等离子体气相沉积非晶SiO2薄膜的特性研究

用傅立叶红外吸收光谱 ,电子自旋共振 ,表面台阶仪等研究了等离子体增强化学气相沉积法制备的非晶SiO2 薄膜的特性与膜厚的关系。当膜厚从 0 1 μm递增到 1 1 μm时 ,1 0 60cm- 1 附近的Si—O—Si伸缩振动吸收峰从 1 0 50cm- 1 漂移到1 0 75cm- 1 ,但是 80 0cm- 1 处的Si—O—Si弯曲振动吸收峰不随膜厚变化而变化。通过比较 ,由于多重反射而引起的Si—O—Si伸缩振动吸收峰漂移的理论计算值 ,认为本研究中的Si—O—Si伸缩振动吸收峰的漂移不仅是由于多重反射效应 ,而且更主要是由于薄膜的物理性能随膜厚增加而发生了变化。Si悬挂键密度、应力以及HF缓冲溶液中的腐蚀速度等实验结果验证了以上的观点     

(Mg1-xSrx)2Al4Si5O18陶瓷的显微结构与微波介电性能研究

采用固相烧结反应法制备(Mg1-xSrx)2Al4Si5O18陶瓷.Sr掺杂促进低温相β-Mg2Al4Si5O18向高温相α-Mg2Al4Si5O18转变,并拓宽了(Mg1-xSrx)2Al4Si5O18陶瓷的致密化烧结温度范围.X射线衍射结果表明在0≤x<0.2范围内,(Mg1-xSrx)2Al4Si5O18陶瓷以(Mg,Sr)2Al4Si5O18堇青石固溶体形式存在;在0.6相似文献   

新型硅基双异质外延SOI材料Si/γ-Al2O3/Si制备

异质外延法是目前制备新型SOI材料的技术途径之一。采用低压化学气相沉积技术(LPCVD)在硅衬底上先外延γ-Al2O3绝缘单晶薄膜，制备出硅衬底上外延氧化物外延结构γ-Al2O3/Si(EOS)，然后采用类似SOS薄膜生长的常压CVD(APCVD)方法在EOS上外延硅单晶薄膜，形成新型硅基双异质SOI材料Si／γ-Al2O3／Si。利用反射高能电子衍射(RHEED)、X射线衍射(XRD)、俄歇电子能谱(AES)及MOS电学测量等技术表征分析了Si(100)／γ-Al2O3(100)／Si(100)SOI异质结构的晶体结构、组分和电学性能。测试结果表明，已成功实现了高质量的新型双异质外延SOI结构材料Si(100)／γ-Al2O3(100)／Si(100)，γ-Al2O3与Si外延薄膜均为单晶，γ-Al2O3薄膜具有良好绝缘性能，SOI结构界面清晰陡峭，该SOI材料可应用于CMOS电路的研制。     

Au—Si界面的室温反应

利用XPS研究了在超高真空条件下形成的Au—Si(113)界面初始阶段的室温反应,测量了Si2p、2S和Au4f光电子发射峰的强度和能量位置随Au复盖量的变化。所有结果表明,与Au—Si(111)和Au～Si(100)系统一样,存在一个发生界面室温反应的临界Au厚度～5ML。从而推断,这个现象可能是Au—Si界面形成过程的普遍特征。根据实验结果,讨论了Au—Si界面室反应的可能模型。     

弧流对Ti—Si—C膜层结构与性能的影响

电弧离子镀沉积膜层具有放电温度高、离化率高和沉积速率快等特点,可以在较低温度下促进Si—C成键,是获得含Si—C键膜层的一种经济实惠的方法。本文使用Ti—Si合金靶,在Ar和C₂H₂气体环境下,在铝合金衬底上制备了Ti—Si—C膜层,并分析和研究了不同弧流下沉积膜层的相组成、磨损和腐蚀性能。结果显示,不同弧流下沉积的膜层是由B1型TiC相、立方结构的SiC相和金属Ti相组成的复合结构;大弧流由于放电温度高,有利于膜层中Si—C键的形成.弧流增加,靶材蒸发速率加快,沉积膜层的厚度增加,同时,由于靶材附近单位时间内气化和离化的Si和Ti数量增加,沉积膜层中Si和Ti含量和增加而C含量降低.弧流增加,膜层中碳化物总含量减少,造成膜层摩擦系数逐渐增加而耐磨性降低,但膜层的耐腐蚀性能增加.适当弧流下的沉积膜层可获得优异的磨损和腐蚀综合性能.     

Mg2(Si,Sn)热电固溶体微波合成研究

为了解决传统方法制备Mg2Si1-xSnx(0≤x≤1.0)固溶体过程中带来Mg的氧化、挥发等问题,引进微波低温合成法,成功合成了Mg2Si1-xSnx热电固溶体,用XRD及SEM分析手段对合成的块体物相和形貌进行了表征,并系统研究了合成工艺对Mg2Si1-xSnx压坯制备的影响及Mg2Si1-xSnx压坯在微波场中的...     

污泥-高钙煤系废物制备地聚合物的技术与性能

鉴于地聚合物是一种低碳排放且能源、资源消耗较少的新型胶凝材料,其制备技术倍受关注。采用热活化污泥和高钙煤系废物制备地聚合物,并与采用高钙粉煤灰和矸石制备地聚合物的反应机制与性能进行了对比分析,确定了制备污泥-高钙煤系废物地聚合物的最佳工艺参数。采用XRD、SEM、TG-DTA及FTIR等对制备的地聚合物的原料组成和性能进行了深入分析。研究表明: 经900℃焙烧45 min掺量为40%(＜50 μm)热活化污泥-煤系废物制备的地聚合物具有较好的抗压强度。无定形地聚合物胶凝包裹在球状粉煤灰颗粒周围,有类沸石矿物生成,Al—O/Si—O对称伸缩峰及Si—O—Si/Si—O—Al弯曲振动峰明显。     

MgxZn1-xO薄膜的红外光谱及其表面浸润性

采用溶胶-凝胶法制备MgxZn1-xO薄膜,利用X射线衍射仪、原子力显微镜、傅里叶变换红外光谱仪和荧光光谱仪等测试分析薄膜的微结构、表面形貌、红外光谱和光致发光特性等,研究结果表明,薄膜中的Zn O成分均呈六角纤锌矿结构,当x=0.15时,薄膜中有Mg O成分析出;随着x从0增大到0.15,均方根粗糙度不断减小;1038 cm-1附近的吸收峰对应于Si-O-Si的对称和反对称伸缩振动模,408 cm-1附近的吸收峰对应于六角结构Zn O的Zn-O振动模,900 cm-1附近的吸收峰则对应于SiO键伸缩振动模,该吸收峰强度的减弱说明薄膜中Si-O键数目减少。近带边发射峰位由410 nm蓝移到370 nm与薄膜导带底或价带顶的局域能级、薄膜禁带宽度变化等因素有关,可见光发射带是单离子氧空位(VO+)和氧填隙(Oi)等薄膜本征缺陷相互竞争的结果。用接触角测试仪测试薄膜的表面接触角,研究Mg含量对薄膜的表面浸润性及其光诱导可逆转变的影响,并探讨其形成机理。     

飞秒脉冲激光沉积Si基α轴择优取向的钛酸铋铁电薄膜及Ⅰ-Ⅴ特性研究

采用飞秒脉冲激光沉积系统,在Si(111)衬底上制备了a轴和c轴择优取向的Bi4Ti3O12薄膜．X射线衍射(XRD)表明:室温(20℃)下沉积的Bi4Ti3O12／Si(111)薄膜呈c轴择优取向,晶粒的平均直径为20nm．在500℃沉积的Bi4Ti3O12／Si(111)薄膜呈a轴择优取向．测量了薄膜的电滞回线和Ⅰ-Ⅴ特性曲线,并用分布参数电路研究了Bi4Ti3O12薄膜的,Ⅰ-Ⅴ特性曲线和铁电性的关联性．a轴择优取向Bi4Ti3O12薄膜的剩余极化强度Pr=15μC／cm2,矫顽力Ec=48kV／cm．     

飞秒脉冲激光沉积Si基a轴择优取向的钛酸铋铁电薄膜及Ⅰ-Ⅴ特性研究

采用飞秒脉冲激光沉积系统,在Si(111)衬底上制备了a轴和c轴择优取向的Bi4Ti3O12薄膜.X射线衍射(XRD)表明室温(20℃)下沉积的Bi4Ti3O12/Si(111)薄膜呈c轴择优取向,晶粒的平均直径为20nm.在500℃沉积的Bi4Ti3O12/Si(111)薄膜呈a轴择优取向.测量了薄膜的电滞回线和Ⅰ-Ⅴ特性曲线,并用分布参数电路研究了Bi4Ti3O12薄膜的Ⅰ-Ⅴ特性曲线和铁电性的关联性.a轴择优取向Bi4Ti3O12薄膜的剩余极化强度Pr=15μC/cm2,矫顽力Ec=48kV/cm.     

利用粘度法和二维红外相关光谱法研究胶原/羟丙甲基纤维素共混物的相互作用

采用粘度法和二维红外相关光谱法对胶原/羟丙甲基纤维素共混体系的相容性及相互作用进行了研究。粘度法测定结果表明,羟丙甲基纤维素含量<30%时共混体系相容,超过50%则不相容。二维红外相关光谱法的分析结果表明,当羟丙甲基纤维素含量<30%时,归属于羟丙甲基纤维素的C—O(H)伸缩振动峰1061cm-1与归属于胶原酰胺带的CO对称伸缩振动峰1660cm-1、N—H摇摆振动峰1553cm-1和N—H面内变形振动峰1238cm-1之间存在同步负交叉峰,表明胶原和羟丙甲基纤维素之间存在氢键作用;而当羟丙甲基纤维素含量>30%时,同步图中负交叉峰强度减小的同时同步峰1061cm-1的强度明显变大,表明此时羟丙甲基纤维素与胶原之间的氢键作用变弱,羟丙甲基纤维素更倾向于在自身分子之间形成氢键。     

采用二维红外技术研究交联对碱溶胶原结构的影响

以N-羟基琥珀酰亚胺己二酸酯(NHS-AA)为交联剂,交联改性碱溶胶原,采用二维红外相关光谱法研究了交联对胶原二级结构的影响。研究发现,交联未影响胶原红外特征吸收峰的位置,但1672、1554和1241cm-1归属于胶原酰胺I带的CO伸缩振动、酰胺Ⅱ带的C—N伸缩与N—H弯曲振动和Ⅲ带的N—H面内变形振动峰之间存在同步正交叉峰,表明随交联共价键的增加,胶原的链段构象发生了变化。在NHS-AA用量增加的过程中,胶原二级结构变化的顺序为:酰胺Ⅲ带>酰胺Ⅰ带>酰胺Ⅱ带>—CH3>—CH—。由此可见,二维红外相关分析法能提供由交联引起的胶原构象动态变化的微观信息,为进一步研究改性胶原结构与功能之间的关系提供实验依据。     

对苯甲酰氨基苯甲酰壳聚糖制备与表征

在乙酸体系中,通过对苯甲酰氨基苯甲酰氯与壳聚糖在超声波振荡下反应制备对苯甲酰氨基苯甲酰壳聚糖。探讨超声波作用下,反应时间、反应温度及反应物投料比对壳聚糖衍生物取代度的影响。采用红外光谱、紫外光谱方法对目标产物进行了结构表征。研究结果表明,产物具有对苯甲酰氨基苯甲酰壳聚糖的结构特征,并具有较好的表面活性、较好的溶解性能和一定的吸收紫外线的能力,有望用于日用化妆品中。     

SiO2/TiO2复合气凝胶的孔道结构研究

为了在常压干燥下制备高比表面积且具有多级孔道结构的SiO2/TiO2复合气凝胶,以正硅酸乙酯、钛酸丁酯为原料,利用低聚体聚合将分相平行引入到溶胶凝胶过程中,获得SiO2/TiO2醇凝胶,并通过溶剂替换技术实现气凝胶的常压干燥制备.不同硅钛比气凝胶的内部结构研究表明:合成的气凝胶是由纳米SiO2和TiO2颗粒分散复合而成的介孔块体,其中Ti—O—Ti、Si—O—Si和Ti—O—Si键相互交织.气凝胶的结构变化是分相与溶胶凝胶过程相互竞争的结果.Si含量能显著改善气凝胶的结构,当n(Ti)∶n(Si)为3∶1时,比表面积高达712.2 m2/g,平均孔径为3.36 nm;当n(Ti)∶n(Si)为1.5∶1时,复合气凝胶具有明显双连续孔道,比表面积高,同时孔状结构清晰.     

Sol-gel synthesis and photoluminescence of III-V semiconductor InAs nanocrystals embedded in silica glasses

III-V semiconductor nanocrystals rarely exist as spherical inclusions inside glasses, due to the difficulties during their preparation, such as high toxic reagents or fast oxidation under usual glass technology temperatures. In this paper a sol-gel method for synthesis of InAs nanocrystals embedded in silica glasses was described. Gels were synthesized by the hydrolysis of a complex solution of Si(OC2H5)4, InCl3 x 4H2O, and As2O3. The gels were then heated at 200-450 degrees C in the presence of H2 gas to form fine cubic InAs crystallites. The X-ray diffraction patterns showed four strong peaks from InAs. The Raman spectrum showed InAs longitudinal-optic (233 cm(-1)) and transverseoptic modes (215 cm-(-1)). The size of InAs nanocrystals was found to be from 5 to 30 nm in diameter by transmission electron microscopy. A strong room temperature photoluminescence with peaks at 601 and 697 nm was observed from InAs nanocrystals embedded in silica glasses. The results suggest that it might be possible to synthesize other III-V semiconductor nanocrystals embedded in silica glasses through the sol-gel process.     

纳米Y_2O_3:Eu~(3+)(Y_2O_3)粉体的红外光谱研究

采用均相沉淀法和燃烧合成法制备了不同粒径的粉体材料Y2O3:Eu3+,着重研究了样品的红外光谱,探讨了纳米晶Y2O3:Eu3+与同质微米材料相比的微观结构的变化.研究发现,波数位于563 cm-1的Y(Eu)—O键的吸收峰校正高度和面积对于纳米级粒径的粉体材料随着颗粒的减小而减小,而对于同质微米材料却相反.经分析认为:Y(Eu)—O键的吸收峰校正高度和面积由Y(Eu)—O键的平均键长和Y(Eu)—O键振动态数目这两个因素决定.对于微米粉体Y(Eu)—O键长的变化起主要作用,而对于纳米粉体由于不饱和键和悬空键的形成,Y(Eu)—O键振动态数目的变化起主要作用.     

溶胶—凝胶制备TiO2／SiO2复合薄膜的FT—IR表征

ＦＴ－ＩＲ吸收谱用来研究具有多孔结构的ＴｉＯ２／ＳｉＯ２复合薄膜；薄膜在１２００ｃｍ＾－１有一较强的肩峰，其强度与峰位随热处理温度度而生变化。在９５５ｃｍ＾－１的吸收峰是由于Ｓｉ－Ｏ－Ｔｉ和Ｓｉ－ＯＨ的结果，并随着热处理 度的提高其吸收峰完全是Ｓｉ－Ｏ－Ｔｉ振动所引起的，其峰位随着ＴｉＯ２的增加，向低频区域移动。     

Effects of annealing temperature on buried oxide precipitates in He and O co-implanted Si

The effects of the processing conditions on the formation of buried oxide precipitates in He and O co-implanted Si were investigated by the combination of Fourier transform infrared (FTIR) absorption spectroscopy, depth-resolved positron annihilation Doppler spectroscopy, and transmission electron microscopy (TEM). Silicon wafers were implanted with 50 keV He ions at a fluence of 2 × 10¹⁶ cm⁻² and subsequent 150 keV O ions at a fluence of 2 × 10¹⁷ cm⁻². For comparison, reference Si wafers were only implanted with 150 keV O ions. The Si–O–Si stretching frequency increases while the peak width of the Si–O–Si stretching absorption band decreases with an increase in annealing temperature. After the same annealing, the peak width of the Si–O–Si stretching absorption band in the He and O co-implanted sample is significantly larger than that in the reference sample. Two kinds of vacancy-type defects are observed by positrons, i.e., vacancy-type defects and vacancy-oxygen complexes. The characteristic S values of vacancy-type defects and vacancy-type complexes in the He and O co-implanted sample are smaller than those of the reference sample. In addition, the thickness of the buried oxide layer in the He and O co-implanted sample is smaller than that in the reference sample. After annealing at 1473 K, the O content is larger in the He and O co-implanted sample compared to that in the reference sample.     

Infrared and near-infrared spectral evidence for water clustering in highly hydrated poly(methyl methacrylate)

First, we developed quantitative analytical methods of water in poly(methyl methacrylate) (PMMA) in various hydrated states by utilizing the first combination and OH stretching bands of water at about 5240 and 3630 cm-1, respectively. Next, we investigated how the state of water depended on its quantity or the mole ratio of water to the CO (denoted as the H2O/CO ratio), which only interacts with water in PMMA, mainly on the basis of the band feature of the OH stretching bands. Below the H2O/CO ratio of 0.032, the contained water, which shows two clear bands at about 3630 and 3550 cm-1, is hydrogen-bonded to two C=O groups as C=O::H-O-H::O=C to form "the hydration core". The spectrum of the water that exceeds the ratio in question shows one broader band only, the frequency of which shifts downward with the increasing hydration. From detailed analysis of the behavior of the OH stretching and combination bands in relation to the H2O/CO ratio, we have concluded that the water that exceeds the hydration ratio becomes mobile to aggregate or "cluster" around hydrated sites rather than nonhydrated ones in the PMMA matrix, although the latter is much larger in population.     

Catalytic effects of Ag2O additives on microstructure and recrystallization in borate glasses

A substitution of Ag2O for B2O3 in a 35BaO–25Fe2O3–(40−x)B2O3–xAg2O, x=0.0, 0.5, 1.0 and 3.0, glass series modifies the B2O3 network and changes infrared frequencies in the 1600–600 cm-1 region. Four bands at 1440, 1280, 1180 and 1120 cm-1 appear in glass containing no Ag2O additive. On adding the Ag2O, the 1120 cm-1 band (which belongs to the BO3→BO4 modified group in the B2O3 network) no longer appears, and the other three bands (belonging to the B–O stretching vibrations in the interconnected boroxol rings) shift 15–40 cm-1 to higher frequencies expected in the reduced structural defects of BO3→BO4 modified groups and non-bridging oxygens. This modified glass crystallizes (at 500–850°C) into acicular BaFe12O19 microcrystals of a higher coercivity of ∼5000 Oe, suitable for high energy-density magnets and other devices. This revised version was published online in November 2006 with corrections to the Cover Date.