电子束蒸发TiO2薄膜的光学特性

研究了不同工艺参数条件下，电子束蒸发TiO2薄膜的光学特性。在正交实验的基础上，利用离子束辅助沉积技术，获得了影响TiO2薄膜折射率的主要因素．得到了TiO2薄膜的折射率随氧气分压的关系。对离子氧和分子氧两种情况下TiO2薄膜的折射率进行了比较．得到了TiO2薄膜的折射率与沉积速度的关系，并给出了TiO2薄膜的红外吸收光谱。     

TiO2薄膜光学性质的研究

以磁控溅射制备的TiO2薄膜为样品,通过对薄膜折射率、吸收系数、膜厚度与入射光波长相互关系的分析。获得了TiO2薄膜的折射率、吸收系数与入射光波长的关系式。以及TiO2薄膜厚度的计算公式．     

离子束反应溅射沉积SiO2薄膜的光学特性

 主要研究采用离子束反应溅射（RIBS）制备SiO2薄膜的折射率、消光系数、化学计量比与氧气在氩氧混合工作气体中含量及其沉积速率的关系。研究结果表明：RIBS制备的SiO2薄膜在0.63 μm处折射率n= 1.48,消光系数小于10-5;随着沉积速率的增加,薄膜的折射率和消光系数随之变大,当沉积速率超过0.3 nm/s,即使是在纯氧环境溅射,折射率值也不低于1.5;通过对红外透射光谱的主吸收峰位置研究得到沉积的SiO2薄膜为缺氧型,化学计量比不超过1.8,且红外吸收峰位置和SiO2折射率存在对应关系,因此在不加热衬底情况下使用RIBS制备SiO2薄膜时,会限制沉积速率的提高。     

温度条件对反应电子束蒸发制备TiO2薄膜结构和性能的影响

研究基片温度(120～300 ℃)和热处理温度(400℃)对电子束蒸发TiO₂薄膜的结构和光学性能的影响.XRD分析表明,在120 ℃, 200 ℃和300 ℃的普通玻璃基片上采用电子枪加热蒸发制备的TiO₂薄膜具有非晶态结构,沉积态薄膜经过400 ℃保温1 h的热处理后得到的相为具有(004)取向的锐钛矿相,晶粒大小在3.6～8.1 nm之间.透射谱分析表明,薄膜的折射率随着基片温度的升高而增加;热处理后,薄膜的折射率也相应提高,其原因来自于薄膜的晶化.     

紫外光辐照对TiO2薄膜光学性能的影响

 采用电子束热蒸发技术在不同工艺下制备了TiO2薄膜,利用椭偏仪和分光光度计研究了紫外光辐照后薄膜光学特性的变化。实验结果表明：不同工艺下制备的TiO2薄膜经相同条件的紫外光辐照后,其折射率均有所下降,折射率的变化量随着沉积速率上升、基底温度上升、工作真空度下降分别有增大的趋势。薄膜的透射率在紫外光辐照后有一定下降。相同工艺条件下制备的TiO2薄膜,其折射率随着辐照时间的增加,先迅速降低,随后又有所增加,但均低于辐照前薄膜的折射率。     

纳米BST薄膜的制备及其折射率特性.

" 采用射频磁控溅射法在石英衬底上沉积了纳米BST(Ba0:65Sr0:35TiO3)薄膜．为了制备优质的BST薄膜,借助X射线衍射仪、场发射扫描电镜和原子力显微镜研究了BST薄膜的晶化行为和显微结构．结果显示在衬底温度600 ℃下制备的BST薄膜经700 ℃退火处理后,具有较强的特征衍射峰和极好的晶化．同时还研究了纳米BST薄膜的制备参数和特性,BST薄膜的折射率是由测量的透射谱中获得的．实验结果表明：纳米BST薄膜的沉积参数对其折射率特性的影响是不尽相同的．折射率随着衬底温度的上升而增加;在较低的溅射     

TiO2纳米薄膜微观结构及光学性能研究

用sol-gel法制备了纳米TiO₂薄膜,用原子力显微镜(AFM)观察了薄膜的表面形貌,测量了薄膜的表面粗糙度(RMS)为2.832 nm;用红外光谱(IR)研究了TiO₂薄膜前驱体溶胶的组成; 探讨了TiO₂薄膜的焙烧温度、层数等制备条件对TiO2光催化活性的影响,结果发现在490℃,8层膜的TiO₂活性最高.     

Zr掺杂TiO_2薄膜的光学性能和光催化性能

为了研究TiO2禁带宽度和光吸收系数对其光催化性能的影响,利用电子束沉积方法在玻璃基底上制备了TiO2薄膜及Zr掺杂TiO2薄膜。采用拉曼光谱仪和分光光度计对膜的结构和吸收光谱进行了表征。研究结果表明:当退火温度为773K时,沉积得到的TiO2薄膜为锐钛矿结构薄膜;掺杂使TiO2禁带宽度变窄,吸收波长红移,在350~450nm附近光吸收系数增大,增强了TiO2的光催化活性。     

磁控反应溅射法制备渐变折射率薄膜的模型分析

阐述了磁控反应溅射法制备渐变折射率薄膜的机理;探讨了磁控反应溅射法制备渐变折射率薄膜的理论模型,给出了渐变折射率薄膜的折射率与反应气体分压的关系,在一定的沉积参数下,由要得到的膜层折射率随膜层几何厚度的变化规律可推导出反应气体分压比随时间的变化规律;最后以制备折射率线性变化的薄膜为例说明了如何推导得到反应气体分压比随时间的变化规律. 关键词： 渐变折射率 磁控反应溅射 模型     

斜角入射沉积法制备渐变折射率薄膜的折射率分析

斜角入射沉积法是一种制备薄膜的新颖方法,它可以用来制备渐变折射率薄膜.本文首先探讨了膜料的沉积入射角为α,薄膜柱状生长倾斜角为β时的薄膜的填充系数;之后利用drude理论,分析研究了斜角入射沉积法制备渐变折射率薄膜的折射率与薄膜的入射角和生长方向的关系. 关键词： 斜角入射沉积 渐变折射率 填充系数     

Influence of Annealing Temperature on Structure, Optical Loss and Laser-Induced Damage Threshold of TiO2 Thin Films

TiO2 thin films are prepared on fused silica with conventional electron beam evaporation deposition. After annealed at different temperatures for 4h, the spectra and XRD patterns of the TiO2 thin film are obtained. Weak absorption of coatings is measured by the surface thermal lensing technique, and laser-induced damage threshold （LIDT） is determined. It is found that with the increasing annealing temperature, the transmittance of TiO2 films decreases. Especially when coatings are annealed at high temperature over 1173K, the optical loss is very serious. Weak absorption detection indicates that the absorption of coatings decreases firstly and then increases, and the absorption and defects play major roles in the LIDT of TiO2 thin films.     

Ion beam sputter deposition of TiO<Subscript>2</Subscript> films using oxygen ions

TiO₂ thin films were grown by ion beam sputter deposition (IBSD) using oxygen ions, with the ion energy and geometrical parameters (ion incidence angle, polar emission angle, and scattering angle) being varied systematically. Metallic Ti and ceramic TiO₂ served as target materials. The thin films were characterized concerning thickness, growth rate, surface topography, structural properties, mass density, and optical properties. It was found that the scattering geometry has the main impact on the film properties. Target material, ion energy, and ion incidence angle have only a marginal influence. Former studies on reactive IBSD of TiO₂ using Ar and Xe ions reported equivalent patterns. Nevertheless, the respective ion species distinctively affects the film properties. For instance, mass density and the refractive index of the TiO₂ thin films are remarkably lower for sputtering with oxygen ions than for sputtering with Ar or Xe ions. The variations in the thin film properties are tentatively attributed to the angular and the energy distribution of the film-forming particles, especially, to those of the backscattered primary particles.     

The effect of oxygen rf discharge on pulsed laser deposition of oxide films

In this work final results on TiO₂ film deposition by Plasma Assisted Pulsed Laser Deposition (PAPLD) with an rf biased substrate are presented. In previous work it has been shown that PAPLD is an improvement over conventional PLD for the elimination of particulates in high refractive index thin film deposition. This paper will give a comparison between conventional PLD and PAPLD on the stoichiometry, morphology, and optical properties of deposited TiO₂ films. It will be demonstrated that oxygen rf discharge during the PLD process makes incorporation of oxygen into the depositing films extremely effective. This effect of the rf discharge allows operation of the PLD process at a lower oxygen background pressure while enhancing the deposition rate. Also, the production of a good quality TiO₂ film by PAPLD using a pure metal titanium target will be shown. PACS 79.20.Ds; 52.80.Pi     

Structural and electrical properties of La0.5Sr0.5CoO3 films on SrTiO3 and porous a-Al2O3 substrates

Films of La_0.5Sr_0.5CoO₃ (LSCO) have been deposited on specially treated TiO₂-terminated (001) SrTiO₃ substrate surfaces and on macroporous polycrystalline !-Al₂O₃ substrates, having a mean pore diameter of 80 nm, by pulsed laser deposition. The films deposited on SrTiO₃ are good conducting, (001) textured, and exceptionally smooth (1-2 Å for 100 nm thick films). LSCO films deposited on porous !-Al₂O₃ are polycrystalline and exhibit good crystallographic and electrical properties despite the large substrate roughness and the differences in lattice parameters and crystal structure between the film and the substrate. Different growth modes have been observed on the porous !-Al₂O₃ substrates depending on the oxygen pressure during film deposition. Films grown at an oxygen pressure of 10^-1 mbar are macroporous, whereas films grown at 10^-2 mbar completely cover the substrate pores. In the latter case, strain effects lead to film cracking.     

LaNiO3 under-electrode layers for the growth of textured (Pb0.4Zr0.6)TiO3 thin films using pulsed laser deposition

We investigated the structural properties of LaNiO₃ thin films of three different thicknesses deposited by pulsed laser deposition on Si(001) mainly by using a synchrotron X-ray scattering measurement. The LaNiO₃ thin films were grown with the (00l) preferred growth direction, showing completely random distribution in the in-plane direction. In the early stage of the growth, the film was almost unstrained. However, as the film grew further, tensile strain was markedly involved. Also its surface became rougher but its crystalline quality improved significantly with increasing film thickness. A completely (00l)-oriented (Pb_0.4Zr_0.6)TiO₃ thin film was successfully grown on such a LaNiO₃/Si(001) substrate at a substrate temperature of 350 °C by using the same pulsed laser deposition. Our results show that the LaNiO₃ film can serve effectively as a bottom electrode layer for the preparation of a well-oriented (Pb_0.4Zr_0.6)TiO₃ thin film on Si substrates.     

Investigation on properties of TiO2 thin films deposited at different oxygen pressures

TiO₂ thin films were prepared by electron beam evaporation at different oxygen partial pressures. The influences of oxygen partial pressure on optical, mechanical and structural properties of TiO₂ thin films were studied. The results showed that with the increase of oxygen partial pressure, the optical transmittance gradually increased, the transmittance edge gradually shifted to short wavelength, and the corresponding refractive index decreased. The residual stresses of all samples were tensile, and the value increased as oxygen partial pressure increasing, which corresponded to the evolutions of the packing densities. The structures of TiO₂ thin films all were amorphous because deposition particles did not possess enough energy to crystallize.     

The effect of different ambient gases, pressures, and substrate temperatures on TiO2 thin films grown on Si(100) by laser ablation technique

Pure titanium dioxide (TiO₂) thin films were deposited on single-crystal Si(100) substrates by laser ablation. We investigated the effects of ambient gas (O₂ or Ar), pressures, and substrate temperatures on film quality. From the annealing experiment of the deposited TiO₂ thin film under Ar or O₂ ambient gas, we see the chemical effect of ambient gas on film quality. The crystallinity of the deposited TiO₂ thin film is best at 700 °C in the substrate temperature range attempted, 400-700 °C, and at pressures of 0.1 Torr and below. The rutile phase is dominant under most experimental conditions. Only under very extreme conditions did we obtain a thin film of the anatase phase.     

Electrically and magnetically tunable microwave device using (Ba, Sr) TiO3/Y3Fe5O12 multilayer

Ferroelectric (Ba_0.6Sr_0.4)TiO₃ (BST) thin films have been deposited by pulsed laser deposition onto single-crystal Y₃Fe₅O₁₂ (YIG) substrates with/without a MgO buffer layer. The structure and microwave properties of the BST films have been investigated as a function of substrate orientation and O₂ deposition pressures (50-800 mTorr). The crystallographic orientation of BST film varies with the deposition conditions. The dielectric properties of the ferroelectric were measured using interdigitated capacitors deposited on top of the BST film. BST films exhibit high tunability (20-40%) and high dielectric Q=1/cos' (30-50) with a dc bias field of 67 kV/cm at 10 GHz. A coplanar waveguide transmission line was fabricated from a (001)-oriented BST film on (111)YIG which exhibited a 17° differential phase shift with an applied dc bias field of 21 kV/cm (10 GHz). An equivalent differential phase shift was achieved with a magnetic field of 160 Gauss.     

A Spectroscopic Ellipsometry Study of TiO2 Thin Films Prepared by dc Reactive Magnetron Sputtering： Annealing Temperature Effect

TiO2 thin films are obtained by dc reactive magnetron sputtering. A target of titanium （99.995%） and a mixture of argon and oxygen gases are used to deposit TiO2 films on to silicon wafers （100）. The crystalline structure of deposited and annealed film are deduced by variable-angle spectroscopic ellipsometry （VASE） and supported by x-ray diffractometry. The optical properties of the films are examined by VASE. Measurements of ellipsometry are performed in the spectral range O. 72-3.55 e V at incident angle 75^o. Several SE models, categorized by physical and optical models, are proposed based on the ＇simpler better＇ rule and curve-fits, which are generated and compared to the experimental data using the regression analysis. It has been found that the triple-layer physical model together with the Cody-Lorentz dispersion model offer the most convincing result. The as-deposited films are found to be inhomogeneous and amorphous, whereas the annealed films present the phase transition to anatase and rutile structures. The refractive index of TiO2 thin films increases with annealing temperature. A more detailed analysis further reveals that thickness of the top sub-layer increases, whereas the region of the bottom amorphous sub-layer shrinks when the films are annealed at 300℃.