Question

When a Boron impurity is doped with silicon, which type of semiconductor is formed?

• A. n-type
• B. p-type
• C. Semiconductors cannot be formed by doping with Boron impurty.
• D. None of the above

Answer 1

The correct option is B p-type

Silicon belongs to the carbon family having four valence electrons. Each silicon is bonded to four other silicon atoms.
When small amount of trivalent element ( boron) is added, all three valence electrons form bond with three silicon atoms and a positive hole is created. The positive hole is free to move and can enhance the electrical conductivity of silicon through positive hole conduction mechanism.
Such semiconductors are called as p-type semiconductor.