For subjects such as biology, which mainly involves the study of cells, a microscope is essential. Cells and other very small objects of study are usually too small for the naked eye to see. A microscope helps researchers to view these objects’ details in different ways. Without microscopes, the study of life in biology would not be as advanced, and many diseases would still be without cures. This article analyses the differences between scanning and transmission electron microscopes.
A Scanning Electron Microscope uses a beam of electrons to scan the surface of an object to create an image detailing the topography and composition of the object’s surface.
A Transmission Electron Microscope is a piece of scientific equipment used to magnify objects. It aims a beam of electrons onto the object to form a magnified image called a micrograph.
|Scanning electron microscope (SEM)||Transmission electron microscope (TEM)|
|Lower resolution of tens of nm (nanometers)||Higher resolution of 1nm or less|
|Shows only morphology of specimens||Shows multiple characteristics of objects such as crystallization, morphology, stress, and many more|
|Simple to prepare specimens||Specimen preparation requires thinning which is tiring and time consuming|
|Relatively safe to use||Relatively detrimental to human health|
The difference lies in their cost, effect on human health, resolution and the information they can obtain from a specimen.
The resolution of a scanning electron microscope is lower than that of a transmission electron microscope. While a transmission electron microscope can view the images of objects to atomic level (which is less than 1nm), a scanning electron microscope can only be used to view images that require tens of nm at most.
A scanning electron microscope only scans a specimen. This limits the amount of information you can get from the specimen – it can only show the morphology of the specimen. Conversely, a transmission electron microscope can help you see a lot of characteristics of the specimen, such as the stress of the specimen, its crystallization, morphology, and even its holography.
When preparing samples to be viewed under these microscopes, each requires different levels of effort. A scanning electron microscope, for instance, can sometimes view specimens directly without preparation. A transmission electron microscope, on the other hand, requires time in order to appropriately thin a specimen, a process that may take up to a day depending on the method used.
In addition, a transmission electron microscope costs more than a scanning electron microscope. It is also more detrimental to human health since it has higher energy electron beams.
Here is a very helpful video of the scanning electron microscope in practice. It discusses the various parts of the microscope and shows how it is used: