Saturday, June 5, 2010

Free electron model

The free electron model of metals has been used to explain the photo-electric effect . This model assumes that electrons are free to move within the metal but are confined to the metal by potential barriers as illustrated by Figure below. The minimum energy needed to extract an electron from the metal equals qFM, where FM is the workfunction. This model is frequently used when analyzing metals. However, this model does not work well for semiconductors since the effect of the periodic potential due to the atoms in the crystal has been ignored.

a)The free electron model of a metal


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