本工作将赝弱相位物体近似像衬理论延伸至球差校正高分辨电子显微像,分析了球差校正像的衬度随样品厚度的变化规律。指出非Schemer聚焦条件下球差校正电镜拍摄的高分辨像仍未必反映晶体结构,讨论了解卷处理方法应用于球差校正像的有效性,并以有12型层错的GaN晶体为例,借助像模拟肯定了解卷处理能用于复原原子分辨率晶体缺陷的结构像。
In the present work the contrast theory for pseudo weak-phase object approximation has been extended to spherical aberration( Cs )- corrected high-resolution electron microscope images. The mechanism of contrast variation with sample thickness has been analyzed. It is pointed out that the Cs-corrected images taken under non-Scherzer focuses may still not reflect the true structures of the crystals. The validity of applying the image deeonvolution method to such images has been discussed and tested with simulated images of GaN having an I2 stacking fault. It is confirmed that the image deconvolution method is available for restoring crystal structures at atomic resolution from Cs-corrected images.