The effect of the texture and the density of ZnO seed layer on the orientation of ZnO nanorod arrays.

The effect of the texture and the density of ZnO seed layer on the orientation of ZnO nanorod arrays (ZNAs) was systematically investigated, and the vertical growth mechanism of ZNAs during hydrothermal deposition was also explained. It is demonstrated that the textured ZnO seed layer determines the orientation of ZNAs which grow on it. The interaction among nanorods, which derives from the high crystal seed density and the incomplete c-axis texture of ZnO seed layer, obviously reinforces the c-axis texture of ZNAs. According to the seed density behavior of ZnO seed layer, the dominate factor which influences the orientation of ZNAs has been studied. And the results classify the growth situations into three categories: the high density seed layer initiated growth, the middle density seed layer initiated growth and the sparsely separated seeds initiated growth. We also establish the correlation between the density and the orientation of ZNAs, this quasi-quantitative correlation can be used to fabricate the ZNAs with suitable density and orientation.