Masking of trap effects on exciton bands by exciton-phonon coupling

✍ Scribed by D.P. Craig; Jai Singh

• Publisher: Elsevier Science
• Year: 1980
• Tongue: English
• Weight: 574 KB
• Volume: 71
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(80)80193-x

✦ Synopsis

In a r@d lattrce the effect on the evcrton band of a trap wrth a lower transihon energy than the host is to push a level down from the band edge to an extent dependmg on the trap depth and the structure of the band. In a non-rigid lattfce, in which the levels of the band have mixed exctton-phonon character, interferences caused by the phonon additions to the ergenstates belongmg to the same total wavevector (euciton plus phonon) can, especrahy for shallow traps, greatly weaken the effect of the traps. The effecttve trap depth may be reduced to a small fraction of its true value. In such cases shaRow traps will not be detectable by thetr influence on evciton band structure. The effect of deep traps is not changed by this mechanism.