Facile synthesis of vertically aligned cone-shaped ZnO/ZnS core/shell arrays using the two-step aqueous solution approach

Core/shell nanostructures, as an important hybrid structure, exhibit enhanced performances in emission efficiency and high electron mobility, which can be a promising route for practical application of electron field emitters and solar tells. Zinc sulfide (ZnS) is a well-known wide band gap semiconductor that can be regarded as a suitable material for the surface-coating layer on zinc oxide (ZnO) to enhance its luminescent property. In this study, we present, for the first time, a simple two-step aqueous solution approach for the synthesis of well-aligned ZnO)/ZnS core/shell nanocone arrays. Transmission electron microscopy and energy-dispersive X-ray spectroscopy results confirm that the ZnO nanocone arrays are homogeneously coated with the ZnS shell layer. X-ray diffraction patterns of the shelled ZnO nanocone arrays show strong preferred orientation along the c-axis of wurtzite ZnO. Raman spectra of ZnO/ZnS core/shell nanocones indicate a redshift of 5 cm(-1) for the E-2 (high) peak compared with bare ZnO nanocone arrays, which can be attributed to stress induction in the ZnO/ZnS heterostructures. These findings will contribute to the development of novel nanoemitters and solar cells using controllable morphology and suitable shell choice for heterostructures. (C) 2015 Elsevier B.V. All rights reserved.