掺氮类金刚石薄膜的制备及其结构表征

采用射频磁控反应溅射法,Ar气为溅射气体,N2气为反应气体,用高纯石墨靶在Si（100）片上制备了掺氮类金刚石薄膜,采用X射线光电子能谱（XPS）、拉曼光谱（Raman）、扫描电子显微镜（SEM）,表征了掺氮类金刚石薄膜的微观结构、表面及截面形貌。Raman光谱结果表明,制备的掺氮类金刚石薄膜中含有特征峰D峰和G峰,分别位于1339．2cm^-1、1554．6cm^-1均向低波数段频移,具有典型的类金刚石结构特征;XPS光谱的C1s和N1s的芯能级证实了薄膜中的碳氮进行了化合,形成了C-N、C=N、C=N,说明薄膜中形成了非晶碳氮结构;同时SEM结果表明实验所制备的薄膜表面均匀、致密、光滑,从截面照片观察,薄膜与衬底结合紧密,薄膜的厚度大约为150nm。     

掺氮类金刚石薄膜的显微结构和光谱学研究

本文利用射频磁控溅射法,以高纯N2、Ar混合气体为溅射气体,用高纯石墨靶在Si（100）基片上制备出掺氮的类金刚石薄膜（DIE：N）。拉曼光谱（Raman）测试表明该薄膜仍然是类金刚石结构,对其进行拟合后得两个特征峰,分别是在1342．9cm^-1的D峰和1555．3cm^-1的G峰,ID／IG=0．45;X射线光电子能谱（XPS）表明薄膜含氮量为24％,XPS光谱的C1s和N1s的芯能级证实了薄膜中的碳氮进行了化合,形成了C-N、C=N、C≡N,说明薄膜中形成了非晶碳氮结构;傅里叶变换红外透射光谱（FTIR）也表明了薄膜中碳氮进行了化合;扫描电子显微镜（SEM）结果表明,实验所制备的薄膜表面均匀、致密、光滑,从横截面图像观察,薄膜与衬底结合紧密,薄膜的厚度大约为150nm。     

氮离子注入法合成CNx膜的化学键表征

采用N离子注入金刚石膜和热解石墨方法合成了CNx膜,用Raman光谱和XPS谱对合成薄膜中C、N的化学键合状态进行了研究.通过与Raman光谱的比较,我们对合成样品XPS谱中N1s的化学键合状态作出如下归属:≈400.0 eV属于sp2 C-N键;≈398.5 eV则属于sp3 C-N键.结果显示:碳原子、氮原子间的化学键合状态,明显地依赖于衬底材料及注入N离子的能量.     

氮离子注入法合成CNx膜的化学键表征

采用N离子注入金刚石膜和热解石墨方法合成了CNx膜,用Raman光谱和XPS谱对合成薄膜中C、N的化学键合状态进行了研究.通过与Raman光谱的比较,我们对合成样品XPS谱中N1s的化学键合状态作出如下归属≈400.0 eV属于sp2 C-N键;≈398.5 eV则属于sp3 C-N键.结果显示碳原子、氮原子间的化学键合状态,明显地依赖于衬底材料及注入N离子的能量.     

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．     

掺氮N型纳米金刚石薄膜的电化学表面氢化及表征

针对掺氮N型纳米金刚石薄膜独特的结构特征,采用温和的电化学阴极表面极化处理成功实现了掺氮N型纳米金刚石薄膜的表面氢化。通过X射线光电子能谱(XPS)、表面接触角、电化学电容-电压分析、Raman光谱、扫描电子显微镜(SEM)表征,详细分析了阴极极化处理前后掺氮N型纳米金刚石薄膜的表面结构以及微观结构。结果表明,该阴极极化处理工艺不仅能够成功获得表面氢终止状态,而且对薄膜的微观结构尤其是晶界处sp2杂化态碳相无明显影响,说明该工艺是一种高效无损的掺氮N型纳米金刚石薄膜表面氢化工艺。     

纳米TiO2的Raman光谱研究进展

Raman光谱是研究纳米TiO2结构的最常用工具之一.纳米T2O2的Raman光谱研究是建立在以前对TiO2体材料的Raman光谱研究的基础之上.但是纳米TiO2与体相材料的表面性质和结构有较大的不同,其Raman光谱会产生明显变化.研究人员对纳米TiO2的Raman光谱已展开研究.本文概述了晶粒大小、结构、氧空位、退火温度、压力、相组成等因素对纳米TiO2的Raman光谱的影响.     

纳米TiO2的Raman光谱研究进展

Raman光谱是研究纳米TiO2结构的最常用工具之一。纳米TiO2的Raman光谱研究是建立在以前对TiO2体材料的Raman光谱研究的基础之上。但是纳米TiO2与体相材料的表面性质和结构有较大的不同，其Raman光谱会产生明显变化。研究人员对纳米TiO2的Raman光谱已展开研究。本文概述了晶粒大小、结构、氧空位、退火温度、压力、相组成等因素对纳米TiO2的Raman光谱的影响。     

常压化学气相沉积方法制备非晶硅薄膜及其光致发光性能研究

使用改进的常压化学气相沉积(APCVD)系统制备了非晶硅薄膜,测量了样品的光致发光特性,使用Raman光谱和X射线光电子能谱(XPS)谱测量了薄膜的微结构特征.样品在523 nm出现发光峰,Raman光谱和XPS谱表明制备的薄膜结构中存在富氧相和富硅相的分相现象,分析认为相界面的存在是产生发光的原因.Raman光谱分峰结果表明薄膜中存在纳米晶粒.     

CNx薄膜的制备和光电性能

以单晶硅片(100)和镀Pt硅片为衬底,用电化学沉积方法在阴极制备出CNx薄膜(x接近于1),薄膜的表面平滑,颗粒均匀.热处理后得到了β-C3N4和α-C3N4多晶结构薄膜.热处理温度的提高使薄膜中的C≡N键逐渐减少而消失,氮元素的流失使薄膜中非晶碳的成分增多,但是薄膜中碳氮逐渐以sp3C-N为主.薄膜的能带在1.1～1.8 eV之间,氮含量对能带大小影响较大.热处理使薄膜的电阻率(高于108Ω@cm)变化不大.氮含量影响PL谱中3.0和3.5 eV处发射峰的峰强,不影响峰位.     

N1s Electron Binding Energies of CN_x Thin Films Grown by Magnetron Sputtering at Different Temperature

Carbon nitride thin films deposited using dc unbalanced magnetron sputtering system have been analyzed by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT1R) and Raman spectroscopy. The XPS data show that N1s binding states depend on substrate temperature Ts, in which the peak at 400.0 eV increases with Ts, whereas the peak at 398.3 eV decreases with Ts slightly On the basis of XPS, FT1R and Raman spectra, the assignment of N1s electron binding energies was made. The peak at 400.0 eV is attributed to N atoms bonded to sp2 coordinated C atoms. The peak at 398.3 eV is attributed to N atoms bonded to sp3 coordinated C atoms as well as N C bonds.     

Influence of Bias on the Properties of Carbon Nitride Films Prepared by Vacuum Cathodic Arc Method

Carbon nitride films have been synthesized in a wide range of biases from 0 to -900 V by vacuum cathodic arc method. The N content was about 12.0-22.0 at. pct. Upon increasing the biases from 0 to -100 V, the N content increased from 15.0 to 22.0 at. pct which could be attributed to the knot-on effect. While the further increasing biases led to the gradual falling of the N content to 12.0 at. pct at -900 V due to the enhancement of the sputtering effect. Below -200 V, with the increasing biases the sp2C fraction in the films decreased, as a result of vvhich the I(D)/I(G) fell in the Raman spectra and the sp peaks also showed the decreasing tendency relative to the s peaks in the VBXPS (valence band X-ray photoelectron spectroscopy). While above -200 V, the sp2C fraction increased and the films became graphitinized gradually, accompanying which the I(D)/I(G) rose from -200 V to -300 V and the Raman spectra even shovved the graphite characteristic above -300 V and the sp peaks rose again relative to the s     

Electronic structure of carbon nitride thin films studied by X-ray spectroscopy techniques

Magnetron-sputtered carbon nitride thin films with different structures and compositions were analyzed by X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS), near-edge X-ray absorption fine structure spectroscopy (NEXAFS), as well as X-ray emission spectroscopy (XES). In all techniques, the carbon spectra are broad and featureless with little variation depending on growth conditions. The nitrogen spectra, on the other hand, show more distinct features, providing a powerful tool for structural characterization. By comparing the experimental spectra with calculations on different model systems, we are able to identify three major bonding structures of the nitrogen—N1: nitrile (CN) bonds; N2: Pyridine-like N, i.e., N bonded to two C atoms; and N3: graphite-like N, i.e., N bonded to three C atoms as if substituted in a graphitic network, however, possibly positioned in a pentagon and/or with sp³ carbon neighbors. The presence of N2 and N3 are best detected by XPS, while N1 is better detected by NEXAFS. The calculated XES spectra also give good indications how valence band spectra should be interpreted. Films grown at the higher temperatures (≥350 °C) show a pronounced angular dependence of the incoming photon beam in NEXAFS measurements, which suggests a textured microstructure with standing graphitic basal planes, while amorphous films grown at low temperatures show isotropic properties.     

Deposition of crystalline C3N4 films via microwave plasma chemical vapour deposition

Crystalline carbon nitride films have been synthesized on polycrystalline Ni substrates by a microwave plasma chemical vapour deposition technique, using a mixture of N₂, CH₄ and H₂ as precursor. Scanning electron microscopy shows that the film consisted of perfect crystals of short and long hexagonal bars, tetragonal bars and irregular particles. From the X-ray photoelectron spectroscopy (XPS) data, a maximum N/C ratio of 1.0 was achieved in the films. The XPS spectra of the film typically showed three peaks in the C 1s core spectrum (centered at 284.78, 285.94, and 287.64 eV) and two peaks in the N 1s core level spectrum (centered at 398.35 and 400.01 eV). This indicates that there are two types of C–N bonds; N is bonded to sp²- or sp³-coordinated C atoms in the as-deposited film. The X-ray diffraction pattern indicates that the film is composed of α-, β-, pseudocubic, graphitic C₃N₄ and an unidentified phase. A series of intense sharp Raman peaks were observed in the range of 100–1500 cm^− 1. These peaks match well with the calculated Raman frequencies of α- and β-C₃N₄, revealing the formation of α- and β-C₃N₄ phase.     

Chemical bond analysis of amorphous carbon films

Hydrogen-free carbon films with the various sp³ bond fractions between 83% and 40% were prepared by mass-separated ion beam deposition (MSIBD). These sp³ bond fractions were obtained by electron energy loss spectroscopy (EELS). Chemical bond analysis of these carbon films was performed by x-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), and Raman spectroscopy, and the comparison of these methods was examined. XPS C1s spectra of carbon films show two contributions at the energies of 284.5 and 285.5 eV, which are originated from sp²-bonds and sp³ bonds, respectively. The sp³ bond fractions obtained by XPS are in good agreement with the values given by EELS. The fine structure of AES spectra at the kinetic energy region between 245 and 265 eV reflects the sp³ bond fraction. AES spectra are changed from the diamond-like feature to the graphite-like one with decreasing the sp³ bond fraction. Raman spectra show two broad peaks of G band and D band, the ratio of two peak intensities is independent on the sp³ bond fraction of films. The shift of G peak position has a correlation with the sp³ bond fraction in the sp³ bond rich region.     

液相法制备掺氮碳膜的实验研究

在低温和常压下,通过电解甲醇和氨水混合溶液,在硅基片上进行沉积掺氮碳膜的尝试,得到了含氮８％的类金刚石薄膜。通过拉曼光谱和Ｘ光电子能谱对样品的测试表明：碳和氮在薄膜中是以ｓｐ＾２和ｓｐ＾３进行化学成键,本文还提出了液相掺氮碳膜生长的化学机制。     

Photoluminescence characteristics of BN(C,H) prepared by chemical vapour deposition

Hexagonal boron nitride (h-BN) containing carbon and hydrogen, BN(C, H), has been prepared by chemical vapour deposition. It shows wide photoluminescence in the range 300–600 nm. The luminescence is mostly bright and white-blue in colour to the naked eye. The peak position and shape of the luminescence spectra are totally different from those reported on BN(C, H) made by heating BN powder in a graphite crucible in the presence of hydrogen in the atmosphere. A study by electron spectroscopy for chemical analysis on BN(C, H) indicates that impurity carbon substitutes for nitrogen atoms in the h-BN crystal. In other words, impurity carbon can be introduced into h-BN as an acceptor.     

合成硼碳氮体系薄膜的XPS研究

采用Ｘ射线光电子谱（ＸＰＳ）分析３００～５００℃等离子体源离子渗氮硼和碳化硼薄膜合成的氮化硼和硼碳氮薄膜。利用合成薄膜成分可控的特点,研究Ｂ、Ｃ、Ｎ对薄膜的ＸＰＳ影响。结果表明,ＸＰＳ分析合成氮化硼薄膜能够确定其化学组成,但不能确定ｓｐ＾２和ｓｐ＾３型键合结构特性;ＸＰＳ分析硼碳氮薄膜能够确定其成分和结构特性。在较高的工艺温度下,等离子体源离子渗氮合成的硼硕氮薄膜具有ｓｐ＾２和ｓｐ＾３型复合的键合     

Structural studies of reactive pulsed laser-deposited CNx films by X-ray photoelectron spectroscopy and infrared absorption

The changes in the structure of reactive pulsed laser-deposited (RPLD) CN_x films with nitrogen content from 3.6–22 at% have been investigated by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and Fourier transform–infrared (FT–IR) absorption. The films were found to be amorphous, and to consist of a network of rings. The rings that were composed solely of carbon atoms gave rise to an XPS peak located between 284.3 and 284.8 eV (C¹ component). The rings containing nitrogen led to another peak located between 285.5 and 286.4 eV (C² component). When the nitrogen content increased, the relative intensity of the C¹ component fell, while that of the C2 component rose, indicating that some carbon atoms in the rings were replaced by nitrogen atoms. C≡N bonds also contributed to the C² component. The FT–IR data were consistent with this interpretation. No evidence for the existence of a β-C₃N₄ phase was found in RPLD CN_x films. This revised version was published online in November 2006 with corrections to the Cover Date.     

FTIR spectroscopy of multiwalled carbon nanotubes: a simple approach to study the nitrogen doping

The nitrogen doped multiwalled carbon nanotubes (MWNTs) were synthesized by microwave plasma chemical vapor deposition (MPCVD) technique. In this paper, we report the results of FTIR, Raman, and TGA studies to confirm the presence of N-doping inside carbon nanotubes. Fourier transform infrared (FTIR) studies were carried out in the range 400-4000 cm(-1) to study the attachment of nitrogen impurities on carbon nanotubes. FTIR spectra of the virgin sample of MWNTs show dominant peaks which are corresponding to Si-O, C-N, N-CH3, CNT, C-O, and C-Hx, respectively. The Si-O peak has its origin in silicon substrate whereas the other peaks are due to the precursor gases present in the gas mixture. The peaks are sharp and highly intense showing the chemisorption nature of the dipole bond. The intensity of the peaks due to N-CH3, C-N, and C-H reduces after annealing. It is interesting to note that these peaks vanish on annealing at high temperature (900 degrees C). The presence of C-N peak may imply the doping of the MWNTs with N in substitution mode. The position of this intense peak is in agreement with the reported peak in carbon nitride samples prepared by plasma CVD process, since the Raman modes are also expected to be delocalized over both carbon and nitrogen sites it was found that the intensity ratio of the D and G peaks, I(D)/I(G), varies as a function of ammonia concentration. The TGA measurements, carried out under argon flow, show that the dominant weight loss of the sample occurs in the temperature range 400-600 degrees C corresponding to the removal of the impurities and amorphous carbon.