Photoluminescence is used to measure the purity and crystalline quality of semiconductors such as Gallium nitride (GaN) and Indium Phosphide (InP).

Photoluminescence is the spontaneous emission of light from a material following photoexcitation. It is a powerful contactless and nondestructive technique used for extracting valuable information about the composition of a semiconductor sample.

There are three forms of photoluminescence – resonant radiation, fluorescence, and phosphorescence.