- #1
hokhani
- 483
- 8
In an indirect absorption process that an electron jumps from the top of the valence band to the bottom of the conduction band,why a phonon must be involved to conserve the momentum? At these two points (top of the valence band and bottom of the conduction band) the electron momentum is zero so the momentum of electron would not change during the process and the momentum is conserved without the need of phonons.