Effects of Isoelectronic Impurities on Indirect Excitons in CdI₂:Br Mixed Crystals

抄録

The decay of indirect exciton luminescence in CdI₂ crystals mixed with CdBr₂ has been measured following pulsed excitation at low temperatures. Three exponential decay components are observed. The intensity distribution among them varies with temperature as well as with Br⁻-concentration. The time-resolved measurement of the emission spectra suggests that the emission of the slow decay component originates from a shallow bound state of an exciton located below the free state. The decay characteristics and the temperature dependence of the emission efficiency are accounted for in terms of changing populations in both the free and bound states. The result of analysis indicates that the potential barrier between the free and the self-trapped exciton states is lifted by the mixing of CdBr₂.