化学溶液沉积(CSD)法制备YBCO薄膜研究进展

采用CSD法制备YBCO薄膜可精确的控制组份,不需要真空设备,成为近年来的研究热点之一。文中概述了CSD法制备YBCO薄膜的研究进展,总结了在不同的CSD工艺中,起始原料、化学添加剂对YBCO薄膜热处理时间、质量、可重复性等因素的影响。     

TFA-MOD方法制备YBCO超导薄膜研究

采用TFA-MOD方法在LaAlO3(001)单晶基片上制备了性能良好的YBCO超导薄膜:临界电流密度(Jc)可达3MA/cm2(77K,0T),超导转变温度Tc≈90K,转变宽度ΔTc=0.5K,其一次涂层厚度达338nm.通过X射线衍射(XRD)分析表明YBCO具有纯c-轴取向、无a-轴取向的晶粒存在.ω扫描分析表明该YBCO薄膜具有很好的面外外延性,其摇摆曲线的半高宽(FWHM)为0.653°. 用SEM分析也表明膜的表面无裂纹存在,表面平整,没有a轴晶粒生长.     

化学溶液沉积法制备YBCO薄膜的快速分解工艺研究

文中对化学溶液沉积法快速制备YBCO薄膜的工艺进行了探索。通过对分解工艺的优化,成功将薄膜的干燥分解时间缩短到1小时以内,而传统工艺则需要10小时以上的处理时间。以快速分解工艺成相的YBCO薄膜的X射线衍射、扫面电镜和物性测量结果表明薄膜具有良好的c轴外延织构,表面微观形貌平整致密,临界超导转变温度(Tc)为92K。     

TFA-MOD法制备YBCO薄膜生长速率研究

采用原位电阻法对TFA-MOD法高温热处理阶段YBCO薄膜生长速率进行了研究。实验结果和分析表明原位电阻测量法是一种估算YBCO层生长速率的有效方法,不同条件下的测量结果表明薄膜生长速率随管式炉内的温度、水分压、气体流量的上升而明显增加,但随薄膜面积的增加而减小。实验结果为进一步探索和优化热处理过程提供了重要的基础。     

溶胶-凝胶法制备发光薄膜现状

发光薄膜在对比度、分辨率、热传导、均匀性、与基底的附着性、释气速率等方面都显示出较强的优越性,在平板显示领域具有很好的应用背景。本文结合我们的工作综述了通过溶胶－凝胶工艺制备发光薄膜的基本过程、薄膜的表征方法、发光薄膜的当前发展及应用情况。依据组成特点,溶胶－凝胶法制备的发光薄膜可分为无机发光薄膜和有机／无机杂化发光薄膜,它们的光致发光、阴极射线发光、场发射发光和电致发光等性质都已被广泛研究。我们除了采用硅酸酯为主要原料制备了一些硅酸盐基发光薄膜外,还以无机盐为主要原料通过Pechini溶胶－凝胶法制备了稀土离子掺杂的钒酸盐发生薄膜,并结合毛细管微模板技术实现了发光薄膜的图案化。最后,我们对未来溶胶－凝胶法制备发光薄膜的发展及应用情况进行了展望。     

电子束蒸发制备YBCO超导薄膜研究

采用电子束沉积制备YBCO超导薄膜,研究了760℃—840℃的不同退火温度下高温热处理对YBCO薄膜双轴织构、表面形貌及超导性能的影响。超导临界电流密度测试、X射线衍射(XRD)和扫描电镜(SEM)的结果表明,退火温度在在800℃时,YBCO薄膜具有良好的织构和平整致密的表面形貌,在77K自场下的临界电流密度J可达4.2×106/cm2。     

溶胶-凝胶法制备Ni_xZn_(1-x)S薄膜的磁性分析

由于离子掺杂可有效改善ZnS薄膜的特性,故本研究以溶胶-凝胶法制备Ni_xZn_(1-x)S薄膜(x=0.00, 0.05, 0.10, 0.15),并利用XRD、PL光谱及磁性测试仪分析Ni掺杂对其磁性的影响.研究结果表明Ni掺杂量x为0.00、0.05、0.10及0.15时薄膜的饱和磁化强度随分别为6.59×10~(-6) emu/cm~3、4.61×10~(-6) emu/cm~3、3.88×10~(-6) emu/cm~3及3.52×10~(-6) emu/cm~3,即饱和磁化强度随x增加而减小. PL分析表明缺陷发光强度随x增加而减弱,能隙发光强度则随之增强,结合束缚极化子理论便知饱和磁化强度会随x增加而减小. XRD分析表示结晶品质随x增加而变好,说明薄膜中的缺陷数量会随x增加而减少,使得磁信号无法通过缺陷方式传导而导致其磁性减弱.     

1感光溶胶-凝胶法制备光波导研究

采用溶胶-凝胶技术与化学修饰相结合的方法,制备了具有紫外感光特性的SiO2/Al2O3溶胶及其凝胶薄膜,并通过在溶胶中加入聚乙二醇使其形成有机-无机复合结构,经一次提拉制膜就可获得18 μm厚的感光性凝胶薄膜.利用薄膜自身的感光性,使紫外光通过掩模照射薄膜,再经过溶洗和200℃、1 h的热处理,就可获得厚度达到15 μm、线宽约为100 μm的波导阵列.对这种波导薄膜的折射率和的透射率进行了研究.     

Photosensitive YBCO gel film and its patterning by sol-gel process

The YBCO precursor solution was prepared using yttrium acetate, barium acetate and copper acetate as starting material, diethylenetriamine, trifluoroacetate, acrylic acid (AA) as chemical additives, methanol as solvent. The precursor solution was modified by AA, in which the Cu²⁺ of Cu(OAc)₂ and AA were reacted to form the photosensitive copper complex. The coated gel film using this precursor solution exhibited the photosensitivity to UV light at around 245 nm. Utilizing the photosensitivity, the patterned YBCO film with a high critical transition temperature (Tc) of 91.5 K was fabricated.     

Properties of YBCO obtained by modified hydroxycarbonate method

YBCO was synthesized by the co-precipitation of stoichiometric amounts of nitrate solutions of Y, Ba and Cu using a mixture of NaOH, Na₂CO₃and H₂C₂O₄in a molar ratio of 5:1:1 as a precipitation agent. Even after prolonged thermal treatment at 950 °C the samples exhibit a zero-resistance critical temperature of about 87 K. This fact indicates a copper deficiency of about 0.1, more reduced than in the case of hydroxycarbonate co-precipitation. The as-synthesized samples have a high density, reaching 94% of the theoretical density. The SEM analyses show a large grain distribution from microns to tens of microns, favourable for good stacking.     

关于YBCO薄膜过热现象的研究

在用YBa₂Cu₃O_z(YBCO)种膜液相外延生长Nd_1+xBa_2-xCuO_z(NdBCO)厚膜的过程中，YBCO晶体在高于熔点的温度下保持不熔化并且起到了外延种子的作用.采用高温金相显微镜,我们实时观察YBCO薄膜的熔化过程，发现了超导氧化物薄膜的过热现象，并且结合XRD极图的分析和Ba-Cu-O熔体的不润湿性现象合理解释了YBCO形成过热的机制.另外，通过对具有不同微观结构的YBCO薄膜熔化行为的横向比较，研究YBCO薄膜品质对于其过热度的影响，并用半共格界面能理论很好地解释了AFM和XRD分析及实时观察熔化过程的实验结果. 关键词： 过热 YBCO薄膜 熔化形核     

前驱液成分对TFA-MOD法制备YBa2Cu3O7-x薄膜超导性能的影响

采用三氟乙酸盐-金属有机沉积法(TFA-MOD)在铝酸镧单晶基体上制备了YBa₂Cu₃O_7-x (YBCO)超导薄膜.通过改变前驱液的成分,研究了金属元素的不同化学计量比对YBCO薄膜的结构和性能的影响.结果表明,按照钇盐Y(CH₃COO)₃与钡盐Ba(CH₃COO)₂的比例为Y ∶Ba=1 ∶1.5时所制备的YBCO薄膜的临界电流密度比严 关键词： 三氟乙酸盐-金属有机沉积 钇钡铜氧薄膜 前驱液成分 磁通钉扎     

Optical activation of patterned Si nanowires grown from sol-gel prepared gold/Er-doped aluminous film

Optical activation of patterned Si nanowires grown from sol-gel prepared gold/Er-doped aluminous film is investigated. The growth of patterned Si nanowires (SiNWs), the doping of Er ions and the sintered process are completed by one step. Si nanowires were grown from a sol-gel solution containing both Au catalysts and Er ions by the vapor-liquid-solid method. Such Er-activated Si nanowires achieve both high carrier-mediated excitation efficiency and high Er luminescence efficiency while at the same time providing high areal density of Er and easy current injection, indicating the possibility of activated patterned Si nanowires grown from sol-gel film as a material platform for Si-based photonics.     

Effect of excimer laser annealing on the properties of ZnO thin film prepared by sol-gel method

Pristine ZnO thin films have been deposited with zinc acetate [Zn(CH₃COO)₂], mono-ethanolamine (stabilizer), and isopropanol solutions by sol-gel method. After deposition, pristine ZnO thin films have been irradiated by excimer laser (λ = 248, KrF) source with energy density of 50 mJ/cm² for 30 sec. The effect of excimer laser annealing on the optical and structural properties of ZnO thin films are investigated by photoluminescence and field emission scanning electron microscope. As-grown ZnO thin films show a huge peak of visible region and a wide full width at half maximum (FWHM) of UV region due to low quality with amorphous ZnO thin films. After KrF excimer laser annealing, ZnO thin films show intense near-band-edge (NBE) emission and weak deep-level emission. The optically improved pristine ZnO thin films have demonstrated that excimer laser annealing is novel treatment process at room temperature.     

Thin film formation on chemically modified surfaces: Au on Mo(110)

The early stages of the formation of Au films on chemically modified Mo(110) surfaces were studied by Auger electron spectroscopy (AES), low energy electron diffraction (LEED), thermal desorption spectroscopy (TDS) and work function change (Δφ) measurements. The surfaces were modified by saturation with oxygen and CO and by carburization. Carburization did not suppress initial two-dimensional (2D) growth but on the oxygen-saturated surface Au grew from the very beginning in small 3D crystals with oscillatory thickness dependence of the Auger signals. CO showed an intermediate behaviour. It is concluded that the bond strength and the location of the chemical modifier normal to the surface is decisive for the growth mode.     

改进的DLA方法模拟薄膜二维生长

对经典的DLA模型进行改进，研究了薄膜的二维生长过程.通过改变表征吸附原子在基底扩散 能力的参量D_T，D_C以及表征沉积速率的参量D_V，得到 了与实验一致的薄 膜分形生长模式和团状生长模式.分析了薄膜的形核阶段原子团的大小分布，以及不同条件 下原子团的数目和大小随覆盖度的变化. 关键词： DLA 薄膜生长 分形生长 团状生长     

Preparation and atomic oxygen erosion resistance of silica film formed on silicon rubber by sol-gel method

Based on the characteristic that silicon coupling agents have the capability to develop ‘molecular bridge’ in the interface of organic materials and inorganic materials, silica films were prepared on the surface of flexible silicon rubber by sol-gel method and the optical transmittance of the sample before and after atomic oxygen irradiation was tested. The surface morphology and structure of silica films were investigated by scanning electronic microscope (SEM) and Fourier transformed infrared spectroscopy (FTIR). The results indicated that the silica sol could easily form a uniform thin film on the surface of silicon rubber pretreated by high concentration silicon coupling agents, and the inorganic silica films could combine with organic silicon rubber without obvious delamination on the interface.     

Sensitivity of the phonon in YBCO to superconductivity by infrared studies on epitaxial film

Epitaxial films of YBCO superconductors whose C axes are primarily perpendicular to the film surface, were prepared. The samples, which were treated by means of a gettered annealing technique, were investigated by the X-ray diffraction pattern method (XRD) and infrared (IR) reflectance spectra in the 140–800 cm⁻¹ spectral range. The strengths of the phonon structures are influenced greatly by the superconductivity of the sample, which can be determined by the annealing conditions. The relation between the resulting IR activity of phonons and the superconductivity is clear and the important role of phonons in superconductivity is demonstrated.