yeh I learned that when I was in rochester too...although not from a class, from trying to use my computerOriginally posted by mwarps
Below about 150K, silicon goes into a regime known as freeze-out.
The dopants in the lattice sites are no longer electrically active because there is almost no possibility of the electrons reaching the conduction band from the valence band. This means silicon starts acting like an insulator, and no longer a semiconductor. Devices no worky when so coldy.