溅射制备非晶氮化镓薄膜的光学性能

利用直流磁控溅射方法制备了GaN薄膜. X射线衍射及Raman光谱结果表明薄膜样品为非晶结构; 傅立叶红外光谱表明薄膜样品的主要吸收峰为Ga--N键的伸缩振动; 光致发光测试得到了360nm处的紫外发光谱; 测量薄膜样品的紫外-可 见谱, 并利用Tauc公式计算得到样品的光学带隙为3.74eV, 这与光致发光谱得到的结果是一致的.     

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．     

周期性梯度富硅SiNx薄膜的微结构与发光特性

采用磁控共溅射结合快速光热退火技术在单晶硅和石英衬底上制备了含硅量子点的周期性梯度富硅SiN_x薄膜(梯度薄膜)和单层富硅SiN_x薄膜(单层薄膜)。采用Raman光谱、掠入射X射线衍射(GIXRD)、透射电子显微镜(TEM)、傅里叶变换红外(FTIR)光谱和光致发光(PL)光谱分析了薄膜的结构特性、键合特性和发光特性。Raman光谱、GIXRD和TEM结果表明, 梯度薄膜和单层薄膜中的硅量子点晶化率分别为41.7%和39.2%; 梯度薄膜的硅量子点密度是单层薄膜的5.4倍。FTIR光谱结果显示两种薄膜均为富硅氮化硅薄膜, 梯度薄膜的硅含量小于单层薄膜。PL光谱结果表明梯度薄膜中的辐射复合缺陷少于单层薄膜。     

溅射Si/Ge多层膜及其发光誊性研究

采用离子束溅射技术,在玻璃衬底上制备了不同周期数的Si/Ge多层膜样品.利用X射线小角衍射、Raman散射光谱和室温光致发光(PL)对样品进行表征.结果表明,2.0～2.3eV之间的发光带是由薄膜中的各种缺陷形成的;1.77～1.84eV之间的发光带来自薄膜中的非晶结构和晶粒间的缺陷;1.53eV发光峰则可能源于纳米Ge晶粒发光.     

非晶氮氧化硅薄膜中新发光缺陷态的研究

利用等离子体增强化学气相淀积(PECVD)方法在室温下制备出非晶氮氧化硅(a-SiNxOy)薄膜。通过调节薄膜中的Si/N比例,可使其光致发光峰位在450~600nm的较宽波长范围内连续可调。对比a-SiNx薄膜和aSiNxOy薄膜的发光特性,发现此薄膜发光来源于由氧引入的新发光缺陷态。由光吸收谱的测量结果可以推断出此发光缺陷态在光吸收边之下约0.65eV处的禁带中。并且,通过傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)测量,证实了这种新发光缺陷态与薄膜中存在的O-Si-N键合结构有关。     

基体负的低偏压对氟化非晶态碳膜结构及性能的影响

为了研究基体负的低偏压Vb对氟化非晶态碳膜的结构、纳米硬度和疏水性能的影响,采用等离子体浸没与离子注入装置,CF4和CH4作为气源,在不同的基体偏压下制备了一系列氟化非晶态碳膜.使用XPS、ATR-FTIR和Raman谱对其成份和结构进行了表征.薄膜硬度通过纳米压痕仪进行测量,采用躺滴法测量薄膜与双蒸水之间的接触角来评价其疏水性能.XPS和FTIR结果表明薄膜中存在C-CF、C-Fx基团.Raman谱结果表明:随着基体偏压的增加,薄膜从类聚合物状结构逐渐转变为类金刚石结构,薄膜的硬度逐渐增加.接触角测量结果表明:在低偏压范围内,单纯地依靠调节偏压并不能显著地提高薄膜的疏水性能.     

掺钼氧化锌薄膜的发光特性

使用磁控溅射法在石英基底上制备钼掺杂氧化锌薄膜.扫描电镜结果表明薄膜由晶粒大小为40～ 80 nm范围内的颗粒组成,薄膜具有六方纤锌矿型结构且沿c轴择优取向生长.在可见光范围(400～760 nm)内所有薄膜的平均光透射率超过90％.退火薄膜的光致发光(PL)光谱表明,退火处理对发光峰的位置有很大影响,随着退火温度的增加,发光峰位置从380 nm红移至400nm或从470 nm红移至525 nm.此外,钼掺杂对退火薄膜PL光谱的强度影响很大.我们认为,薄膜中缺陷浓度的变化是导致发光峰红移的主要原因,讨论了PL谱中不同的可见光的发光机制.     

射频磁控溅射制备掺Al的纳米Si-SiO2复合薄膜及其光致发光特性

采用射频磁控技术和退火处理制备掺Al的纳米Si-SiO2复合薄膜.通过X射线衍射(XRD)、X射线光电子能谱(XPS)和傅里叶变换红外光谱(FTIR)表征了薄膜的结构,组分和成键情况.掺Al在SiO2中造成氧空位,使薄膜光致发光强度增强,并出现新的发光峰.退火温度对掺Al薄膜的光致发光的峰位和峰强有较大影响.     

退火对两种硅基薄膜的结构及发光影响

采用双离子束共溅射沉积方法制备了两种复合硅基薄膜SiOxCy和SiOxNy薄膜,对两种薄膜进行后退火处理,并分别对样品进行PL、FTIR、XPS谱测试分析,比较退火前后的发光及结构的变化。两种样品的光致发光测试谱(PL)表明:退火前后都有两个发光峰位-都存在470nm的发光峰位,它来自于硅基薄膜中中性氧空位缺陷(O3≡Si-Si≡O3),是由于氧原子配位的二价硅的单态-单态之间的跃迁所致,其发光强度随退火温度的升高而变化。进一步的FTIR和XPS的测试谱表明另外一个发光峰位420nm(SiOxCy薄膜)和400nm(SiOxNy薄膜)分别来自于掺杂杂质(C和N)与硅基薄膜中的Si、O组成的复合结构。而两种样品经过退火处理后掺杂所引起的发光峰位强度随退火温度的升高而增强,说明退火温度的升高有利于发光机制的形成。     

ZnO薄膜中与Zn原子缺陷相关的发光特性研究

ZnO薄膜中可见光的发射与缺陷有关,为了研究ZnO薄膜中与Zn原子缺陷相关的发光特性,将不同Zn缓冲层厚度的ZnO薄膜沉积在Si衬底上,且所有样品在400℃下真空中退火1 h,采用X射线衍射谱(XRD)、吸收谱和光致发光谱(PL)表征了样品的晶体结构和光学特性。结果表明,随着Zn缓冲层溅射时间的增加,ZnO薄膜中的紫光峰向长波段发生了红移,且所有的发光峰强度逐渐增加;缓冲层和真空中退火都使得样品中有过量的Zn原子缺陷出现,薄膜中所有的发光峰与Zn原子缺陷相关。     

Growth of dielectric-embedded silicon nanocrystallites for light-emitting device application

Dielectric films with embedded silicon Si nanocrystallites (Si-Nc) have been recognized as promising light-emitting materials for future integrated photonics based on silicon technology. This work reports a novel method of making this kind of material by high-temperature annealing of Si-rich oxide or nitride films which gives rise to the phase separation reaction and the formation of crystalline silicon nanoclusters in the films. Various characteristics of these materials were studied in detail by using transmission electron microscope, X-ray photoelectron spectroscopy (XPS), Raman, and photoluminescence (PL). Strong transverse optical (TO) mode of Si-Nc at around 516 cm(-1) was found in the Raman spectra of the annealed dielectric films. XPS studies indicate that the Si 2p spectra could be transformed from a random bonding structure (as-deposited) to a random mixing of Si-Nc with stoichiometric oxide or nitride phase after the high-temperature annealing. The energy locations of PL were found to depend on the amount of rich Si and the annealing conditions. Longer and higher temperature annealing can result in the growth of the Si-Nc size and leads to a red-shift of PL. Direct correlation among the crystallite sizes with the PL peaks was found.     

Luminescence properties of spark-processed SiC

The photoluminescence (PL) properties of spark-processed SiC (sp-SiC) have been studied at various temperatures. Furthermore, scanning electron micrographs (SEM), X-ray diffraction (XRD) measurements, Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy have been applied. The luminescence properties of sp-SiC are quite different from unspark-treated reference 6 H SiC. Specifically, the PL intensities of sp-SiC are at least two orders of magnitude larger than the reference SiC. Furthermore, the room temperature PL spectrum of sp-SiC exhibits two luminescence bands peaking at 3.18 eV, which are considerably blue shifted from SiC band gap of 2.9 and 2.43 eV. However, these two luminescence bands show an unusual red-shift of PL peak energies with decreasing temperature. Raman spectroscopy studies of sp-SiC display the emergence of a crystalline Si vibrational mode, whereas vibrational modes associated with 6H SiC are completely annihilated. XRD analysis exhibits the formation of polycrystalline Si after spark processing. Vibrational modes obtained from FTIR for sp-SiC are mainly composed of Si–O modes with some OH vibration. The results of low temperature PL studies, FTIR, XRD, XPS and Raman spectroscopy demonstrate that the luminescence properties of sp-SiC are similar to spark-processed Si.     

电化学沉积DLC膜及其表征

采用电化学沉积方法，甲醇有机溶剂作碳源，在直流电源作用下在单晶硅表面沉积得到碳薄膜。薄膜不溶于苯、丙酮等有机溶剂，具有较高的硬度(16GPa左右)，用AFM、Raman和FTIR分析手段对该薄膜表面形貌和结构进行表征，Raman和FTIR结果表明电化学沉积得到的是含氢的类金刚石碳薄膜。通过研究样品薄膜的XPS和XAES谱图特征，进一步证实薄膜是DLC薄膜，并用线性插入法估算出样品薄膜中SP^3的相对含量为60％，同时推测了电化学沉积DLC薄膜的生长机理。     

Structural characteristics of phosphorus-doped C60 thin film prepared by radio frequency-plasma assisted thermal evaporation technique

Phosphorus doped C60 (P:C60) thin films were prepared by a radio frequency plasma assisted thermal evaporation technique using C60 powder as a carbon source and a mixture of argon and phosphine (PH3) gas as a dopant precursor. The effects of the plasma power on the structural characteristics of the as-prepared films were then studied using Raman spectroscopy, Auger electron spectroscopy (AES) and X-ray photo-electrons spectroscopy (XPS). XPS and Auger analysis indicated that the films were mainly composed of C and P and that the concentration of P was proportional to the plasma power. The Raman results implied that the doped films contained a more disordered carbon structure than the un-doped samples. The P:C60 films were then used as a coating layer for the Si anodes of lithium ion secondary batteries. The cyclic voltammetry (CV) analysis of the P:C60 coated Si electrodes demonstrated that the P:C60 coating layer might be used to improve the transport of Li-ions at the electrode/electrolyte interface.     

Preparation of diamond-like carbon films by cathodic micro-arc discharge in aqueous solutions

Diamond-like carbon films (DLC) and silicon doped diamond-like carbon films were deposited on Ni substrate by cathodic micro-arc discharge at room temperature in aqueous solutions. The deposit potential was 130 V. The structure of the films was characterized by a scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Raman spectra and XPS analysis demonstrated that the films were diamond-like carbon clearly. SEM observation showed that the DLC films were uniform and the thickness was about 200 nm. Potentiodynamic polarization curve indicated the corrosion resistance of the Ni substrate was markedly improved by DLC films.     

Annealing characteristics of Si doped amorphous silica films by rf sputtering

Si doped amorphous silica films were prepared by rf magnetron sputtering technique. As-deposited films which had relatively low Si dopant were annealed in inert atmosphere, and spectroscopic analyses were performed for as-deposited and all the annealed samples by infrared (IR) absorption, X-ray fluorescence analysis, X-ray photoelectron spectroscopy (XPS) and 29Si magic angle sample spinning nuclear magnetic resonance spectroscopy (29Si MAS-NMR). When the sample was annealed at 800°C, the IR absorption peak located at 1080 cm–1 shifted to slightly higher wave number. On the other hand, the decrease of Si clusters or Si–Si bonds in as-deposited film was deduced from X-ray fluorescence and XPS spectra for the sample annealed at 800°C. These annealing characteristics of the films prepared in this study were discussed based on the random bonding model of SiOx film, and the spectral variations with thermal annealing were interpreted by the rearrangement of Si and O atoms in as-deposited films, rather than the simple clustering of excess Si atoms.     

前驱气体CH_4、N_2的流量比对CH_x膜Raman谱的影响

沉积在Ｓｉ（１００）基片上的ＣＮｘ膜是用微波等离子体化学气相沉积法（ＭＷＰＣＶＤ）制备的。本文着重探讨了ＣＨ４、Ｎ２的流量比对ＣＮｘ膜的Ｒａｍａｎ谱的影响，并采用了Ｘ－射线光电子能谱（ＸＰＳ）方法分析了ＣＮｘ膜的化学状态。     

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.     

Understanding spectroscopic phonon-assisted defect features in CVD grown 3C-SiC/Si(1 0 0) by modeling and simulation

New phonon-assisted defect features are observed using photoluminescence (PL) and Raman scattering spectroscopy on 3C-SiC/Si(1 0 0) films grown by chemical vapor deposition (CVD) technique. The ultraviolet excitation room-temperature (RT) PL-Raman spectra show a luminescence band near 2.3 eV due to RT recombination over the 3C-SiC indirect band gap. In addition to the strong Raman lines characteristic of Si substrate and 3C-SiC we also observed weaker impurity modes near 620, 743 and 833 cm⁻¹. These frequencies are compared with the results of Green's function simulations of impurity modes with plausible defect structures to best support the observed Raman features as well as modes of some prototypical defect center.     

高频溅射法氮碳膜的生长及结构

本文用扫描电镜、红外吸收光谱、X射线光电子能谱和X射线衍射技术对高频溅射沉积法制备的氮化碳膜的生长过程进行了研究．改变溅射条件,研究了氮化碳膜的形貌和结构与其性质之间的关系,通过溅射条件的优化,可使氮化碳膜中的氮含量增加,薄膜的结构接近β-C₃N₄相．