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 using quantum mechanical tunneling. Electrons tunnel across the vacuum gap when a sharp conducting tip is brought near a conductive or semiconductive surface. The resulting tunneling current, dependent on the tip-sample distance, enables atomic-scale resolution imaging.
• Key Feature: STM provides real-time visualization of surface atomic arrangements.
• Application: STM is extensively used to study nanoscale surface structures, defects, and electronic properties.