Surface Effect On The Size- And Orientation-dependent Elastic Properties Of Single-crystal Zno Nanostructures

摘要

We studied the elastic properties of ZnO nanofilms (NFs) and nanowires (NWs) terminated by either (1010) or (1120) surfaces, based on the empirical Buckingham-type potential. It is found that the Young's moduli of ZnO NFs increase as the thicknesses decrease and that of (l0l0)-surface terminated NFs are systematically larger than that of (1120)-surface terminated ones. In these NFs, the surface atomic layers of both types of NFs are stiffened significantly with respect to the bulk ZnO, and the (1010)-surface layer is much stiffer than the (1120)-surface layer. In contrast, all the interior atomic layers are only slightly stiffer than the bulk ZnO, and are independent on the orientations. The ZnO NWs show similar size- and orientation-dependent mechanical behaviors which also originate from the significant stiffening of the surface atomic layers. Through this study, we predict that the mechanical properties of ZnO nanostructures can be manipulated through controlling the size and orientations of these materials.