Abnormal temperature behavior of photoluminescence in CdSe/ZnSe self-assembled quantum dots

We report on the temperature dependence of photoluminescence (PL) of CdSe/ZnSe self-assembled quantum dots (QDs). In the temperature range of 19-120 K, although the energy gap of CdSe shrinks by 25 meV, the PL of CdSe QDs does not show any line shift or shape change. According to the equilibrium theories of heteroepitaxial growth, a model involving the presence of interface disorders is suggested to be responsible for this invariant PL. In the temperature range of 120-300 K, the PL peak of CdSe QDs initially blue-shifts and then red-shifts with increasing temperature arising from the thermally activated detrapping of carriers.