In a PL spectrum, is it possible to detect emissions due to inter-band recombination (conduction band to valence band direct transition) and at the same time also observe PL emissions due to free exciton recombinations?
In other words, are all PL emissions near the band edge always due to only excitons recombining? Is there such a thing as electrons and hole pair recombining radiatively but are not excitons?
Helen, exciton emission and band edge emission is the different mechanisms and even have the different peak wavelenght in the same material, because exciton has smaller recombination energy due to bond energy. These two mechanisms can coexist, but excitonic recombination usually observed at low temperatures, when lifetimes of photoexcited carriers are long enough to form excitonic complex. See e.g. Phys.Rev. paper: link.aps.org/doi/10.1103/PhysRev.174.898
Good luck!
Answer to a the part of your question Is there such a thing as electrons and hole pair recombining radiatively but are not excitons? ", may be in considering the shallow trap states too.
- Badges
- Science topic
- Similar topics
- Mathematical Sciences
- Graphs