多孔硅光致发光热稳定性研究

运用微拉曼谱仪以不同功率的激光入射到用阳极脉冲腐蚀制备的多孔硅样品研究多孔硅的热稳定性．用斯托克斯与反斯托克斯散射强度的比率确定样品的温度．观察比较不同温度下多孔硅样品的拉曼谱趋向．发现在激光功率与样品温度之间的关系曲线上分为3个过程,与拉曼频移和拉曼强度的曲线相一致．所有现象都可以用Si—O健和非晶Si被光氧化的机制解释．     

射频磁控溅射制备类金刚石薄膜

采用射频磁控溅射法在Si和Ti合金基体上沉积出类金刚石(DLC)薄膜.利用拉曼光谱仪、划痕仪和扫描电子显微镜分析了DLC薄膜的结构、膜基附着力和表面形貌.结果表明:射频磁控溅射法能够制备出表面平整、结构致密的DLC薄膜;同时基体材料的不同不会影响DLC薄膜的键合结构,Si基体上涂层附着力为30N,Ti基体上膜基结合力大于40 N.     

磁激励RF-PECVD法低温制备类金刚石薄膜及其特性

采用磁激励射频等离子体增强化学气相沉积(M-RF-PECVD)方法,室温下分别在玻璃和Si(100)衬底上制备类金刚石(DLC)薄膜,通过扫描电镜(SEM)、傅里叶红外光谱(FTIR)和Raman光谱对不同沉积条件下制备的薄膜进行表征。结果表明,在反应压强为30 Pa、入射功率为50 W、CH4/Ar=5/90、衬底温度为40℃的实验条件下,制备的含氢DLC薄膜表面平整、结构致密,膜基结合度良好,薄膜中以sp3键为主。     

射频溅射功率和掺杂氢对硅氢薄膜结构的影响

采用SEM和Raman谱对射频磁控溅射法制备的硅氢薄膜结构进行了研究,讨论了在100～400W范围内溅射功率和氢气分压对硅氢薄膜结构的影响。结果表明,制备的硅氢薄膜为致密的颗粒膜,添加氢气后,颗粒状的硅氢薄膜出现了粒径更为细小的纳米级小颗粒亚结构;随着氢气分压的增加,其直径先增加后减小,平均直径在氢气分压为50％时达到最大;随着溅射功率的增加,硅氢薄膜的颗粒平均直径增加,当溅射功率达到400W时,颗粒的平均直径为104nm。拉曼光谱分析结果显示硅氢薄膜为非晶态。     

Structure and photoluminescence of mullite-Ge nanocomposite

Al12Si3.75Ge0.25O26 ceramic powder was prepared by sol-gel method using Al（NO3）3,Si（OC2H5）4 and Cl3GeCH2-CH2COOH as precursors.The structural formation of Al12Si3.75Ge0.25O26 ceramic powder was analyzed by XRD.After reduction by flowing H2/Ar mixture gas,strong room temperature photoluminescence （PL） can be observed at 565 nm,613 nm,682 nm,731 nm and 777 nm,respectively.The PL intensity scarcely depends on the reduction temperature and duration,while the sample reduced at 500 ℃ for A^3 hours has the highest PL intensity.Before and after reduction at 500 ℃,the volume of unit cell of mullite solid solution decreases to 0.4699 3.Based on the analysis of XPS and Raman spectra,it can be approved that the PL phenomenon at room temperature is caused by the embedded Ge nanoparticles with the average size of about 1.95 nm.     

麦秆喇曼光谱研究

利用喇曼光谱技术对麦秆表面元素分布进行研究,对麦秆材料中的相邻部位、不同层次间进行多次、反复激光扫描,得到一系列谱线,其中除谱峰略微漂移外,整体上重复性很好.在其中选出重复性较好的一组谱线,与已研究出的喇曼谱图对比,可知麦秆表面主要含有C、O、N、Si等元素.研究表明麦秆中Si元素主要以SiO2的形式存在,主要分布在外表面角质层中.     

微波等离子体化学气相沉积法制备的新型纳米片状碳膜

在甲烷和氢气的混合系统中,利用石英管型微波等离子体化学气相沉积方法,在硅片上制备了新型的纳米片状碳膜．利用场发射扫描电子显微镜和拉曼光谱仪对碳膜的结构进行了表征,结果表明碳膜是由长1μm、宽100nm的纳米碳片相互缠绕而成．最后简单讨论了新型碳纳米片的形成机理．     

机械致单轴应变SOI晶圆的制备

提出了一种晶圆级单轴应变绝缘层上硅(SOI)的新方法,并阐述了其工艺原理．将直径为100mm(4英寸)的SOI晶圆片在曲率半径为0.75m的弧形弯曲台上进行机械弯曲,弯曲状态下的SOI晶圆片在250℃下进行了20h的热退火处理．对弯曲退火后SOI晶圆片进行了拉曼光谱表征,其拉曼频移为520.3cm^{-1,小于体硅的典型值,拉曼频移差达到-0.3cm-1,说明弯曲退火后的SOI晶圆片发生了单轴张应变．相应的应变量计算为0.077%,高于文献报道的0.059%．}     

Si(100)上Ge_(1-x)C_x合金薄膜的CVD外延生长

用化学气相淀积生长方法,以乙烯为碳源、锗烷为锗源,在Si(100)衬底上外延生长出了C组分达3%的Ge1-xCx合金薄膜,研究表明随着生长温度和乙烯分压的提高均可导致Ge1-xCx薄膜中碳组分的增加;X射线衍射测量显示随着C组分的增加合金薄膜晶格常数不断减小,这表明外延薄膜中的C原子主要以替位式存在。红外吸收谱的测量结果显示Ge1-xCx合金的禁带宽度随着C组分的增加而线性增加,从0 67eV到0 87eV,与理论相符,说明碳的掺入有效地调节了禁带宽度。另外拉曼光谱显示Ge1-xCx合金在387cm-1出现一新峰,该峰是Ge1-xCx薄膜中的Ge在K点的双声子振动引起的。     

Structure characterization of F-doped silica glass

Pure and fluorine-doped silica glass were fabricated by plasma chemical vapour deposition (PCVD) and characterized using Raman and infrared spectrum. The change in Raman intensity of 945 cm⁻¹ peak, relating to ≡Si—F stretching vibration, agrees with the change of F content. Compared with measured wavenumber in IR spectrum, the calculated absorption wavelength confirms the incorporation form of F into the glass, the detail of which is a tetrahedron with a Si atom in the center coupled with one F atom and three network O atoms. Such structure identification may be useful for explaining some properties of F-doping silica glass.     

聚乙烯密度的拉曼光谱检测

通过分析若干聚乙烯样品的拉曼光谱,对聚乙烯密度的检测方法进行了研究.分别采用拉曼光谱内标法(RISM)和偏最小二乘法(PLS)建立聚乙烯密度预测模型,其中RISM方法建模所得检测结果与真实值的相关系数为0.558,平均相对偏差为1.1%,标准偏差(SD)为11.7,而PLS方法建模所得检测结果的相关系数、平均相对偏差和交叉验证误差均方根分别为0.985、0.2%和2.2.研究表明:通过拉曼光谱能够实现聚乙烯密度的快速检测;且基于PLS的建模分析方法检测结果更优.     

MPECVD法在抛光石英玻璃上沉积金刚石薄膜

采用微波等离子体增强化学气相沉积方法(MPECVD),利用氢气和甲烷混合气体,在抛光石英基片上低温沉积出金刚石薄膜。用扫描电子显微镜(SEM)、激光拉曼光谱仪(Raman)和傅立叶红外光谱仪(FTIR)对薄膜的表面形貌、颗粒尺寸、纯度和光学透过性能进行了表征。通过SEM发现,得到的金刚石薄膜的颗粒尺寸为0.2~0.3μm,形核密度超过109cm-2,从薄膜形貌可以发现,较高温度有利于提高薄膜的生长速率和颗粒尺寸的均匀性。通过拉曼光谱和红外透射光谱分析发现,较高温度下沉积的薄膜具有较高的金刚石相含量,薄膜的光学透过性能也相对较好。     

Al-induced Lateral Crystallization of Amorphous Si Thin Films by Microwave Annealing

Al-induced lateral crystallization of amorphous silicon thin films by micr owave annealing is investigated,The erystallized Si films are examined by optical microscopy,Raman spectroscopy ,transimission electron microscopy and transmission electron diffraction micrography.After microwave annealing at 480 ℃ for 50min the amorphous Si is completely cystallized with lagrge grains of main (111) orientation,The rate of lateral crystallization is 0.04μm/min,This process,labeled MILC-MA ,not only lowers the temperature but also reduces the time of crystallization.The crystallization.mechanism during microwave annealing and the electrical properies of polycrystalline Si thin films are analyzed.This MILC-MA process has potentila application in large area electronics.     

P-C法涂覆中碳结构钢的表面耐蚀性

应用Ｐ－Ｃ法对中碳结构钢进行Ｃｒ－Ｓｉ－Ａｌ复合涂覆,用电子探针及扫描电镜测定了涂层的表面成分及Ｃｒ,Ｓｉ,Ａｌ在涂层中的分布,用Ｘ射线衍测定了涂层中的相结构,将涂覆后的试样在酸、碱、盐溶液中进行腐蚀试验,结果表明,中碳结构钢经Ｐ－Ｃ法复合涂履后,表面优良的抗多种介质腐蚀的能力。     

Growth of graphite film over the tops of vertical carbon nanotubes using Ni/Ti/Si substrate

A substrate with Ni/Ti/Si structure was used to grow vertical carbon nanotubes (CNTs) with a graphite film over CNT tops by thermal chemical vapor deposition with CH4 gas as carbon source.The carbon nanotubes and the substrate were character-ized by a field emission scanning electron microscope for the morphologies,a transmission electron microscope for the microstruc-tures,a Raman spectrograph for the crystallinity,and an Auger electron spectrometer for the depth distribution of elements.The re-sult shows that when the thickness ratio of Ni layer to Ti layer in substrate is about i,a graphite film with relatively good quality canbe formed on the CNT tops.     

Optimization of material structure of ploy-Si thin film based on Al induced crystallization

Based on Al induced crystallization (AIC) method, influences of different material structures on formation and characteristics of ploy-silicon thin films were studied and optimized. Al-Si films on glass with different structures (Si/Al/Glass, Al/Si/Glass, Si/Al/…/Si/Al/Glass) were deposited on glass substrates by sputtering method. All samples were annealed for MIC with varied time processes under 500℃ N2 environment. X-ray diffraction test and scanning electron microscope were adopted to characterize cryst...     

在LaNiO3衬底上（Pb,La）TiO3铁电薄膜的制备和研究

首先通过金属有机化合物热分解(MOD)法在Si(100)基片上制备出LaNiO3(LNO)薄膜,再通过溶胶-凝胶(sol-gel)法,在LNO/Si(100)衬底上制备出(PbxLa1-x)TiO3(PLT)铁电薄膜。经XRD分析表明,LNO薄膜具有(100)择优取向的类钙钛矿结构,PLT/LNO/Si薄膜具有四方相钙钛矿结构,同时以(100)择优取向。最后对薄膜的介电性和铁电性进行了测试,发现薄膜介电常数适中,铁电性良好。     

氧化石墨还原法制备石墨烯及其吸附性能

利用液相化学氧化法制备氧化石墨,通过水合肼还原氧化石墨制备石墨烯.采用X射线衍射分析、激光拉曼光谱和透射电子显微镜等测试方法,对石墨烯材料的结构和吸附性能进行分析表征.结果表明,通过氧化石墨还原法制得的石墨烯晶体结构完整性有所降低;石墨烯对极性较大的有机染料亚甲基蓝、甲基橙和罗丹明B的吸附率都在95%以上,对极性较小的有机污染物苯酚和氯苯酚的吸附能力较弱.     

离子束增强沉积Al-N共掺杂ZnO薄膜的制备

用Al2O3粉体与ZnO粉体均匀混合,压制成溅射靶。在Si和SiO2/Si衬底上,用离子束增强沉积(IBED)方法对沉积 膜作Ar+/N+注入,制备Al-N共掺杂氧化锌薄膜(ANZO)。在氮气氛中作适当的退火,可以方便地获得取向单一、结构致 密、性能良好的共掺杂ZnO薄膜。探索用IBED方法在Si和SiO2衬底上制备优质掺杂薄膜的可能性。初步研究了ANZO共掺 杂薄膜的结构、电学和光学性能。     

Comparative study of β-Si3N4 powders prepared by SHS sintered by spark plasma sintering and hot pressing

β-Si3N4 powders prepared by self-propagating high-temperature synthesis (SHS) with additions of Y2O3 and Al2O3 were sintered by spark plasma sintering (SPS). The densification, microstructure, and mechanical properties of Si3N4 ceramics prepared using this method were compared with those obtained by hot pressing process. Well densified Si3N4 ceramics with finer and homogeneous microstructure and better mechanical properties were obtained in the case of the SPS technique at 200℃ lower than that of hot pressing. The microhardness is 15.72 GPa, the bending strength is 716.46 MPa, and the fracture toughness is 7.03 MPa.m1/2.