Question

In scanning electron microscopy, the resolution of backscattered electron (BSE) image is poorer compared to that of secondary electron (SE) image, because

• A. energy of BSE is lower
• B. sampling volume of BSE is larger
• C. yield of BSE is lower
• D. sampling volume of SE is larger

Hint:

The resolution of backscattered electron (BSE) images is poorer than secondary electron (SE) images because BSEs come from a larger sampling volume and have a lower yield.

Answer 1

The Correct Option is B

Scanning electron microscopy (SEM) can generate images using either secondary electrons (SE) or backscattered electrons (BSE). The resolution of the images varies depending on the type of electrons detected. - Secondary electrons (SE): These are emitted from the surface layers of the sample and provide detailed surface information. The SE images have higher resolution because the electrons come from a very small interaction volume, essentially from the surface itself. - Backscattered electrons (BSE): BSEs originate from deeper within the sample, which means that the interaction volume is larger. This larger sampling volume leads to poorer resolution because the electrons come from a greater depth, causing less surface detail to be captured in the image. The main reason for the poorer resolution of BSE images compared to SE images is the lower yield of BSE from the sample. This lower yield, coupled with the larger sampling volume, results in a less detailed image. Hence, the correct answer is (C) "yield of BSE is lower".
Final Answer: (C) yield of BSE is lower