Synthesis and wavelength-tunable luminescence property of wurtzite Zn _xCd_1-xS nstructures

High-quality nanostructured Zn_xCd_1-xS has been synthesized through a method of two-step thermal evaporation. The typical morphologies of the nanomaterials were investigated by SEM and TEM. The first step of synthesis is the preparation of ZnS nanoribbons. With ZnS nanoribbons being used as templates, a series of wurtzite Zn_xCd_1-xS (x = 0.47, 0.70, 0.77, 0.85, and 0.94) nanobelts can be produced. Furthermore, by adopting ZnS nanoribbons of a particular width, Zn_xCd_1-xS nanobelts of a desired width can be fabricated. In XRD analysis, we find that with an increase in Zn content (x), the peaks corresponding to the wurtzite structures shift to larger 26. As a deduction based on Vegard's law, the Zn _xCd_1-xS are solid solutions of similar crystal structure. The results of HRTEM and SAED investigations reveal that the ZnS nanoribbons and Zn_xCd_1-xS nanobelts grow along the (1010) direction. With an increase in Zn content, we observe a gradual blue shift of photoluminescence emission (from 443 to 352 nm), further indicating the homogeneity of the Zn_xCd_1-xS solid solutions. After proper thermal annealing, there is better crystallinity of Zn_xCd_1-xS and higher specificity of near-band emission.