For an unbiased p-n junction, the energy at the bottom of the conduction band on the n side is:
A)higher than the energy at the bottom of the conduction band on the p side
B)lower than the energy at the bottom of the conduction band on the p side
C)lower than energy at the top of the valence band on the n side
D)lower than energy at the top of the valence band on the p side
E)the same as the energy at the bottom of the conduction band on the p side

Question

Quizplus · Accepted Answer

In an unbiased p-n junction, the Fermi-level is the same throughout the device. Thus the energy at the bottom of the conduction band and the top of the valence band should be the same on both sides of the junction. However, due to the built-in electric field at the junction, the energy bands shift downward on the p-side and upward on the n-side. Therefore, the energy at the bottom of the conduction band on the n-side is lower than the energy at the bottom of the conduction band on the p-side.

For an Unbiased P-N Junction, the Energy at the Bottom