Pure silicon is a semiconductor with a valence of four. Aluminium is a Group 13 element and acts as a trivalent impurity (valence of three) when doped into silicon. When a trivalent impurity replaces a silicon atom in the crystal lattice, it creates a 'hole' (absence of an electron) in the covalent bond structure. These holes act as positive charge carriers, making the doped semiconductor p-type.
When a piece of pure silicon is doped with aluminium, then
Asked in UPSC CDS 1 2017 · Topic: Conductivity (Intrinsic and Extrinsic Semiconductors: Doping, carrier concentration, and Fermi level)
More Physics questions
- Suitable impurities are added to a semiconductor depending on its use. This is done in order to
- The majority charge carriers in a p-type semiconductor are
- The valence electron of the impurity atom that is to be added to germanium crystal so as to make it a n-type semiconductor is
- Electric conduction in a semiconductor takes place due to
- In N-type semiconductor, ultrapure Si is doped with
- An n-type semiconductor is
- When a small amount of a suitable impurity is added to the pure elemental semiconductor, the conductivity of the semiconductor is increased manifold. Such materials are known as - - (5) Question not attempted
- Which of the following liquids is a bad conductor of electricity?
