Spectral-Kinetic Characteristics of ZnS Phosphors Obtained Using the Method of Vapor Transport Synthesis in a Closed System

Samples of crystalline ZnS phosphors are obtained using the method of vapor transport synthesis in a closed system. Employing X-ray phase and structural analysis, two types of the resulting sample structures are revealed. The structural composition of 70% sphalerite+30% wurtzite is obtained under the oxygen excess conditions, whereas a nearly pure wurtzite modification is produced in the deficiency of oxygen. The spectral and kinetic characteristics of the two types of samples with the photoluminescence peaks at 510 and 630 nm are studied. These are attributed to the photoluminescence mechanisms involving self-activated oxygen centers and donor-acceptor pairs. The biexponential form of the photoluminescence decay in the two types of samples is observed, related to the presence of electron capture traps near the level of interstitial zinc. The proposed method of vapor transport synthesis of ZnS in a closed system allows simple monitoring of the thermodynamic parameters of the system and provides chemical stability to the initial and final synthesis products.