Why does the resistance decreases with increase in temp for semi- conductors?

[Abhishakes]

Why does the resistance decreases with increase in temp for semi- conductors?

 

[vanesch]

Essentially because there are more electron-hole pairs (which contribute to conduction) when temperature rises. This effect wins from the standard effect in metals which increases the probability of scattering and hence the slowing down of the carriers (very crude picture) with increasing temperature. In metals, the first effect is absent, as all or most of the carriers are already available.

 

[astrokreng]

The resistance of a semiconductor decreases with an increase in temperature due to the behavior of its charge carriers. In a semiconductor, the charge carriers are electrons and holes, which are responsible for conducting electricity. As the temperature increases, the thermal energy of these charge carriers also increases, causing them to move more freely and at a faster rate. This increased mobility of charge carriers leads to a decrease in resistance.

Additionally, at higher temperatures, more electrons are able to break free from their bound states and become available for conduction. This increases the number of charge carriers and further reduces the resistance of the semiconductor.

Furthermore, the atomic lattice structure of a semiconductor also plays a role in its resistance. As temperature increases, the atoms in the lattice vibrate more vigorously, creating more thermal energy. This thermal energy can disrupt the regularity of the lattice, making it easier for charge carriers to move through it, thus reducing resistance.

In summary, the decrease in resistance of semiconductors with an increase in temperature is due to the increased mobility of charge carriers, the availability of more charge carriers, and the disruption of the atomic lattice structure. This phenomenon is important in understanding and designing electronic devices that utilize semiconductors.