The valence and conduction bands in an n-type material are at slightly lower energy levels
than the valence and conduction bands in a p-type material. Recall that p-type material has
trivalent impurities and n-type material has pentavalent impurities. The trivalent impurities
exert lower forces on the outer-shell electrons than the pentavalent impurities. The lower
forces in p-type materials mean that the electron orbits are slightly larger and hence have
greater energy than the electron orbits in the n-type materials.