HREM

High-resolution electron microscopy, often abbreviated as HREM, is a powerful transmission electron microscopy technique that allows for the direct imaging of the atomic structure of materials. It achieves resolutions better than atomic dimensions, enabling scientists to visualize individual atoms and their arrangements within a sample. HREM works by carefully aligning the electron beam and exploiting the interference between the transmitted and diffracted electron waves. By collecting a specific set of diffracted beams and combining them with the transmitted beam in the objective lens, an image can be formed that approximates the projected potential of the atomic columns. The interpretation of HREM images requires specialized knowledge, as they are not direct photographs of atoms but rather complex representations of the electron scattering process. However, with proper image simulation and analysis, HREM provides invaluable insights into crystalline structures, defects such as dislocations and stacking faults, grain boundaries, and the interfaces between different materials. It is widely used in fields like materials science, solid-state physics, chemistry, and nanoscience for understanding structure-property relationships at the atomic scale.