热致变色VO2薄膜的制备及光学性能研究

利用等离子体发射光谱监测系统(PEM)控制钒的等离子强度,在石英基底上磁控溅射制备了VO2薄膜。采用XRD、XPS、SEM、紫外-可见-近红外分光光度计及傅立叶红外分光光度计研究薄膜的结构、光学及相变特性。结果表明,所制备的VO2薄膜具有(011)取向,VO2薄膜的热滞回线宽度为25℃,可见光透过率和太阳光调节率分别可达Tlum,l=34.1%、Tlum,h=35.3%和ΔTsol=6.8%,相变前后,红外光区的反射率变化最大值可达44.4%。     

Preparation and optical properties of phase-change VO2 thin films

In this work, VO₂ thin films were prepared on three kinds of substrates by the sol-gel dipcoating method followed by heat treatment under vacuum. These thin films were analysed by x-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. The infrared and ultraviolet-visible spectra of the VO₂ thin films were also recorded during heating and cooling between room temperature and 100°C. The experimental results show that VO₂ thin films thus prepared exhibit thermally induced reversible phase transition, and the largest changes in transmittance and reflectivity are approximately 58 and 25%, respectively, in the case of vacuum heat treatment at 400°C and silica glass substrates. The refractive index (n) decreases and the absorption coefficient (k) increases when heating these thin films from room temperature to 100°C, and vice versa for cooling. The reasons why the optical constants and infrared absorption spectra change so remarkably are discussed.     

Preparation of V2O5 thin film and its optical characteristics

A two-step method was proposed to synthesize V₂O₅ films on planar substrates, i.e., depositing a V₂O₃ thin film at ∼160°C (by heating a pure sheet of vanadium in a rough vacuum) and then heat-treating it in air at ∼600°C. The films, made up of nano crystal particles, had good photoluminescence (PL) properties, and the peak was in the position of about 700 nm. Further, photosensitivity characteristics of these V₂O₅ thin films were investigated at room temperature. The results show that this film is sensitive to ultraviolet rays, which indicates good potential application for an ultraviolet photo detector (UVPD).     

Application of novel azo metal thin film in optical recording

The absorption spectrum of spin-coated azo metal thin film showed a comparatively large absorption band in the wavelength region (500–600 nm), which matched with the wavelength of the GaAlInP semiconductor diode laser (630–650 nm). The optical recording performance of the film was investigated.     

二氧化钒超薄纳米片的制备及其光学性能研究

采用V2O5作为钒源,以乙二醇(EG))为还原剂,在190℃的条件下,通过简单的水热途径制备出了VO2 (B)超薄纳米片晶.并利用X射线衍射(XRD)、扫描电镜(SEM)、荧光分光光度计(PL)对样品的结构、形貌及荧光性能进行表征.研究结果表明:以乙二醇(EG)为还原剂制备出的晶体为纳米VO2 (B),长180～350...     

Transverse recording using thin film recording heads

This paper presents the results of an investigation of a high density magnetic recording technique utilizing a thin film recording head and a transverse mode of recording on thin media. The significant results of this investigation are as follows. 1) Densities as high as 18 500 transitions per inch were experimentally written in a 300-Å thick FeCr medium having an Hcof 70 oersteds. 2) These densities were written with a thin film, vapor-deposited, recording head having a MATED-FILM® structure with a 0.4-mil etched gap. 3) Track widths of 1-mil on 2-mil centers were experimentally achieved. 4) Optical readout of a 0.2-mil wide transition (width of beam) region corresponding to 5000 transitions per inch was achieved using a laser beam and a linear motion transport system under ideal experimental conditions. 5) The magnetic field from the Néel wall separating recording domains was detected using a MATED-FILM Etched Gap head making this a possible readout method. Maximum achieved linear bit densities as a function of recording media coercivities are given.     

Phase transformation and optical characteristics of porous germanium thin film

In this study, we proposed a method to prepare GeO₂ by treating porous Ge thin film with thermal annealing in O₂ ambient. After annealing, the morphological transformation from porous thin film to an island structure was observed. The crystallization and composition of the porous Ge thin film prepared using different annealing time in O₂ ambient were confirmed by X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectra. Initial Ge composition was gradually oxidized to GeO₂ with increasing annealing time. Comparing the photoluminescence (PL) results between Ge and GeO₂, it was found that the visible photoluminescence originated from the germanium oxide. Photoluminescence measurements obtained at different temperatures exhibited a maximum integrated PL intensity at around 200 K. A possible explanation for this behavior might be the competition between radiative recombination and nonradiative hopping process.     

Preparation of plasma poly(1-isoquinolinecarbonitrile) thin film and its ultrafast nonlinear optical property

How to get a uniform, defect-free, and reproducible conjugated polymer thin films is now becoming the main fabrication problem for the practical application of these materials as the fast switches and modulators in opto-electronic devices. In this research, a novel plasma-polymerized 1-isoquinolinecarbonitrile (PPIQCN) thin film was prepared by plasma polymerization under different glow discharge conditions. The effect of the discharge power on the chemical structure and surface compositions of the deposited PPIQCN films was investigated by Fourier transform infrared (FTIR), UV-Visible absorption spectra and X-ray photoelectron spectroscopy (XPS). The results show that a high retention of the aromatic ring structure of the starting monomer in the deposited plasma films is obtained when a low discharge power of 10 W was used during film formation. In the case of higher discharge power of 30 W, more severe monomer molecular fragmentation can be observed, which results in a decrease in the effective conjugation length of PPIQCN film. The morphology characterized by atomic force microscopy (AFM) indicates that a fine, homogenous PPIQCN film could be obtained under a relatively low discharge power. A femtosecond time-resolved optical Kerr effect technique at a wavelength of 820 nm has been applied to investigate the third-order nonlinearity of the plasma PPIQCN film. For the first time, a non-resonant optical Kerr effect and ultrafast response of the PPIQCN film was observed.     

化学水浴法制备ZnS薄膜及其光学性能

以酒石酸与柠檬酸钠为络合剂,采用化学水浴法(CBD)沉积ZnS薄膜.利用X射线衍射仪(XRD)、X射线能谱仪(EDAX)、扫描电镜(SEM)、紫外-可见分光光度计(UV-Vis)研究ZnS薄膜的结构、组成、形貌及光学性能,利用透射光谱计算ZnS薄膜的光学禁带宽度(Eg).结果表明:ZnS薄膜呈立方相晶体结构,经过300℃熟处理1h的ZnS薄膜原子比为Zn:S=1:0.85,表面均一致密,在可见光区的平均透射率达到80%,光学禁带宽度为3.74ev,适合作为太阳能电池过渡层.     

Thermally driven sign switch of static dielectric constant of VO2 thin film

Smart multifunctional materials exhibiting phase transition and tunable optical and/electrical properties provide a new direction towards engineering switchable devices. Specifically, the reversible, tunable and sign switch dielectric constants via external temperature stimuli observed in vanadium dioxide (VO₂) make it a candidate of choice for tunable and switchable technologies devices. Here we report new aspect of the metal-insulator transition (MIT) through the sign switch of the static dielectric constant ε_S of pure VO₂. As it is shown, the static dielectric constant showed an abrupt change from positive at T < 70 °C to negative at T > 70 °C. ε_S > 0 confirms the insulating phase where charges are localized while ε_S < 0 confirms the metallic phase of VO₂ where charges are delocalized. We report for the first time the tunability of the dielectric constant from a negative sign for the static dielectric constant of VO₂ thin film rarely found in real physical systems. We also demonstrate the tunability and switchability of the real and imaginary part of the dielectric constant (ε) via external temperature stimuli. More specifically, the real (ε) and Imaginary (ε) showed an abrupt thermal hysteresis which clearly confirms the phase transition.     

纳米TiO2薄膜的制备及其紫外光吸收性能的研究

采用sol-gel法制备TiO2薄膜。用XRD、AFM对其结构及表面形态进行了表征。用UV、SPS测试其光谱吸收、表面光伏特性。结果表明,在高软化温度ITO玻璃上得到比较好的锐钛矿型TiO2薄膜,且具有很强的紫外光吸收特性。随着烧结温度的升高,锐钛矿晶型更加趋于完整,使得紫外吸收曲线的带边蓝移。在紫外光照射下,所制得的薄膜有明显的光伏效应。较之粉体材料,吸收峰更趋向紫外区。为进一步研制新型紫外光传感器提供实验依据。     

相变光透射特性具有窗口结构的VO2薄膜

利用无机溶胶凝胶法制备出具有优良热致相变光学特性的VO2薄膜,通过改变制备过程中的条件,发现在一定的制备参数下,可得到光透射性具有窗口形状的热致相变薄膜,该类薄膜相变前后在600～850nm范围出现显著透光度窗口状态化现象。利用XRD、XPS对相变光学特性具有窗口结构的薄膜和具有典型相变特性的薄膜进行对比分析,结果显示利用无机溶胶-凝胶法得到的薄膜表面没有衬底离子出现,衬底扩散离子主要存在于薄膜和衬底界面之间。通过对引起相变过程中光透射窗口状变化的原因进行讨论,得到薄膜在相变过程中出现透射光谱窗口状的变化是来源于V^3 和衬底扩散离子Na^ 的共同作用。     

具有一定取向的TiO2薄膜的研究与制备

用浸渍法将P25粉末涂敷于溶胶-凝胶法制备的TiO2预制膜上,进行一系列的热处理,制备TiO2薄膜样品.用X射线衍射法对样品进行晶体结构分析,发现用这种方法可以得到具有一定取向的TiO2薄膜.其结晶程度和取向度与浸渍时间和热处理时间相关,在浸渍时间为10h、热处理温度为500℃时,得到沿(101)面方向取向生长的TiO2薄膜.     

FePt/B4C垂直磁记录介质薄膜的制备与表征

采用直流及射频磁控溅射结合真空退火的方法成功制备了（001）择优生长的FcPt/B4C多层薄膜并对其结构与磁性能做了初步的表征．结果表明，在每一个FbPt单元层中能得到较好（001）面择优的fet相FbPt合金，并且随着B4C含量的增大，薄膜的有序度提高．高分辨透射电子显微镜及其傅立叶变换表明，FePt层为具有（001）织构的fct相Fe55Pt45合金．样品的M-H曲线显示其垂直膜面方向矫顽力约为302.481kA/m；平行膜面方向矫顽力很小．     

ZAO薄膜的光电特性与应用前景

综述了ZAO透明导电薄膜的光电特性及其导电机理、制备技术与研究现状,认为ZAO薄膜在平板显示、太阳能电池和低辐射器件领域具有广泛的应用前景,要达到工业应用还需对一些关键问题进行系统的研究.     

CuInS2薄膜的制备及光学特性

真空共蒸发在玻璃衬底上制备CuInS2薄膜.研究不同Cu、In、S元素配比、不同热处理条件对薄膜的结构、化学计量比及光学性能的影响.实验结果给出:在元素配比中S的原子比x选择极为重要(实验选0.2≤x≤2),本实验Cu、In、S最佳原子比为1:0.1:1.2.用x(Cu).x(In):x(S)=1:0.1:1.2原子比...     

HfO2薄膜的制备与光学性能

采用射频磁控反应溅射法，以高纯热压HfO2陶瓷为靶材，在Si衬底上成功制备出HfO2薄膜。系统研究了工艺参数对薄膜沉积速率的影响规律，并对薄膜的光学性能进行了研究。结果表明，射频功率对薄膜沉积速率的影响最为明显，O2／Ar流量比和衬底温度对沉积速率的作用不明显，所制备薄膜的折射率较高在近红外波段趋于1．95，在500-1650nm波段范围内薄膜几乎无吸收，透过率较高。     

溶胶-凝胶法制备微纳米级LiCoO2的研究

采用溶胶-凝胶法,以LiNO3,Co(NO3)2和PAA为主要原料,研究制备LiCoO2薄膜过程中不同实验条件对晶体形成过程及形貌的影响.经偏光显微镜、扫描电镜、原子力显微镜对所形成的薄膜表面进行分析发现聚丙烯酸的含量、Li+离子和Co2+离子的总浓度和配比、烧焙温度及升温速度等均会对薄膜中的成分、纳米化的晶体的形成及表面形貌有着较大的影响.实验表明,最佳烧结温度在600℃左右时有利于LiCoO2晶体的形成.