Question

In a semiconducting material, μ_e and μ_h are the mobilities of electrons and holes respectively. Choose the correct relation from the following.

1. μe > μh
2. μe < μh
3. μe = μh
4. None of the above

Answer 1

Correct Answer - Option 1 : μe > μh

The correct answer is option 1) i.e. μe > μh

CONCEPT:

• Semiconductors: Semiconductors are materials that have conductivity between conductors and that of insulators.
  • The missing electrons (holes) are the positively charged particles whereas electrons are the negatively charged particles in a semiconductor. The electrons and holes have an equal magnitude of charge but opposite polarity.

EXPLANATION:

• In semiconductors, the excited electron jumps from the valence band to the conduction band. This creates a free electron in the conduction band and a hole in the valence band.
• Holes are created when electrons move from innermost shells to higher shells or shells with higher energy levels.
• So, the holes in a semiconductor are subjected to a stronger influence by the nucleus than the electrons residing in the higher shells or farther shells.
• Also due to the excitation energy, the electrons have better mobility.
• Therefore, the mobility of holes is lesser than the mobility of electrons.

​⇒ μe > μh