LED vs PN Diode: Intensity & Barrier Potential

[miss photon]

when forward bias of led is increased, the intensity of emitted light increases until it reaches a max after which it starts decreasing again...why?
also, in which of the two cases is barrier potential greater, led or pn diode?

 

[sphyics]

pls make u r question more clear... (led is a type of pn diode) so wat do u mean by whose potential (barrier) is greater!

 

[edmondng]

i think he mean the intensity of LED increase as current increase, but then if current goes beyond rated max of LED, why the intensity goes down..??

http://en.wikipedia.org/wiki/Light-emitting_diode

 

[dlgoff]

The light intensity will go to zero if the current gets too high.

 

[miss photon]

pls make u r question more clear... (led is a type of pn diode) so wat do u mean by whose potential (barrier) is greater!

i mean the normal pn diode used in circuits

 

[NoTime]

For single color LEDs (not the "white" ones) the barrier potential is coupled to the light output frequency.
If you look at the specs you will find that Red, Green and Blue LEDs have different barrier potentials.