Carrier Actions

What causes band bending?

Band Bending and Potential & Kinetic Energies

Band bending occurs when an electric field is applied to a semiconductor. When there isn't an electric field being applied, the energy bands are not a function of position. Therefore, when an electric field is applied, energy is being supplied to the carriers in the material. Where band bending has occurred, we can measure the energy being given to the electrons or holes by taking a reference energy and measuring the distance between it and the energy the carrier is at.

In essence, the potential energy of an electron is the distance the electron is from the reference energy to E_c, the lowest conduction band energy. The kinetic energy of an electron is the distance between E_cand the energy it is at. For holes, it's similar. A hole's potential energy is measured as being the distance between the reference energy and E_v, the highest valence band energy. The kinetic energy of a hole is measured by taking the difference between E_v and the energy the hole is at.

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