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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >Trapped-electron centers in pure and doped glassy silica: A review and synthesis
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Trapped-electron centers in pure and doped glassy silica: A review and synthesis

机译：纯和掺杂玻璃态二氧化硅中的陷阱电子中心：综述与合成

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摘要

This paper reviews half a century of research on radiation-induced point defects in pure and doped glassy silica and its crystalline polymorph α quartz, placing emphasis on trapped-electron centers because the vast majority of all presently known point defects in various forms of SiO_2 are of the trapped-hole variety. The experimental technique most discussed here is electron spin resonance (ESR) because it provides the best means of identifying the point defects responsible for the otherwise difficult-to-attribute optical bands. It is emphasized that defects in α quartz have been unambiguously identified by exacting analyses of the angular dependencies of their ESR spectra in terms of the g matrix of the unpaired electron spin and the matrices of this spin's hyperfine interactions with non-zero-nuclear-spin ~(29)Si and ~(17)O nuclides in pure α quartz and/or with substitutional 27Al, 31P, or 73Ge in quartz crystals respectively doped with Al, P, or Ge. Many defects in pure and doped glassy silica can be unambiguously identified by noting the virtual identities of their spin Hamiltonian parameters with those of their far better characterized doppelgangers in α quartz. In fact, the Ge(1) trapped-electron center in irradiated Ge-doped silica glass is shown here to have a crystal-like nature(!), being virtually indistinguishable from the Ge(II) center in Ge-doped α quartz [R.J. McEachern, J.A. Weil, Phys. Rev. B 49 (1994) 6698]. Still, there are other defects occurring in glassy silica that are not found in quartz, and vice versa. Nevertheless, those defects in glasses without quartz analogues can be identified by analogies with chemically similar defects found in one or both polymorphs and/or by comparison with the vast literature of ESR of paramagnetic atoms and small molecules. Oxygen "pseudo vacancies" comprising trigonally coordinated borons paired with trigonally coordinated silicons were proposed to exist in unirradiated B_2O_3-3SiO_2 glasses in order to account for observations of γ-ray-induced trapped-electron-type B- and Si-E′ centers [D.L. Griscom et al., J. Appl. Phys. 47 (1976) 960]. Analogous Al-E′ trapped-electron centers have been elucidated in silica glasses with Al impurities [K.L. Brower, Phys. Rev. B 20 (1979) 1799]). And it has been proposed [D.L. Griscom et al., J. Appl. Phys. 47 (1976) 960] that trapping of a second electron on such oxygen pseudo vacancies accounts for the predominant ESR-silent trapped-electron centers in irradiated silica glasses containing B or Al. The present paper additionally attempts to divine the identities of some of the ESR-silent radiation-induced trapped-electron centers in silica glasses free of foreign network-forming cations. This quest led to the doorstep of the most famous ESR-silent defect of all, the twofold-coordinated silicon, which is found only in silica glasses (not in quartz) and is responsible for the UV/visible optical properties of the oxygen-deficiency center known as ODC(II). The oxygen-deficiency center called ODC(I) is associated with an absorption band at 7.6 eV and, though commonly believed to be a simple oxygen mono-vacancy, is clearly more complicated than that [e.g., A.N. Trukhin, J. Non-Cryst. Solids 352 (2006) 3002]. Certain well documented but persistently enigmatic ODC(I)?ODC(II) " interconversions" [reviewed by L. Skuja, J. Non-Cryst. Solids 239 (1998) 16] have never been explained to universal satisfaction.
机译：本文回顾了半个世纪以来对纯掺杂玻璃态二氧化硅及其晶体多晶型物α石英中辐射诱发的点缺陷的研究，重点放在了陷阱电子中心，因为目前已知的各种形式SiO_2的绝大多数点缺陷都是被困的种类。这里讨论最多的实验技术是电子自旋共振（ESR），因为它提供了识别导致原本难以归因的光学波段的点缺陷的最佳方法。要强调的是，通过对未配对电子自旋的g矩阵以及该自旋与非零核自旋的超精细相互作用的矩阵进行严格的ESR光谱角度依赖性分析，可以明确地识别出α石英中的缺陷。纯α石英中的〜（29）Si和〜（17）O核素和/或分别掺杂有Al，P或Ge的石英晶体中的取代27Al，31P或73Ge。可以通过注意到自旋哈密顿参数的虚拟身份和其在α石英中表征得更好的多普勒钢斑的虚拟身份来明确识别纯净掺杂玻璃态二氧化硅中的许多缺陷。实际上，此处显示的是在掺Ge的石英玻璃中，Ge（1）的俘获电子中心具有晶体性质（！），与掺Ge的α石英中的Ge（II）中心几乎没有区别。 RJ McEachern，J.A.威尔，物理学家。 B 49版（1994）6698]。尽管如此，玻璃态二氧化硅中仍存在其他缺陷，而石英中未发现这些缺陷，反之亦然。然而，没有石英类似物的玻璃中的那些缺陷可以通过与在一种或两种多晶型物中发现的化学上相似的缺陷进行类比和/或与顺磁性原子和小分子的大量ESR文献进行比较来鉴定。有人提出在未经辐照的B_2O_3-3SiO_2玻璃中存在由三角配位的硼与三角配位的硅配对的氧“伪空位”，以解释观察到的γ射线诱导的俘获电子型B-和Si-E'中心[ DL Griscom等人，J.Appl.Chem。物理47（1976）960]。在具有铝杂质的石英玻璃中已经阐明了类似的Al-E'陷阱电子中心。浏览器，物理。 Rev.B 20（1979）1799]）。并且已经提出了[D.L. Griscom等人，J.Appl.Chem。物理47（1976）960]认为，在这样的氧伪空位上俘获第二个电子是辐照含B或Al的石英玻璃中主要的ESR沉默的俘获电子中心。本论文还试图确定没有外来网络形成阳离子的石英玻璃中某些ESR沉默的辐射诱导的俘获电子中心的身份。这项探索导致所有最著名的ESR沉默缺陷-双重配位的硅-仅在石英玻璃中发现（而不是在石英中），并导致缺氧的UV /可见光学特性中心称为ODC（II）。缺氧中心称为ODC（I）与7.6 eV的吸收带相关联，尽管通常被认为是简单的单氧空位，但显然比[A.N. Trukhin，J。Non-Cryst。 Solids 352（2006）3002]。某些有据可查但却始终令人迷惑的ODC（I）？ODC（II）“相互转换” [L. Skuja，J. Non-Cryst。 Solids 239（1998）16]从来没有得到普遍满意的解释。

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