Cathodoluminescence microcharacterization of point defects in α-quartz
Cathodoluminescence microcharacterization of point defects in α-quartz
复制标题
α-石英点缺陷的阴极发光微观表征
作者：
M. Stevens;M. Stevens
摘要 SEM 中的阴极发光 (CL) 光谱已用于研究 295 K 下透明天然 α-石英的点缺陷结构。研究了影响 α-石英 CL 光谱的阴极发光过程和实验因素。电子辐照可能会引起石英平均局部晶体微观结构的变化，将其局部转变为密度较低的非晶态。观察到的 CL 发射通过一系列天然和杂质缺陷中心进行识别，包括： 0.968 eV 的间隙分子 O；约 1.65 eV 的电荷补偿替代 Fe3+ 杂质中心； 1.9 eV 处的非桥接氧空穴中心 (NBOHC)；具有 OH-前体的 NBOHC，1.95 eV；具有约 1.9 eV 的非桥接杂质（例如 Li+、Na+ 或 K+）前体的 NBOHC；与 2.3 eV 电子辐照非晶化石英 Eʹ 中心相关的自陷激子 (STE) 的辐射复合；与 α-石英中 E1ʹ 中心相关的 STE 在 2.7 eV 下的辐射重组； 3.3 eV 处的电荷补偿取代 Al3+ 杂质中心；以及 4.3 eV 处的中性弛豫 O 空位。此外，电子辐照非晶化 SiO2 中缺氧缺陷的未解决贡献可能约为 2.7 和 4.3 eV。
Abstract Cathodoluminescence (CL) spectroscopy in an SEM has been used to investigate the point defect structure of clear natural α-quartz at 295 K. Cathodoluminescence processes and experimental factors that influence the CL spectra from α-quartz are investigated. Electron irradiation may induce changes in the average local crystal microstructure of quartz, locally transforming it to a less dense, amorphized state. The observed CL emissions are identified with a range of native and impurity defect centres including: interstitial molecular O at 0.968 eV; a charge-compensated substitutional Fe3+ impurity centre at ~1.65 eV; a non-bridging oxygen hole centre (NBOHC) at 1.9 eV; an NBOHC with OH- precursor at 1.95 eV; an NBOHC with a non-bridging impurity (e.g. Li+, Na+ or K+) precursor at ~1.9 eV; a radiative recombination of the self-trapped exciton (STE) associated with an Eʹcentre in electron-irradiation-amorphized quartz at 2.3 eV; a radiative recombination of the STE associated with the E1ʹ centre in α-quartz at 2.7 eV; a charge-compensated-substitutional Al3+ impurity centre at 3.3 eV; and a neutral relaxed O vacancy at 4.3 eV. In addition, unresolved contributions from O-deficient defects in electron-irradiation-amorphized SiO2 are likely at ~2.7 and 4.3 eV.