[????????]Photo Luminescence

Photoluminescence (PL) is the optical radiation emitted by a semiconducting crystal after excitation with incident light source (usually a laser).
Photoluminescence?
semi conducting crystal? band gap ??? ???? ?? ?? ?? ???? conduction band? ??? ???? ??? ?? relaxation? ??? ?? ?? ??? ? ?? Photo-Luminescence?? ???.
Korea University
Photoluminescence spectroscopy is a contactless, nondestructive method of probing the electronic structure of materials.
PL spectroscopy
PL spectroscopy? ??? ??? ??? ???? contactless?? nondestructive? ?????.
PL process? ??? ???? ??? ????.
??? ?? ??? laser beam? ????? valence band? ??? conduction band? ??(excitation)???.
??? conduction band? ???? ????? ?? ??? ??? ??? ? ?? ??? ?? conduction band edge? ???? ???.
?? ??? ??? ?? valence band? ???? electron-hole ???(recombination)? ?????.
??, ?? electron? hole? valence band? conduction band ??? ???? donor state? acceptor state (Et)? ??? ?? ???? ?? ? ????? ???.
??? ?? ?? ??? ?? ??? ??? ???? ???? ??? ??? ????, sample? ??? ?? ???? ?? spectrum? ?????.
?? ?? process? ?? ???? ?? spectrum?? ?????? ?? ??? ?? ??? ?? ?? ??? ?? ??, ?? ?? ?? ??? ? ????.