Question

Which of the following techniques is most commonly used for imaging at the nanoscale?

• A. Optical microscopy
• B. Scanning Electron Microscopy (SEM)
• C. X-ray diffraction
• D. Transmission Electron Microscopy (TEM)

Hint:

For nanoscale imaging, techniques like SEM and TEM are the most effective.
- SEM is commonly used for surface imaging and fine structural details at the nanoscale.
- TEM is useful for ultra-high resolution imaging at the atomic level, but SEM is more widely used for general nanoscale imaging.

Answer 1

The Correct Option is B

To determine which technique is most commonly used for imaging at the nanoscale, let’s examine the different options and their capabilities.
Step 1: Understand the nanoscale
The nanoscale refers to structures and materials that are in the range of 1 to 100 nanometers (nm). Imaging at this scale requires specialized techniques capable of resolving very fine details.
Step 2: Analyze Option A - Optical microscopy
Optical microscopy is one of the oldest and most widely used techniques for imaging; however, its resolution is limited by the wavelength of visible light, which is typically around 400–700 nm.
This resolution is insufficient for imaging at the nanoscale, as it cannot distinguish objects that are smaller than the wavelength of light. Therefore, optical microscopy is not suitable for nanoscale imaging.
Thus, option A is incorrect.
Step 3: Analyze Option B - Scanning Electron Microscopy (SEM)
Scanning Electron Microscopy (SEM) is a powerful technique that uses electrons rather than light to image specimens.
Because electrons have much shorter wavelengths than visible light, SEM can achieve resolutions on the order of a few nanometers, making it an ideal technique for imaging at the nanoscale. SEM is widely used for high-resolution imaging of surfaces and fine structures.
Therefore, option B is the correct answer.
Step 4: Analyze Option C - X-ray diffraction
X-ray diffraction is primarily used for studying the crystal structure of materials at the atomic scale. While it can provide information about the atomic arrangement in solids, it is not typically used for imaging at the nanoscale.
X-ray diffraction is more useful for analyzing bulk properties and atomic arrangements rather than visualizing fine structures at the nanoscale.
Thus, option C is incorrect.
Step 5: Analyze Option D - Transmission Electron Microscopy (TEM)
Transmission Electron Microscopy (TEM) is another powerful technique that uses electron beams to transmit through a sample and produce high-resolution images.
TEM can achieve extremely high resolutions, even at the atomic level, making it useful for imaging at the nanoscale. However, SEM is more commonly used due to its relative ease of use and ability to produce high-quality surface images.
Thus, while TEM can be used for nanoscale imaging, SEM is more widely used in practice.
Therefore, option D is not the most commonly used technique, although it is a close contender.
Step 6: Conclusion
Scanning Electron Microscopy (SEM) is the most commonly used technique for imaging at the nanoscale due to its combination of high resolution and ease of use.
Thus, option B is the correct answer.