dear Sajid,deep and shallow emission refers to the energy of emitting states, which are traps in this case. In general, luminescence can occur because of band-to-band radiative recombination, or via defect (or trap)-mediated recombination of excited electrons.. In this latter case electrons in the conduction band are first captured by a defect (with a non-radiative process) and then recombine radiatively. If the energy of the trap is close to the conduction band minimum then the trap is a shallow one, otherwise, if the trap energy is placed around midgap, it is a deep trap. The emission energy of shallow traps is close to that due to band-to-band recombination (approximately equal to the material bandgap), while deep defects emit at much lower energies, so you can distinguish the two cases.I hope this answered your question.
dear Sajid,deep and shallow emission refers to the energy of emitting states, which are traps in this case. In general, luminescence can occur because of band-to-band radiative recombination, or via defect (or trap)-mediated recombination of excited electrons.. In this latter case electrons in the conduction band are first captured by a defect (with a non-radiative process) and then recombine radiatively. If the energy of the trap is close to the conduction band minimum then the trap is a shallow one, otherwise, if the trap energy is placed around midgap, it is a deep trap. The emission energy of shallow traps is close to that due to band-to-band recombination (approximately equal to the material bandgap), while deep defects emit at much lower energies, so you can distinguish the two cases.I hope this answered your question.
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