Why is High Transition Probability Important in Semiconductor Lasers?

[kpstp88]

i am not able to understand this line..

in semiconductor laser the transition probability for a radiative transition across the conduction and valence gap must be high and must exceed the probability for non -radiative transfer of energy to the lattice.

please explain this theory.

 

[Dr Transport]

In other words, you won't have a laser if the electron transfers its energy to the lattice.

 

[mathur.tushi]

it is so because, all the photons are not used in emitting light..the probability of radiative photons should be more so that we can get enough radiations in form of laser.actually some of the photons are absorbed in the material for the recombination of electron hole pairs.thus they do not emit radiations.