碳、碳氮和硼碳氮纳米管场发射性能的比较研究

采用高温热解法在860℃分别制备出了碳、碳氮和硼碳氮纳米管，提纯后利用丝网印刷工艺分别将它们制备成薄膜，并测试了它们的场发射性能.结果表明：碳纳米管、碳氮纳米管和硼碳氮纳米管薄膜的开启电场分别为2.22，1.1和4.4V/μm，当电场增加到5.7V/μm时，它们的电流密度分别达到1400，3000μA/cm²和小于50μA/cm².碳和碳氮纳米管薄膜的场增强因子分别为10062和11521.可见，碳氮纳米管的场发射性能优于碳纳米管，而硼碳氮纳米管的场发射性能比前两者要差.解释了这三种纳米管场发射性能差别的原因. 关键词： 碳纳米管 碳氮纳米管 硼碳氮纳米管 场发射     

类金刚石和碳氮薄膜的电化学沉积及其场发射性能研究

利用电化学方法在室温下成功地沉积了类金刚石(DLC)薄膜和非晶CN_x薄膜，并 对制备条件进行了讨论.通过扫描电子显微镜、傅里叶变换红外光谱技术，分析了薄膜的表面形貌和化学结合状态.场发射测量结果表明：DLC膜和非晶CN_x的开启场分别为88和 10V/μm；并且在23V/μm的电场下，DLC膜和非晶CN_x膜的发射电流密度分别达到10 和037mA/cm². 关键词： 电化学沉积 类金刚石薄膜 x薄膜')" href="#">CN_x薄膜 场致电子发射     

脉冲偏压电弧离子镀CNx薄膜研究

用脉冲偏压电弧离子镀通过控制不同的氮流量在(100)单晶Si基片上制备了不同成分的CN_x薄膜.用光学显微镜,XPS,XRD,激光Raman和Nanoindenter等方法研究了薄膜的形貌、成分、结构和性能.结果表明,薄膜表面平整致密、氮含量随着氮流量的降低而降低、结构为非晶且为类金刚石薄膜;随着氮含量从18.9%降低到5.3%(摩尔百分比,全文同),薄膜的硬度和弹性模量单调增加而且增幅较大,其中硬度从15.0 GPa成倍增加到30.0 GPa;通过氮流量的调整能够敏感地改变薄膜中的sp³键的含量,是CN_x薄膜的硬度和弹性模量获得大幅度调整的本质原因. 关键词： x薄膜')" href="#">CN_x薄膜 脉冲偏压 电弧离子镀 硬度     

C3N4/TiN交替复合膜的微结构研究

采用双阴极封闭型非平衡磁场dc反应磁控溅射离子镀制备C₃N₄/TiN复合交替膜,用X射线光电子能谱法分析了薄膜的组成,测量了薄膜的X射线衍射谱和氮化碳的透射电子衍射图像.氮化碳经氮化钛的强迫晶化作用,生成了β-C₃N₄和c-C₃N₄. 关键词：     

Ti-Si-N复合膜的界面相研究

为了揭示Ti_Si_N复合膜中Si₃N₄界面相的存在方式及其对薄膜力学 性能的影响 ，采用x射线衍射仪、高分辨透射电子显微镜、俄歇电子能谱仪和显微硬度仪对比研究了磁 控溅射Ti_Si_N复合膜和TiN/Si₃N₄多层膜的微结构和力学性能. 实 验结果表明 ，Ti_Si_N复合膜均形成了Si₃N₄界面相包裹TiN纳米晶粒的微结构. 其中低Si 含量的Ti_Si_N复合膜中Si₃N₄界面相的厚度小于1nm，且以晶体态 存在，薄膜 呈现高硬度. 而高Si含量的Ti_Si_N复合膜中的Si₃N₄界面相以非晶 态存在，薄 膜的硬度也相应降低. 显然，Ti_Si_N复合膜中Si₃N₄界面相以晶体 态形式存在 是薄膜获得高硬度的重要微结构特征，其强化机制可能与多层膜的超硬效应是相同的. 关键词： Ti－Si－N复合膜 界面相 微结构 超硬效应     

高温退火对非晶CNx薄膜场发射特性的影响

采用射频磁控溅射方法在纯N₂气氛中沉积了非晶CN_x薄膜样品，并 在真空中退火至900 ℃.对高温退火引起的CN_x薄膜化学成分、键合结构及其场发射特性方面的变 化进行研究.用傅里叶变换红外光谱和x射线光电子能谱分析样品的内部成分及键合结构的变化，其中sp²键及薄膜中N的含量与薄膜的场发射特性密切相关.退火实验的结果表明 高温退火可以导致CN_x薄膜中N含量大量损失，并在薄膜中形成大量sp^{2< 关键词： x薄膜')" href="#">CN_x薄膜 化学键合 退火温度 场致电子发射}     

TiN和Ti1-xSixNy薄膜的微观结构分析

使用x射线衍射(XRD)、x射线光电子谱(XPS)、高分辨透射电子显微镜(HRTEM)和原子力显微镜（AFM）多种观测手段分析了TiN薄膜和Ti_1-xSi_xN_y纳米复合薄膜的微观结构.实验分析证明Ti_1-xSi_xN_y薄膜是由直径为3—5nm的纳米晶TiN和非晶Si₃N₄相构成，并且Ti_1-xSi_{x关键词： 纳米复合薄膜 自由能 表面粗糙度 TiN 1-x}Si_xN_y')" href="#">Ti_1-xSi_xN_y     

Cu/TiOx复合薄膜的电子态分析及其对亲水性的影响

在室温下,采用射频磁控溅射法制备了Cu/TiO_x纳米晶复合薄膜.利用X射线粉末衍射（XRD）、X射线光电子能谱（XPS）对其结构进行表征,并研究了Cu/TiO_x复合薄膜的UV-vis吸收谱和亲水性.结果表明,退火前后薄膜中钛元素皆以Ti³⁺形式存在.薄膜在可见区有吸收,吸收限为600 nm左右.Cu/TiO_x复合薄膜具有良好的亲水性.这主要是由于Cu的掺杂,使得薄膜的性能的亲水性变好. 关键词： x复合薄膜')" href="#">Cu/TiO_x复合薄膜 射频磁控溅射 XPS 亲水性     

Photoluminescence and transmission spectra of nanocrystalline GaAs（1-x）Sbx embedded in silica films

The composite films of the nanocrystMline GaAs（1-x）Sbx-SiO2 have been successfully deposited on glass and GaSb substrates by radio frequency magnetron co-sputtering. The 10K photoluminescence （PL） properties of the nanocrystalline GaAs（1-x）Sbx indicated that the PL peaks of the GaAs（1-x）Sbx nanocrystals follow the quantum confinement model very closely. Optical transmittance spectra showed that there is a large blue shift of optical absorption edge in nanocrystMline GaAs（1-x）Sbx-SiO2 composite films, as compared with that of the corresponding bulk semiconductor, which is due to the quantum confinement effect.     

类富勒烯纳米晶CNx薄膜及其场致电子发射特性

利用微波等离子体增强化学气相沉积技术制备出了CN_x薄膜,并利用x射线光电子能谱、x射线衍射、扫描电子显微镜和Raman光谱等测试手段对所制备的CN_x薄膜的微结构和成分进行了分析.研究了其场致电子发射特性.发现薄膜的结构和场发射特性与反应系中的甲烷、氮气及氢气的流量比有关,当甲烷、氢气及氮气流量比为8/50/50 sccm时,制备的薄膜具有弯曲层状的纳米石墨晶体结构（类富勒烯结构）和很好的场发射特性.场发射阈值电场降低至1.1V/μm.当电场为5.9V/μm时,平 关键词： 类富勒烯 x薄膜')" href="#">CN_x薄膜 场致电子发射 微波等离子体增强化学气相沉积     

Capacitance humidity sensor with carbon nitride detecting element

The humidity sensitive properties of carbon nitride (CN_x) films deposited by two methods, inductively coupled plasma chemical vapour deposition utilizing transport reactions and pulsed laser deposition combined with an rf discharge, have been investigated. For this purpose capacitance humidity sensors with a CN_x detecting element have been fabricated and tested. Fast and significant responses toward moisture are registered by the changes of the electrical parameters. The CN_x films sensing mechanism has been discussed. The results obtained show unambiguously that CN_x films appear to be a promising candidate as a humidity sensitive element in up-to-date electronic noses. Received: 6 December 1999 / Accepted: 7 January 2000 / Published online: 24 March 2000     

Influence of temperature on structure as well as adhesion and friction and wear behavior of hydrogenated carbon nitride films prepared on silicon substrate

Hydrogenated-carbon nitride (CN_x:H) films were synthesized on silicon substrate in a large quantity by the pyrolysis of ethylenediamine in a temperature range of 700-950 °C. The influence of temperature on the morphology, structure, adhesion to substrate, and friction and wear behavior of CN_x:H films was investigated. It has been found that CN_x:H films obtained at 700 °C and 800 °C are amorphous, and those prepared at 900 °C and 950 °C consist of carbon nitride nanocrystal. Besides, CN_x:H film sample obtained at 700 °C has the maximum N content of 9.1 at.% but the poorest adhesion to Si substrate, while the one prepared at 900 °C has the lower N content and the highest adhesion to substrate. As a result, nanocrystalline CN_x:H (nc-CN_x:H) film synthesized at 900 °C possesses the best wear resistance when slides against stainless steel counterpart. N atom is incorporated into the graphitic network in three different bonding forms, and their relative content is closely related to temperature, corresponding to different adhesion as well as friction and wear behavior of the films obtained at different temperatures. Furthermore, the friction coefficient and antiwear life of as-deposited CN_x:H films vary with varying deposition temperature and thickness, and the film with thickness of 1.3 μm, obtained at 900 °C, has the longest antiwear life of over 180,000 s.     

Improving mechanical properties of a-CNx films by Ti-TiN/CNx gradient multilayer

Amorphous carbon nitride (a-CN_x) films with functional gradient Ti-TiN/CN_x underlayer were deposited by direct current magnetron sputtering. Microstructure and composition of the films were characterized by means of X-ray diffraction (XRD), Raman spectroscopy, atomic force microscope (AFM) and transmission electron microscopy (TEM). Mechanical and tribological properties were investigated by nanoindenter, scratch and ball-on-disk tribometer. The a-CN_x-based films suffer a graphitization process with the increasing deposition temperature, thus the hardness and elastic modulus decrease. With the design of the Ti-TiN/CN_x gradient underlayers, some important advantages of relatively thick CN_x films can be achieved, such as increased hardness, improved adhesion strength, and the wear resistance of the a-CN_x-based films can be also improved significantly.     

Preparation and magnetic property of the composite of nitrogen-doped carbon nanotubes decorated with nickel nanoparticles

A magnetic composite of nitrogen-doped carbon nanotubes (CN_x) decorated with nickel nanoparticles was synthesized by a chemical precipitation and deoxidization method. The decorated CN_x were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The XRD pattern showed that CN_x, nickel nanoparticles and little nickel oxides coexisted in the composite, TEM observation indicated that nickel nanoparticles were highly dispersed on the outer walls of CN_x, Magnetic measurements by VSM demonstrated that the saturated magnetization and remanence of CN_x were improved, while the coercivity was lowered after decorating with nickel nanoparticles.     

Preparation and magnetic property of the composite of nitrogen-doped carbon nanotubes decorated with nickel nanoparticles

A magnetic composite of nitrogen-doped carbon nanotubes (CN_x) decorated with nickel nanoparticles was synthesized by a chemical precipitation and deoxidization method. The decorated CN_x were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The XRD pattern showed that CN_x, nickel nanoparticles and little nickel oxides coexisted in the composite, TEM observation indicated that nickel nanoparticles were highly dispersed on the outer walls of CN_x, Magnetic measurements by VSM demonstrated that the saturated magnetization and remanence of CN_x were improved, while the coercivity was lowered after decorating with nickel nanoparticles.     

Synthesis, characterization and low field emission of CNx nanotubes

Aligned CN_x nanotubes were fabricated by pyrolyzing ethylenediamine on p-type Si(1 1 1) substrates using iron as the catalyst. Scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectrum (XPS) and Raman spectroscopy were used to characterize the CN_x nanotubes. The CN_x nanotubes with the average length of 20 μm and diameters in the range of 50–100 nm have the “bamboo-like” structure and worse crystalline order. The low-field emission measurements of the CN_x nanotubes indicated that 20 μA/cm² current densities were observed at an electric field of 1.4 V/μm and 1.280 mA/cm² were obtained at 2.54 V/μm. The CN_x nanotubes exhibit better field emission properties than the carbon nanotubes and the BCN nanotubes. The emission mechanism of CN_x nanotubes is also discussed.     

Investigations of the sorption behaviour of amorphous nitrogen-rich carbon nitride films as sensitive layers for cantilever-based chemical sensors

We present investigations of the sorption behaviour of amorphous nitrogen-rich carbon nitride films (CN_x) towards water vapour and volatile organic compounds, for example methanol, ethanol, i-propanol and acetone, in order to evaluate their potential as sensitive layers for cantilever-based chemical sensor applications. The CN_x films were deposited by inductively coupled plasma chemical vapour deposition (ICP-CVD) utilizing transport reactions from a solid carbon source. In order to study the influence of the thickness of the sensitive layer on its sensitivity and selectivity, two series of cantilevers coated with 120 nm and 240 nm CN_x films were prepared. We found that the variation of the film thickness affected the sorption process of the CN_x film quantitatively as well as qualitatively. For thin films (120 nm), the sensor dynamic responses (frequency shift) increased with increasing molecular weight of the analytes. The largest responses were observed towards acetone and i-propanol ; here, the cantilever acted as a resonant microbalance. When the film thickness was increased from 120 to 240 nm, the analytes with higher dipole moments caused stronger response signals. In this case we observed, for example, an increase of the sensitivity towards methanol by a factor of more than three. The performance of the cantilever-based sensors functionalised with CN_x coatings was compared to that of organic polymers, and the observed peculiarities were explained by the chemical nature of the sensitive materials. PACS 81.05.-t; 85.85.+j; 07.07.Df     

Correlation between photoluminescence, optical and structural properties of amorphous nitrogen-rich carbon nitride films

Amorphous nitrogen-rich carbon nitride (CN_x) films have been prepared by inductively coupled plasma chemical vapour deposition (ICP-CVD) utilizing transport reactions from a solid carbon source. The nitrogen atomic fraction N/(C+N) is about 1 or even higher as detected by various surface and bulk sensitive methods. An investigation of the chemical bonding structure showed that the films are composed of >C=N units with a small fraction of C≡N groups. Based on these findings, several structural units derived from cis- and trans-conjugated carbon–nitrogen chains are proposed. The optical properties of the CN_x films were studied by transmission spectroscopy and spectral ellipsometry; the optical Tauc gap was determined to 2.1±0.05 eV. The photoluminescence characteristics were measured at three different excitation wavelengths (476, 488 and 515 nm) and revealed two individual contributions. These data are interpreted in terms of the different structural units comprising the nitrogen-rich CN_x films. Received: 14 July 2000 / Accepted:17 July 2000 / Published online: 22 November 2000     

Influence of growth and anneal conditions on the surface roughness of L10 Fe50PdxPt50−x thin films

We deposit Fe₅₀Pd_xPt_50−x alloy thin films by magnetron sputtering onto a TiN seed layer. Chemically ordered L1₀ films are obtained which display large perpendicular magnetic anisotropy. We find that the surface roughness of the film depends strongly on the growth and anneal conditions as well as the Pd composition of the film. Smooth films are obtained by deposition above the chemical ordering temperature and by removing Pd from the alloy.     

不同氮源制备CNx纳米管薄膜及其低场致电子发射性能

采用高温热解法，分别以氯化铵(NH₄Cl)和乙二胺(C₂H₈N₂)为氮源在洁净的硅片上沉积生长CN_x纳米管薄膜.利用扫描电子显微镜、高分辨率透射电子显微镜和拉曼光谱对CN_x纳米管进行形貌观察和表征.结果显示不同氮源制备出的CN_x纳米管薄膜的洁净度、有序度以及纳米管的结构明显不同.热解乙二胺(C₂H₈N₂)/二茂铁(C₁₀H₁₀Fe)制备出的结晶度较低的“竹节状” 结构CN_x纳米管平行基底表面有序生长，而且低场致电子发射性能优越,开启电场1.0V/μm，外加电场达到2.89V/μm时发射电流密度为860μA/cm². 关键词： x纳米管')" href="#">CN_x纳米管 高温热解 “竹节状”结构 场致发射