A. Why does the conductivity of a semiconductor and some insulators change with impurity content? Compare this with the behaviour of metallic conductors. B. Discuss the location of the Fermi levels of intrinsic and extrinsic (n-type and p-type) semiconductors in low temperature and high temperature ranges. C. Discuss why the structure of the p-n junction is so important to modern technologies that impact our daily life.
A. Why does the conductivity of a semiconductor and some insulators change with impurity content? Compare this with the behaviour of metallic conductors.
B. Discuss the location of the Fermi levels of intrinsic and extrinsic (n-type and p-type) semiconductors in low temperature and high temperature ranges.
C. Discuss why the structure of the p-n junction is so important to modern technologies that impact our daily life.
A - The conductivity of a semiconductor and some insulators changes with impurity content due to a phenomenon known as doping. Doping involves intentionally introducing a small amount of impurities, typically other atoms, into the crystal lattice of a semiconductor.
- N-type Semiconductor ( Dping with Donors ) - When a small number of atoms with extra electrons are introduced into the crystal lattice of a semiconductor, they provide excess electrons that can move freely. These extra electrons increase the material's electron concentration and enhance its electrical conductivity.
- P-type Semiconductor (Doping with acceptors) - Conversely when atoms with fewer electrons are added to the semiconductor lattice, they create holes where electrons are missing. These holes act as positive charge carriers. As a result the material conducts electricity via the movement of these positive charge carriers.
This behavior is in contrast to metallic conductors, where the conduction band is already partially filled with free electrons and these electrons can move easily throughout the lattice.
Step by step
Solved in 3 steps
