From ZnS nanobelts to ZnO/ZnS heterostructures: Microscopy analysis and their tunable optical property

Ultrathin ZnS nanobelts were assembled by ultrasmall nanocrystals with oriented self assembly, which were then transformed into their single-crystal counterparts by thermal treatment in N-2. ZnO/ZnS heterostructures were also obtained at elevated temperature in open air, where well aligned ZnO nanocones were grown along the ZnS nanobelts with a definite orientation relationship described as [0001](ZnS)parallel to[0001](ZnO) and (10 (1) over bar0)(ZnS)parallel to(10 (1) over bar0)(ZnO). Mixed transition and tuned band gaps of the heterostructure were experimentally observed, which was in good agreement with the theoretical predications and can be interpreted based on the model of a strained staggered type-II band structure. (C) 2010 American Institute of Physics. [doi:10.1063/1.3474609]