Isolated quantum emitters originating from defect centers in a ZnSe/ZnMgSSe heterostructure

On the basis of low-temperature (5 K) microphotoluminescence measurements in a wide ZnSe/ZnMgSSe quantum well, the existence of isolated quantum emitters in this heterostructure is demonstrated. Characteristically, the corresponding emission lines experience stepwise spectral shifts by a few meV on a time scale of 1–10 min. The unconventional properties of the observed emitters are explained by considering the picture of a system with a large dipole moment in the ground state, such as a single donor–acceptor pair or a similar system located near an extended defect.