Question

Scanning tunneling microscope works on the principle of:

• A. Quantum mechanical tunneling
• B. Photoelectric effect
• C. Stefan’s Law
• D. Meissner effect

Hint:

The scanning tunneling microscope has a metallic tip with a small vacuum gap and it works by detecting changes in a tunneling current of electrons, which is exponentially dependent on the gap distance, and so, by controlling this, it can get highly accurate imaging at the atomic scale.

Answer 1

The Correct Option is A

The scanning tunneling microscope (STM) operates on the principle of quantum mechanical tunneling. When a sharp conducting tip is brought very close to a conductive or semiconductive surface, electrons tunnel through the vacuum gap between the tip and the surface. The tunneling current depends on the tip-sample distance, allowing atomic-scale resolution imaging.
• Key Feature: The STM provides real-time visualization of atomic arrangements on surfaces.
• Application: STM is widely used to study surface structures, defects, and electronic properties at the nanoscale.