Photoluminescence at a heterojunction

[Benevito]

Do I understand it correctly that photoluminescence at a semiconductor heterojunction occurs because of intralayer recombination? If so, why can't photoluminescence occur because of interlayer recombination? Is it because momentum cannot be conserved in such a process ( like in the indirect gap semiconductor?)

 

[BigJDubs]

No, photoluminescence at a semiconductor heterojunction does not necessarily occur because of intralayer recombination. It can also occur due to interlayer recombination, where momentum can be conserved. In fact, in some cases, interlayer recombination can be more efficient than intralayer recombination for producing photoluminescence. The difference is that intralayer recombination typically produces more intense light emissions than interlayer recombination. So the choice of which process to use depends on the application and the desired outcome.