why does the electrical conductivity of semiconductors increse with rise in temperature?

Explanation

This is explained with the help of band theory for metallic bond. In semi-conductors, the energy gaps between valence bands and conduction bands are small. With rise in temperature, the kinetic energy of electrons increases. This means that more electrons can move from valence bands to comduction bands. Consequently, the electrical, the electrical conductivity increases with rise in temperature.