Question:

In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is a/an

Updated On: Jul 5, 2022
  • p-type semiconductor
  • insulator
  • metal
  • n-type semiconductor
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is A

Solution and Explanation

The given figure represents $p$-type semiconductor as described below : When one of the silicon atoms (valence =4) has been replaced by an atom of aluminium (valence $=3$ ), the aluminium atom can bond covalently with only three silicon atoms, so there is now a "missing" electron (a hole) in one aluminium-silicon bond with a small expenditure of energy, an electron can be torn from a neighbouring silicon-silicon bond to fill this hole, thereby creating a hole in that bond. Similarly, an electron from some other bond can be moved to fill the second hole. In this way, the hole can migrate through the lattice.
Was this answer helpful?
0
0

Questions Asked in AIIMS exam

View More Questions

Concepts Used:

Band theory of solids

Band theory of solids expresses the quantum state that an electron takes inside a metal solid. Every molecule comprises various discrete energy levels. In the band theory, you will get to know how the electrons behave inside a molecule.

Energy Bands in Solids:

Valence band

The energy band that consists of the valence electrons' energy levels is called the valence band. The valence band is available just below the conduction band and the electrons of this band are loosely bound to the nucleus of the atom.

Conduction band

The energy band comprises free electrons energy levels, known as the conduction band. For electrons to be free, external energy must be applied such that the valence electrons get struck to the conduction band and become free.

Forbidden band

The energy gap between the valence band and the conduction band is commonly known as the forbidden band which is also known as the forbidden gap. The electrical conductivity of a solid is set by the forbidden gap and the classification of the materials is done as conductors, semiconductors, and insulators.