Synthesis and characterization of ZnS tetrapods and ZnO/ZnS heterostructures

ZnS nanomaterials at different dimensions, from nanoparticles, nanobelts to nanotetrapods have been synthesized in the same solvothermal system, which is kinetically controlled by ethylenediamine. Microscopy analysis reveals that the four arms of tetrapod are grown from Zn-terminated surfaces of an octahedral core by alternately stacking zinc blende and wurtzite structures along [111]/[0001] direction, while the ZnS nanobelts are self-assembled along [0001] direction by ultra-small wurtzite nanocrystals. These nanobelts can be transformed into their single-crystal counterparts and ZnO/ZnS heterostructures by thermal treatment. Uv-visible analysis demonstrates that the heterostructure presents a strain-induced staggered Type-II band structure. These investigation results suggest an efficient approach for phase-controlled synthesis of nanostructures in group II-VI semiconductors.