纳米石墨晶薄膜的场发射特性

研究了纳米石墨晶的场发射特性，介绍了纳米石墨晶薄膜的制备方法，通过扫描电镜和Raman光谱对纳米石墨晶的结构进行了分析，场发射特性测试表明纳米石墨晶薄膜的场发射阈值电场为1.8V/μm。根据实验结果计算出纳米石墨晶的有效功函数在0.75-1.62eV之间，研究表明纳米石墨晶薄膜具有一些独到的特点，也非常适合场发射显示用冷阴极的制备。     

类石墨薄膜的场致电子发射研究

利用脉冲激光烧蚀技术在硅衬底上制备了类石墨薄膜，以该薄膜为阴极进行了场致电子发射实验。当在阴阳极之间加电场后，两极之间出现了放电现象。放电之后．类石墨薄膜的阈值电场大大降低了．当电场为20V／μm时．该薄膜的发射点密度可以达到10^6/cm^2。利用Raman光谱、扫描电镜和X射线光电子谱对薄膜的表面形貌和微结构进行了测试．薄膜中的类石墨微结构对该薄膜的场致电子发射特性起了促进作用．场致电子发射实验显示类石墨薄膜作为冷阴极电子材料具有潜在的应用价值。     

氢原子侵蚀作用的研究

通过热力学计算和动力学分析，研究了热丝ＣＶＤ金刚石薄膜沉积过程中，氢原子对石墨相和金刚石相的侵蚀作用。结果表明；当衬底温度在８２３Ｋ－１２７３Ｋ间变化时，氢原子和石墨相反应的表观活化能小于氢原子和金刚石相反应的表观活化能，这是氢原子更易侵蚀石墨相的原因所在。     

高结晶度石墨薄膜结构的AFM研究

制备了不同条件下的高结晶度石墨薄膜，产用原子微镜镜（ＡＦＭ）系统地研究了其表面结构，获得了原子分辨率的图像，探讨了温度对薄膜石墨化程度的影响，及温度、拉伸比对其微观结构的影响。     

磁控溅射C/W纳米多层膜的微观结构分析

利用非平衡磁控溅射离子镀技术以纯钨靶和纯石墨靶作为溅射源制备了C/W纳米多层膜。采用X射线衍射（XRD）、X射线光电子能谱（XPS）和高分辨透射电子显微镜（HRTEM）对薄膜相组成及其微观组织结构进行了分析。结果表明：W含量约为9 at.%的C/W薄膜具有周期厚度约为6.5 nm的多层结构;沉积的W元素不以单质态存在,而是与碳元素反应生成了WC纳米晶;薄膜中的碳为非晶态,碳主要以sp2键类石墨态存在。     

石墨上多晶硅薄膜的制备及择优取向的调控

利用磁控溅射在石墨衬底上制备了非晶硅薄膜,并使用快速热退火对薄膜进行了晶化处理。XRD分析表明,直接溅射沉积在石墨衬底上的硅薄膜经过快速热退火后具有高度的(220)择优取向。通过在硅薄膜和石墨衬底界面处引入一定厚度的ZnO中间层,晶化后的多晶硅薄膜择优取向实现了从(220)向(400)的转变,从而非常有利于将成熟的制绒工艺应用于该材料体系的电池制备过程中。对于择优取向的转变提出了解释,认为Si(100)面和ZnO(001)面晶格匹配是主要原因。喇曼分析表明ZnO中间层的引入提高了多晶硅薄膜的晶体质量。     

LSMCD技术制备PLT铁电薄膜的退火工艺研究

液态源雾化化学沉积(LSMCD)技术自1992年问世以来就引起了各国科学家的广泛关注。目前，已成功制备出了多种铁电薄膜。该文系统的分析了采用LSMCD技术制备PLT铁电薄膜在退火温度和退火方式的选择对其相结构的影响，在保证PbO不挥发的情况下，退火温度越高，薄膜的结晶越好；采用混合热处理(RCA)制备的薄膜晶粒尺寸较大，形成了连续致密的薄膜，而快速热处理(RTA)虽可以消除焦绿石相，但薄膜晶粒较小。     

脉冲激光沉积类金刚石膜技术

脉冲激光沉积(PLD)技术制备类金刚石(DLC)薄膜存在着金刚石相含量较低、石墨颗粒多、薄膜与衬底附着力差、膜内应力大等技术难题,为此,研究人员研究出了多种技术措施,如通过引入背景气体、超快激光、偏压、磁场以及加热等措施提高了薄膜金刚石相含量;采用金刚石或丙酮靶材、减小单脉冲能量等措施减少了石墨颗粒;采用间歇沉积、真空退火、超快激光等措施减少了膜内应力;合理没计过渡层改善了膜与衬底间的附着力等.这些技术有力地推动了脉冲激光沉积技术的发展.     

硫化锌薄膜的结构分析

用热蒸发法和磁控离子射频溅射法制备了ＺｎＳ薄膜，利用Ｘ射线衍射技术对据 薄膜的结构相特性进行了研究，为研制高效的光电材料提供依据。     

不同方法及衬底类型对CdS多晶薄膜性能的影响

采用化学水浴法和磁控溅射法分别在AZO、FTO、ITO透明导电玻璃衬底上制备了CdS薄膜,利用扫描电镜、XRD以及透射光谱等测试手段,研究了两种制备方法对不同衬底生长CdS薄膜形貌、结构和光学性能的影响.研究结果表明,不同方法制备的CdS薄膜表面形貌均依赖于衬底的类型,水浴法制备的CdS薄膜晶粒度较大,表面相对粗糙.不同方法制备的CdS薄膜均为立方相和六角相的混相结构,溅射法制备的多晶薄膜衍射峰清晰、尖锐,结晶性较好.水浴法制备的CdS薄膜透过率整体低于溅射法,但在短波处优势明显.     

Efficiency of the intercalation of aluminum atoms under a monolayer and submonolayer two-dimensional graphite film on a metal

Intercalation of aluminum atoms under a two-dimensional graphite film on a metal was studied by high-resolution Auger spectroscopy. The spectra were recorded directly from the highly heated (up to 2100 K) sample. It is shown that the efficiency of this process increases significantly if the film is of the island type, rather than continuous, and if part of the metal surface is not covered with graphite. It is concluded that the graphite-island boundaries are the defects via which the intercalating atoms penetrate under the graphite film.     

Crystalline CoFeB/Graphite Interfaces for Carbon Spintronics Fabricated by Solid Phase Epitaxy

Structurally ordered interfaces between ferromagnetic electrodes and graphene or graphite are of great interest for carbon spintronics, since they allow spin‐filtering due to k‐vector conservation. By solid phase epitaxy of amorphous/nanocrystalline CoFeB at elevated temperatures, the feasibility of fabricating crystalline interfaces between a 3d ferromagnetic alloy and graphite is demonstrated, without suffering from the unwetting problem that was commonly seen in many previous studies with 3d transition metals. The films fabricated on graphite in this way are found to have a strong body‐centered‐cubic (110) texture, albeit without a unique, well‐defined in‐plane epitaxial relationship with the substrate lattice. Using various X‐ray spectroscopic techniques, it is shown that boron suppresses the formation of CoFe‐O during CoFeB deposition, and then diffuses out of the CoFe lattice. Segregation of B occurred exclusively to the film surface upon in situ annealing, and not to the interface between CoFeB and graphite. This is favorable for obtaining a high spin polarization at the hybrid CoFe/graphite crystalline interface. The Co and Fe spin moments in the crystalline film, determined by X‐ray magnetic circular dichroism, are found to be bulk‐like, while their orbital moments show an unusual giant enhancement which has yet to be understood.     

Surface morphology of 6H-SiC after thermal diffusion

Diffusion of aluminum into 6H-SiC has been carried out in the temperature range of 1800–2100°C. Aluminum carbide (Al₄C₃) was used for a p-type impurity source; the diffused surface exhibited good stoichiometry and surface morphology. A thin-layer graphite film was developed to protect the wafer surface from deterioration during the high-temperature diffusion process. A high-resolution optical microscope (HROM) and atomic force microscopy (AFM) were employed to evaluate the surface morphology of the diffused samples. The protective graphite layer significantly decreased the surface roughness. X-ray photoelectron spectroscopy (XPS) was used to identify the Si/C ratio near the surface regions. Very little surface graphitization occurred during diffusion. In addition, secondary ion-mass spectroscopy (SIMS) was used to investigate the influence of the thin graphite film on the diffusion properties in SiC. There were no significant differences in doping profiles in the samples with and without the graphite film.     

掺N类金刚石薄膜的制备及微观结构分析

采用直流磁控溅射法,在光学玻璃衬底上沉积类金刚石(DLC)和掺N类金刚石薄膜(DLC:N)。用喇曼光谱、X射线光电子能谱(XPS)、傅里叶红外光谱(FTIR)等研究分析了所制备薄膜的微观结构。喇曼光谱的结果表明,掺N类金刚石膜仍具有典型的类金刚石膜结构,在类金刚石薄膜中掺N不仅有助于提高膜中sp3/sp2的比例,而且还能阻止sp2键向石墨相的转化,稳定并优化薄膜的类金刚石属性。FTIR表明,薄膜中N与C原子形成了C—N、CN及C≡N等键合方式。XPS谱表明,掺N类金刚石膜中除了C和N元素外,还出现了少量的O元素,而C1s和N1s的解谱显示,掺N后的类金刚石膜中的C、N结合能发生了明显的移动,由计算得出薄膜中N的含量为13.5%。薄膜的表面形貌图(AFM)表明,在类金刚石薄膜中掺N能够改善其表面形貌。     

无铅石墨导电浆料的制备和性能

以导电石墨粉、低熔无铅玻璃和乙基纤维素松油醇溶液制备了无铅石墨导电浆料。分析了浆料中玻璃粉含量对烧结膜表面电阻、威氏硬度和附着力的影响,给出了石墨导电浆料的配方。研究了浆料的流变性、触变性和粘弹性。用玻璃转变温度为476℃的无铅低熔玻璃配制的浆料在520~580℃烧结后,外观致密光洁;当烧结膜厚度为(25±3)μm时,方阻为80~135?/□,硬度为12.3 N/mm2,附着力为45.6 N。     

钢球在石墨层间化合物上微滑动的SEM观察

用溶剂法合成了南墅大鳞片氯化铁石墨层间化合物,利用Ｘ射线衍射粉末法及透射电子显微镜探讨了这种化合物的结构。应用ＳＥＭ观察了钢球在石墨球层化合物上的微滑动及石墨层间化合物在金属上擦涂的形貌。在钢球划行或其擦涂于金属表面上时,ＧＩＣ表面出现脱插的氯化铁颗粒,表明它与金属表面发生反应附着,从而提高了石墨的耐极压性。     

Efficient Reduction of Graphite Oxide by Sodium Borohydride and Its Effect on Electrical Conductance

The conductivity of graphite oxide films is modulated using reducing agents. It is found that the sheet resistance of graphite oxide film reduced using sodium borohydride (NaBH₄) is much lower than that of films reduced using hydrazine (N₂H₄). This is attributed to the formation of C? N groups in the N₂H₄ case, which may act as donors compensating the hole carriers in reduced graphite oxide. In the case of NaBH₄ reduction, the interlayer distance is first slightly expanded by the formation of intermediate boron oxide complexes and then contracted by the gradual removal of carbonyl and hydroxyl groups along with the boron oxide complexes. The fabricated conducting film comprising a NaBH₄‐reduced graphite oxide reveals a sheet resistance comparable to that of dispersed graphene.