Here is a brief introduction I made to the difference between the two of them to share with you.
There is a difference in sample processing:
Scanning electron microscope samples need to be coated with a conductive layer to avoid charge buildup, which affects imaging. Transmission electron microscopy samples need to be made into ultra-thin slices to allow electrons to pass through.
Differences in imaging principles:
The electron beam of the SEM excites signals, such as secondary electrons, backscattered electrons, etc., which are received by the detector and converted into an image. The electron beam of a transmission electron microscope is amplified by a multi-stage electromagnetic lens to form a projected image, which is recorded by a fluorescent screen or a photographic dry plate.
Differences in application:
Scanning electron microscopy observes the surface morphology and structure of a sample, and is suitable for small-scale microstructures. Transmission electron microscopy to observe the internal structure and morphology of the sample, applicable to large-scale tissues, cells and other structures.