Keggin结构钒取代硅钨酸/聚丙烯酰胺复合膜的制备及光致变色性能研究

制备了一、三钒取代的Keggin结构硅钨酸(SiW12-nVn,n=1,3)/聚丙烯酰胺(PAM)复合膜,采用红外光谱对其进行了表征.并研究了杂多酸的种类、含量以及照射光波长对SiW12-nVn/PAM复合膜光致变色性能的影响,通过ESR光谱推断了其可能的变色机理.结果表明:高含量、强氧化能力的多酸以及短波长的照射光波有利于SiW12-nVn/PAM复合膜的光致变色发生.     

负偏压对反应磁控溅射AlN薄膜的影响

利用反应磁控溅射制备AlN薄膜,研究了基底负偏压对薄膜结构及其性能的影响.XRD和SEM结果表明:用此方法获得的AlN薄膜呈晶态,负偏压对AlN择优取向产生一定的影响,随着偏压的增大,薄膜表面晶粒尺寸有长大趋势.根据透射谱测试和包络线计算结果可知,薄膜在可见光和红外区域透射率高,随着偏压的增大,薄膜的折射率也随之增大.     

钨磷酸/聚乙烯基吡咯烷酮纳米复合膜的光致变色性能

制备了一系列不同配比的钨磷酸/聚乙烯基吡咯烷酮纳米复合薄膜.通过原子力显微镜、红外光谱和紫外-可见吸收光谱对复合薄膜的结构和光致变色性能进行了研究.AFM结果表明,复合前后聚乙烯基吡咯烷酮表面形貌因杂多酸的掺杂而发生了显著变化.红外光谱分析结果表明,Keggin结构钨磷酸和聚乙烯基吡咯烷酮分子的基本结构在复合薄膜中仍然存在,乙烯基吡咯烷酮分子基团质子化后与杂多阴离子成盐,形成电荷转移桥.在紫外光照射下,复合薄膜由无色变为蓝色,在空气中暗处放置后复合膜重新恢复为无色.复合膜的升色速度和褪色速度均随着杂多酸含量的增加而加快.结果表明,杂多酸含量对复合膜的光致变色性能存在显著影响.     

Structure,optical, and magnetic properties of Mn-doped ZnO films prepared by sputtering

The microstructural, optical, and magnetic properties and room-temperature photoluminescence (PL) of Mn-doped ZnO thin films were studied. The chemical compositions were examined by energy dispersive X-ray spectroscopy (EDS) and the charge state of Mn ions in the ZnO:Mn films was characterized by X-ray photoelectronic spectrometry (XPS). From the X-ray diffraction (XRD) data of the samples, it can be found that Mn doping does not change the orientation of ZnO thin films. All the films prepared have a wurtzite structure and grow mainly along the c-axis orientation. The grain size and the residual stress were calculated from the XRD results. The optical transmittance of the film decreases with the increase of manganese content in ZnO. The room-temperature photoluminescence of the films shows that the intensity of near band energy (NBE) emission depends strongly on the Mn content. The hysteresis behavior indicates that the films with the Mn content below 9at% are ferromagnetic at room temperature.     

Texture of the nano-crystalline AlN thin films and the growth conditions in DC magnetron sputtering

DC reactive magnetron sputtering technique has been used for the preparation of Al N thin fi lms. The deposition temperature and the fl ow ratio of N2/Ar were varied and subsequent dependency of the fi lms crystallites orientation/texture has been addressed. In general, deposited fi lms were found hexagonal polycrystalline with a(002) preferred orientation. The X-ray diffraction(XRD) data revealed that the fi lm crystallinity improves,with the increase of substrate temperature from 300 ℃to 500℃. The dropped in full width half maximum(FWHM) of the XRD rocking curve value further con fi rmed it. However, increasing substrate temperature above 500 ℃or reducing the nitrogen condition(from 60 to 30% in the environment) induced the growth of crystallites with(102) and(103) orientations. The rise of rocking curve FWHM for the corresponding conditions depicted that the fi lms texture quality deteriorated. A further con fi rmation of the variation in fi lm texture/orentation with the growth conditions has been obtained from the variation in FWHM values of a dominant E1(TO) mode in the Fourier transform infrared(FTIR) spectra and the E2(high) mode in Raman spectra. We have correlated the columnar structure in AFM surface analyses with the(002) or c-axis orientation as well. Spectroscopic ellipsometry of the samples have shown a higher refractive index at 500 ℃growth temperature.     

电化学法制备晶面优势取向的微量铂电极

研究了用电化学方法在导电玻璃上沉积具有晶面优势取向的微量铂的方法。结果表明,用快速循环伏安法可以导电玻璃上电沉积得到亚微米级的、均匀分散的、具有晶面优势取向的铂微料。在快速扫描时,初期产生的铂微晶中,（100）面和（111）面的微晶产生的机会大致相等。由于（111）面的微晶的阳极溶解速度高于（100）面的,所以在反复多次循环扫描的沉积-溶解过程中（111）面的微晶微目减少,（100）面的微晶趋于优势取向。在较正的扫描下限和较短的扫描时间时得到的是二维微晶。对I3^-/I^-电化学反应来说,二维晶体和（100）面的电催化活性分别高于三维晶体和（111）面的。因此,可以控制循环伏安扫描的参数,在导电玻璃上得到高比表面的、二维的、具有晶面优势取向的微量铂沉积,制备高活性的新型光化学电池对电极。     

以1,4-二碘丁烷为中间体双螺环螺恶嗪的合成与表征

有关螺恶嗪的衍生物的光致变色研究已有多人报道．主要集中在两个方面：一是设计不同的螺恶嗪分子，研究分子结构对光致变色行为的影响；另一方面是探讨介质对光致变色行为的影响。文中以1，4-二碘丁烷为中间体，合成了双螺环螺恶嗪。通过IR,^1HNMR手段进行表征。确认了产物结构。     

Influence of substrate metals on the crystal growth of AlN films

AlN films were deposited by reactive radio frequency (RF) sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of AlN thin films were investigated. The results of X-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy show that the orientation of AlN films depends on the kinds of substrate metals evidently. The differences of AlN films deposited on various metal electrodes are attributed to the differences in lattice mismatch and thermal expansion coefficient between the AlN material and substrate metals. The AlN film deposited on the Pt/Ti electrode reveals highly the c-axis orientation with well-textured columnar structure. The positive role of the Pt/Ti electrode in achieving the high-quality AlN films and high-performance film bulk acoustic resonator (FBAR) may be attributed to the smaller lattice mismatch as well as the similarity of thermal expansion coefficient between the deposited AlN material and the Pt/Ti electrode substrate.     

BaMoO_4微晶的微乳液可控合成及形成机理探讨

采用聚乙二醇对异辛基苯基醚(Triton X-100)/正戊醇/环己烷/水溶液所形成的微乳液体系,控制合成出了四方晶系BaMoO4微晶,考察了微乳液中水与表面活性剂物质的量之比和反应物浓度对产物形貌的影响。采用扫描电子显微镜(SEM)、X-射线衍射(XRD)分别对产物的结构、粒度和形貌进行了表征。结果表明,在微乳液体系中,控制不同的实验条件,可以成功地合成蝴蝶结状以及不同长度树枝状的BaMoO4微晶,并且粒径分布集中,无团聚现象。论文还对不同形貌BaMoO4微晶的形成机理进行了初步探索。     

新型有机光致变色材料螺噁嗪的合成

文中以1,3,3-三甲基-2-甲叉吲哚啉和亚硝基酚为原料合成了四种螺噁嗪光致变色化合物,分别是:(1)化合物A:1,3,3-三甲基螺吲哚啉-2,3′-[3H]萘并[2,12b][1,4]嗪;(2)化合物B:1,3,3-三甲基-6′-哌啶-螺吲哚啉-2,3′-[3H]萘并[2,12b][1,4]嗪;(3)化合物C:1,3,3-三甲基-6′-二甲胺基-螺吲哚啉-2,3′-[3H]苯并[2,12b][1,4]嗪;(4)化合物D:1,3,3-三甲基-6′-二乙胺基-螺吲哚啉-2,3′-[3H]苯并[2,12b][1,4]嗪。对各化合物进行了一些光致变色试验,并对所产生的现象进行了简要的讨论。     

Influence of target-substrate distance and sputtering power on chromium oxide films prepared by medium-frequency magnetron sputtering

Chromium oxide films were deposited on Si (100) substrates by medium-frequency (MF) unbalanced magnetron sputtering at different target-substrate distances D _TS (60, 100, 120 mm) and sputtering power (2.8, 5.6, 11.2 kW), respectively. The structure, surface morphologies, and microhardness of the chromium oxide films were examined by X-ray diffraction (XRD), atomic force microscopy (AFM), and microhardness tester. The results indicate that elevated MF sputtering power can improve the crystallization of the films; The D _TS value affects the structure of the films by changing the preferential orientation from CrO₃ (221) to Cr₂O₃ (116); The microhardness of the chromium oxide films is found to increase with the sputtering power. For preparing the Cr₂O₃-dominated films with comparatively high-performance, the optimized condition is the target-substrate distance of 100 mm and MF sputtering power of 11.2 kW.     

Fabrication and Photocatalytic Characteristics of TiO2 Films on Silicon Substrates

Silicon ( 111 ) and Silicon (100) have been employed for fabrication of TiO2 films by metal organic chemical vapor deposition (MOCVD). Titanium (Ⅳ) isopropoxide (Ti[O (C3H7)4 ])was used as a precursor. The as-deposited TiO2 films have been characterized with Field emission scanning electron microscopy (FE-SEM), X ray diffraction (XRD) and atomic force microscopy (AFM). The photocatalytic properties were investigated by decomposition of aqueous orange Ⅱ. The crystalline and structural properties of TiO2 film had crucial influences on the photodegradation efficiency. For MOCVD in-situ deposited films on Si substrates, thephotoactivities varied following a shape of “M”: At lower (350 ℃ ) middle (500 ℃) and higher (800 ℃) temperature of deposition, relative lower photodegradation activities have been observed. At 400 ℃ and 700 ℃ of deposition, relative higher efficiencies of degradation have been obtained, because one predominant crystallite orientation could be obtained as deposition at those two temperatures, especially a single anatase crystalline TiO2 film could be obtained at 700 ℃ growth.     

Ordering and self-organization in nanocrystalline silicon

The spontaneous formation of organized nanocrystals in semiconductors has been observed during heteroepitaxial growth and chemical synthesis. The ability to fabricate size-controlled silicon nanocrystals encapsulated by insulating SiO2 would be of significant interest to the microelectronics industry. But reproducible manufacture of such crystals is hampered by the amorphous nature of SiO2 and the differing thermal expansion coefficients of the two materials. Previous attempts to fabricate Si nanocrystals failed to achieve control over their shape and crystallographic orientation, the latter property being important in systems such as Si quantum dots. Here we report the self-organization of Si nanocrystals larger than 80 A into brick-shaped crystallites oriented along the (111) crystallographic direction. The nanocrystals are formed by the solid-phase crystallization of nanometre-thick layers of amorphous Si confined between SiO2 layers. The shape and orientation of the crystallites results in relatively narrow photoluminescence, whereas isotropic particles produce qualitatively different, broad light emission. Our results should aid the development of maskless, reproducible Si nanofabrication techniques.     

衬底对沉积类金刚石薄膜结构和摩擦学性能的影响

利用直流-射频等离子化学气相沉积技术在玻璃、硅和钢表面沉积得到了薄膜,并用拉曼光谱和原子力对薄膜的结构和形貌进行了表征,用静动摩擦实验机对薄膜的摩擦学性能进行了测试．结果表明：沉积在硅和钢表面的薄膜具有典型类金刚石薄膜的特征,而沉积在玻璃表面的薄膜呈现类聚合物结构的特征,且沉积在玻璃表面的薄膜具有比较粗糙的表面,而沉积在硅表面的薄膜则比较光滑致密．摩擦学实验表明,沉积在硅表面的薄膜具有良好的摩擦学性能．     

射频功率对射频磁控反应溅射制备AlN薄膜的影响

采用射频磁控溅射法在Si(100)衬底上制备了AlN薄膜,通过控制工艺参数可以沉积出不同择优取向的AlN薄膜,各工艺参数中射频功率对其择优取向的影响最大.XRD表征了AlN薄膜的结构,进而选择出最优射频功率.     

La0.67Ca0.33MnO3薄膜中的非欧姆行为研究

 用四探针法对不同倾斜衬底La_0.67Ca_0.33MnO₃薄膜进行了不同电流下的电阻温度关系测试,发现了3个结果:①偏电流>1mA时,焦耳热作用使电阻温度曲线的转变点温度下降;②偏电流<1mA时,薄膜的转变点电阻随所加的偏电流的增加而减小,这是对欧姆行为的偏离(即非欧姆行为);③这一偏离随衬底倾斜角度的增加而增加.对经过氧气氛高温退火的La_0.67Ca_0.33MnO₃薄膜进行了测量,发现峰值电阻及峰值电阻的变化明显减小.初步分析的结果是:①大电流的加热效应是峰值温度偏移;②可能是晶界作为隧穿结导致了薄膜中的非欧姆行为.     

分子筛晶粒外表面催化活性作用

小晶粒分子筛具有与一般分子筛不同的动力学行为.半径为100至300nm左右的晶粒有明显较大比例的外表面积.用表观速率常数和对比效率因子.可描述小晶粒分子筛的等温一级反应动力学行为.由于外表面的活性贡献,小晶粒分子筛能有更好的表观活性.晶粒半径大于10~3nm后,其外表面积比例可忽略.小晶粒分子筛的外表面积可能比一般分子筛明显要高.     

衬底材料对Bi4Ti3O12薄膜取向度的影响

以正丁醇钛和硝酸铋为原料,用Ｓｏｌ－Ｇｅｌ技术分别在Ｐｔ／Ｔｉ／Ｓｉ、Ｓｉ、Ｙ－ＺｒＯＴｉＯ３（１００）和石英玻璃基片上生长出ｃ轴取向的Ｂｉ４Ｔｉ３Ｏ１２薄膜,研究了衬底材料表面结构对Ｂｉ４Ｔｉ３Ｏ１２薄膜取得度的影响,晶格失配能和Ｂｉ４ＴｉＯ１２晶体的晶面能决定了薄膜的取向程度。     

The preparation and characterization of amorphous SiCN thin films

Radio Frequency plasma enhanced Chemical Vapor Deposition (RF CVD) using N₂, SiH₄ and C₂H₄ as the reaction sources was used to prepare amorphous ternary Si _x C _y N _z thin films. The chemical states of the C, Si and N atoms in the films were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR). The refractive indexn, extinction coefficientk and optical band gapE _opt of the thin films were investigated by UV-visible spectrophotometer and spectroscopic ellipsometer. The results show that a complex chemical bonding network rather than a simple mixture of Si₃N₄, SiC, CN _x and a-C etc., may exist in the ternary thin films. Then's of the films are within the range of 1. 90–2. 45, andE _opt's of all samples are within the range of 2. 71–2. 86 eV. Foundation item: Supported by the National Natural Science Foundation of China (19975035) Biography: Li Jin-chai (1946-), male, Professor, research direction: novel functional materials films & ion beam modification of materials.     

厚度对ZnS薄膜结构和应力的影响

用射频磁控溅射法在单晶Si基片上制备了4种不同厚度的ZnS膜,采用XRD和光学干涉相移法对薄膜的微结构和应力进行研究。结构分析表明,不同厚度的ZnS膜均呈多晶状态,并有明显的(220)晶面择优取向,晶体结构为立方晶型(闪锌矿)结构;随着薄膜厚度的增加,平均晶粒尺寸随之增大;薄膜的晶格常数在不同厚度下均比标准值稍大。应力分析表明,随着膜厚的增加,ZnS膜的应力差减小,在厚度为768 nm时的选区范围内应力差最小,应力分布较均匀。