LUMINESCENCE
Introduction :
Generally semiconductors absorb energy. The general property of ligth emmision is called Luminescence. It is a two step process : Excitation of system and the subsequent emission of photons.
Manny semiconductors exhibit the property of luminescence, specially the direct band gap compound semiconductors. which are - GaAs, GaSb, GaN, InP, InAs, InSb, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe etc.
On the basis of excitation mechanism, luminescence can be divided into three sub categories. Which are -
Photoluminescence:
It occurs when the carriers are excited by photon absorption. (For more detailed information about Photoluminescence click here or click on the figure where Photoluminescence is mentioned.)
Cathodoluminescence :
it occurs when the carriers are excited by electron bombardment. (For more detailed information about Cathodoluminescence click here or click on the figure where Cathodooluminescence is mentioned.)
Electroluminescence:
it occurs when the carriers are excited by introduction of current. The radiation results from the recombination of excited carriers. For more detailed information about Electroluminescence click here or click on the figure where Cathodooluminescence is mentioned.)