Semiconductor Basics

A semiconductor is formed by ……… bonds.

• Covalent

• Electrovalent

• Co-ordinate

• None of the above

The most commonly used semiconductor is ………..

• Germanium

• Silicon

• Carbon

• Sulphur

A semiconductor has generally ……………… valence electrons.

• 2

• 3

• 6

• 4

When a pure semiconductor is heated, its resistance …………..

• Goes up

• Goes down

• Remains the same

• Can’t say

When a pentavalent impurity is added to a pure semiconductor, it becomes ………

• An insulator

• An intrinsic semiconductor

• p-type semiconductor

• n-type semiconductor

A trivalent impurity has ….. valence electrons

• 4

• 5

• 6

• 3

In a semiconductor, current conduction is due to ……..

• Only holes

• Only free electrons

• Holes and free electrons

• None of the above

In semiconductor the forbidden energy gap lies

• Just below the conduction band

• Just above the conduction band

• Either above or below the conduction band

• Between the valence band and conduction band

Which of the following doping elements would not be suitable for converting intrinsic semiconductor

• Phosphorous

• Indium

• Antimony

• Arsenic

In a N-type semiconductor, the Fermi level lies in

• centre of the energy gap

• lower than the centre of energy gap

• higher than the centre of energy gap

• Can be anywhere depending upon the doping concentration