Lasing Transitions in p+-n-n+ (AlGa) As–Ga As Heterojunction Lasers

A study of the lasing and spontaneous emission from p+-n-n+ heterojunction lasers with lightly doped n-type active regions shows that the stimulated emission is not due to a simple band-to-band recombination process. It is further shown that the 300 K gain coefficient dependence on the junction current differs greatly from that predicted on the basis of band-to-band lasing involving a parabolic density-of-states distribution.