Oleshko V P, Gijbels R H, Van Daele A J, Jacob W A, Xu Y E, Wang S E, Park I Y, Kang T S
Micro- and Trace Analysis Center, Department of Chemistry, University of Antwerp (UIA), Wilrijk-Antwerpen, Belgium.
Microsc Res Tech. 1998 Jul 15;42(2):108-22. doi: 10.1002/(SICI)1097-0029(19980715)42:2<108::AID-JEMT5>3.0.CO;2-P.
The combination of cryo-energy filtering transmission electron microscopy (EFTEM)/electron spectroscopic diffraction (ESD)/electron energy-loss spectroscopy (EELS) and cryo-energy-dispersive X-ray (EDX) analysis in the scanning transmission (STEM) and scanning (SEM) modes was applied for the characterization of composite tabular Ag(Br,I) microcrystals. A low-loss fine structure in EEL spectra between 4 and 26 eV was attributed to excitons and plasmons possibly superimposed with interband transitions and many-electron effects. The contrast tuning under the energy-filtering in the low-loss region was used to image the crystal morphology, defect structure (random dislocations and ¿111¿ stacking faults) and bend and edge contours as well as electron excitations in the microcrystals. Sharp extra reflections at commensurate positions in between the main Bragg reflections and diffuse honeycomb contours in ESD patterns of the microcrystals taken near the [111] zone were assigned to the number of defects in the shell region parallel to the grain edges and polyhedral clusters of interstitial silver cations, respectively. The imaginary part of the energy-loss function, Im (-1/epsilon), and the real and imaginary parts, epsilon1 and epsilon2, of the dielectric permittivity were determined by means of a Kramers-Kronig analysis. An assignment of exciton peaks based on calculations of electronic band structure of silver bromide is proposed. Inner-shell excitation bands of silver halide were detected in line with EDX-analyses. The energy-loss near-edge structure (ELNES) of the AgM4,5-edge governed by spin-orbital splitting between the 3d3/2- and 3d5/2-states has been evaluated. Combined silver and halide distributions were obtained by a three-window method (EFTEM) and by EDX/STEM including area mapping and line profiling of iodide.
将低温能量过滤透射电子显微镜（EFTEM）/电子光谱衍射（ESD）/电子能量损失谱（EELS）与扫描透射（STEM）和扫描（SEM）模式下的低温能量色散X射线（EDX）分析相结合，用于表征复合片状Ag(Br,I)微晶。EEL谱中4至26 eV之间的低损耗精细结构归因于激子和等离子体激元，可能与带间跃迁和多电子效应叠加。低损耗区域能量过滤下的对比度调节用于成像微晶的晶体形态、缺陷结构（随机位错和〈111〉堆垛层错）、弯曲和边缘轮廓以及电子激发。在[111]区附近拍摄的微晶ESD图案中，主布拉格反射之间相应位置的尖锐额外反射和漫散蜂窝状轮廓分别归因于平行于晶粒边缘的壳层区域中的缺陷数量和间隙银阳离子的多面体簇。通过克莱默斯-克勒尼希分析确定能量损失函数的虚部Im(-1/ε)以及介电常数的实部和虚部ε1和ε2。提出了基于溴化银电子能带结构计算的激子峰归属。与EDX分析一致，检测到卤化银的内壳层激发带。评估了由3d3/2和3d5/2态之间的自旋轨道分裂控制的AgM4,5边缘的能量损失近边结构（ELNES）。通过三窗口方法（EFTEM）以及包括碘化物面积映射和线轮廓分析的EDX/STEM获得了银和卤化物的组合分布。
