At what temp would an intrensic semiconductor behave like a perfect insulator?Why?

Answer 1

n an intrinsic semiconductor such as silicon at temperatures above absolute zero, there will be some electrons which are excited across the band gap into the conduction band and which can support current flow. When the electron in pure silicon crosses the gap, it leaves behind an electron vacancy or "hole" in the regular silicon lattice. Under the influence of an external voltage, both the electron and the hole can move across the material.

So the answer is , at absolute zero Kelvins.