Composition-controllable synthesis and optical properties of non-integral stoichiometry compound ZnxCd1−xS nanorods

Homogeneous non-integral stoichiometry semiconductor compound ZnxCd1−xS nanorods have been successfully synthesized at 180 °C by the reaction of a mixture ZnCl2 and CdCl2 with thiosemicarbazide (NH2SNHNH2) in the ethylenediamine. The compositions over the whole range according to JCPDS cards have been controlled only by changing the cation molar ratio of Zn:Cd in the reactants. The composition dependence of UV–vis spectra and the photoluminescence (PL) spectra of the series ZnxCd1−xS nanocrystals has been revealed. The lattice parameters (a, c) calculated from XRD patterns increase linearly with the increasing of Cd content, which is consistent with Vegard's law. Two well-defined relationships have been established among the lattice parameters, the band gap energy (Eg), and the composition value (x) of the ZnxCd1−xS. The mechanism of reaction and the selection of the reagents have also been investigated.