Te-doped ZnSe indicates strong emission bands in the blue-green region at low temperatures. The ZnSe-ZnTe superlattices with thin ZnTe layers (less than 1 monolayer), whose X-ray proles show a trace of satellite peaks due to the superstructure, have very high photoluminescence (PL) efficiency at 2.3 eV at room temperature. In the samples that have no superstructure in the X-ray measurements, Te acts as an isoelectronic impurity indicating strong PL at only low temperatures. In the sample with a superstructure, the ZnTe parts consist of dots with high PL efficiency.