Semiconductor Quiz

The expected energy of the electrons at absolute zero is called

• Fermi energy

• Emission energy

• Work function

• Potential energy

When a semiconductor is heated, its resistance

• Decreases

• Increases

• Remains unchanged

• Nothing is definite

In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of

• MeV1

• MeV1.0

• eV1

• eV5

The forbidden energy band gap in conductors, semiconductors and insulators are E_G1, E_G2 and E_G3 respectively. The relation among them is

• E_G1 = E_G2 = E_G3

• E_G1 < E_G2 < E_G3

• E_G1 > E_G2 > E_G3

• E_G1 > E_G2 < E_G3

Wires P and Q have the same resistance at ordinary (room) temperature. When heated, resistance of P increases and that of Q decreases. We conclude that

• P and Q are conductors of different materials

• P is N-type semiconductor and Q is P-type semiconductor

• P is semiconductor and Q is conductor

• P is conductor and Q is semiconductor

In intrinsic semiconductor at room temperature, number of electrons and holes are

• Equal

• Zero

• Unequal

• Infinite

If P_N and e_N be the numbers of holes and conduction electrons in an extrinsic semiconductor, then

• e_N > P_N

• e_N = P_N

• e_N < P_N

• e_N > P_N or e_N < P_N depending on the nature of impurity

Fermi level of energy of an intrinsic semiconductor lies

At room temperature, a P-type semiconductor has

• Large number of holes and few electrons

• Large number of free electrons and few holes

• Equal number of free electrons and holes

• No electrons or holes

Which impurity is doped in Si to form N-type semi-conductor?

• Al

• B

• As

• None of these