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Properties of Closed-Shell Titanium Silicate and Gallium-Containing Semiconductor Systems.

机译：闭壳硅酸钛和含镓半导体系统的性能。

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摘要

We demonstrate that an atomic-scale approach may be appropriate for the analysis of the compositional and bonding properties of titanium silicate alloys and shallow d-core level reflectance spectra of gallium-compound semiconductors.;Ti silicate analysis was conducted using X-Ray Absorption Spectroscopy (XAS), X-Ray Photoemission Spectroscopy (XPS), and Spectroscopic Ellipsometry (SE) data taken on a range of Ti-silicate alloys. XAS data were obtained by the Lucovsky group at Stanford Synchrotron Radiation Laboratories (SSRL) at the Stanford Linear Accelerator Center (SLAC), and were used as the primary source of information. To bolster conclusions we solicited XPS data from the Opila Laboratory at the University of Delaware, which were provided by Les Fleming. We also took SE data on Ti silicate alloys annealed at different temperatures using two ellipsometers, one of which was built by the author specifically to probe energies in the vacuum uv range. Reflectance data from 20 to 25 eV, which contain spectral features due to transitions from Ga3d core levels, were obtained on GaP, GaAs, GaSb, GaSe, and GaPxAs1ƒ{x at the storage ring Tantalus 1 at the Stoughton Synchrotron Radiation Center by Aspnes and co-workers from about 1980 to 1982.;Ti L2,3 XAS data were fitted with reference spectra to obtain 4-fold coordination concentrations (in differing symmetries) and 6-fold coordination concentrations with respect to alloy composition and annealing. Analyzing the concentrations allowed us to draw conclusions on coordination with respect to alloy composition and annealing. We were able to model the 4-fold ¡§in solution¡¨ to 6-fold phase-segregated conversion as a stochastic process, and we found a complete conversion to 6-fold phase-segregated TiO 2 through annealing with at least 36% Ti and above. We attributed this phase segregation to a striation effect previously reported in the literature. XAS OK1 spectra corroborate these results. Investigation of the XPS Ti L 2,3 data verified the formal Ti valence in the Ti silicate alloys as +4. Through atomic-multiplet calculations, we show that because of Coulombic and spin orbit effects the final states of the Ti L2,3 spectra do not maintain any significant degeneracy, even in the absence of a crystal field. Dielectric functions from 1.5 to 9.0 eV, extracted from the SE data obtained on annealed Ti silicate alloys, verified that significant coordination change occurred between the annealing temperature of 500 and 700 °C.;A local atomic multiplet theory was applied to investigate the Ga3d shallow core-level spectra of GaP, GaAs, GaSb, GaSe, and GaAs1-xP x. This is a novel application of an existing theory that is typically used for higher-energy transitions. We modeled these spectra quantitatively as a Ga+3 closed-shell ion affected by perturbations on 3d hole-4p electron final states, specifically spin-orbit effects on the hole and electron, and a crystal-field effect on the hole. The crystal-field perturbation arises from the surrounding bond charges and positive ligand anions. Radial-strength parameters were obtained through a least-squares process, and general trends identified with respect to anion electronegativity. Primary conclusion drawn is that the crystal-field effect, in addition to the spin-orbit interaction, plays a significant role in breaking d-level degeneracy, and consequently is necessary to understand shallow 3d core level spectra.
机译：我们证明了原子尺度方法可能适用于分析硅酸钛合金的组成和键合特性以及镓化合物半导体的浅d核能级反射光谱。;使用X射线吸收光谱法进行硅酸钛分析（XAS），X射线光发射光谱（XPS）和光谱椭偏仪（SE）数据取自一系列钛硅酸盐合金。 XAS数据是由斯坦福线性加速器中心（SLAC）的斯坦福同步加速器辐射实验室（SSRL）的Lucovsky组获得的，并用作主要信息来源。为了增强结论，我们从Les Fleming提供了特拉华大学Opila实验室的XPS数据。我们还使用两个椭圆仪获取了在不同温度下退火的钛硅酸盐合金的SE数据，其中之一是由作者专门设计用来探测真空uv范围内的能量的。在20到25 eV的反射数据中，由于在Gaough，GaAs，GaSb，GaSe和GaPxAs1ƒ{x上在Stoughton同步加速器辐射中心的储存环Tantalus 1上，由Aspnes和Ti L2,3 XAS数据与参考光谱进行了拟合，得出关于合金成分和退火的4倍配位浓度（不同对称性）和6倍配位浓度。分析浓度可以使我们得出关于合金成分和退火的配合的结论。我们能够对4种“解决方案”进行建模。到6倍相分离的转化是随机过程，我们发现通过退火（至少含36％Ti或更高）可以完全转化为6倍相分离的TiO 2。我们将此相分离归因于先前在文献中报道的条纹效应。 XAS OK1光谱证实了这些结果。 XPS Ti L 2,3数据的研究证实，钛硅酸盐合金中的形式Ti价为+4。通过原子多重计算，我们表明，由于库仑和自旋轨道效应，即使在没有晶体场的情况下，Ti L2,3光谱的最终状态也不会保持任何明显的简并性。从退火的钛硅酸盐合金获得的SE数据中提取介电函数为1.5至9.0 eV，证明在500至700°C的退火温度之间发生了显着的配位变化。;采用局部原子多重理论研究Ga3d浅层GaP，GaAs，GaSb，GaSe和GaAs1-xP x的核能级谱。这是通常用于更高能量跃迁的现有理论的新颖应用。我们将这些光谱定量建模为受3d空穴-4p电子最终态的扰动影响的Ga + 3闭壳离子，特别是对空穴和电子的自旋轨道效应，以及对空穴的晶体场效应。晶体场扰动是由周围的键电荷和正配体阴离子引起的。径向强度参数通过最小二乘法获得，并确定了有关阴离子电负性的一般趋势。得出的主要结论是，除了自旋轨道相互作用外，晶体场效应在打破d级简并性中也起着重要作用，因此了解浅3d核心级谱是必要的。

著录项

  • 作者

    Stoute, Nicholas Aaron.;

  • 作者单位

    North Carolina State University.;

  • 授予单位 North Carolina State University.;
  • 学科 Physics Condensed Matter.;Physics Atomic.;Engineering Materials Science.
  • 学位 Ph.D.
  • 年度 2011
  • 页码 132 p.
  • 总页数 132
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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