Spine Fit

Whenever a p-n junction is forward biased, the electrons cross the p-n junction form the n type semiconductor material and recombine with the holes in the p type semiconductor material. The free electrons are in the conduction band while the holes are present in valence band. Thus the free electrons are at higher energy level with respect to the holes. When a free electron recombines with hole, it falls from conduction band to a valence band. Thus the energy level associated with it changes from higher value to lower value. The energy corresponding to the difference between higher level and lower level is released by an electron while travelling from the conduction band to valence band. In normal diodes, this energy released is in the form of heat.