How does the conductivity and resistivity change with rise of temperature in case of intrinsic semiconductor?

Explanation

When the temperature of the semiconductor is raised, more covalent bonds are broken in the given semiconductor. Due to it, there is a large increase in the charge carrier concentration in semiconductor. The fraction (f) of the number of electrons raised from valeance band to conduction band at temperature TK in intrinsic semiconductor is given by
`fprope^(-E_(g)//2kT)`
where `E_(g)` is the value of forbidden energy gap. If means, if T increases, f also increases, i.e., with the increase in temperature, the number of electrons in conduction band increases. This leads to increase in conductivity of intrinsic semiconductor. As resistivity is the reciprocal of electrical conductivity, hence resistivity of pure semiconductor decreases with increase in temperature.