Interface and defect structures of Zn-ZnO core-shell heteronanobelts

Interface and defect structures of Zn-ZnO core-shell nanobelts have been investigated using high-resolution transmission electron microscopy. Most of the nanobelts can be classified into two types from their growth directions: [2 (1) over bar(1) over bar0] and [0001], with the top/bottom surfaces being (0001) and (2 (1) over bar(1) over bar0), respectively. The Zn core and ZnO shell overlapped areas display a two-dimensional moire pattern resulting from the lattice mismatch. In the <2 (1) over bar(1) over bar0> growth nanobelts, a network of three sets of misfit dislocations relaxes the mismatch strain in the top/bottom interfaces, and every set rotates 60degrees with respect to the other; there are two types of grains oriented in specific orientations that compose the side wall of the ZnO shell. In the [0001] growth nanobelts, a network containing a set of stacking faults in (0001) planes and a set of misfit dislocations in (0 (1) over bar(1) over bar0) planes takes the main role in the misfit relaxation. Threading dislocations indicated by terminating moire fringes are present in both of them, which are located at the small angle rotated boundary between adjacent misoriented ZnO grains. (C) 2004 American Institute of Physics.