Surface polarity induced three-dimensional wurtzite ZnS/ZnS _xSe_1-x nano-heterostructures with integrating emission property

By controlling the reaction conditions and molar ratio of precursors carefully, three-dimensional ZnS/ZnS_0.3Se_0.7 nano-heterostructures were synthesized via a simple two-step magnetic force assistant growth technique. Scanning electron microscopy, X-ray powder diffraction, energy dispersive X-ray spectroscopy and transmission electron microscopy were used to characterize and analyze the morphology, phase structure, crystallinity and composition of the as-prepared nano- heterostructures. Remarkably, the epitaxial ZnS nanoribbon is single crystalline and preserves the structure and orientation of the matrix ZnS _xSe_1-x nanobelt with an epitaxial relationship of (0001)_ZnS//(0001)_ZnS0.3Se0.7 and (1010) _ZnS//(1010)_ZnS0.3Se0.7. A polar-surface induced growth process for the three-dimensional nano-heterostructures is proposed according to the experimental results and crystallography relationship. This approach can offer a prevailing way to fabricate more complex three-dimensional nanostructures with built-in heterojunctions. Room temperature PL spectra were used to investigate the emission property of the as-prepared samples. The PL spectra of ZnSe and ZnS_xSe_1-x nanobelts show strong near bandgap emission, demonstrating a high crystal quality of these as-synthesized nanobelts. The PL spectrum of three-dimensional ZnS/ZnS_0.3Se _0.7 nano-heterostructures shows the near bandgap emission of ZnS and ZnS_0.3Se_0.7 simultaneously, demonstrating the incorporating function. These three-dimensional nano-heterostructures with unique structure and morphology can be used to investigate the incorporating function and find extensive applications in nanophotonics.