共查询到20条相似文献,搜索用时 150 毫秒
1.
2.
通过对衬底施加负偏压吸引等离子体中的阳离子对衬底轰击,从而用射频磁控溅射法在水冷透明绦纶聚脂胶片上制备出相对透过率为80%左右、最小电阻率为63×10-4Ωcm、附着良好的ITO(Indium Tin Oxide)透明导电膜.SnO2最佳掺杂浓度为7.5%—10%(w.t.),最佳氩分压为0.5—1Pa.当衬底负偏压为20—40V时,晶粒平均尺寸最大,制备出的薄膜的电阻率有最小值.薄膜为多晶纤锌矿结构,垂直于衬底的c轴具有[222]方向的择优取向,随衬底负偏压
关键词: 相似文献
3.
4.
报道用SiF4和H2的间接微波等离子体化学气相沉积方法低温生长多晶硅(poly-Si)薄膜.实验发现,等离子体中的离子、荷电集团对薄膜生长表面的轰击是影响薄膜结晶质量的重要因素之一.通过外加偏压抑制这些荷电粒子的动能是控制表面生长反应、制备高质量ploy-Si薄膜的有效方法.在合适的外加偏压下制备的poly-Si薄膜,氢含量仅约为0.9at%,中心位于520cm-1的Raman特征峰半高宽约为4.4cm-1.
关键词:
多晶硅薄膜
低温生长
表面生长反应
外加偏压 相似文献
5.
ICP等离子体鞘层附近区域发光光谱特性分析 总被引:1,自引:0,他引:1
为了独立控制鞘层附近区域离子密度和离子能最分布,采用光发射谱(OES)测量技术,对不同射频功率、放电气压和基底偏压下感应耦合等离子体鞘层附近区域辉光特性进行了研究.原子谱线和离子谱线特性分析表明,在鞘层附近区域感应耦合等离子体具有较高的离子密度和较低的电子温度.改变放电气压和射频功率,对得到的光谱特性分析表明,鞘层附近区域离子密度随射频功率的增大而线性增大,在低压下随气压的升高而增大.低激发电位原子谱线强度增加迅速,高激发电位原子谱线强度增加缓慢,而离子谱线强度增加很不明显.改变基底直流偏压,对得到的发射光谱强度变化分析表明,谱线强度随基底正偏压的增加而增大.随着基底负偏压的加入,谱线强度先减小而后增大;直流偏压为-30 V时,光谱强度最弱.快速离子和电子是引起Ar激发和电离过程的主要能量来源. 相似文献
6.
建立了气体放电空心圆筒阴极鞘层离子的自洽蒙特-卡罗模拟模型,对鞘层区内离子的输运过程进行了研究。考虑了离子与中性原子的电荷交换碰撞和弹性散射,用到了精确依赖于离子能量的电荷交换和动量输运截面。模拟了氩离子在空心阴极鞘层中的运动,得到了不同放电条件下自洽电场分布,离子的能量分布,角分布以及电子密度分布和离子密度分布。计算结果表明:离子在由鞘层边界向阴极运动过程中,离子能量分布的高能部分逐渐增大,角分布向小角度部分压缩,鞘层中的强电场对离子起加速和聚焦作用;在鞘层内离子密度分布比较均匀,只是在鞘层边界附近变化
关键词: 相似文献
7.
采用两维PIC/MCC模型模拟了氮气微空心阴极放电以及轰击离子 (N2+,N+) 的钛阴极溅射. 主要计算了氮气微空心阴极放电离子 (N2+,N+) 及溅射原子Ti的行为分布, 并研究了溅射Ti 原子的热化过程. 结果表明: 在模拟条件下, 空心阴极效应是负辉区叠加的电子震荡; 在对应条件下, 微空心较传统空心放电两种离子 (N2+,N+) 密度均大两个量级, 两种离子的平均能量的分布及大小几乎相同; 在放电空间N+的密度约为N2+的1/6, 最大能量约大2倍; 在不同参数 (P, T, V)下, 轰击阴极内表面的氮离子(N2+,N+)的密度近似均匀, 其平均能量几乎相等; 从阴极溅射出的Ti原子的初始平均能量约6.8 eV, 离开阴极约0.15 mm处几乎完全被热化. 模拟结果为N2微空心阴极放电等离子体特性的认识提供了参考依据.
关键词:
微空心阴极放电
PIC/MC模拟
2等离子体')" href="#">N2等离子体 相似文献
8.
采用过滤阴极真空电弧技术,通过施加0—2000 V衬底负偏压使沉积离子获得不同能级的入射能量,在单晶硅上制备了四面体非晶碳薄膜.拉曼光谱分析表明,薄膜的结构为非晶sp3骨架中镶嵌着平面关联长度小于1 nm的sp2团簇.原子力显微镜研究表明:在低能级、富sp3能量窗口和次高能级,薄膜中sp3的含量越多,其表面就越光滑,应用sp3浅注入生长机制能够圆满地解释薄膜表面形态与离子入射能量之间的关系;但在高
关键词:
四面体非晶碳
过滤阴极真空电弧
能级 相似文献
9.
10.
11.
12.
Aligned growth and alignment mechanism of carbon nanotubes by hot filament chemical vapor deposition
Carbon nanotubes (CNTs) growth on Inconel sheets was carried out using hot filament chemical vapor deposition (HFCVD) in a
gas mixture of methane and hydrogen. Scanning electron microscopy, transmission electron microscopy and field electron emission
(FEE) measurement were applied to study the structure and FEE properties of the deposited CNTs. The effect of bias voltage
and substrate surface roughness on the growth of vertically aligned carbon nanotubes was investigated. Well-aligned CNTs were
synthesized by bias enhanced HFCVD. The results show that a bias of −500 V generates the best alignment. It has been observed
that at the early growth stage, aligned and non-aligned CNTs are growing simultaneously on the unscratched sheets, whereas
only aligned CNTs are growing on the scratched sheets. The results indicate that tip growth is not necessary for the electric
field to align the CNTs, and larger catalyst particles created by scratching before the heat treatment can induce alignment
of CNTs at the early growth stage. In addition, tree-like CNTs bundles grown on the scratched substrates exhibit better FEE
performances than dense carbon nanotube forest grown on the unscratched substrates due to the reduced screen effect. 相似文献
13.
Z.P. Huang D.Z. Wang J.G. Wen M. Sennett H. Gibson Z.F. Ren 《Applied Physics A: Materials Science & Processing》2002,74(3):387-391
The effect of pure nickel, iron and cobalt on growth of aligned carbon nanotubes was systematically studied by plasma-enhanced
hot-filament chemical vapor deposition. It is found that the catalyst has a strong effect on the nanotube diameter, growth
rate, wall thickness, morphology and microstructure. Ni yields the highest growth rate, largest diameter and thickest wall,
whereas Co results in the lowest growth rate, smallest diameter and thinnest wall. The carbon nanotubes catalyzed by Ni have
the best alignment and the smoothest and cleanest wall surface, whereas those from Co are covered with amorphous carbon and
nanoparticles on the outer surface. The carbon nanotubes produced from Ni catalyst also exhibit a reasonably good graphitization.
Therefore, Ni is considered as the most suitable catalyst for growth of aligned carbon nanotubes.
Received: 30 November 2001 / Accepted: 3 December 2001 / Published online: 4 March 2002 相似文献
14.
We report here a facile way to grow aligned multi-walled carbon nanotubes (MWCNTs) on various metal (e.g. gold, tungsten, vanadium and copper)/silicon electrically conductive substrates by aerosol-assisted chemical vapor deposition (AACVD). Without using any buffer layers, integration of high quality MWCNTs to the conductive substrates has been achieved by introducing appropriate amount of water vapor into the growth system. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) determination indicate tidy morphology and narrow diameter distribution of the nanotubes as well as promising growth rate suitable for industrial applications. Raman spectra analysis illustrates that the structural order and purity of the nanotubes are significantly improved in the presence of water vapor. The growth mechanism of the nanotubes has been discussed. It is believed that water vapor plays a key role in the catalyst-substrate interaction and nucleation of the carbon nanotubes on the conductive substrates. This synthesis approach is expected to be extended to other catalyst-conductive substrate systems and provide some new insight in the direct integration of carbon nanotubes onto conductive substrates, which promises great potential for applications in electrical interconnects, contacts for field emitters, and other electronic nanodevices. 相似文献
15.
16.
《Current Applied Physics》2014,14(1):8-12
We report the drastic growth yield enhancement of carbon nanotubes (CNT) on Inconel 600 metal substrate which contains catalytic components through the surface pretreatments combining thermal annealing and plasma ion bombardment. We comparatively investigated the effect of different substrate pretreatments of air annealing, plasma treatment, and their combination affecting CNT growth yield. The roughness of the substrates was significantly enhanced by the air annealing at 725 °C but reduced after the following plasma treatment, which produce nano-sized particle structures. Finally, a significant enhancement in the CNT growth yield was observed when the Inconel 600 substrate was undergone the pretreatment, which consists of oxidative annealing and subsequent plasma treatment. 相似文献
17.
Stimulation of the local growth of aligned carbon nanotubes by pulse laser exposure of the substrate
The local stimulation of carbon nanotubes (CNT) growth at the laser-modified sites that have been obtained by excimer laser irradiation at 248 nm causing a local surface modification has been investigated by two different processing methods. The influence of the laser processing parameters on the CNT growth is compared for the irradiation of thin spin-coated iron nitrate films on silicon substrates and the backside irradiation of a fused silica substrate being in contact with an iron nitrate solution. Both techniques cause the formation of catalytic surface sites either by decomposition of the film or by deposition from the solution. For both laser modification approaches the local growth of vertical aligned nanotubes has been observed. In the case of spin-coated film the laser irradiation conditions have only a small influence on the CNT growth whereas at backside modification by means of a solution a strong dependence on the laser processing parameters has been found. 相似文献
18.
Ki-Hong Lee Kwanghyun Baik Jung-Sik Bang Seung-Woo Lee Wolfgang Sigmund 《Solid State Communications》2004,129(9):583-587
Silicon enhances carbon nanotube growth on nickel films by chemical vapor deposition using methane and hydrogen. Nanotube growth characteristic is significantly improved on nickel films patterned by argon plasma etching on silicon oxide layers. Auger electron spectroscopy shows that a reduced silicon phase forms in the surface silicon oxide layer by Ar ion bombardment used for patterning. The enhanced growth of carbon nanotubes could be ascribed to an oxygen removal effect by silicon in the process of synthesis. 相似文献
19.
Honeycomb-like alignments of carbon nanotubes were prepared by pyrolysis of a metal phthalocyanine at 950 °C in an Ar/H2 flow. A simple synthetic method has been developed for a large-scale synthesis of aligned carbon nanotubes normal to a substrate
surface.
Received: 15 June 2000 / Accepted: 21 June 2000 / Published online: 2 August 2000 相似文献
20.
J.L. Qi X. Wang W.T. Zheng H.W. Tian C. Liu Y.L. Lu Y.S. Peng G. Cheng 《Applied Surface Science》2009,256(5):1542-1547
The effects of total CH4/Ar gas pressure on the growth of carbon nanomaterials on Si (1 0 0) substrate covered with CoO nanoparticles, using plasma-enhanced chemical vapor deposition (PECVD), were investigated. The structures of obtained products were correlated with the total gas pressure and changed from pure carbon nanotubes (CNTs) through hybrid CNTs/graphene sheets (GSs), to pure GSs as the total gas pressure changed from 20 to 4 Torr. The total gas pressure influenced the density of hydrogen radicals and Ar ions in chamber, which in turn determined the degree of how CoO nanoparticles were deoxidized and ion bombardment energy that governed the final carbon nanomaterials. Moreover, the obtained hybrid CNTs/GSs exhibited a lower turn-on field (1.4 V/μm) emission, compared to either 2.7 V/μm for pure CNTs or 2.2 V/μm for pure GSs, at current density of 10 μA/cm2. 相似文献