How does temperature affect semiconductor properties?

Temperature affects semiconductor properties by altering the number of charge carriers and their mobility.

Semiconductors are materials with a conductivity between that of an insulator and a conductor. They have a bandgap, which is the energy difference between the valence band and the conduction band. At low temperatures, the valence band is full and the conduction band is empty, so there are no free charge carriers. As the temperature increases, some electrons gain enough energy to jump from the valence band to the conduction band, creating free electrons and holes. The number of charge carriers increases with temperature.

The mobility of charge carriers also depends on temperature. At low temperatures, the mobility is low because the lattice vibrations scatter the charge carriers. As the temperature increases, the lattice vibrations increase, and the mobility increases. However, at very high temperatures, the mobility decreases again because the lattice vibrations become so strong that they disrupt the crystal structure.

Temperature also affects the bandgap of semiconductors. As the temperature increases, the bandgap decreases, which means that less energy is required to excite an electron from the valence band to the conduction band. This can result in increased leakage current and decreased efficiency in electronic devices.

In summary, temperature affects semiconductor properties by altering the number of charge carriers and their mobility, as well as the bandgap. Understanding these effects is important for designing and optimizing electronic devices.