一、前言 透射电镜显微术(TEM)在材料科学中的用途已获公认。但是对于晶体,传统的成象方法只是利用透过薄晶体的平面波中的某一支波而实现的,利用透射束而成的象称为明场象(BF),利用衍射束而成的象被称为暗场象(DF),从成象机制上说,这种成象方法所利用的是晶体物质对电子的衍射而对电子波产生的调制。这一调制带来的成象电子束 I. INTRODUCTION Transmission electron microscopy (TEM) has been recognized for its use in materials science. However, with crystals, the conventional imaging method utilizes only one of the plane waves transmitted through the thin crystal, and the image formed by the transmitted beam is called a bright field image (BF). An image obtained by using a diffraction beam Known as the dark field image (DF), from the imaging mechanism, this method of imaging utilizes the modulation of the generation of electronic waves by the crystal material on the diffraction of electrons. This modulation brings the imaging electron beam