak behavior. Meanwhile, an increase in the film thickness promotes an enhancement in sp³ content, the film roughness remains nearly constant as probed by spectroscopic techniques and AFM, respectively. The effect of thickness on local bonding states of ultrathin ta-C films proves to be the limiting factor for their potential use in magnetic and optical storage devices.     

纳米金增强掺磷四面体非晶碳膜的电化学活性

采用电沉积法在过滤阴极真空电弧技术合成的掺磷四面体非晶碳(ta-C∶P)薄膜表面沉积纳米金团簇,制备纳米金修饰的掺磷非晶碳(Au/ta-C∶P)薄膜电极。利用X射线光电子能谱、拉曼光谱、扫描电子显微镜和电化学伏安法表征ta-C∶P和Au/ta-C∶P的微观结构、表面形貌和电化学行为。结果表明,-80V的脉冲偏压更利于磷原子进入碳的网络,并明显增加薄膜的电导率和电化学活性。纳米金团簇可增加ta-C∶P电极的有效面积,提高对铁氰化钾氧化还原反应的活性和电极可逆性,增强对多巴胺的催化活性。研究结果揭示ta-C∶P和Au/ta-C∶P薄膜在电分析及生物传感器方面的潜在应用。     

不同厚度四面体非晶碳薄膜的拉曼表征和内应力

为了探讨膜厚对四面体非晶碳薄膜拉曼结构表征和内应力的影响规律，进而确定应力与拉曼光谱之间的关系，采用过滤阴极真空电弧技术以相同的工艺条件在P（100）单晶抛光硅衬底上制备了从3nm～350nm不同厚度的四面体非晶碳薄膜。利用表面轮廓仪和原子力显微镜测试膜厚，表面轮廓仪确定曲率半径并计算薄膜应力，共聚焦拉曼光谱表征薄膜的结构细节。实验发现，随着膜厚的增加，四面体非晶碳薄膜的应力持续下降，当膜厚超过30nlll时，应力的下降趋势变得平缓，并保持在小于5GPa的较低水平。随着膜厚的增加，可见光拉曼光谱中衬底硅的一阶和二阶谱峰强度逐渐降低，在50nm～80nm膜厚范围，半高宽最窄，峰强最高，能够最有效地获得拉曼结构信息。随着膜厚的增加和应力的下降，非晶碳一阶谱峰的峰位表现为逐渐向低频偏移。     

Stripping voltammetric behavior of nitrogen-doped tetrahedral amorphous carbon thin film electrodes in NaCl solutions

Conductive nitrogen-doped tetrahedral amorphous carbon (ta-C:N) thin films fabricated with a filtered cathodic vacuum arc technique were investigated for their ability to detect multiple trace heavy metals such as mercury, copper and lead by linear sweep anodic stripping voltammetry in sodium chloride aqueous solutions. The ta-C:N film electrodes exhibited a significant stripping response for determination of individual elements (Pb²⁺ and Hg²⁺) and multiple elements (Pb²⁺ + Hg²⁺ and Cu²⁺ + Hg²⁺), indicating that these electrodes have a great potential for simultaneously tracing multiple heavy metals in aqueous solutions.     

Investigation of silicon implanted with carbon ions

The properties of silicon single crystals implanted with carbon ions were studied by two independent methods. It is demonstrated that the concentration of implanted carbon can be monitored by measuring the density of divacancies.     

Deuterium influence on optical gap of amorphous carbon diamond-like carbon (DLC) thin film

This present study aims to determine the hydrogen influence on the electrical gap of diamond-like carbon (DLC) film. DLC thin layers were deposited on silicon wafer by plasma enhanced chemical vapour deposition (PECVD). With this method we obtain a a-C:H film structure. To understand the mechanism of deposition, local structure and hydrogen effect in DLC we replace our methane plasma source by deuterated methane one. In this article, hydrogen rate is obtained by elastic recoil detection analysis (ERDA), electronic and bulk density is performed with X-ray reflectometry (XRR) and the determination of electrical gap is carried out using ultraviolet-visible absorption spectrometry. A specific attention is carried about the self-bias voltage and time variations to get different DLC and DDLC film compositions and also different electrical properties. We found that including deuterium in carbon increases the Tauc energy while keeping the same density. A comparison between these two sorts of film is expected to improve our understanding of the hydrogen role in the DLC films.     

A tribological study of tetrahedral amorphous carbon films prepared by filtered cathodic vacuum arc technique

In this study, a series of tetrahedral amorphous carbon films (ta-C) were deposited on silicon, W18Cr4 V high-speed and Cr18Ni9 stainless steel substrates respectively by using pulsed filtered cathodic vacuum arc system with a MEVVA source, and ta-C film’s tribological properties, including the structure, mechanical performance, adhesion, friction and wear character, were investigated. The results show: the hardness and elastic modulus of ta-C film on a high-speed substrate were reached to 76 and 453 Gpa, respectively; and the effects of substrate and film thickness on ta-C film’s friction coefficients have been studied as well; moreover, the corresponding adhesion damage mechanism and wear damage mechanism have been investigated, respectively.     

Effects of mass density on the microhardness and modulus of tetrahedral amorphous carbon films

Tetrahedral amorphous carbon (ta-C) films were deposited by filtered cathodic vacuum arc technique with substrate negative bias setting in the range of 0–200 V. The film density, hardness and Young's modulus were respectively obtained from the X-ray reflectivity and nanoindentation measurements. A maximum value of density was identified in the middle range of incident ion energy. Correlations between the density and elastic behavior of the films were then discussed theoretically based on the constraint-counting model of Philips and Thorpe. The measured Young's modulus and hardness almost vary linearly with the increasing density which agrees quite well with the theoretic predictions.