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首页> 外文学位 >The structure of sputter-deposited aluminum trioxide-titanium dioxide nanolaminate films and its effect on film behavior.
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The structure of sputter-deposited aluminum trioxide-titanium dioxide nanolaminate films and its effect on film behavior.

机译：溅射沉积的三氧化二铝-二氧化钛纳米层合膜的结构及其对膜行为的影响。

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摘要

The subject of this thesis is the fabrication, structure and optical behavior of Al2O3-TiO2 nanolaminate thin films. Al2O3-TiO2 nanocomposites are of current interest for optical, catalytic, and sensor applications. Five nanolaminate architectures were grown on unheated substrates by sequential reactive sputter deposition of metal targets using Ar-20% O2 radio frequency-excited discharges. For comparison purposes, single layers of TiO2 and Al2O3 were grown under the same deposition conditions used to grow the nanolaminates. TiO2 layer thickness was varied from 2 to 72 nm while Al2O3 layer thickness was kept constant at 7 nm in the nanolaminates. X-ray diffraction, Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and spectrophotometry were used for film analysis. The films were sequentially annealed at 700°C and 1000°C. The x-ray diffraction and Raman spectroscopy results showed that the as-deposited nanolaminates have rutile long range and short range order. No anatase was present, nor was anatase formed by annealing. Al2O3 was amorphous in the as-deposited and annealed films. No significant changes were observed in the nanolaminates annealed at 700°C. Annealing at 1000°C caused significant amorphous to crystalline transitions in the nanolaminates. We proposed that beta-Al2TiO 5 phase crystallized from an (Al, Ti)-oxide that formed at bilayer interfaces. The beta-Al2TiO5 phase decomposed into alpha-Al 2O3 and rutile TiO2 in nanolaminates N1, N2, and N3 and retained in N4 and N5. Another scenario was proposed to account for the shift in the XRD peaks of the (Al, Ti)-oxide phase to a lower angle and for the strong XRD peaks from a mixed cation crystalline oxide in Ti-rich nanolaminates. The second scenario suggested phase separation or even a solid solution has occurred in nanolaminates N1, N2, and N3, and a pseudobrookite with a structure isomorphous with Ti3O5 crystallizes at the interfaces of N4 and N5. The optical absorption edge was shifted to lower energy with increasing the TiO2 layer thickness in the asdeposited nanolaminates and after annealing at 700°C. Optical transmission spectra changed slightly after annealing at 700°C. However, spectra for nanolaminates annealed at 1000°C showed a significant decrease in transmission maxima and the optical edge was shifted to a lower energy.
机译：本文的主题是Al2O3-TiO2纳米层压薄膜的制备，结构和光学性能。 Al2O3-TiO2纳米复合材料目前在光学，催化和传感器应用中受到关注。通过使用Ar-20％O2射频激励放电对金属靶进行顺序反应性溅射沉积，在未加热的基板上生长了五种纳米层状结构。为了进行比较，在与用于生长纳米层压材料的相同沉积条件下生长了TiO2和Al2O3的单层。 TiO 2层的厚度在2到72 nm之间变化，而Al2O3层的厚度在纳米层压板中保持恒定在7 nm。 X射线衍射，拉曼光谱，透射电子显微镜（TEM），扫描电子显微镜（SEM）和分光光度法用于膜分析。将膜依次在700℃和1000℃下退火。 X射线衍射和拉曼光谱结果表明，沉积的纳米层合物具有金红石的长程和短程有序。不存在锐钛矿，也不通过退火形成锐钛矿。 Al2O3在沉积和退火后的薄膜中为非晶态。在700°C退火的纳米层压板中未观察到明显变化。在1000°C下退火会在纳米层压板中引起明显的无定形到晶体的转变。我们建议β-Al2TiO5相从在双层界面处形成的（Al，Ti）-氧化物结晶。 β-Al2TiO5相在纳米层压板N1，N2和N3中分解为α-Al2O3和金红石TiO2，并保留在N4和N5中。提出了另一种情况以说明（Al，Ti）-氧化物相的XRD峰向较低角度的移动以及富Ti纳米层合物中混合阳离子晶体氧化物产生的强XRD峰。第二种情况表明在纳米层压板N1，N2和N3中发生了相分离甚至发生固溶，结构与Ti3O5同构的假板钛矿在N4和N5的界面上结晶。随着所沉积的纳米层压板中TiO2层厚度的增加以及在700°C退火后，光吸收边缘向较低能量转移。在700°C退火后，光学透射光谱略有变化。但是，在1000°C退火的纳米层压板的光谱显示出透射最大值显着降低，并且光学边缘移到了较低的能量。

著录项

  • 作者

    Omari, Mohammad.;

  • 作者单位

    The University of Wisconsin - Milwaukee.;

  • 授予单位 The University of Wisconsin - Milwaukee.;
  • 学科 Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2005
  • 页码 117 p.
  • 总页数 117
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

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