QUESTIONS

Distinguish between intrinsic and extrinsic semiconductors.

Distinguish between $p$-type and $n$-type semiconductors.

Explain briefly what is meant by extrinsic semiconductors, including the terms donor and acceptor impurities as well as $p$-type and $n$-type semiconductors.

Using the concept of electron and hole currents, derive expression for the conductivity of a semiconductor.

What do you understand by band theory of energy in solids? Define valence band, conduction band and forbidden gap.

Explain formation of energy bands in solids. Distinguish conductors, insulators and semiconductors on the basis of forbidden gap by using symbolic diagram.

What is doping in semiconductors? Explain $p$ and $n$-type of semiconductors by selecting an element from third and fifth group and also explain acceptor and donor nature of these elements mixed with a pure semiconductor.

What do you understand by intrinsic and extrinsic semiconductor? Explain the conductivity of semiconductor and its dependency on change in temperature.