After completing this section, you should understand:
- the difference between thermal and drift velocities of carriers
- the reasons for the low resistivity of perfect crystals and constant resistivity in terms of electron scattering
- the existence of many scattering mechanisms in crystals, the effect of which can be added using Mattheissen's Rule
- the Wiedermann-Franz Law
- the nature of current carriers in semiconductors and the concept of mobility
- the semiconductor equation np = constant and its independence of doping.