Question

necessary: 3) Figrues to the right hand side indicate full marks
SECTION -A
Q.1) Select and Write the correct answers:
i) P-type semiconductors are made by mixing silicon with impurities of ....
a) germanium b) boron
c) arsenic
d) antimony
Molarity is need​

Answer 1

Answer:

Answer is Boron.

Explanation:

The logic here is that Boron , having 3 valence electrons makes positively charged electron gaps in the semiconductor hence improving its conductivity.

Answer 2

Answer:

Explanation:

Option b) Boron ( B ) is the correct answer

The Dopant is a trivalent element

It has one valenece electron less than Silicon , so it forms covalent bonds with nearer Si atoms .

But as it is a trivalent element it only makes covalent bonds with 3 atoms of Si and has no electron left for the fourth atom , so a vacancy or a hole is left there and this hole helps in conduction .

Number of holes >> Number of Conduction Electrons for P Type Semiconductors