Question

Atomic Force Microscopy is a modified version of:

• A. Scanning Electron Microscopy
• B. Transmission Electron Microscopy
• C. Positron Emmision Tomography
• D. Scanning Tunneling Microscopy

Hint:

Remember that STM and AFM are the two main types of Scanning Probe Microscopy (SPM). STM came first and uses current. AFM came second as a modification to use force, making it more versatile.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
This question concerns the lineage and relationship between different microscopy techniques, specifically Atomic Force Microscopy (AFM).
Step 2: Detailed Explanation:
Scanning Tunneling Microscopy (STM) was invented in 1981 by Gerd Binnig and Heinrich Rohrer. It revolutionized surface science but had a major limitation: it could only be used on conducting or semiconducting surfaces, as it relies on a tunneling current.
To overcome this limitation, the same team, along with Calvin Quate, invented the Atomic Force Microscope (AFM) in 1986. The AFM is a type of Scanning Probe Microscope (SPM), just like the STM. It uses a similar principle of scanning a sharp probe over a surface. However, instead of measuring a tunneling current, the AFM measures the minute forces (e.g., van der Waals forces) between the probe tip and the sample surface.
Because the AFM measures forces rather than current, it can image virtually any type of surface, including non-conducting materials like polymers, glass, and biological samples. Due to its similar operational principle (scanning a probe) and its development as a successor to overcome the limitations of STM, the AFM is considered a direct modification and evolution of the Scanning Tunneling Microscope.
Step 3: Final Answer:
Atomic Force Microscopy was developed from the principles of Scanning Tunneling Microscopy to allow imaging of non-conductive surfaces.