沉积温度对YBCO薄膜取向的影响

采用脉冲激光沉积技术(PLD)在SrTiO3(100)单晶衬底上制备YBCO薄膜,用X射线对薄膜的取向和织构进行表征,用扫描电子显微镜(SEM)对薄膜的表面形貌进行观察.实验主要研究了衬底温度对薄膜外延取向的影响,结果表明在770℃温度下制备的YBCO有较多的a轴晶粒生成,在800℃温度下制备的YBCO是纯的c轴取向,且平均面内φ扫描半高宽(FWHM)为1.2°,超导转变宽度(△Tc)为0.9K.     

反应溅射法连续制备CeO2隔离层

用带有反应溅射装置的走带系统在立方织构的Ni-5% W衬底上连续制备了长10 cm的CeO2隔离层.为避免金属衬底氧化,以H2O作为反应气体.论文主要研究了衬底温度、走带速率对CeO2隔离层外延生长的影响.用X射线θ～2θ扫描,ψ扫描对薄膜的取向和织构进行表征.结果显示在温度650 ℃,走带速度2.5 mm/s的条件下,连续制备的CeO2隔离层有效地继承并改善了基底的织构,平均平面内ψ扫描半高宽为6.18°,扫描电镜(SEM)观察表明薄膜表面致密,且无裂纹生成.     

VO_2/AZO复合薄膜的制备及其光电特性研究

采用直流磁控溅射和后退火氧化的方法在掺铝氧化锌(AZO)导电玻璃上制备了二氧化钒(VO2)薄膜,研究了不同的退火温度、退火时间对VO2/AZO复合薄膜制备的影响,并对复合薄膜的结构、组分、光电特性进行了测试与分析.结果表明,导电玻璃上的AZO没有改变VO2的取向生长,但明显改变了VO2薄膜的表面形貌特征.与用相同工艺和条件在普通玻璃基底上制备的VO2薄膜相比,VO2/AZO复合薄膜的相变温度降低约25?C,热滞回线宽度收窄至6?C,相变前后可见光透过率均在50%以上,1500 nm处红外透过率约为55%和21%,电阻率变化达3个数量级.该复合薄膜表面平滑致密,制备工艺简单,性能稳定,可应用于新型光电器件.     

Ni基带上的氧化物过渡层制备

本文采用溅射沉积方法在双轴织构的Ni-W5%基带上制备了CeO2和Y2O3薄膜.研究表明CeO2薄膜在Ni基带上的外延方式受生长速率、生长温度的控制.在快速沉积情况下,CeO2薄膜为(111)取向,在沉积速率较低时,以(00l)取向为主.CeO2薄膜沉积过程中,可以有效避免Ni的氧化.在Y2O3的沉积过程中,Ni基带的氧化不可避免,但其氧化物也有良好的取向.     

氧化法结合快速热处理制备VOx薄膜及其性质研究

采用磁控溅射法在单晶Si〈100〉基底上沉积金属钒(V)薄膜,在高纯氧环境下快速热处理制备具有相变特性的氧化钒(VOx)薄膜.利用X射线衍射仪、X射线光电子能谱和扫描电子显微镜对薄膜结晶结构、薄膜中V的价态与组分及表面微观形貌进行分析,应用四探针测试方法和太赫兹时域频谱技术对样品的电学和光学特性进行测试.结果表明:在一定范围的快速热处理保温温度和保温时间下,都可以制备出具有热致相变特性的氧化钒薄膜,相变前后薄膜的方块电阻变化超过两个数量级,薄膜成分主要由V2O5和VO2混合组成,薄膜中V整体价态不因热处理条件改变而不同.在快速热处理条件范围内,500℃ 25 s左右条件下(中温区)制备出的氧化钒薄膜相变特性最佳,并且对THz波有一定的调制作用.     

Tl-2212超导薄膜的制备

以铝酸镧晶体为基片,采用两步法制备Tl-2212超导薄膜,包括在低温(150℃)下利用激光脉冲沉积(PLD)工艺沉淀Ba2CaCu2Ox非晶前驱体薄膜和在高温(740～830℃)下前驱体薄膜的铊化结晶、取向生长过程.实验结果表明所制得的膜的相组成为Tl-2212,表面存在大量均匀分布的成分为Tl2Ba2CaCu2Ox的亚微米颗粒.其零电阻温度为101K.薄膜与基片之间界面清晰,没有过渡层,薄膜具有良好的c取向外延条纹.     

ZnO薄膜的性质对水热生长ZnO纳米线阵列的影响

用水热法在ZnO薄膜上制备了直径、密度及取向可控的ZnO纳米线阵列。ZnO薄膜是通过原子层沉积(ALD)方法制备并在不同温度下退火处理得到的,退火温度对ZnO薄膜的晶粒尺寸、结晶质量和缺陷性质有很大的影响。而ZnO薄膜的性质对随后生长的ZnO纳米线的直径、密度及取向能起到调节控制的作用。通过扫描电子显微镜(SEM)、X射线衍射(XRD)仪和光致发光(PL)测试对ZnO薄膜和ZnO纳米线进行了表征。最后得到的垂直取向的ZnO纳米线阵列适合在发光二极管和太阳能电池等领域使用。     

VO$lt;sub$gt;2$lt;/sub$gt;/AZO复合薄膜的制备及其光电特性研究

采用直流磁控溅射和后退火氧化的方法在掺铝氧化锌(AZO)导电玻璃上制备了二氧化钒(VO₂)薄膜,研究了不同的退火温度、退火时间对VO₂/AZO复合薄膜制备的影响,并对复合薄膜的结构、组分、光电特性进行了测试与分析. 结果表明,导电玻璃上的AZO没有改变VO₂的取向生长,但明显改变了VO₂薄膜的表面形貌特征. 与用相同工艺和条件在普通玻璃基底上制备的VO₂薄膜相比,VO₂/AZO复合薄膜的相变温度降低约25 ℃,热滞回线宽度收窄至6 ℃,相变前后可见光透过率均在50%以上,1500 nm处红外透过率约为55%和21%,电阻率变化达3 个数量级. 该复合薄膜表面平滑致密,制备工艺简单,性能稳定,可应用于新型光电器件. 关键词： 2')" href="#">VO₂ AZO 热致相变 光电特性     

表面氧化外延法中温制备涂层导体NiO种子层

高温超导涂层导体是解决当今能源危机的重要复合材料之一,而经济、有效、节能的制备技术是涂层导体广泛应用的关键.本文采用表面氧化外延法在Ni-wt.5%W基带上普氩下中温氧化制备了立方织构的NiO种子层.通过对氧化温度和氧化时间两个主要因素分析,确定了NiO生长条件为普氩中790℃内保温20mins。与高温(空气中1000℃以上)制备相比,降低了氧化膜制备温度.薄膜厚度大约为650nm.最后在生成的NiO薄膜上化学溶液沉积了YBa2Cu3O7-δ/SmBiO_3复合层,所得样品超导转变温度为89 K,77 K自场下临界电流密度为1.46 MA/cm2(77K,零场).中温表面氧化外延法为涂层导体制备提供了一种实用可行路径.     

蓝宝石衬底上射频溅射法生长CeO2外延薄膜研究

实验采用射频溅射法在(1 102)蓝宝石基片上制备(00l)取向CeO2外延薄膜.低温、低溅射功率都会导致CeO2薄膜呈(111)取向生长.当基片温度在700℃～750℃,溅射功率在100～150W范围内能够制备得到高质量(00l)取向CeO2缓冲层.所制备的CeO2薄膜具有优良的面内面外取向性和平整的表面.用这些缓冲层作为生长面制备得到的YBa2Cu3O7-δ(YBCO)超导薄膜为完全(00l)取向,且面内取向性良好,并具有优越的电学性能:其临界转变温度(Tc)为89.5K,临界电流密度Jc(77K,0T)约1.8×106 A/cm2,微波表面电阻Rs(77K,10GHz)大约为0.50mΩ,能较好的满足微波器件应用中的需要.     

高温热处理气氛对低氟MOD法制备YBCO超导薄膜的影响研究

金属有机物沉积法(MOD)制备YBa2Cu3O7-x(YBCO)涂层导体是最具有商业前景的方法之一.本文使用环烷酸铜代替三氟乙酸铜,降低了前驱液中大约50%的氟含量.然后在带有缓冲层(Y2O3/YSZ/CeO2)的Ni-5at.%W基带上采用MOD法制备了YBCO薄膜并系统研究了高温热处理过程中气体流速和氧分压对YBC...     

Improved initial epitaxial growth of superconducting YBa2Cu3O7 thin films on Y–ZrO2 substrates with a La1.85Sr0.15CuO4 buffer layer

Epitaxial thin films of YBa₂Cu₃O₇ (YBCO) have been deposited on Y–ZrO₂ (YSZ) substrates by means of the pulse laser deposition technique. It has been found that the initial epitaxy of YBCO thin films grown on YSZ can be significantly improved by using La_1.85Sr_0.15CuO₄ (LSCO) as a buffer layer. X-ray diffraction measurements show that the epitaxial YBCO films have single in-plane orientation with YBCO [100]LSCO [100] and LSCO [100]YSZ [110]. The real-time resistance measurements reveal that with LSCO buffer layers the initial formation of the YBCO ultra-thin films changes from the island growth to the layer-by-layer growth.     

离轴生长的MgB_2超导薄膜的研究

通过混合物理化学沉积法(hybrid physical-chemical vapor deposition,简称为HPCVD),我们在多种单晶衬底上制备出了MgB2超导薄膜.经测量发现MgB2薄膜在6H-SiC、c-Al2O3、MgO(111)和YSZ(111)衬底上基本是沿c轴外延生长的,形成单晶薄膜;在MgO(211)、MgO(100)和钇稳定氧化锆(YSZ)(110)衬底上,MgB2晶粒的生长表现出明显的择优取向生长方式,并与晶格常数匹配关系所预言的结果一致。     

Thickness-dependent orientation evolution in nickel thin films grown on yttria-stabilized zirconia single crystals

Microstructure evolution along with crystallographic orientation change as a function of film thickness was investigated in Ni thin films grown on (100) yttria-stabilized zirconia (YSZ) single crystal substrates. Texture development with two different orientation relationships, OR1: Ni {111}//YSZ {100} and OR2: Ni {100}//YSZ {100}, cube on cube orientation were identified by X-ray diffraction and transmission electron microscopy depending on the film thickness. The observed orientation transition reveals the existence of a critical thickness (～320?nm) favoring two different orientations in sputtered Ni films on YSZ (100) substrate.     

Deposition of highly oriented Bi12SiO20 thin films on Y-stabilized zirconia and SiO2 by pulsed-laser deposition

We describe the deposition and characterization of Bi₁₂SiO₂₀ (bismuth silicon oxide; BSO) thin films on Y-stabilized zirconia (YSZ) and SiO₂ glass substrates by pulsed-laser deposition (PLD) for the application of an electric field sensor. It was found that all films deposited on YSZ substrates heated at 400 °C and more were crystallized and the (310) plane was perpendicular to the substrate normal. The highly (310) oriented crystallized films were even deposited on SiO₂ glass substrates, and this will make it possible to grow the crystallized films on the end surface of a SiO₂ glass fiber.     

Influences of Y2O3 dopant content on residual stress,structure, and optical properties of ZrO2 thin films

Four kinds of Y2O3 stabilized ZrO2 （YSZ） thin films with different Y2O3 contents （from 0 to 12 mol%） are deposited on BK7 glass substrates by electron-beam evaporation method. The effects of different Y2O3 dopant contents on residual stress, structure, and optical properties of ZrO2 thin films are investigated. The results show that residual stress in YSZ thin films varies from tensile to compressive with the increase of Y2O3 molar content. The addition of Y2O3 is beneficial to the crystallization of YSZ thin film and transformation from amorphous to high temperature phase, and the refractive index decreases with the increase of Y2O3 molar content. Moreover, the variations of residual stress and the shifts of refractive index correspond to the evolution of structures induced by the addition of Y2O3.     

Epitaxial growth of yttria-stabilised zirconia buffer layers on X-cut LiNbO3 for superconducting electrodes

We report on the epitaxial growth of yttria-stabilised zirconia (YSZ) buffer layers on X-cut LiNbO₃ (LNO) single crystals by pulsed laser deposition. Despite the low chemical stability of the substrates at high temperature, high quality fully reproducible films were obtained over a relatively broad range of processing conditions. The films were (00h) out-of-plane single oriented and the in-plane edge of the YSZ unit cell was aligned with the polar axis of the LNO. However, the YSZ deposition also promoted the formation of the compound LiNb₃O₈. This compound is epitaxial and located at the interface. The homogeneous YSZ film presents a uniform surface, free of outgrowths and with a low roughness. These characteristics are suitable for the epitaxial growth of other oxides, as has been demonstrated with the preparation of YBa₂Cu₃O₇/CeO₂/YSZ/LNO heterostructures. The superconducting YBa₂Cu₃O₇ films were epitaxial, with the c axis perpendicular to the surface and single in-plane orientation, and presented good transport properties (critical temperatures around 86 K and critical current densities close to 10⁶ A/cm² at 77 K). Received: 5 April 2001 / Accepted: 30 July 2001 / Published online: 30 October 2001     

La1-xNaxMnO3/YSZ膜的化学溶液法制备及输运性能研究

本文采用化学溶液法在钇稳定的二氧化锆(Y-stabilized ZrO2,YSZ)单晶基板上制备了La1-xNaxMnO3(LNMO)膜并对其输运性能进行了研究.X-射线衍射(XRD)结果表明,所获得的LNMO膜为高度(h00)取向;输运结果表明,所制备的LNMO膜表现为外延膜的性能,且La0.7Na0.3MnO3薄膜在300K、0.5T磁场下可获得～5%磁阻值.     

Microstructure and surface morphology of YSZ thin films deposited by e-beam technique

In present study yttrium-stabilized zirconia (YSZ) thin films were deposited on optical quartz (amorphous SiO₂), porous Ni-YSZ and crystalline Alloy 600 (Fe-Ni-Cr) substrates using e-beam deposition technique and controlling technological parameters: substrate temperature and electron gun power which influence thin-film deposition mechanism. X-ray diffraction, scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used to investigate how thin-film structure and surface morphology depend on these parameters. It was found that the crystallite size, roughness and growth mechanism of YSZ thin films are influenced by electron gun power. To clarify the experimental results, YSZ thin-film formation as well evolution of surface roughness at its initial growing stages were analyzed. The evolution of surface roughness could be explained by the processes of surface mobility of adatoms and coalescence of islands. The analysis of these experimental results explain that surface roughness dependence on substrate temperature and electron gun power non-monotonous which could result from diffusivity of adatoms and the amount of atomic clusters in the gas stream of evaporated material.     

Y2O3 stabilized ZrO2 thin films deposited by electron beam evaporation: Structural, morphological characterization and laser induced damage threshold

Four kinds of Y₂O₃ stabilized ZrO₂ (YSZ) thin films with different Y₂O₃ content have been prepared on BK7 substrates by electron-beam evaporation method. Structural properties and surface morphology of thin films were investigated by X-ray diffraction (XRD) spectra and scanning probe microscope. Laser induced damage threshold (LIDT) was determined. It was found that crystalline phase and microstructure of YSZ thin films was dependent on Y₂O₃ molar content. YSZ thin films changed from monoclinic phase to high temperature phase (tetragonal and cubic) with the increase of Y₂O₃ content. The LIDT of stabilized thin film is more than that of unstabilized thin films. The reason is that ZrO₂ material undergoes phase transition during the course of e-beam evaporation resulting in more numbers of defects compared to that of YSZ thin films. These defects act as absorptive center and the original breakdown points.