Why does electrical conductivity of semiconductors increase with the rise in temperature?

In semiconductors, electrons occupy different energy bands namely valence band and conduction band. There is an energy difference between the highest occupied valence band and lowest unoccupied conduction band. This is known as the bandgap which is quite small in semiconductors.

With the increase in temperature, electrons in the valance band get excited and jump to the conduction band, which increases ii's electrical conductivity.