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氮气对纳米金刚石膜的生长结构及晶界处H含量的影响

  • 王振湉
  • ， 翁俊
  • ， 汪建华
  • ， 刘繁

武汉工程大学 等离子体化学与新材料湖北省重点试验室, 武汉 430205；

Effects of N2 on Growth Structure and Amount of H in Grain Boundaries of Nanocrystalline Diamond Films

  • Wang Zhen
  • ， Weng Jun
  • ， Wang Jianhua
  • ， Liu Fan

Key Laboratory of Plasma Chemistry and Advanced Materials of Hubei Province, Wuhan Institute of Technology, Wuhan 430205 , China；

通讯作者:

翁俊(1986—),男(汉),讲师,博士;研究方向:微波等离子体;E-mail:wj.204@163.com

中图分类号:TG174.444

文献标识码:A

文章编号:1007-9289(2020)01-0039-08

DOI:10.11933/j.issn.1007-9289.20190616001

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目录contents

    摘要

    采用 MPCVD 技术,研究了 CO2 -CH4 -N2 体系中 N2 对纳米金刚石膜生长状态及晶界处 H 含量的影响。 利用 SEM,XRD,Raman,FTIR 及 TEM 对纳米金刚石膜的形貌、结构和质量进行研究,并利用 Raman 及 FTIR 对晶界处 H 的含量进行计算分析。 结果表明,N2 流量的增加会在促使纳米金刚石膜的晶粒团聚体从球状逐渐转变为针状的同时减小晶粒尺寸,并使择优取向由<111>转变为<110>。 随着 N2 流量的增加,纳米金刚石膜的质量也随之降低,但晶界处的 H 含量逐渐上升。 具有针状晶粒团聚体的纳米金刚石膜具有明显的金刚石相和晶体石墨相。 N2 流量的增加不仅可以有效降低纳米金刚石膜的晶粒尺寸,改变晶粒的团聚形态及择优取向,还可以显著增加晶界处 H 的含量,促进石墨相的生成。

    Abstract

    An investigation on the influence of N2 on the growth structure and the amount of H in the grain boundary of nanocrystalline diamond films have been carried out in a MPCVD apparatus. The morphology, texture and quality of the deposited nanocrystalline diamond films were evaluated by SEM, XRD and Raman spectroscopy, FTIR and TEM. The content of hydrogen in the grain boundaries of nanocrystalline diamond film was calculated with the results of Raman spectra and FTIR. Results show that with the increase of N2 , the shape of the grain clusters transforms from spherality to needle-like and the preferred orientation changs from <111>to<110>with the grain size and the quality decreasing dramatically. The amount of hydrogen, however, increases significantly with the increase of N2 in CO2 -CH4 -N2 gas mixtures. Besides that, diamond and crystal graphite are two main phases in the needle-like diamond films demonstrated by the results of TEM. The research indicates that increasing N2 in CO2 -CH4 -N2 gas mixtures is benefiting not only for the decrease of grain size and the transformation of the shape of the aggregates and the preferred orientation, but also for the increase of the amount of hydrogen in grain boundaries and inducing the production of crystal graphite in nanocrystalline diamond films.

  • 0 引言

  • 纳米金刚石( Nanocrystalline diamond,NCD)具有表面平整度高,摩擦因数低,电子发射效率高,化学稳定性优良,生物相容性良好等优异的物理化学性能[1-2]。 近年来,纳米金刚石膜也在量子信息、微/纳机电系统、光电器件、生物医药等高新技术领域获得了成功应用[3-4],被认为是在众多领域中均具有广泛应用前景的理想材料。

  • 纳米金刚石膜独特的物理化学性能不仅与晶粒尺寸的大小有关,还与晶界的状态存在一定关系,例如纳米金刚石膜的硬度、弹性模量以及热导率均受到晶界数量和结构的影响[5-7]。 影响纳米金刚石膜晶界状态的因素较多。 从纳米金刚石膜的生长结构来看,晶界处多余能量会通过碳的杂化形式的改变而释放,从而在晶界中产生一些结构上更有序的以sp2 成键的碳结构相,减小纳米金刚石膜材料的结合能[8]。 从纳米金刚石膜的形貌结构来看,受膜厚影响的晶粒尺寸也会引起纳米金刚石膜晶界状态的变化[9]。 近年来的相关研究发现,纳米金刚石膜在生长过程中,晶界处的H元素会产生足以改善纳米金刚石膜电学性能的点缺陷,因此影响纳米金刚石膜晶界中H含量的因素受到了广泛关注[10-13]。在纳米金刚石膜的生长过程中,晶界中氢的成键结构及数量会受到微波输入功率、沉积气压以及气源组分等因素的共同作用[14],其中气源组分被认为是影响纳米金刚石膜晶界中H含量的最直接的影响因素之一[15-17]。 表征纳米金刚石膜中H的成键状态及数量的方法较多[18-20],利用有效的表征方法分析影响纳米金刚石膜中晶界处H含量的因素,是目前研究的主要方向之一[10]。

  • 文中利用微波等离子体化学气相沉积(Microwave plasma chemical vapor deposition,MPCVD)这一无极放电技术,在CO2-CH4-N2 所组成的无氢气环境中,制备得到了不同表面形貌的纳米金刚石膜。 综合利用Raman光谱及红外吸收光谱等表征方法,分析不同形貌结构的纳米金刚石膜中H的含量及成键状态,研究了N2 对纳米金刚石膜的生长结构以及晶界处氢元素含量的影响。

  • 1 试验与方法

  • 试验所用设备为2.0 kW-MPCVD( 韩国Woosinent公司), 其结构示意图见图1。 在该MPCVD设备中,基片温度由置于基片台下方的独立加热系统精确控制。 在N2 流量变化时,确保基片温度恒定。 试验所用基片材料为尺寸1.0 cm×1.0 cm,厚度(400±50) μm的单面抛光(100)单晶硅片。

  • 图1 2.0 kW-MPCVD设备的结构示意图

  • Fig.1 Schematic diagram of the 2.0 kW-MPCVD apparatus

  • 金刚石膜沉积试验开始前先用100 nm的金刚石粉对所有单晶硅片表面进行机械研磨处理20 min,再将研磨处理后的硅片分别置于丙酮、无水乙醇、去离子水中各超声处理10 min,以去除硅片表面的杂质,然后在氮气气氛中对单晶硅片干燥后置于反应腔中进行氢等离子体处理,进一步除去硅片表面可能存在的氧化物杂质。 氢等离子体处理的具体参数为:微波功率700 W,腔体气压4.0 kPa,基片温度550℃,氢气流量100 mL/min,处理时间30 min。 氢等离子体处理完成后,关闭微波源并将腔体抽真空至0.1 Pa后,再重新通入工作气体进行纳米金刚石膜的沉积试验,以排除氢等离子体处理过程中的氢气对试验结果的影响。 试验中所用单晶硅片均经上述预处理工艺后,再进行金刚石膜的沉积试验。 具体沉积工艺参数如表1所示。

  • 表1 纳米金刚石膜的沉积工艺参数

  • Table1 Deposition parameters of the nanocrystalline diamond films

  • 样品的表面形貌由扫描电子显微镜( Scanning electron microscope, SEM) 表征。 SEM表征利用高位二次电子模式,光斑大小控制在(20 ±4)μm。 利用X射线衍射( X-ray diffraction,XRD) 及透射电镜( Transmission electron microscope, TEM)对纳米金刚石膜的生长取向、 晶粒尺寸及相组成结构等进行表征, 其中X射线由CuKα 产生,扫描角度(2θ)为20°~140°。 拉曼光谱(Raman)用来分析金刚石膜的质量、 应力、 晶界中氢原子含量等的变化规律, 采用Ar激光,波长为632 nm。

  • 2 结果与讨论

  • 样品的表面形貌如图2 所示。 从图2 中可以看出,沉积得到的样品均具有纳米金刚石膜典型的形貌特征。 氮气流量在0~15 mL/min的范围时,纳米金刚石膜表面呈现出明显的晶粒团聚现象,如图2(a)(b)(c)所示,晶粒团聚体呈现球状。当氮气流量逐渐升高至20~25 mL/min时,纳米金刚石膜表面逐渐被针状的晶粒团聚体所覆盖,如图2( d)( e) 所示。 当氮气流量达到30 mL/min时,如图2(f)所示,纳米金刚石膜表面主要由清晰的针状晶粒团聚体组成。 导致纳米金刚石膜的形貌及晶粒细化的原因可归结为:在基片温度一定的情况下,氮气的引入会增加基片表面的碳过饱和度[21],提高金刚石膜生长过程中的二次形核率,使晶粒易于产生团聚现象;随着氮气浓度的提高,基片表面随之增加的碳过饱和度会进一步促进二次形核的产生,降低晶粒团聚体的尺寸;等离子体中含氮的活性基团会优先附着在晶粒团聚体中微小晶粒的(110)晶面上,并进一步吸附有利于二次形核的C2 基团,从而导致晶粒的团聚体优先向< 110>方向生长,呈现出针状的表面形貌特征[22]。

  • 图2 不同氮气流量时沉积得到的纳米金刚石膜的表面形貌

  • Fig.2 Surface morphologies of the nanocrystalline diamond films deposited with different flow rate of nitrogen gas

  • 为了探讨在不同氮气流量的情况下,纳米金刚石膜晶粒尺寸及择优取向的变化情况,对试验的样品进行XRD表征,其结果如图3 所示。 从图3 可以看出,样品的XRD图谱均在2θ=43.9°附近和2θ=73.7°附近表现出明显的(111)特征峰和(220)特征峰,且随着氮气流量的增加,(111)与(220)特征峰的宽化程度也随之增大。 该现象说明氮气流量的增加明显降低了纳米金刚石膜的晶粒尺寸。 进一步利用谢乐公式

  • Dhkl=Kλβ(2θ)⋅cos⁡θ
    (1)

  • 其中,K为谢乐常数、β 2θ 为样品对应的衍射峰半高宽、θ 为衍射角、λ 为X射线波长。 根据样品XRD图谱中(111)特征峰的半高宽(Full width at half maximum,FWHM)具体计算了纳米金刚石膜的平均晶粒尺寸,具体计算过程中扣除了应变宽化,同时通过具体比较(220)与(111)特征峰的强度,以确认纳米金刚石膜生长的择优取向,结果如表2 所示。

  • 由表2 可知,当氮气流量从0 mL/min增加至30 mL/min,纳米金刚石膜的晶粒尺寸从84.9 nm下降至15.3 nm,这一结果证明在CO2-CH4 体系

  • 图3 不同氮气流量下纳米金刚石膜的XRD图谱

  • Fig.3 XRD patterns of the nanocrystalline diamond films deposited at different nitrogen gas flow rate

  • 中添加氮气可以有效降低纳米金刚石膜的晶粒尺寸。 以天然金刚石 I (220)/I (111)=0.25 为参考值[23],从表2 的结果也不难看出,氮气流量的增加改变了纳米金刚石膜的生长取向。 当氮气流量为0~15 mL/min时,纳米金刚石膜以<111>为择优的生长取向。 此时,纳米金刚石膜的表面形貌表现为球状团聚体,如图2( a)( b)( c) 所示。当氮气流量升高至20~30 mL/min时,纳米金刚石膜表现为<110>择优生长取向。 虽然<111>和<110>生长取向均是纳米金刚石膜沉积过程当中常见的两个取向生长[24-25],但从试验结果来看,CO2-CH4-N2 体系中氮气的体积分数会对纳米金刚石膜的形貌及状态产生重大影响。

  • 表2 沉积得到的纳米金刚石膜的平均晶粒尺寸及择优取向

  • Table2 Average grain size and preferred orientation of deposited nanocrystalline diamond films

  • 拉曼光谱是一种表征金刚石膜质量的有效方法,利用拉曼光谱对所获得的纳米金刚石膜进行了表征,结果如图4 所示。 从图4 中可以看出,纳米金刚石膜的Raman光谱均在1332 cm-1附近和1580 cm-1 附近表现出明显的金刚石特征峰(D峰)和石墨特征峰(G峰),且各样品的金刚石特征峰均出现了宽化,其宽化程度随氮气流量的增加而增加。 该现象说明,氮气流量的增加不仅降低了纳米金刚石膜的质量,同时也增加了纳米金刚石膜的晶界数量[26]。 同时在图4 中也可观察到,在1140 cm-1 附近和1480 cm-1 附近存在较为微弱的特征峰信号,这两个特征峰信号被认为是C-C和C-H振动模式的特征峰[27-28] 或反聚乙炔的特征峰[29]。 对较为明显的金刚石特征峰和石墨特征峰进行了洛伦兹拟合,并对拟合曲线做基线,计算拟合曲线的基线斜率m,其结果如图4 所示。 Ferrari A C和Marchon B指出纳米金刚石膜中H含量的增加,会明显增加Raman光谱中的荧光背底,同时对Raman光谱中金刚石特征峰和石墨特征峰进行拟合后的光谱斜率m与G峰的强度 I(G)的比值m/I(G),可以反应纳米金刚石膜晶界处原子H的含量[30-31]。 从图4中还不难看出,在氮气流量从0 mL/min增加至30 mL/min的过程中,样品a~f的Raman光谱的斜率有明显增加的趋势。 由于在金刚石膜的生长过程中,原子氢是影响金刚石膜中sp3 含量的关键因素,因此进一步计算了样品a~f的Raman光谱中D峰的半高宽FWHM(D) 和m/I(G) 的值。 FWHM(D)的值可以直接反应纳米金刚石膜质量的高低。 其结果如图5 所示。

  • 图4 不同氮气流量下纳米金刚石膜的Raman图谱

  • Fig.4 Raman spectra of the nanocrystalline diamond films deposited at different nitrogen gas flow rate

  • 从图5 中可以看出,当氮气流量从0 mL/min增加至30 mL/min时,纳米金刚石膜的m/I (G)值与FWHM(D)同时增加。 该现象说明,氮气流量的增加虽然增加了纳米金刚石膜晶界中H的含量,但并没有提高纳米金刚石膜的质量。 从金刚石膜的生长机理分析,等离子体中的活性氢原子有可能以成键的方式驻留在金刚石膜的表面或亚表面内,从而增加金刚石膜中氢的含量,也有可能在发生化学反应后回到等离子体中或不参与到金刚石膜生长的表面反应中,从而降低金刚石膜中氢的含量[10]。 等离子体中原子氢的这两种途径共同决定了金刚石膜中原子氢的含量。从图5 所呈现的计算结果来看,虽然氮气流量的增加有利于CH4 中的H元素进入到纳米金刚石膜的晶界中,但却不利于纳米金刚石膜质量的提高。

  • 图5 纳米金刚石膜的Raman光谱m/I(G)与FWHM(D)的变化趋势

  • Fig.5 Variation of m/I(G) and FWHM(D) of the Raman spectra for the deposited nanocrystalline diamond films

  • 由于活性H不仅可以对非金刚石相产生刻蚀作用,还可以与C、N等元素形成活性基团参与到金刚石膜的生长过程中[32-33]。 为此对样品b,d和f进行了红外光谱表征,并重点对三声子区进行放大分析,同时对2775~3100 cm-1 的放大光谱的基线进行了拟合,其结果如图6 所示。 从图6 中可以看到在2880 cm-1 附近出现了sp3CH振动峰,在2850 cm-1 及2920 cm-1 附近出现了属于sp3CH2 的C-H振动峰,以及在2860 cm-1 附近出现了属于sp3CH3 的C-H的伸缩振动峰[10]。与此同时,在2820 cm-1 附近还观察到一个明显的以N为振动中心的N-CH3 振动峰[34]。 由于在膜厚相似的情况下(由于沉积时间较短,样品b、d和f的膜厚均为1.1 μm。),三声子区的光谱与基线所组成的峰面积可以反应金刚石膜中成键H的数量[10]。 因此进一步计算三声子区的光谱与基线所组成的峰面积,得到样品b、d与f在三声子区CH振动峰的峰面积大小分别为2.3,4.2和6.1。 由此可见,随着氮气浓度的增加,纳米金刚石膜中成键H的含量呈现上升趋势, 这与Raman光谱分析的结果一致。 结合红外吸收光谱及Raman光谱的表征结果分析,在试验条件下等离子体中存在的活性H对非金刚石相的刻蚀作用并不强烈。 在氮气的参与下,从CH4 中活化出的H元素可能更多的以CHx 和N-CH3 的形式参与到了纳米金刚石膜的生长过程中,使纳米金刚石膜在生长过程产生的sp2 相没有受到充分的刻蚀作用,同时也使纳米金刚石膜中成键H的含量增加,从而使纳米金刚石膜中形成了较多的石墨相。

  • 图6 不同氮气流量沉积得到的纳米金刚石膜的红外吸收光谱

  • Fig.6 Fourier transform infrared spectrometer(FTIR) spectrum of the nanocrystalline diamond films deposited with different flow rate of the nitrogen gas

  • 图7 为氮气流量30 mL/min时,纳米金刚石膜的TEM形貌。 从图7( a)中可以看出,纳米金刚石膜中晶粒的团聚体呈现出明显针状结构,且针状团聚体之间存在间隙,此形貌结构与图2( f) 中SEM的表征结果一致。 图7( b) 为100 nm内的选区电子衍射花样, 从图7( b) 中可以明显看到两种晶相, 面间距d为0.21 nm和0.13 nm所对应的是金刚石相的(111) 面和(220)面,分别标注为D(111)和D(220);面间距 d 为0.34 nm和0.17 nm所对应的是晶体石墨相的( 002) 面和( 004) 面, 分别标注为G(002)和G(004)。 TEM的结果与XRD表征的结果一致。 试验获得的针状纳米金刚石膜的微观结构符合电极材料的基本结构特性[35],在接下来的试验研究中将试图实现对这种晶形呈针状结构的纳米金刚石膜中的石墨相与金刚石相的存在位点进行有效控制,进一步研究纳米金刚石膜的微结构与电学性能之间的关系,使这种具有针状晶形的纳米金刚石膜在电极材料领域获得较好的应用。

  • 图7 氮气流量为30 mL/min时沉积得到的纳米金刚石膜的TEM形貌

  • Fig.7 TEM images of the nanocrystalline diamond films deposited with the nitrogen gas flow rate of 30 mL/min

  • 3 结论

  • 采用MPCVD技术,研究了CO2-CH4-N2 体系中N2 的体积分数对纳米金刚石膜生长状态的影响,并对纳米金刚石膜晶界中的H含量进行了重点研究,主要结论如下:

  • (1) 随着氮气流量的增加,纳米金刚石膜的晶粒团聚体逐渐由球状转变为针状。 当氮气流量为30 mL/min时,纳米金刚石膜表面主要由针状的晶粒团聚体所覆盖。

  • (2) 氮气流量的增加会促使纳米金刚石膜晶粒的减小,同时改变纳米金刚石膜的生长取向。随着氮气流量从0 mL/min增加至30 mL/min,纳米金刚石膜的晶粒尺寸从84.9 nm下降至15.3 nm,择优生长取向从< 111> 取向转变为<110>取向。

  • (3) 氮气流量的增加明显降低了纳米金刚石膜的质量,同时也提高了晶界处H元素的含量,可见反应体系中的H元素对非金刚石相的刻蚀能力有限。

  • (4) 当氮气流量为30 mL/min时,沉积得到的纳米金刚石膜具有明显的金刚石相和晶体石墨相结构,表现出导电材料所具有的基本结构特点。

  • 参考文献

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    • [20] MICHAELSON S,TERNYAK O,HOFFMAN A,et al.Correlation between diamond grain size and hydrogen retention in diamond films studied by scanning electron microscopy and secondary ion mass spectroscopy [J].Applied Physics Letters,2007,90(3):031914.

    • [21] ACHARD J,SILVA F,BRINZA O,et al.Coupled effect of nitrogen addition and surface temperature on the morphology and the kinetics of thick CVD diamond single crystals[J].Diamond and Related Materials,2007,16(4-7):685-689.

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    • [26] FUENTES-FERNANDEZ E M A,ALCANTAR-PEÑA J J,LEE G,et al.Synthesis and characterization of microcrystalline diamond to ultrananocrystalline diamond films via hot filament chemical vapor deposition for scaling to large area applications[J].Thin Solid Films,2016,603:62-68.

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  • 基本信息

    中图分类号: TG174.444
    文献标识码: A
    DOI: 10.11933/j.issn.1007-9289.20190616001
    文章编号: 1007-9289(2020)01-0039-08

    基金信息

    湖北省教育厅科学技术研究计划优秀中青年人才项目(Q20151517)；
    武汉工程大学科学研究基金(K201506)；
    Supported by Science and Technology Research Program of Hubei Education Department (Q20151517) ；
    Research Fund of Wuhan Institute of Technology (K201506)；

    引用信息

    王振湉,翁俊,汪建华,等. 氮气对纳米金刚石膜的生长结构及晶界处 H 含量的影响[J]. 中国表面工程, 2020, 33(1): 39-46.

    WANG Z T,WENG J,WANG J H,et al. Effects of N2 on growth structure and amount of H in grain boundaries of nanocrystalline diamond films[J]. China Surface Engineering,2020, 33(1): 39-46.

    稿件历史

    收稿日期: 2019-06-16
    修回日期: 2020-01-04

  • 参考文献

    • [1] TANG C J,FERNANDES A J S,GRANADA M,et al.High rate growth of nanocrystalline diamond films using high microwave power and pure nitrogen/methane/hydrogen plasma [J].Vacuum,2015,122:342-346.

    • [2] VOLODIN V A,MORTET V,TAYLOR A,et al.Raman scattering in boron doped nanocrystalline diamond films:Manifestation of Fano interference and phonon confinement effect[J].Solid State Communications,2018,276:33-36.

    • [3] RODIEK B,LOPEZ M,HOFER H,et al.Experimental realization of an absolute single-photon source based on a single nitrogen vacancy center in a nanodiamond[J].Optica,2017,4(1):71.

    • [4] STEHLIK S,VARGA M,STENCLOVA P,et al.Ultrathin nanocrystalline diamond films with silicon vacancy color centers via seeding by 2 nm detonation nanodiamonds[J].ACS Applied Materials & Interfaces,2017,9(44):38842-38853.

    • [5] WIORA M,BRÜHNE K,FLOTER A,et al.Grain size dependent mechanical properties of nanocrystalline diamond films grown by hot-filament CVD[J].Diamond and Related Materials,2009,18(5-8):927-930.

    • [6] HESS P.The mechanical properties of various chemical vapor deposition diamond structures compared to the ideal single crystal[J].Journal of Applied Physics,2012,111(5):051101.

    • [7] MOHR M,DACCACHE L,HORVAT S,et al.Influence of grain boundaries on elasticity and thermal conductivity of nanocrystalline diamond films [J].Acta Materialia,2017,122:92-98.

    • [8] KEBLINSKI P,WOLF D,PHILLPOT S R,et al.Role of bonding and coordination in the atomic structure and energy of diamond and silicon grain boundaries[J].Journal of Materials Research,1998,13(8):2077-2100.

    • [9] TANG C J,NEVES A J,FERNANDES A J S.Influence of nucleation density on film quality,growth rate and morphology of thick CVD diamond films[J].Diamond and Related Materials,2003,12(9):1488-1494.

    • [10] TANG C J,FERNANDES A J S,JIANG X F,et al.Impact of high microwave power on hydrogen impurity trapping in nanocrystalline diamond films grown with simultaneous nitrogen and oxygen addition into methane/hydrogen plasma[J].Journal of Crystal Growth,2016,434:36-41.

    • [11] YAN Y F,LI J B,WEI S H,et al.Possible approach to overcome the doping asymmetry in wideband gap semiconductors[J].Physical Review Letters,2007,98(13):135506.

    • [12] YAN C X,DAI Y,LONG R,et al.Effect of excess hydrogen on the electronic properties of passivated diamond[J].Journal of the Physics & Chemistry of Solids,2009,70(2):307-311.

    • [13] AUCIELLO O,SUMANT A V.Status review of the science and technology of ultrananocrystalline diamond(UNCD)films and application to multifunctional devices[J].Diamond and Related Materials,2010,19(7-9):699-718.

    • [14] MICHAELSON S,LIFSHITZ Y,TERNYAK O,et al.Hydrogen incorporation in diamond films [J].Diamond and Related Materials,2007,16:845-850.

    • [15] TANG C J,ABE I,VIEIRA L G,et al.Investigation of nitrogen addition on hydrogen incorporation in CVD diamond films from polycrystalline to nanocrystalline [J].Diamond and Related Materials,2010,19(5-6):404-408.

    • [16] RAKHA S A,JIANQING C,HUIHAO X,et al.Incorporation of hydrogen in diamond thin films[J].Diamond and Related Materials,2009,18(10):1247-1252.

    • [17] MICHAELSONS,TERNYAK O,HOFFMAN A,et al.Correlation between diamond grain size and hydrogen retention in diamond films studied by scanning electron microscopy and secondary ion mass spectroscopy[J].Applied Physics Letters,2007,90(3):031914-031914-3.

    • [18] MCNAMARA KM,LEVYDH.Nuclear magnetic resonance and infrared absorption studies of hydrogen incorporation in polycrystalline diamond[J].Applied Physics Letters,1992,60(5):580-582.

    • [19] KIMURA A,NAKATANI Y,YAMADA K,et al.Hydrogen detection in CVD diamond films by elastic recoil detection analysis[J].Diamond and Related Materials,1999,8(1):37-41.

    • [20] MICHAELSON S,TERNYAK O,HOFFMAN A,et al.Correlation between diamond grain size and hydrogen retention in diamond films studied by scanning electron microscopy and secondary ion mass spectroscopy [J].Applied Physics Letters,2007,90(3):031914.

    • [21] ACHARD J,SILVA F,BRINZA O,et al.Coupled effect of nitrogen addition and surface temperature on the morphology and the kinetics of thick CVD diamond single crystals[J].Diamond and Related Materials,2007,16(4-7):685-689.

    • [22] SHALINI J,LIN Y,CHANG T,et al.Ultra-nanocrystalline diamond nanowires with enhanced electrochemical properties [J].Electrochimica Acta,2013,92:9-19.

    • [23] ALI M,ÜRGEN M.Surface morphology,growth rate and quality of diamond films synthesized in hot filament CVD system under various methane concentrations[J].Applied Surface Science,2011,257(20):8420-8426.

    • [24] SILVA F,BÉNÉDIC F,BRUNO P,et al.Formation of texture during nanocrystalline diamond growth:An Xray diffraction study [J].Diamond and Related Materials,2005,14(3-7):398-403.

    • [25] TANG C J,NEVES A J,PEREIRA S,et al.Effect of nitrogen and oxygen addition on morphology and texture of diamond films(from polycrystalline to nanocrystalline)[J].Diamond and Related Materials,2008,17(1):72-78.

    • [26] FUENTES-FERNANDEZ E M A,ALCANTAR-PEÑA J J,LEE G,et al.Synthesis and characterization of microcrystalline diamond to ultrananocrystalline diamond films via hot filament chemical vapor deposition for scaling to large area applications[J].Thin Solid Films,2016,603:62-68.

    • [27] KLAUSERF,STEINMÜLLER-NETHLD,KAINDLR,et al.Memmel,ramanstudies of nano-and ultra-nanocrystalline diamond films grown by hot-filament CVD [J].Chemical Vapor Deposition,2010,16(4-6):127-135.

    • [28] FERRARIAC,ROBERTSONJ.Origin of the 1150cm-1 Raman mode in nanocrystalline diamond [J].Physical Review B,2001,63:121405.

    • [29] PFEIFFER R,KUZMANY H,SALK N,et al.Evidence for trans-polyacetylene in nanocrystalline diamond films from HD isotropic substitution experiments [J].Applied Physics Letters,2003,82(23):4149-4150.

    • [30] FERRARI A C,ROBERTSON J.Interpretation of Raman spectra of disordered and amorphous carbon[J].Physical Review B(Condensed Matter),2000,61(20):14095-14107.

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